0.3.6: WIP

patch/chrono-0.4.41/src/date.rs

@@ -0,0 +1,663 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+//! ISO 8601 calendar date with time zone.
+#![allow(deprecated)]
+
+#[cfg(feature = "alloc")]
+use core::borrow::Borrow;
+use core::cmp::Ordering;
+use core::ops::{Add, AddAssign, Sub, SubAssign};
+use core::{fmt, hash};
+
+// #[cfg(feature = "rkyv")]
+// use rkyv::{Archive, Deserialize, Serialize};
+
+#[cfg(all(feature = "unstable-locales", feature = "alloc"))]
+use crate::format::Locale;
+#[cfg(feature = "alloc")]
+use crate::format::{DelayedFormat, Item, StrftimeItems};
+use crate::naive::{IsoWeek, NaiveDate, NaiveTime};
+use crate::offset::{TimeZone, Utc};
+use crate::{DateTime, Datelike, TimeDelta, Weekday};
+
+/// ISO 8601 calendar date with time zone.
+///
+/// You almost certainly want to be using a [`NaiveDate`] instead of this type.
+///
+/// This type primarily exists to aid in the construction of DateTimes that
+/// have a timezone by way of the [`TimeZone`] datelike constructors (e.g.
+/// [`TimeZone::ymd`]).
+///
+/// This type should be considered ambiguous at best, due to the inherent lack
+/// of precision required for the time zone resolution.
+///
+/// There are some guarantees on the usage of `Date<Tz>`:
+///
+/// - If properly constructed via [`TimeZone::ymd`] and others without an error,
+///   the corresponding local date should exist for at least a moment.
+///   (It may still have a gap from the offset changes.)
+///
+/// - The `TimeZone` is free to assign *any* [`Offset`](crate::offset::Offset) to the
+///   local date, as long as that offset did occur in given day.
+///
+///   For example, if `2015-03-08T01:59-08:00` is followed by `2015-03-08T03:00-07:00`,
+///   it may produce either `2015-03-08-08:00` or `2015-03-08-07:00`
+///   but *not* `2015-03-08+00:00` and others.
+///
+/// - Once constructed as a full `DateTime`, [`DateTime::date`] and other associated
+///   methods should return those for the original `Date`. For example, if `dt =
+///   tz.ymd_opt(y,m,d).unwrap().hms(h,n,s)` were valid, `dt.date() == tz.ymd_opt(y,m,d).unwrap()`.
+///
+/// - The date is timezone-agnostic up to one day (i.e. practically always),
+///   so the local date and UTC date should be equal for most cases
+///   even though the raw calculation between `NaiveDate` and `TimeDelta` may not.
+#[deprecated(since = "0.4.23", note = "Use `NaiveDate` or `DateTime<Tz>` instead")]
+#[derive(Clone)]
+// #[cfg_attr(feature = "rkyv", derive(Archive, Deserialize, Serialize))]
+pub struct Date<Tz: TimeZone> {
+    date: NaiveDate,
+    offset: Tz::Offset,
+}
+
+/// The minimum possible `Date`.
+#[allow(deprecated)]
+#[deprecated(since = "0.4.20", note = "Use Date::MIN_UTC instead")]
+pub const MIN_DATE: Date<Utc> = Date::<Utc>::MIN_UTC;
+/// The maximum possible `Date`.
+#[allow(deprecated)]
+#[deprecated(since = "0.4.20", note = "Use Date::MAX_UTC instead")]
+pub const MAX_DATE: Date<Utc> = Date::<Utc>::MAX_UTC;
+
+impl<Tz: TimeZone> Date<Tz> {
+    /// Makes a new `Date` with given *UTC* date and offset.
+    /// The local date should be constructed via the `TimeZone` trait.
+    #[inline]
+    #[must_use]
+    pub fn from_utc(date: NaiveDate, offset: Tz::Offset) -> Date<Tz> {
+        Date { date, offset }
+    }
+
+    /// Makes a new `DateTime` from the current date and given `NaiveTime`.
+    /// The offset in the current date is preserved.
+    ///
+    /// Returns `None` on invalid datetime.
+    #[inline]
+    #[must_use]
+    pub fn and_time(&self, time: NaiveTime) -> Option<DateTime<Tz>> {
+        let localdt = self.naive_local().and_time(time);
+        self.timezone().from_local_datetime(&localdt).single()
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute and second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Panics on invalid hour, minute and/or second.
+    #[deprecated(since = "0.4.23", note = "Use and_hms_opt() instead")]
+    #[inline]
+    #[must_use]
+    pub fn and_hms(&self, hour: u32, min: u32, sec: u32) -> DateTime<Tz> {
+        self.and_hms_opt(hour, min, sec).expect("invalid time")
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute and second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Returns `None` on invalid hour, minute and/or second.
+    #[inline]
+    #[must_use]
+    pub fn and_hms_opt(&self, hour: u32, min: u32, sec: u32) -> Option<DateTime<Tz>> {
+        NaiveTime::from_hms_opt(hour, min, sec).and_then(|time| self.and_time(time))
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and millisecond.
+    /// The millisecond part can exceed 1,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Panics on invalid hour, minute, second and/or millisecond.
+    #[deprecated(since = "0.4.23", note = "Use and_hms_milli_opt() instead")]
+    #[inline]
+    #[must_use]
+    pub fn and_hms_milli(&self, hour: u32, min: u32, sec: u32, milli: u32) -> DateTime<Tz> {
+        self.and_hms_milli_opt(hour, min, sec, milli).expect("invalid time")
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and millisecond.
+    /// The millisecond part can exceed 1,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Returns `None` on invalid hour, minute, second and/or millisecond.
+    #[inline]
+    #[must_use]
+    pub fn and_hms_milli_opt(
+        &self,
+        hour: u32,
+        min: u32,
+        sec: u32,
+        milli: u32,
+    ) -> Option<DateTime<Tz>> {
+        NaiveTime::from_hms_milli_opt(hour, min, sec, milli).and_then(|time| self.and_time(time))
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and microsecond.
+    /// The microsecond part can exceed 1,000,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Panics on invalid hour, minute, second and/or microsecond.
+    #[deprecated(since = "0.4.23", note = "Use and_hms_micro_opt() instead")]
+    #[inline]
+    #[must_use]
+    pub fn and_hms_micro(&self, hour: u32, min: u32, sec: u32, micro: u32) -> DateTime<Tz> {
+        self.and_hms_micro_opt(hour, min, sec, micro).expect("invalid time")
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and microsecond.
+    /// The microsecond part can exceed 1,000,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Returns `None` on invalid hour, minute, second and/or microsecond.
+    #[inline]
+    #[must_use]
+    pub fn and_hms_micro_opt(
+        &self,
+        hour: u32,
+        min: u32,
+        sec: u32,
+        micro: u32,
+    ) -> Option<DateTime<Tz>> {
+        NaiveTime::from_hms_micro_opt(hour, min, sec, micro).and_then(|time| self.and_time(time))
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and nanosecond.
+    /// The nanosecond part can exceed 1,000,000,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Panics on invalid hour, minute, second and/or nanosecond.
+    #[deprecated(since = "0.4.23", note = "Use and_hms_nano_opt() instead")]
+    #[inline]
+    #[must_use]
+    pub fn and_hms_nano(&self, hour: u32, min: u32, sec: u32, nano: u32) -> DateTime<Tz> {
+        self.and_hms_nano_opt(hour, min, sec, nano).expect("invalid time")
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and nanosecond.
+    /// The nanosecond part can exceed 1,000,000,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Returns `None` on invalid hour, minute, second and/or nanosecond.
+    #[inline]
+    #[must_use]
+    pub fn and_hms_nano_opt(
+        &self,
+        hour: u32,
+        min: u32,
+        sec: u32,
+        nano: u32,
+    ) -> Option<DateTime<Tz>> {
+        NaiveTime::from_hms_nano_opt(hour, min, sec, nano).and_then(|time| self.and_time(time))
+    }
+
+    /// Makes a new `Date` for the next date.
+    ///
+    /// Panics when `self` is the last representable date.
+    #[deprecated(since = "0.4.23", note = "Use succ_opt() instead")]
+    #[inline]
+    #[must_use]
+    pub fn succ(&self) -> Date<Tz> {
+        self.succ_opt().expect("out of bound")
+    }
+
+    /// Makes a new `Date` for the next date.
+    ///
+    /// Returns `None` when `self` is the last representable date.
+    #[inline]
+    #[must_use]
+    pub fn succ_opt(&self) -> Option<Date<Tz>> {
+        self.date.succ_opt().map(|date| Date::from_utc(date, self.offset.clone()))
+    }
+
+    /// Makes a new `Date` for the prior date.
+    ///
+    /// Panics when `self` is the first representable date.
+    #[deprecated(since = "0.4.23", note = "Use pred_opt() instead")]
+    #[inline]
+    #[must_use]
+    pub fn pred(&self) -> Date<Tz> {
+        self.pred_opt().expect("out of bound")
+    }
+
+    /// Makes a new `Date` for the prior date.
+    ///
+    /// Returns `None` when `self` is the first representable date.
+    #[inline]
+    #[must_use]
+    pub fn pred_opt(&self) -> Option<Date<Tz>> {
+        self.date.pred_opt().map(|date| Date::from_utc(date, self.offset.clone()))
+    }
+
+    /// Retrieves an associated offset from UTC.
+    #[inline]
+    #[must_use]
+    pub fn offset(&self) -> &Tz::Offset {
+        &self.offset
+    }
+
+    /// Retrieves an associated time zone.
+    #[inline]
+    #[must_use]
+    pub fn timezone(&self) -> Tz {
+        TimeZone::from_offset(&self.offset)
+    }
+
+    /// Changes the associated time zone.
+    /// This does not change the actual `Date` (but will change the string representation).
+    #[inline]
+    #[must_use]
+    pub fn with_timezone<Tz2: TimeZone>(&self, tz: &Tz2) -> Date<Tz2> {
+        tz.from_utc_date(&self.date)
+    }
+
+    /// Adds given `TimeDelta` to the current date.
+    ///
+    /// Returns `None` when it will result in overflow.
+    #[inline]
+    #[must_use]
+    pub fn checked_add_signed(self, rhs: TimeDelta) -> Option<Date<Tz>> {
+        let date = self.date.checked_add_signed(rhs)?;
+        Some(Date { date, offset: self.offset })
+    }
+
+    /// Subtracts given `TimeDelta` from the current date.
+    ///
+    /// Returns `None` when it will result in overflow.
+    #[inline]
+    #[must_use]
+    pub fn checked_sub_signed(self, rhs: TimeDelta) -> Option<Date<Tz>> {
+        let date = self.date.checked_sub_signed(rhs)?;
+        Some(Date { date, offset: self.offset })
+    }
+
+    /// Subtracts another `Date` from the current date.
+    /// Returns a `TimeDelta` of integral numbers.
+    ///
+    /// This does not overflow or underflow at all,
+    /// as all possible output fits in the range of `TimeDelta`.
+    #[inline]
+    #[must_use]
+    pub fn signed_duration_since<Tz2: TimeZone>(self, rhs: Date<Tz2>) -> TimeDelta {
+        self.date.signed_duration_since(rhs.date)
+    }
+
+    /// Returns a view to the naive UTC date.
+    #[inline]
+    #[must_use]
+    pub fn naive_utc(&self) -> NaiveDate {
+        self.date
+    }
+
+    /// Returns a view to the naive local date.
+    ///
+    /// This is technically the same as [`naive_utc`](#method.naive_utc)
+    /// because the offset is restricted to never exceed one day,
+    /// but provided for the consistency.
+    #[inline]
+    #[must_use]
+    pub fn naive_local(&self) -> NaiveDate {
+        self.date
+    }
+
+    /// Returns the number of whole years from the given `base` until `self`.
+    #[must_use]
+    pub fn years_since(&self, base: Self) -> Option<u32> {
+        self.date.years_since(base.date)
+    }
+
+    /// The minimum possible `Date`.
+    pub const MIN_UTC: Date<Utc> = Date { date: NaiveDate::MIN, offset: Utc };
+    /// The maximum possible `Date`.
+    pub const MAX_UTC: Date<Utc> = Date { date: NaiveDate::MAX, offset: Utc };
+}
+
+/// Maps the local date to other date with given conversion function.
+fn map_local<Tz: TimeZone, F>(d: &Date<Tz>, mut f: F) -> Option<Date<Tz>>
+where
+    F: FnMut(NaiveDate) -> Option<NaiveDate>,
+{
+    f(d.naive_local()).and_then(|date| d.timezone().from_local_date(&date).single())
+}
+
+impl<Tz: TimeZone> Date<Tz>
+where
+    Tz::Offset: fmt::Display,
+{
+    /// Formats the date with the specified formatting items.
+    #[cfg(feature = "alloc")]
+    #[inline]
+    #[must_use]
+    pub fn format_with_items<'a, I, B>(&self, items: I) -> DelayedFormat<I>
+    where
+        I: Iterator<Item = B> + Clone,
+        B: Borrow<Item<'a>>,
+    {
+        DelayedFormat::new_with_offset(Some(self.naive_local()), None, &self.offset, items)
+    }
+
+    /// Formats the date with the specified format string.
+    /// See the [`crate::format::strftime`] module
+    /// on the supported escape sequences.
+    #[cfg(feature = "alloc")]
+    #[inline]
+    #[must_use]
+    pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
+        self.format_with_items(StrftimeItems::new(fmt))
+    }
+
+    /// Formats the date with the specified formatting items and locale.
+    #[cfg(all(feature = "unstable-locales", feature = "alloc"))]
+    #[inline]
+    #[must_use]
+    pub fn format_localized_with_items<'a, I, B>(
+        &self,
+        items: I,
+        locale: Locale,
+    ) -> DelayedFormat<I>
+    where
+        I: Iterator<Item = B> + Clone,
+        B: Borrow<Item<'a>>,
+    {
+        DelayedFormat::new_with_offset_and_locale(
+            Some(self.naive_local()),
+            None,
+            &self.offset,
+            items,
+            locale,
+        )
+    }
+
+    /// Formats the date with the specified format string and locale.
+    /// See the [`crate::format::strftime`] module
+    /// on the supported escape sequences.
+    #[cfg(all(feature = "unstable-locales", feature = "alloc"))]
+    #[inline]
+    #[must_use]
+    pub fn format_localized<'a>(
+        &self,
+        fmt: &'a str,
+        locale: Locale,
+    ) -> DelayedFormat<StrftimeItems<'a>> {
+        self.format_localized_with_items(StrftimeItems::new_with_locale(fmt, locale), locale)
+    }
+}
+
+impl<Tz: TimeZone> Datelike for Date<Tz> {
+    #[inline]
+    fn year(&self) -> i32 {
+        self.naive_local().year()
+    }
+    #[inline]
+    fn month(&self) -> u32 {
+        self.naive_local().month()
+    }
+    #[inline]
+    fn month0(&self) -> u32 {
+        self.naive_local().month0()
+    }
+    #[inline]
+    fn day(&self) -> u32 {
+        self.naive_local().day()
+    }
+    #[inline]
+    fn day0(&self) -> u32 {
+        self.naive_local().day0()
+    }
+    #[inline]
+    fn ordinal(&self) -> u32 {
+        self.naive_local().ordinal()
+    }
+    #[inline]
+    fn ordinal0(&self) -> u32 {
+        self.naive_local().ordinal0()
+    }
+    #[inline]
+    fn weekday(&self) -> Weekday {
+        self.naive_local().weekday()
+    }
+    #[inline]
+    fn iso_week(&self) -> IsoWeek {
+        self.naive_local().iso_week()
+    }
+
+    #[inline]
+    fn with_year(&self, year: i32) -> Option<Date<Tz>> {
+        map_local(self, |date| date.with_year(year))
+    }
+
+    #[inline]
+    fn with_month(&self, month: u32) -> Option<Date<Tz>> {
+        map_local(self, |date| date.with_month(month))
+    }
+
+    #[inline]
+    fn with_month0(&self, month0: u32) -> Option<Date<Tz>> {
+        map_local(self, |date| date.with_month0(month0))
+    }
+
+    #[inline]
+    fn with_day(&self, day: u32) -> Option<Date<Tz>> {
+        map_local(self, |date| date.with_day(day))
+    }
+
+    #[inline]
+    fn with_day0(&self, day0: u32) -> Option<Date<Tz>> {
+        map_local(self, |date| date.with_day0(day0))
+    }
+
+    #[inline]
+    fn with_ordinal(&self, ordinal: u32) -> Option<Date<Tz>> {
+        map_local(self, |date| date.with_ordinal(ordinal))
+    }
+
+    #[inline]
+    fn with_ordinal0(&self, ordinal0: u32) -> Option<Date<Tz>> {
+        map_local(self, |date| date.with_ordinal0(ordinal0))
+    }
+}
+
+// we need them as automatic impls cannot handle associated types
+impl<Tz: TimeZone> Copy for Date<Tz> where <Tz as TimeZone>::Offset: Copy {}
+unsafe impl<Tz: TimeZone> Send for Date<Tz> where <Tz as TimeZone>::Offset: Send {}
+
+impl<Tz: TimeZone, Tz2: TimeZone> PartialEq<Date<Tz2>> for Date<Tz> {
+    fn eq(&self, other: &Date<Tz2>) -> bool {
+        self.date == other.date
+    }
+}
+
+impl<Tz: TimeZone> Eq for Date<Tz> {}
+
+impl<Tz: TimeZone> PartialOrd for Date<Tz> {
+    fn partial_cmp(&self, other: &Date<Tz>) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl<Tz: TimeZone> Ord for Date<Tz> {
+    fn cmp(&self, other: &Date<Tz>) -> Ordering {
+        self.date.cmp(&other.date)
+    }
+}
+
+impl<Tz: TimeZone> hash::Hash for Date<Tz> {
+    fn hash<H: hash::Hasher>(&self, state: &mut H) {
+        self.date.hash(state)
+    }
+}
+
+impl<Tz: TimeZone> Add<TimeDelta> for Date<Tz> {
+    type Output = Date<Tz>;
+
+    #[inline]
+    fn add(self, rhs: TimeDelta) -> Date<Tz> {
+        self.checked_add_signed(rhs).expect("`Date + TimeDelta` overflowed")
+    }
+}
+
+impl<Tz: TimeZone> AddAssign<TimeDelta> for Date<Tz> {
+    #[inline]
+    fn add_assign(&mut self, rhs: TimeDelta) {
+        self.date = self.date.checked_add_signed(rhs).expect("`Date + TimeDelta` overflowed");
+    }
+}
+
+impl<Tz: TimeZone> Sub<TimeDelta> for Date<Tz> {
+    type Output = Date<Tz>;
+
+    #[inline]
+    fn sub(self, rhs: TimeDelta) -> Date<Tz> {
+        self.checked_sub_signed(rhs).expect("`Date - TimeDelta` overflowed")
+    }
+}
+
+impl<Tz: TimeZone> SubAssign<TimeDelta> for Date<Tz> {
+    #[inline]
+    fn sub_assign(&mut self, rhs: TimeDelta) {
+        self.date = self.date.checked_sub_signed(rhs).expect("`Date - TimeDelta` overflowed");
+    }
+}
+
+impl<Tz: TimeZone> Sub<Date<Tz>> for Date<Tz> {
+    type Output = TimeDelta;
+
+    #[inline]
+    fn sub(self, rhs: Date<Tz>) -> TimeDelta {
+        self.signed_duration_since(rhs)
+    }
+}
+
+impl<Tz: TimeZone> fmt::Debug for Date<Tz> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.naive_local().fmt(f)?;
+        self.offset.fmt(f)
+    }
+}
+
+impl<Tz: TimeZone> fmt::Display for Date<Tz>
+where
+    Tz::Offset: fmt::Display,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.naive_local().fmt(f)?;
+        self.offset.fmt(f)
+    }
+}
+
+// Note that implementation of Arbitrary cannot be automatically derived for Date<Tz>, due to
+// the nontrivial bound <Tz as TimeZone>::Offset: Arbitrary.
+#[cfg(all(feature = "arbitrary", feature = "std"))]
+impl<'a, Tz> arbitrary::Arbitrary<'a> for Date<Tz>
+where
+    Tz: TimeZone,
+    <Tz as TimeZone>::Offset: arbitrary::Arbitrary<'a>,
+{
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Date<Tz>> {
+        let date = NaiveDate::arbitrary(u)?;
+        let offset = <Tz as TimeZone>::Offset::arbitrary(u)?;
+        Ok(Date::from_utc(date, offset))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Date;
+
+    use crate::{FixedOffset, NaiveDate, TimeDelta, Utc};
+
+    #[cfg(feature = "clock")]
+    use crate::offset::{Local, TimeZone};
+
+    #[test]
+    #[cfg(feature = "clock")]
+    fn test_years_elapsed() {
+        const WEEKS_PER_YEAR: f32 = 52.1775;
+
+        // This is always at least one year because 1 year = 52.1775 weeks.
+        let one_year_ago = Utc::today() - TimeDelta::weeks((WEEKS_PER_YEAR * 1.5).ceil() as i64);
+        // A bit more than 2 years.
+        let two_year_ago = Utc::today() - TimeDelta::weeks((WEEKS_PER_YEAR * 2.5).ceil() as i64);
+
+        assert_eq!(Utc::today().years_since(one_year_ago), Some(1));
+        assert_eq!(Utc::today().years_since(two_year_ago), Some(2));
+
+        // If the given DateTime is later than now, the function will always return 0.
+        let future = Utc::today() + TimeDelta::weeks(12);
+        assert_eq!(Utc::today().years_since(future), None);
+    }
+
+    #[test]
+    fn test_date_add_assign() {
+        let naivedate = NaiveDate::from_ymd_opt(2000, 1, 1).unwrap();
+        let date = Date::<Utc>::from_utc(naivedate, Utc);
+        let mut date_add = date;
+
+        date_add += TimeDelta::days(5);
+        assert_eq!(date_add, date + TimeDelta::days(5));
+
+        let timezone = FixedOffset::east_opt(60 * 60).unwrap();
+        let date = date.with_timezone(&timezone);
+        let date_add = date_add.with_timezone(&timezone);
+
+        assert_eq!(date_add, date + TimeDelta::days(5));
+
+        let timezone = FixedOffset::west_opt(2 * 60 * 60).unwrap();
+        let date = date.with_timezone(&timezone);
+        let date_add = date_add.with_timezone(&timezone);
+
+        assert_eq!(date_add, date + TimeDelta::days(5));
+    }
+
+    #[test]
+    #[cfg(feature = "clock")]
+    fn test_date_add_assign_local() {
+        let naivedate = NaiveDate::from_ymd_opt(2000, 1, 1).unwrap();
+
+        let date = Local.from_utc_date(&naivedate);
+        let mut date_add = date;
+
+        date_add += TimeDelta::days(5);
+        assert_eq!(date_add, date + TimeDelta::days(5));
+    }
+
+    #[test]
+    fn test_date_sub_assign() {
+        let naivedate = NaiveDate::from_ymd_opt(2000, 1, 1).unwrap();
+        let date = Date::<Utc>::from_utc(naivedate, Utc);
+        let mut date_sub = date;
+
+        date_sub -= TimeDelta::days(5);
+        assert_eq!(date_sub, date - TimeDelta::days(5));
+
+        let timezone = FixedOffset::east_opt(60 * 60).unwrap();
+        let date = date.with_timezone(&timezone);
+        let date_sub = date_sub.with_timezone(&timezone);
+
+        assert_eq!(date_sub, date - TimeDelta::days(5));
+
+        let timezone = FixedOffset::west_opt(2 * 60 * 60).unwrap();
+        let date = date.with_timezone(&timezone);
+        let date_sub = date_sub.with_timezone(&timezone);
+
+        assert_eq!(date_sub, date - TimeDelta::days(5));
+    }
+
+    #[test]
+    #[cfg(feature = "clock")]
+    fn test_date_sub_assign_local() {
+        let naivedate = NaiveDate::from_ymd_opt(2000, 1, 1).unwrap();
+
+        let date = Local.from_utc_date(&naivedate);
+        let mut date_sub = date;
+
+        date_sub -= TimeDelta::days(5);
+        assert_eq!(date_sub, date - TimeDelta::days(5));
+    }
+}

patch/chrono-0.4.41/src/format/formatting.rs

@@ -0,0 +1,945 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+//! Date and time formatting routines.
+
+#[cfg(all(feature = "alloc", not(feature = "std"), not(test)))]
+use alloc::string::{String, ToString};
+#[cfg(feature = "alloc")]
+use core::borrow::Borrow;
+#[cfg(feature = "alloc")]
+use core::fmt::Display;
+use core::fmt::{self, Write};
+
+#[cfg(feature = "alloc")]
+use crate::offset::Offset;
+#[cfg(any(feature = "alloc", feature = "serde"))]
+use crate::{Datelike, FixedOffset, NaiveDateTime, Timelike};
+#[cfg(feature = "alloc")]
+use crate::{NaiveDate, NaiveTime, Weekday};
+
+#[cfg(feature = "alloc")]
+use super::locales;
+#[cfg(any(feature = "alloc", feature = "serde"))]
+use super::{Colons, OffsetFormat, OffsetPrecision, Pad};
+#[cfg(feature = "alloc")]
+use super::{Fixed, InternalFixed, InternalInternal, Item, Numeric};
+#[cfg(feature = "alloc")]
+use locales::*;
+
+/// A *temporary* object which can be used as an argument to `format!` or others.
+/// This is normally constructed via `format` methods of each date and time type.
+#[cfg(feature = "alloc")]
+#[derive(Debug)]
+pub struct DelayedFormat<I> {
+    /// The date view, if any.
+    date: Option<NaiveDate>,
+    /// The time view, if any.
+    time: Option<NaiveTime>,
+    /// The name and local-to-UTC difference for the offset (timezone), if any.
+    off: Option<(String, FixedOffset)>,
+    /// An iterator returning formatting items.
+    items: I,
+    /// Locale used for text.
+    /// ZST if the `unstable-locales` feature is not enabled.
+    locale: Locale,
+}
+
+#[cfg(feature = "alloc")]
+impl<'a, I: Iterator<Item = B> + Clone, B: Borrow<Item<'a>>> DelayedFormat<I> {
+    /// Makes a new `DelayedFormat` value out of local date and time.
+    #[must_use]
+    pub fn new(date: Option<NaiveDate>, time: Option<NaiveTime>, items: I) -> DelayedFormat<I> {
+        DelayedFormat { date, time, off: None, items, locale: default_locale() }
+    }
+
+    /// Makes a new `DelayedFormat` value out of local date and time and UTC offset.
+    #[must_use]
+    pub fn new_with_offset<Off>(
+        date: Option<NaiveDate>,
+        time: Option<NaiveTime>,
+        offset: &Off,
+        items: I,
+    ) -> DelayedFormat<I>
+    where
+        Off: Offset + Display,
+    {
+        let name_and_diff = (offset.to_string(), offset.fix());
+        DelayedFormat { date, time, off: Some(name_and_diff), items, locale: default_locale() }
+    }
+
+    /// Makes a new `DelayedFormat` value out of local date and time and locale.
+    #[cfg(feature = "unstable-locales")]
+    #[must_use]
+    pub fn new_with_locale(
+        date: Option<NaiveDate>,
+        time: Option<NaiveTime>,
+        items: I,
+        locale: Locale,
+    ) -> DelayedFormat<I> {
+        DelayedFormat { date, time, off: None, items, locale }
+    }
+
+    /// Makes a new `DelayedFormat` value out of local date and time, UTC offset and locale.
+    #[cfg(feature = "unstable-locales")]
+    #[must_use]
+    pub fn new_with_offset_and_locale<Off>(
+        date: Option<NaiveDate>,
+        time: Option<NaiveTime>,
+        offset: &Off,
+        items: I,
+        locale: Locale,
+    ) -> DelayedFormat<I>
+    where
+        Off: Offset + Display,
+    {
+        let name_and_diff = (offset.to_string(), offset.fix());
+        DelayedFormat { date, time, off: Some(name_and_diff), items, locale }
+    }
+
+    /// Formats `DelayedFormat` into a `core::fmt::Write` instance.
+    /// # Errors
+    /// This function returns a `core::fmt::Error` if formatting into the `core::fmt::Write` instance fails.
+    ///
+    /// # Example
+    /// ### Writing to a String
+    /// ```
+    /// let dt = chrono::DateTime::from_timestamp(1643723400, 123456789).unwrap();
+    /// let df = dt.format("%Y-%m-%d %H:%M:%S%.9f");
+    /// let mut buffer = String::new();
+    /// let _ = df.write_to(&mut buffer);
+    /// ```
+    pub fn write_to(&self, w: &mut impl Write) -> fmt::Result {
+        for item in self.items.clone() {
+            match *item.borrow() {
+                Item::Literal(s) | Item::Space(s) => w.write_str(s),
+                #[cfg(feature = "alloc")]
+                Item::OwnedLiteral(ref s) | Item::OwnedSpace(ref s) => w.write_str(s),
+                Item::Numeric(ref spec, pad) => self.format_numeric(w, spec, pad),
+                Item::Fixed(ref spec) => self.format_fixed(w, spec),
+                Item::Error => Err(fmt::Error),
+            }?;
+        }
+        Ok(())
+    }
+
+    #[cfg(feature = "alloc")]
+    fn format_numeric(&self, w: &mut impl Write, spec: &Numeric, pad: Pad) -> fmt::Result {
+        use self::Numeric::*;
+
+        fn write_one(w: &mut impl Write, v: u8) -> fmt::Result {
+            w.write_char((b'0' + v) as char)
+        }
+
+        fn write_two(w: &mut impl Write, v: u8, pad: Pad) -> fmt::Result {
+            let ones = b'0' + v % 10;
+            match (v / 10, pad) {
+                (0, Pad::None) => {}
+                (0, Pad::Space) => w.write_char(' ')?,
+                (tens, _) => w.write_char((b'0' + tens) as char)?,
+            }
+            w.write_char(ones as char)
+        }
+
+        #[inline]
+        fn write_year(w: &mut impl Write, year: i32, pad: Pad) -> fmt::Result {
+            if (1000..=9999).contains(&year) {
+                // fast path
+                write_hundreds(w, (year / 100) as u8)?;
+                write_hundreds(w, (year % 100) as u8)
+            } else {
+                write_n(w, 4, year as i64, pad, !(0..10_000).contains(&year))
+            }
+        }
+
+        fn write_n(
+            w: &mut impl Write,
+            n: usize,
+            v: i64,
+            pad: Pad,
+            always_sign: bool,
+        ) -> fmt::Result {
+            if always_sign {
+                match pad {
+                    Pad::None => write!(w, "{v:+}"),
+                    Pad::Zero => write!(w, "{:+01$}", v, n + 1),
+                    Pad::Space => write!(w, "{:+1$}", v, n + 1),
+                }
+            } else {
+                match pad {
+                    Pad::None => write!(w, "{v}"),
+                    Pad::Zero => write!(w, "{v:0n$}"),
+                    Pad::Space => write!(w, "{v:n$}"),
+                }
+            }
+        }
+
+        match (spec, self.date, self.time) {
+            (Year, Some(d), _) => write_year(w, d.year(), pad),
+            (YearDiv100, Some(d), _) => write_two(w, d.year().div_euclid(100) as u8, pad),
+            (YearMod100, Some(d), _) => write_two(w, d.year().rem_euclid(100) as u8, pad),
+            (IsoYear, Some(d), _) => write_year(w, d.iso_week().year(), pad),
+            (IsoYearDiv100, Some(d), _) => {
+                write_two(w, d.iso_week().year().div_euclid(100) as u8, pad)
+            }
+            (IsoYearMod100, Some(d), _) => {
+                write_two(w, d.iso_week().year().rem_euclid(100) as u8, pad)
+            }
+            (Quarter, Some(d), _) => write_one(w, d.quarter() as u8),
+            (Month, Some(d), _) => write_two(w, d.month() as u8, pad),
+            (Day, Some(d), _) => write_two(w, d.day() as u8, pad),
+            (WeekFromSun, Some(d), _) => write_two(w, d.weeks_from(Weekday::Sun) as u8, pad),
+            (WeekFromMon, Some(d), _) => write_two(w, d.weeks_from(Weekday::Mon) as u8, pad),
+            (IsoWeek, Some(d), _) => write_two(w, d.iso_week().week() as u8, pad),
+            (NumDaysFromSun, Some(d), _) => write_one(w, d.weekday().num_days_from_sunday() as u8),
+            (WeekdayFromMon, Some(d), _) => write_one(w, d.weekday().number_from_monday() as u8),
+            (Ordinal, Some(d), _) => write_n(w, 3, d.ordinal() as i64, pad, false),
+            (Hour, _, Some(t)) => write_two(w, t.hour() as u8, pad),
+            (Hour12, _, Some(t)) => write_two(w, t.hour12().1 as u8, pad),
+            (Minute, _, Some(t)) => write_two(w, t.minute() as u8, pad),
+            (Second, _, Some(t)) => {
+                write_two(w, (t.second() + t.nanosecond() / 1_000_000_000) as u8, pad)
+            }
+            (Nanosecond, _, Some(t)) => {
+                write_n(w, 9, (t.nanosecond() % 1_000_000_000) as i64, pad, false)
+            }
+            (Timestamp, Some(d), Some(t)) => {
+                let offset = self.off.as_ref().map(|(_, o)| i64::from(o.local_minus_utc()));
+                let timestamp = d.and_time(t).and_utc().timestamp() - offset.unwrap_or(0);
+                write_n(w, 9, timestamp, pad, false)
+            }
+            (Internal(_), _, _) => Ok(()), // for future expansion
+            _ => Err(fmt::Error),          // insufficient arguments for given format
+        }
+    }
+
+    #[cfg(feature = "alloc")]
+    fn format_fixed(&self, w: &mut impl Write, spec: &Fixed) -> fmt::Result {
+        use Fixed::*;
+        use InternalInternal::*;
+
+        match (spec, self.date, self.time, self.off.as_ref()) {
+            (ShortMonthName, Some(d), _, _) => {
+                w.write_str(short_months(self.locale)[d.month0() as usize])
+            }
+            (LongMonthName, Some(d), _, _) => {
+                w.write_str(long_months(self.locale)[d.month0() as usize])
+            }
+            (ShortWeekdayName, Some(d), _, _) => w.write_str(
+                short_weekdays(self.locale)[d.weekday().num_days_from_sunday() as usize],
+            ),
+            (LongWeekdayName, Some(d), _, _) => {
+                w.write_str(long_weekdays(self.locale)[d.weekday().num_days_from_sunday() as usize])
+            }
+            (LowerAmPm, _, Some(t), _) => {
+                let ampm = if t.hour12().0 { am_pm(self.locale)[1] } else { am_pm(self.locale)[0] };
+                for c in ampm.chars().flat_map(|c| c.to_lowercase()) {
+                    w.write_char(c)?
+                }
+                Ok(())
+            }
+            (UpperAmPm, _, Some(t), _) => {
+                let ampm = if t.hour12().0 { am_pm(self.locale)[1] } else { am_pm(self.locale)[0] };
+                w.write_str(ampm)
+            }
+            (Nanosecond, _, Some(t), _) => {
+                let nano = t.nanosecond() % 1_000_000_000;
+                if nano == 0 {
+                    Ok(())
+                } else {
+                    w.write_str(decimal_point(self.locale))?;
+                    if nano % 1_000_000 == 0 {
+                        write!(w, "{:03}", nano / 1_000_000)
+                    } else if nano % 1_000 == 0 {
+                        write!(w, "{:06}", nano / 1_000)
+                    } else {
+                        write!(w, "{nano:09}")
+                    }
+                }
+            }
+            (Nanosecond3, _, Some(t), _) => {
+                w.write_str(decimal_point(self.locale))?;
+                write!(w, "{:03}", t.nanosecond() / 1_000_000 % 1000)
+            }
+            (Nanosecond6, _, Some(t), _) => {
+                w.write_str(decimal_point(self.locale))?;
+                write!(w, "{:06}", t.nanosecond() / 1_000 % 1_000_000)
+            }
+            (Nanosecond9, _, Some(t), _) => {
+                w.write_str(decimal_point(self.locale))?;
+                write!(w, "{:09}", t.nanosecond() % 1_000_000_000)
+            }
+            (Internal(InternalFixed { val: Nanosecond3NoDot }), _, Some(t), _) => {
+                write!(w, "{:03}", t.nanosecond() / 1_000_000 % 1_000)
+            }
+            (Internal(InternalFixed { val: Nanosecond6NoDot }), _, Some(t), _) => {
+                write!(w, "{:06}", t.nanosecond() / 1_000 % 1_000_000)
+            }
+            (Internal(InternalFixed { val: Nanosecond9NoDot }), _, Some(t), _) => {
+                write!(w, "{:09}", t.nanosecond() % 1_000_000_000)
+            }
+            (TimezoneName, _, _, Some((tz_name, _))) => write!(w, "{tz_name}"),
+            (TimezoneOffset | TimezoneOffsetZ, _, _, Some((_, off))) => {
+                let offset_format = OffsetFormat {
+                    precision: OffsetPrecision::Minutes,
+                    colons: Colons::Maybe,
+                    allow_zulu: *spec == TimezoneOffsetZ,
+                    padding: Pad::Zero,
+                };
+                offset_format.format(w, *off)
+            }
+            (TimezoneOffsetColon | TimezoneOffsetColonZ, _, _, Some((_, off))) => {
+                let offset_format = OffsetFormat {
+                    precision: OffsetPrecision::Minutes,
+                    colons: Colons::Colon,
+                    allow_zulu: *spec == TimezoneOffsetColonZ,
+                    padding: Pad::Zero,
+                };
+                offset_format.format(w, *off)
+            }
+            (TimezoneOffsetDoubleColon, _, _, Some((_, off))) => {
+                let offset_format = OffsetFormat {
+                    precision: OffsetPrecision::Seconds,
+                    colons: Colons::Colon,
+                    allow_zulu: false,
+                    padding: Pad::Zero,
+                };
+                offset_format.format(w, *off)
+            }
+            (TimezoneOffsetTripleColon, _, _, Some((_, off))) => {
+                let offset_format = OffsetFormat {
+                    precision: OffsetPrecision::Hours,
+                    colons: Colons::None,
+                    allow_zulu: false,
+                    padding: Pad::Zero,
+                };
+                offset_format.format(w, *off)
+            }
+            (RFC2822, Some(d), Some(t), Some((_, off))) => {
+                write_rfc2822(w, crate::NaiveDateTime::new(d, t), *off)
+            }
+            (RFC3339, Some(d), Some(t), Some((_, off))) => write_rfc3339(
+                w,
+                crate::NaiveDateTime::new(d, t),
+                *off,
+                SecondsFormat::AutoSi,
+                false,
+            ),
+            _ => Err(fmt::Error), // insufficient arguments for given format
+        }
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl<'a, I: Iterator<Item = B> + Clone, B: Borrow<Item<'a>>> Display for DelayedFormat<I> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let mut result = String::new();
+        self.write_to(&mut result)?;
+        f.pad(&result)
+    }
+}
+
+/// Tries to format given arguments with given formatting items.
+/// Internally used by `DelayedFormat`.
+#[cfg(feature = "alloc")]
+#[deprecated(since = "0.4.32", note = "Use DelayedFormat::fmt or DelayedFormat::write_to instead")]
+pub fn format<'a, I, B>(
+    w: &mut fmt::Formatter,
+    date: Option<&NaiveDate>,
+    time: Option<&NaiveTime>,
+    off: Option<&(String, FixedOffset)>,
+    items: I,
+) -> fmt::Result
+where
+    I: Iterator<Item = B> + Clone,
+    B: Borrow<Item<'a>>,
+{
+    DelayedFormat {
+        date: date.copied(),
+        time: time.copied(),
+        off: off.cloned(),
+        items,
+        locale: default_locale(),
+    }
+    .fmt(w)
+}
+
+/// Formats single formatting item
+#[cfg(feature = "alloc")]
+#[deprecated(since = "0.4.32", note = "Use DelayedFormat::fmt or DelayedFormat::write_to instead")]
+pub fn format_item(
+    w: &mut fmt::Formatter,
+    date: Option<&NaiveDate>,
+    time: Option<&NaiveTime>,
+    off: Option<&(String, FixedOffset)>,
+    item: &Item<'_>,
+) -> fmt::Result {
+    DelayedFormat {
+        date: date.copied(),
+        time: time.copied(),
+        off: off.cloned(),
+        items: [item].into_iter(),
+        locale: default_locale(),
+    }
+    .fmt(w)
+}
+
+#[cfg(any(feature = "alloc", feature = "serde"))]
+impl OffsetFormat {
+    /// Writes an offset from UTC with the format defined by `self`.
+    fn format(&self, w: &mut impl Write, off: FixedOffset) -> fmt::Result {
+        let off = off.local_minus_utc();
+        if self.allow_zulu && off == 0 {
+            w.write_char('Z')?;
+            return Ok(());
+        }
+        let (sign, off) = if off < 0 { ('-', -off) } else { ('+', off) };
+
+        let hours;
+        let mut mins = 0;
+        let mut secs = 0;
+        let precision = match self.precision {
+            OffsetPrecision::Hours => {
+                // Minutes and seconds are simply truncated
+                hours = (off / 3600) as u8;
+                OffsetPrecision::Hours
+            }
+            OffsetPrecision::Minutes | OffsetPrecision::OptionalMinutes => {
+                // Round seconds to the nearest minute.
+                let minutes = (off + 30) / 60;
+                mins = (minutes % 60) as u8;
+                hours = (minutes / 60) as u8;
+                if self.precision == OffsetPrecision::OptionalMinutes && mins == 0 {
+                    OffsetPrecision::Hours
+                } else {
+                    OffsetPrecision::Minutes
+                }
+            }
+            OffsetPrecision::Seconds
+            | OffsetPrecision::OptionalSeconds
+            | OffsetPrecision::OptionalMinutesAndSeconds => {
+                let minutes = off / 60;
+                secs = (off % 60) as u8;
+                mins = (minutes % 60) as u8;
+                hours = (minutes / 60) as u8;
+                if self.precision != OffsetPrecision::Seconds && secs == 0 {
+                    if self.precision == OffsetPrecision::OptionalMinutesAndSeconds && mins == 0 {
+                        OffsetPrecision::Hours
+                    } else {
+                        OffsetPrecision::Minutes
+                    }
+                } else {
+                    OffsetPrecision::Seconds
+                }
+            }
+        };
+        let colons = self.colons == Colons::Colon;
+
+        if hours < 10 {
+            if self.padding == Pad::Space {
+                w.write_char(' ')?;
+            }
+            w.write_char(sign)?;
+            if self.padding == Pad::Zero {
+                w.write_char('0')?;
+            }
+            w.write_char((b'0' + hours) as char)?;
+        } else {
+            w.write_char(sign)?;
+            write_hundreds(w, hours)?;
+        }
+        if let OffsetPrecision::Minutes | OffsetPrecision::Seconds = precision {
+            if colons {
+                w.write_char(':')?;
+            }
+            write_hundreds(w, mins)?;
+        }
+        if let OffsetPrecision::Seconds = precision {
+            if colons {
+                w.write_char(':')?;
+            }
+            write_hundreds(w, secs)?;
+        }
+        Ok(())
+    }
+}
+
+/// Specific formatting options for seconds. This may be extended in the
+/// future, so exhaustive matching in external code is not recommended.
+///
+/// See the `TimeZone::to_rfc3339_opts` function for usage.
+#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
+#[allow(clippy::manual_non_exhaustive)]
+pub enum SecondsFormat {
+    /// Format whole seconds only, with no decimal point nor subseconds.
+    Secs,
+
+    /// Use fixed 3 subsecond digits. This corresponds to [Fixed::Nanosecond3].
+    Millis,
+
+    /// Use fixed 6 subsecond digits. This corresponds to [Fixed::Nanosecond6].
+    Micros,
+
+    /// Use fixed 9 subsecond digits. This corresponds to [Fixed::Nanosecond9].
+    Nanos,
+
+    /// Automatically select one of `Secs`, `Millis`, `Micros`, or `Nanos` to display all available
+    /// non-zero sub-second digits.  This corresponds to [Fixed::Nanosecond].
+    AutoSi,
+
+    // Do not match against this.
+    #[doc(hidden)]
+    __NonExhaustive,
+}
+
+/// Writes the date, time and offset to the string. same as `%Y-%m-%dT%H:%M:%S%.f%:z`
+#[inline]
+#[cfg(any(feature = "alloc", feature = "serde"))]
+pub(crate) fn write_rfc3339(
+    w: &mut impl Write,
+    dt: NaiveDateTime,
+    off: FixedOffset,
+    secform: SecondsFormat,
+    use_z: bool,
+) -> fmt::Result {
+    let year = dt.date().year();
+    if (0..=9999).contains(&year) {
+        write_hundreds(w, (year / 100) as u8)?;
+        write_hundreds(w, (year % 100) as u8)?;
+    } else {
+        // ISO 8601 requires the explicit sign for out-of-range years
+        write!(w, "{year:+05}")?;
+    }
+    w.write_char('-')?;
+    write_hundreds(w, dt.date().month() as u8)?;
+    w.write_char('-')?;
+    write_hundreds(w, dt.date().day() as u8)?;
+
+    w.write_char('T')?;
+
+    let (hour, min, mut sec) = dt.time().hms();
+    let mut nano = dt.nanosecond();
+    if nano >= 1_000_000_000 {
+        sec += 1;
+        nano -= 1_000_000_000;
+    }
+    write_hundreds(w, hour as u8)?;
+    w.write_char(':')?;
+    write_hundreds(w, min as u8)?;
+    w.write_char(':')?;
+    let sec = sec;
+    write_hundreds(w, sec as u8)?;
+
+    match secform {
+        SecondsFormat::Secs => {}
+        SecondsFormat::Millis => write!(w, ".{:03}", nano / 1_000_000)?,
+        SecondsFormat::Micros => write!(w, ".{:06}", nano / 1000)?,
+        SecondsFormat::Nanos => write!(w, ".{nano:09}")?,
+        SecondsFormat::AutoSi => {
+            if nano == 0 {
+            } else if nano % 1_000_000 == 0 {
+                write!(w, ".{:03}", nano / 1_000_000)?
+            } else if nano % 1_000 == 0 {
+                write!(w, ".{:06}", nano / 1_000)?
+            } else {
+                write!(w, ".{nano:09}")?
+            }
+        }
+        SecondsFormat::__NonExhaustive => unreachable!(),
+    };
+
+    OffsetFormat {
+        precision: OffsetPrecision::Minutes,
+        colons: Colons::Colon,
+        allow_zulu: use_z,
+        padding: Pad::Zero,
+    }
+    .format(w, off)
+}
+
+#[cfg(feature = "alloc")]
+/// write datetimes like `Tue, 1 Jul 2003 10:52:37 +0200`, same as `%a, %d %b %Y %H:%M:%S %z`
+pub(crate) fn write_rfc2822(
+    w: &mut impl Write,
+    dt: NaiveDateTime,
+    off: FixedOffset,
+) -> fmt::Result {
+    let year = dt.year();
+    // RFC2822 is only defined on years 0 through 9999
+    if !(0..=9999).contains(&year) {
+        return Err(fmt::Error);
+    }
+
+    let english = default_locale();
+
+    w.write_str(short_weekdays(english)[dt.weekday().num_days_from_sunday() as usize])?;
+    w.write_str(", ")?;
+    let day = dt.day();
+    if day < 10 {
+        w.write_char((b'0' + day as u8) as char)?;
+    } else {
+        write_hundreds(w, day as u8)?;
+    }
+    w.write_char(' ')?;
+    w.write_str(short_months(english)[dt.month0() as usize])?;
+    w.write_char(' ')?;
+    write_hundreds(w, (year / 100) as u8)?;
+    write_hundreds(w, (year % 100) as u8)?;
+    w.write_char(' ')?;
+
+    let (hour, min, sec) = dt.time().hms();
+    write_hundreds(w, hour as u8)?;
+    w.write_char(':')?;
+    write_hundreds(w, min as u8)?;
+    w.write_char(':')?;
+    let sec = sec + dt.nanosecond() / 1_000_000_000;
+    write_hundreds(w, sec as u8)?;
+    w.write_char(' ')?;
+    OffsetFormat {
+        precision: OffsetPrecision::Minutes,
+        colons: Colons::None,
+        allow_zulu: false,
+        padding: Pad::Zero,
+    }
+    .format(w, off)
+}
+
+/// Equivalent to `{:02}` formatting for n < 100.
+pub(crate) fn write_hundreds(w: &mut impl Write, n: u8) -> fmt::Result {
+    if n >= 100 {
+        return Err(fmt::Error);
+    }
+
+    let tens = b'0' + n / 10;
+    let ones = b'0' + n % 10;
+    w.write_char(tens as char)?;
+    w.write_char(ones as char)
+}
+
+#[cfg(test)]
+#[cfg(feature = "alloc")]
+mod tests {
+    use super::{Colons, OffsetFormat, OffsetPrecision, Pad};
+    use crate::FixedOffset;
+    #[cfg(feature = "alloc")]
+    use crate::{NaiveDate, NaiveTime, TimeZone, Timelike, Utc};
+
+    #[cfg(feature = "alloc")]
+    #[test]
+    fn test_delayed_write_to() {
+        let dt = crate::DateTime::from_timestamp(1643723400, 123456789).unwrap();
+        let df = dt.format("%Y-%m-%d %H:%M:%S%.9f");
+
+        let mut dt_str = String::new();
+
+        df.write_to(&mut dt_str).unwrap();
+        assert_eq!(dt_str, "2022-02-01 13:50:00.123456789");
+    }
+
+    #[cfg(all(feature = "std", feature = "unstable-locales", feature = "alloc"))]
+    #[test]
+    fn test_with_locale_delayed_write_to() {
+        use crate::DateTime;
+        use crate::format::locales::Locale;
+
+        let dt = DateTime::from_timestamp(1643723400, 123456789).unwrap();
+        let df = dt.format_localized("%A, %B %d, %Y", Locale::ja_JP);
+
+        let mut dt_str = String::new();
+
+        df.write_to(&mut dt_str).unwrap();
+
+        assert_eq!(dt_str, "火曜日, 2月 01, 2022");
+    }
+
+    #[test]
+    #[cfg(feature = "alloc")]
+    fn test_date_format() {
+        let d = NaiveDate::from_ymd_opt(2012, 3, 4).unwrap();
+        assert_eq!(d.format("%Y,%C,%y,%G,%g").to_string(), "2012,20,12,2012,12");
+        assert_eq!(d.format("%m,%b,%h,%B").to_string(), "03,Mar,Mar,March");
+        assert_eq!(d.format("%q").to_string(), "1");
+        assert_eq!(d.format("%d,%e").to_string(), "04, 4");
+        assert_eq!(d.format("%U,%W,%V").to_string(), "10,09,09");
+        assert_eq!(d.format("%a,%A,%w,%u").to_string(), "Sun,Sunday,0,7");
+        assert_eq!(d.format("%j").to_string(), "064"); // since 2012 is a leap year
+        assert_eq!(d.format("%D,%x").to_string(), "03/04/12,03/04/12");
+        assert_eq!(d.format("%F").to_string(), "2012-03-04");
+        assert_eq!(d.format("%v").to_string(), " 4-Mar-2012");
+        assert_eq!(d.format("%t%n%%%n%t").to_string(), "\t\n%\n\t");
+
+        // non-four-digit years
+        assert_eq!(
+            NaiveDate::from_ymd_opt(12345, 1, 1).unwrap().format("%Y").to_string(),
+            "+12345"
+        );
+        assert_eq!(NaiveDate::from_ymd_opt(1234, 1, 1).unwrap().format("%Y").to_string(), "1234");
+        assert_eq!(NaiveDate::from_ymd_opt(123, 1, 1).unwrap().format("%Y").to_string(), "0123");
+        assert_eq!(NaiveDate::from_ymd_opt(12, 1, 1).unwrap().format("%Y").to_string(), "0012");
+        assert_eq!(NaiveDate::from_ymd_opt(1, 1, 1).unwrap().format("%Y").to_string(), "0001");
+        assert_eq!(NaiveDate::from_ymd_opt(0, 1, 1).unwrap().format("%Y").to_string(), "0000");
+        assert_eq!(NaiveDate::from_ymd_opt(-1, 1, 1).unwrap().format("%Y").to_string(), "-0001");
+        assert_eq!(NaiveDate::from_ymd_opt(-12, 1, 1).unwrap().format("%Y").to_string(), "-0012");
+        assert_eq!(NaiveDate::from_ymd_opt(-123, 1, 1).unwrap().format("%Y").to_string(), "-0123");
+        assert_eq!(NaiveDate::from_ymd_opt(-1234, 1, 1).unwrap().format("%Y").to_string(), "-1234");
+        assert_eq!(
+            NaiveDate::from_ymd_opt(-12345, 1, 1).unwrap().format("%Y").to_string(),
+            "-12345"
+        );
+
+        // corner cases
+        assert_eq!(
+            NaiveDate::from_ymd_opt(2007, 12, 31).unwrap().format("%G,%g,%U,%W,%V").to_string(),
+            "2008,08,52,53,01"
+        );
+        assert_eq!(
+            NaiveDate::from_ymd_opt(2010, 1, 3).unwrap().format("%G,%g,%U,%W,%V").to_string(),
+            "2009,09,01,00,53"
+        );
+    }
+
+    #[test]
+    #[cfg(feature = "alloc")]
+    fn test_time_format() {
+        let t = NaiveTime::from_hms_nano_opt(3, 5, 7, 98765432).unwrap();
+        assert_eq!(t.format("%H,%k,%I,%l,%P,%p").to_string(), "03, 3,03, 3,am,AM");
+        assert_eq!(t.format("%M").to_string(), "05");
+        assert_eq!(t.format("%S,%f,%.f").to_string(), "07,098765432,.098765432");
+        assert_eq!(t.format("%.3f,%.6f,%.9f").to_string(), ".098,.098765,.098765432");
+        assert_eq!(t.format("%R").to_string(), "03:05");
+        assert_eq!(t.format("%T,%X").to_string(), "03:05:07,03:05:07");
+        assert_eq!(t.format("%r").to_string(), "03:05:07 AM");
+        assert_eq!(t.format("%t%n%%%n%t").to_string(), "\t\n%\n\t");
+
+        let t = NaiveTime::from_hms_micro_opt(3, 5, 7, 432100).unwrap();
+        assert_eq!(t.format("%S,%f,%.f").to_string(), "07,432100000,.432100");
+        assert_eq!(t.format("%.3f,%.6f,%.9f").to_string(), ".432,.432100,.432100000");
+
+        let t = NaiveTime::from_hms_milli_opt(3, 5, 7, 210).unwrap();
+        assert_eq!(t.format("%S,%f,%.f").to_string(), "07,210000000,.210");
+        assert_eq!(t.format("%.3f,%.6f,%.9f").to_string(), ".210,.210000,.210000000");
+
+        let t = NaiveTime::from_hms_opt(3, 5, 7).unwrap();
+        assert_eq!(t.format("%S,%f,%.f").to_string(), "07,000000000,");
+        assert_eq!(t.format("%.3f,%.6f,%.9f").to_string(), ".000,.000000,.000000000");
+
+        // corner cases
+        assert_eq!(
+            NaiveTime::from_hms_opt(13, 57, 9).unwrap().format("%r").to_string(),
+            "01:57:09 PM"
+        );
+        assert_eq!(
+            NaiveTime::from_hms_milli_opt(23, 59, 59, 1_000).unwrap().format("%X").to_string(),
+            "23:59:60"
+        );
+    }
+
+    #[test]
+    #[cfg(feature = "alloc")]
+    fn test_datetime_format() {
+        let dt =
+            NaiveDate::from_ymd_opt(2010, 9, 8).unwrap().and_hms_milli_opt(7, 6, 54, 321).unwrap();
+        assert_eq!(dt.format("%c").to_string(), "Wed Sep  8 07:06:54 2010");
+        assert_eq!(dt.format("%s").to_string(), "1283929614");
+        assert_eq!(dt.format("%t%n%%%n%t").to_string(), "\t\n%\n\t");
+
+        // a horror of leap second: coming near to you.
+        let dt = NaiveDate::from_ymd_opt(2012, 6, 30)
+            .unwrap()
+            .and_hms_milli_opt(23, 59, 59, 1_000)
+            .unwrap();
+        assert_eq!(dt.format("%c").to_string(), "Sat Jun 30 23:59:60 2012");
+        assert_eq!(dt.format("%s").to_string(), "1341100799"); // not 1341100800, it's intentional.
+    }
+
+    #[test]
+    #[cfg(feature = "alloc")]
+    fn test_datetime_format_alignment() {
+        let datetime = Utc
+            .with_ymd_and_hms(2007, 1, 2, 12, 34, 56)
+            .unwrap()
+            .with_nanosecond(123456789)
+            .unwrap();
+
+        // Item::Literal, odd number of padding bytes.
+        let percent = datetime.format("%%");
+        assert_eq!("   %", format!("{percent:>4}"));
+        assert_eq!("%   ", format!("{percent:<4}"));
+        assert_eq!(" %  ", format!("{percent:^4}"));
+
+        // Item::Numeric, custom non-ASCII padding character
+        let year = datetime.format("%Y");
+        assert_eq!("——2007", format!("{year:—>6}"));
+        assert_eq!("2007——", format!("{year:—<6}"));
+        assert_eq!("—2007—", format!("{year:—^6}"));
+
+        // Item::Fixed
+        let tz = datetime.format("%Z");
+        assert_eq!("  UTC", format!("{tz:>5}"));
+        assert_eq!("UTC  ", format!("{tz:<5}"));
+        assert_eq!(" UTC ", format!("{tz:^5}"));
+
+        // [Item::Numeric, Item::Space, Item::Literal, Item::Space, Item::Numeric]
+        let ymd = datetime.format("%Y %B %d");
+        assert_eq!("  2007 January 02", format!("{ymd:>17}"));
+        assert_eq!("2007 January 02  ", format!("{ymd:<17}"));
+        assert_eq!(" 2007 January 02 ", format!("{ymd:^17}"));
+
+        // Truncated
+        let time = datetime.format("%T%.6f");
+        assert_eq!("12:34:56.1234", format!("{time:.13}"));
+    }
+
+    #[test]
+    fn test_offset_formatting() {
+        fn check_all(precision: OffsetPrecision, expected: [[&str; 7]; 12]) {
+            fn check(
+                precision: OffsetPrecision,
+                colons: Colons,
+                padding: Pad,
+                allow_zulu: bool,
+                offsets: [FixedOffset; 7],
+                expected: [&str; 7],
+            ) {
+                let offset_format = OffsetFormat { precision, colons, allow_zulu, padding };
+                for (offset, expected) in offsets.iter().zip(expected.iter()) {
+                    let mut output = String::new();
+                    offset_format.format(&mut output, *offset).unwrap();
+                    assert_eq!(&output, expected);
+                }
+            }
+            // +03:45, -03:30, +11:00, -11:00:22, +02:34:26, -12:34:30, +00:00
+            let offsets = [
+                FixedOffset::east_opt(13_500).unwrap(),
+                FixedOffset::east_opt(-12_600).unwrap(),
+                FixedOffset::east_opt(39_600).unwrap(),
+                FixedOffset::east_opt(-39_622).unwrap(),
+                FixedOffset::east_opt(9266).unwrap(),
+                FixedOffset::east_opt(-45270).unwrap(),
+                FixedOffset::east_opt(0).unwrap(),
+            ];
+            check(precision, Colons::Colon, Pad::Zero, false, offsets, expected[0]);
+            check(precision, Colons::Colon, Pad::Zero, true, offsets, expected[1]);
+            check(precision, Colons::Colon, Pad::Space, false, offsets, expected[2]);
+            check(precision, Colons::Colon, Pad::Space, true, offsets, expected[3]);
+            check(precision, Colons::Colon, Pad::None, false, offsets, expected[4]);
+            check(precision, Colons::Colon, Pad::None, true, offsets, expected[5]);
+            check(precision, Colons::None, Pad::Zero, false, offsets, expected[6]);
+            check(precision, Colons::None, Pad::Zero, true, offsets, expected[7]);
+            check(precision, Colons::None, Pad::Space, false, offsets, expected[8]);
+            check(precision, Colons::None, Pad::Space, true, offsets, expected[9]);
+            check(precision, Colons::None, Pad::None, false, offsets, expected[10]);
+            check(precision, Colons::None, Pad::None, true, offsets, expected[11]);
+            // `Colons::Maybe` should format the same as `Colons::None`
+            check(precision, Colons::Maybe, Pad::Zero, false, offsets, expected[6]);
+            check(precision, Colons::Maybe, Pad::Zero, true, offsets, expected[7]);
+            check(precision, Colons::Maybe, Pad::Space, false, offsets, expected[8]);
+            check(precision, Colons::Maybe, Pad::Space, true, offsets, expected[9]);
+            check(precision, Colons::Maybe, Pad::None, false, offsets, expected[10]);
+            check(precision, Colons::Maybe, Pad::None, true, offsets, expected[11]);
+        }
+        check_all(
+            OffsetPrecision::Hours,
+            [
+                ["+03", "-03", "+11", "-11", "+02", "-12", "+00"],
+                ["+03", "-03", "+11", "-11", "+02", "-12", "Z"],
+                [" +3", " -3", "+11", "-11", " +2", "-12", " +0"],
+                [" +3", " -3", "+11", "-11", " +2", "-12", "Z"],
+                ["+3", "-3", "+11", "-11", "+2", "-12", "+0"],
+                ["+3", "-3", "+11", "-11", "+2", "-12", "Z"],
+                ["+03", "-03", "+11", "-11", "+02", "-12", "+00"],
+                ["+03", "-03", "+11", "-11", "+02", "-12", "Z"],
+                [" +3", " -3", "+11", "-11", " +2", "-12", " +0"],
+                [" +3", " -3", "+11", "-11", " +2", "-12", "Z"],
+                ["+3", "-3", "+11", "-11", "+2", "-12", "+0"],
+                ["+3", "-3", "+11", "-11", "+2", "-12", "Z"],
+            ],
+        );
+        check_all(
+            OffsetPrecision::Minutes,
+            [
+                ["+03:45", "-03:30", "+11:00", "-11:00", "+02:34", "-12:35", "+00:00"],
+                ["+03:45", "-03:30", "+11:00", "-11:00", "+02:34", "-12:35", "Z"],
+                [" +3:45", " -3:30", "+11:00", "-11:00", " +2:34", "-12:35", " +0:00"],
+                [" +3:45", " -3:30", "+11:00", "-11:00", " +2:34", "-12:35", "Z"],
+                ["+3:45", "-3:30", "+11:00", "-11:00", "+2:34", "-12:35", "+0:00"],
+                ["+3:45", "-3:30", "+11:00", "-11:00", "+2:34", "-12:35", "Z"],
+                ["+0345", "-0330", "+1100", "-1100", "+0234", "-1235", "+0000"],
+                ["+0345", "-0330", "+1100", "-1100", "+0234", "-1235", "Z"],
+                [" +345", " -330", "+1100", "-1100", " +234", "-1235", " +000"],
+                [" +345", " -330", "+1100", "-1100", " +234", "-1235", "Z"],
+                ["+345", "-330", "+1100", "-1100", "+234", "-1235", "+000"],
+                ["+345", "-330", "+1100", "-1100", "+234", "-1235", "Z"],
+            ],
+        );
+        #[rustfmt::skip]
+        check_all(
+            OffsetPrecision::Seconds,
+            [
+                ["+03:45:00", "-03:30:00", "+11:00:00", "-11:00:22", "+02:34:26", "-12:34:30", "+00:00:00"],
+                ["+03:45:00", "-03:30:00", "+11:00:00", "-11:00:22", "+02:34:26", "-12:34:30", "Z"],
+                [" +3:45:00", " -3:30:00", "+11:00:00", "-11:00:22", " +2:34:26", "-12:34:30", " +0:00:00"],
+                [" +3:45:00", " -3:30:00", "+11:00:00", "-11:00:22", " +2:34:26", "-12:34:30", "Z"],
+                ["+3:45:00", "-3:30:00", "+11:00:00", "-11:00:22", "+2:34:26", "-12:34:30", "+0:00:00"],
+                ["+3:45:00", "-3:30:00", "+11:00:00", "-11:00:22", "+2:34:26", "-12:34:30", "Z"],
+                ["+034500", "-033000", "+110000", "-110022", "+023426", "-123430", "+000000"],
+                ["+034500", "-033000", "+110000", "-110022", "+023426", "-123430", "Z"],
+                [" +34500", " -33000", "+110000", "-110022", " +23426", "-123430", " +00000"],
+                [" +34500", " -33000", "+110000", "-110022", " +23426", "-123430", "Z"],
+                ["+34500", "-33000", "+110000", "-110022", "+23426", "-123430", "+00000"],
+                ["+34500", "-33000", "+110000", "-110022", "+23426", "-123430", "Z"],
+            ],
+        );
+        check_all(
+            OffsetPrecision::OptionalMinutes,
+            [
+                ["+03:45", "-03:30", "+11", "-11", "+02:34", "-12:35", "+00"],
+                ["+03:45", "-03:30", "+11", "-11", "+02:34", "-12:35", "Z"],
+                [" +3:45", " -3:30", "+11", "-11", " +2:34", "-12:35", " +0"],
+                [" +3:45", " -3:30", "+11", "-11", " +2:34", "-12:35", "Z"],
+                ["+3:45", "-3:30", "+11", "-11", "+2:34", "-12:35", "+0"],
+                ["+3:45", "-3:30", "+11", "-11", "+2:34", "-12:35", "Z"],
+                ["+0345", "-0330", "+11", "-11", "+0234", "-1235", "+00"],
+                ["+0345", "-0330", "+11", "-11", "+0234", "-1235", "Z"],
+                [" +345", " -330", "+11", "-11", " +234", "-1235", " +0"],
+                [" +345", " -330", "+11", "-11", " +234", "-1235", "Z"],
+                ["+345", "-330", "+11", "-11", "+234", "-1235", "+0"],
+                ["+345", "-330", "+11", "-11", "+234", "-1235", "Z"],
+            ],
+        );
+        check_all(
+            OffsetPrecision::OptionalSeconds,
+            [
+                ["+03:45", "-03:30", "+11:00", "-11:00:22", "+02:34:26", "-12:34:30", "+00:00"],
+                ["+03:45", "-03:30", "+11:00", "-11:00:22", "+02:34:26", "-12:34:30", "Z"],
+                [" +3:45", " -3:30", "+11:00", "-11:00:22", " +2:34:26", "-12:34:30", " +0:00"],
+                [" +3:45", " -3:30", "+11:00", "-11:00:22", " +2:34:26", "-12:34:30", "Z"],
+                ["+3:45", "-3:30", "+11:00", "-11:00:22", "+2:34:26", "-12:34:30", "+0:00"],
+                ["+3:45", "-3:30", "+11:00", "-11:00:22", "+2:34:26", "-12:34:30", "Z"],
+                ["+0345", "-0330", "+1100", "-110022", "+023426", "-123430", "+0000"],
+                ["+0345", "-0330", "+1100", "-110022", "+023426", "-123430", "Z"],
+                [" +345", " -330", "+1100", "-110022", " +23426", "-123430", " +000"],
+                [" +345", " -330", "+1100", "-110022", " +23426", "-123430", "Z"],
+                ["+345", "-330", "+1100", "-110022", "+23426", "-123430", "+000"],
+                ["+345", "-330", "+1100", "-110022", "+23426", "-123430", "Z"],
+            ],
+        );
+        check_all(
+            OffsetPrecision::OptionalMinutesAndSeconds,
+            [
+                ["+03:45", "-03:30", "+11", "-11:00:22", "+02:34:26", "-12:34:30", "+00"],
+                ["+03:45", "-03:30", "+11", "-11:00:22", "+02:34:26", "-12:34:30", "Z"],
+                [" +3:45", " -3:30", "+11", "-11:00:22", " +2:34:26", "-12:34:30", " +0"],
+                [" +3:45", " -3:30", "+11", "-11:00:22", " +2:34:26", "-12:34:30", "Z"],
+                ["+3:45", "-3:30", "+11", "-11:00:22", "+2:34:26", "-12:34:30", "+0"],
+                ["+3:45", "-3:30", "+11", "-11:00:22", "+2:34:26", "-12:34:30", "Z"],
+                ["+0345", "-0330", "+11", "-110022", "+023426", "-123430", "+00"],
+                ["+0345", "-0330", "+11", "-110022", "+023426", "-123430", "Z"],
+                [" +345", " -330", "+11", "-110022", " +23426", "-123430", " +0"],
+                [" +345", " -330", "+11", "-110022", " +23426", "-123430", "Z"],
+                ["+345", "-330", "+11", "-110022", "+23426", "-123430", "+0"],
+                ["+345", "-330", "+11", "-110022", "+23426", "-123430", "Z"],
+            ],
+        );
+    }
+}

patch/chrono-0.4.41/src/format/locales.rs

@@ -0,0 +1,103 @@
+#[cfg(feature = "unstable-locales")]
+mod localized {
+    use pure_rust_locales::{Locale, locale_match};
+
+    pub(crate) const fn default_locale() -> Locale {
+        Locale::POSIX
+    }
+
+    pub(crate) const fn short_months(locale: Locale) -> &'static [&'static str] {
+        locale_match!(locale => LC_TIME::ABMON)
+    }
+
+    pub(crate) const fn long_months(locale: Locale) -> &'static [&'static str] {
+        locale_match!(locale => LC_TIME::MON)
+    }
+
+    pub(crate) const fn short_weekdays(locale: Locale) -> &'static [&'static str] {
+        locale_match!(locale => LC_TIME::ABDAY)
+    }
+
+    pub(crate) const fn long_weekdays(locale: Locale) -> &'static [&'static str] {
+        locale_match!(locale => LC_TIME::DAY)
+    }
+
+    pub(crate) const fn am_pm(locale: Locale) -> &'static [&'static str] {
+        locale_match!(locale => LC_TIME::AM_PM)
+    }
+
+    pub(crate) const fn decimal_point(locale: Locale) -> &'static str {
+        locale_match!(locale => LC_NUMERIC::DECIMAL_POINT)
+    }
+
+    pub(crate) const fn d_fmt(locale: Locale) -> &'static str {
+        locale_match!(locale => LC_TIME::D_FMT)
+    }
+
+    pub(crate) const fn d_t_fmt(locale: Locale) -> &'static str {
+        locale_match!(locale => LC_TIME::D_T_FMT)
+    }
+
+    pub(crate) const fn t_fmt(locale: Locale) -> &'static str {
+        locale_match!(locale => LC_TIME::T_FMT)
+    }
+
+    pub(crate) const fn t_fmt_ampm(locale: Locale) -> &'static str {
+        locale_match!(locale => LC_TIME::T_FMT_AMPM)
+    }
+}
+
+#[cfg(feature = "unstable-locales")]
+pub(crate) use localized::*;
+#[cfg(feature = "unstable-locales")]
+pub use pure_rust_locales::Locale;
+
+#[cfg(not(feature = "unstable-locales"))]
+mod unlocalized {
+    #[derive(Copy, Clone, Debug)]
+    pub(crate) struct Locale;
+
+    pub(crate) const fn default_locale() -> Locale {
+        Locale
+    }
+
+    pub(crate) const fn short_months(_locale: Locale) -> &'static [&'static str] {
+        &["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
+    }
+
+    pub(crate) const fn long_months(_locale: Locale) -> &'static [&'static str] {
+        &[
+            "January",
+            "February",
+            "March",
+            "April",
+            "May",
+            "June",
+            "July",
+            "August",
+            "September",
+            "October",
+            "November",
+            "December",
+        ]
+    }
+
+    pub(crate) const fn short_weekdays(_locale: Locale) -> &'static [&'static str] {
+        &["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
+    }
+
+    pub(crate) const fn long_weekdays(_locale: Locale) -> &'static [&'static str] {
+        &["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]
+    }
+
+    pub(crate) const fn am_pm(_locale: Locale) -> &'static [&'static str] {
+        &["AM", "PM"]
+    }
+
+    pub(crate) const fn decimal_point(_locale: Locale) -> &'static str {
+        "."
+    }
+}
+
+#[cfg(not(feature = "unstable-locales"))]
+pub(crate) use unlocalized::*;

patch/chrono-0.4.41/src/format/mod.rs

@@ -0,0 +1,557 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+//! Formatting (and parsing) utilities for date and time.
+//!
+//! This module provides the common types and routines to implement,
+//! for example, [`DateTime::format`](../struct.DateTime.html#method.format) or
+//! [`DateTime::parse_from_str`](../struct.DateTime.html#method.parse_from_str) methods.
+//! For most cases you should use these high-level interfaces.
+//!
+//! Internally the formatting and parsing shares the same abstract **formatting items**,
+//! which are just an [`Iterator`](https://doc.rust-lang.org/std/iter/trait.Iterator.html) of
+//! the [`Item`](./enum.Item.html) type.
+//! They are generated from more readable **format strings**;
+//! currently Chrono supports a built-in syntax closely resembling
+//! C's `strftime` format. The available options can be found [here](./strftime/index.html).
+//!
+//! # Example
+//! ```
+//! # #[cfg(feature = "alloc")] {
+//! use chrono::{NaiveDateTime, TimeZone, Utc};
+//!
+//! let date_time = Utc.with_ymd_and_hms(2020, 11, 10, 0, 1, 32).unwrap();
+//!
+//! let formatted = format!("{}", date_time.format("%Y-%m-%d %H:%M:%S"));
+//! assert_eq!(formatted, "2020-11-10 00:01:32");
+//!
+//! let parsed = NaiveDateTime::parse_from_str(&formatted, "%Y-%m-%d %H:%M:%S")?.and_utc();
+//! assert_eq!(parsed, date_time);
+//! # }
+//! # Ok::<(), chrono::ParseError>(())
+//! ```
+
+#[cfg(all(feature = "alloc", not(feature = "std"), not(test)))]
+use alloc::boxed::Box;
+use core::fmt;
+use core::str::FromStr;
+#[cfg(feature = "std")]
+use std::error::Error;
+
+use crate::{Month, ParseMonthError, ParseWeekdayError, Weekday};
+
+mod formatting;
+mod parsed;
+
+// due to the size of parsing routines, they are in separate modules.
+mod parse;
+pub(crate) mod scan;
+
+pub mod strftime;
+
+#[allow(unused)]
+// TODO: remove '#[allow(unused)]' once we use this module for parsing or something else that does
+// not require `alloc`.
+pub(crate) mod locales;
+
+pub use formatting::SecondsFormat;
+pub(crate) use formatting::write_hundreds;
+#[cfg(feature = "alloc")]
+pub(crate) use formatting::write_rfc2822;
+#[cfg(any(feature = "alloc", feature = "serde"))]
+pub(crate) use formatting::write_rfc3339;
+#[cfg(feature = "alloc")]
+#[allow(deprecated)]
+pub use formatting::{DelayedFormat, format, format_item};
+#[cfg(feature = "unstable-locales")]
+pub use locales::Locale;
+pub(crate) use parse::parse_rfc3339;
+pub use parse::{parse, parse_and_remainder};
+pub use parsed::Parsed;
+pub use strftime::StrftimeItems;
+
+/// An uninhabited type used for `InternalNumeric` and `InternalFixed` below.
+#[derive(Clone, PartialEq, Eq, Hash)]
+enum Void {}
+
+/// Padding characters for numeric items.
+#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
+pub enum Pad {
+    /// No padding.
+    None,
+    /// Zero (`0`) padding.
+    Zero,
+    /// Space padding.
+    Space,
+}
+
+/// Numeric item types.
+/// They have associated formatting width (FW) and parsing width (PW).
+///
+/// The **formatting width** is the minimal width to be formatted.
+/// If the number is too short, and the padding is not [`Pad::None`](./enum.Pad.html#variant.None),
+/// then it is left-padded.
+/// If the number is too long or (in some cases) negative, it is printed as is.
+///
+/// The **parsing width** is the maximal width to be scanned.
+/// The parser only tries to consume from one to given number of digits (greedily).
+/// It also trims the preceding whitespace if any.
+/// It cannot parse the negative number, so some date and time cannot be formatted then
+/// parsed with the same formatting items.
+#[non_exhaustive]
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
+pub enum Numeric {
+    /// Full Gregorian year (FW=4, PW=∞).
+    /// May accept years before 1 BCE or after 9999 CE, given an initial sign (+/-).
+    Year,
+    /// Gregorian year divided by 100 (century number; FW=PW=2). Implies the non-negative year.
+    YearDiv100,
+    /// Gregorian year modulo 100 (FW=PW=2). Cannot be negative.
+    YearMod100,
+    /// Year in the ISO week date (FW=4, PW=∞).
+    /// May accept years before 1 BCE or after 9999 CE, given an initial sign.
+    IsoYear,
+    /// Year in the ISO week date, divided by 100 (FW=PW=2). Implies the non-negative year.
+    IsoYearDiv100,
+    /// Year in the ISO week date, modulo 100 (FW=PW=2). Cannot be negative.
+    IsoYearMod100,
+    /// Quarter (FW=PW=1).
+    Quarter,
+    /// Month (FW=PW=2).
+    Month,
+    /// Day of the month (FW=PW=2).
+    Day,
+    /// Week number, where the week 1 starts at the first Sunday of January (FW=PW=2).
+    WeekFromSun,
+    /// Week number, where the week 1 starts at the first Monday of January (FW=PW=2).
+    WeekFromMon,
+    /// Week number in the ISO week date (FW=PW=2).
+    IsoWeek,
+    /// Day of the week, where Sunday = 0 and Saturday = 6 (FW=PW=1).
+    NumDaysFromSun,
+    /// Day of the week, where Monday = 1 and Sunday = 7 (FW=PW=1).
+    WeekdayFromMon,
+    /// Day of the year (FW=PW=3).
+    Ordinal,
+    /// Hour number in the 24-hour clocks (FW=PW=2).
+    Hour,
+    /// Hour number in the 12-hour clocks (FW=PW=2).
+    Hour12,
+    /// The number of minutes since the last whole hour (FW=PW=2).
+    Minute,
+    /// The number of seconds since the last whole minute (FW=PW=2).
+    Second,
+    /// The number of nanoseconds since the last whole second (FW=PW=9).
+    /// Note that this is *not* left-aligned;
+    /// see also [`Fixed::Nanosecond`](./enum.Fixed.html#variant.Nanosecond).
+    Nanosecond,
+    /// The number of non-leap seconds since the midnight UTC on January 1, 1970 (FW=1, PW=∞).
+    /// For formatting, it assumes UTC upon the absence of time zone offset.
+    Timestamp,
+
+    /// Internal uses only.
+    ///
+    /// This item exists so that one can add additional internal-only formatting
+    /// without breaking major compatibility (as enum variants cannot be selectively private).
+    Internal(InternalNumeric),
+}
+
+/// An opaque type representing numeric item types for internal uses only.
+#[derive(Clone, Eq, Hash, PartialEq)]
+pub struct InternalNumeric {
+    _dummy: Void,
+}
+
+impl fmt::Debug for InternalNumeric {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "<InternalNumeric>")
+    }
+}
+
+/// Fixed-format item types.
+///
+/// They have their own rules of formatting and parsing.
+/// Otherwise noted, they print in the specified cases but parse case-insensitively.
+#[non_exhaustive]
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
+pub enum Fixed {
+    /// Abbreviated month names.
+    ///
+    /// Prints a three-letter-long name in the title case, reads the same name in any case.
+    ShortMonthName,
+    /// Full month names.
+    ///
+    /// Prints a full name in the title case, reads either a short or full name in any case.
+    LongMonthName,
+    /// Abbreviated day of the week names.
+    ///
+    /// Prints a three-letter-long name in the title case, reads the same name in any case.
+    ShortWeekdayName,
+    /// Full day of the week names.
+    ///
+    /// Prints a full name in the title case, reads either a short or full name in any case.
+    LongWeekdayName,
+    /// AM/PM.
+    ///
+    /// Prints in lower case, reads in any case.
+    LowerAmPm,
+    /// AM/PM.
+    ///
+    /// Prints in upper case, reads in any case.
+    UpperAmPm,
+    /// An optional dot plus one or more digits for left-aligned nanoseconds.
+    /// May print nothing, 3, 6 or 9 digits according to the available accuracy.
+    /// See also [`Numeric::Nanosecond`](./enum.Numeric.html#variant.Nanosecond).
+    Nanosecond,
+    /// Same as [`Nanosecond`](#variant.Nanosecond) but the accuracy is fixed to 3.
+    Nanosecond3,
+    /// Same as [`Nanosecond`](#variant.Nanosecond) but the accuracy is fixed to 6.
+    Nanosecond6,
+    /// Same as [`Nanosecond`](#variant.Nanosecond) but the accuracy is fixed to 9.
+    Nanosecond9,
+    /// Timezone name.
+    ///
+    /// It does not support parsing, its use in the parser is an immediate failure.
+    TimezoneName,
+    /// Offset from the local time to UTC (`+09:00` or `-04:00` or `+00:00`).
+    ///
+    /// In the parser, the colon can be omitted and/or surrounded with any amount of whitespace.
+    /// The offset is limited from `-24:00` to `+24:00`,
+    /// which is the same as [`FixedOffset`](../offset/struct.FixedOffset.html)'s range.
+    TimezoneOffsetColon,
+    /// Offset from the local time to UTC with seconds (`+09:00:00` or `-04:00:00` or `+00:00:00`).
+    ///
+    /// In the parser, the colon can be omitted and/or surrounded with any amount of whitespace.
+    /// The offset is limited from `-24:00:00` to `+24:00:00`,
+    /// which is the same as [`FixedOffset`](../offset/struct.FixedOffset.html)'s range.
+    TimezoneOffsetDoubleColon,
+    /// Offset from the local time to UTC without minutes (`+09` or `-04` or `+00`).
+    ///
+    /// In the parser, the colon can be omitted and/or surrounded with any amount of whitespace.
+    /// The offset is limited from `-24` to `+24`,
+    /// which is the same as [`FixedOffset`](../offset/struct.FixedOffset.html)'s range.
+    TimezoneOffsetTripleColon,
+    /// Offset from the local time to UTC (`+09:00` or `-04:00` or `Z`).
+    ///
+    /// In the parser, the colon can be omitted and/or surrounded with any amount of whitespace,
+    /// and `Z` can be either in upper case or in lower case.
+    /// The offset is limited from `-24:00` to `+24:00`,
+    /// which is the same as [`FixedOffset`](../offset/struct.FixedOffset.html)'s range.
+    TimezoneOffsetColonZ,
+    /// Same as [`TimezoneOffsetColon`](#variant.TimezoneOffsetColon) but prints no colon.
+    /// Parsing allows an optional colon.
+    TimezoneOffset,
+    /// Same as [`TimezoneOffsetColonZ`](#variant.TimezoneOffsetColonZ) but prints no colon.
+    /// Parsing allows an optional colon.
+    TimezoneOffsetZ,
+    /// RFC 2822 date and time syntax. Commonly used for email and MIME date and time.
+    RFC2822,
+    /// RFC 3339 & ISO 8601 date and time syntax.
+    RFC3339,
+
+    /// Internal uses only.
+    ///
+    /// This item exists so that one can add additional internal-only formatting
+    /// without breaking major compatibility (as enum variants cannot be selectively private).
+    Internal(InternalFixed),
+}
+
+/// An opaque type representing fixed-format item types for internal uses only.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct InternalFixed {
+    val: InternalInternal,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+enum InternalInternal {
+    /// Same as [`TimezoneOffsetColonZ`](#variant.TimezoneOffsetColonZ), but
+    /// allows missing minutes (per [ISO 8601][iso8601]).
+    ///
+    /// # Panics
+    ///
+    /// If you try to use this for printing.
+    ///
+    /// [iso8601]: https://en.wikipedia.org/wiki/ISO_8601#Time_offsets_from_UTC
+    TimezoneOffsetPermissive,
+    /// Same as [`Nanosecond`](#variant.Nanosecond) but the accuracy is fixed to 3 and there is no leading dot.
+    Nanosecond3NoDot,
+    /// Same as [`Nanosecond`](#variant.Nanosecond) but the accuracy is fixed to 6 and there is no leading dot.
+    Nanosecond6NoDot,
+    /// Same as [`Nanosecond`](#variant.Nanosecond) but the accuracy is fixed to 9 and there is no leading dot.
+    Nanosecond9NoDot,
+}
+
+/// Type for specifying the format of UTC offsets.
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub struct OffsetFormat {
+    /// See `OffsetPrecision`.
+    pub precision: OffsetPrecision,
+    /// Separator between hours, minutes and seconds.
+    pub colons: Colons,
+    /// Represent `+00:00` as `Z`.
+    pub allow_zulu: bool,
+    /// Pad the hour value to two digits.
+    pub padding: Pad,
+}
+
+/// The precision of an offset from UTC formatting item.
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub enum OffsetPrecision {
+    /// Format offset from UTC as only hours. Not recommended, it is not uncommon for timezones to
+    /// have an offset of 30 minutes, 15 minutes, etc.
+    /// Any minutes and seconds get truncated.
+    Hours,
+    /// Format offset from UTC as hours and minutes.
+    /// Any seconds will be rounded to the nearest minute.
+    Minutes,
+    /// Format offset from UTC as hours, minutes and seconds.
+    Seconds,
+    /// Format offset from UTC as hours, and optionally with minutes.
+    /// Any seconds will be rounded to the nearest minute.
+    OptionalMinutes,
+    /// Format offset from UTC as hours and minutes, and optionally seconds.
+    OptionalSeconds,
+    /// Format offset from UTC as hours and optionally minutes and seconds.
+    OptionalMinutesAndSeconds,
+}
+
+/// The separator between hours and minutes in an offset.
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
+pub enum Colons {
+    /// No separator
+    None,
+    /// Colon (`:`) as separator
+    Colon,
+    /// No separator when formatting, colon allowed when parsing.
+    Maybe,
+}
+
+/// A single formatting item. This is used for both formatting and parsing.
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
+pub enum Item<'a> {
+    /// A literally printed and parsed text.
+    Literal(&'a str),
+    /// Same as `Literal` but with the string owned by the item.
+    #[cfg(feature = "alloc")]
+    OwnedLiteral(Box<str>),
+    /// Whitespace. Prints literally but reads zero or more whitespace.
+    Space(&'a str),
+    /// Same as `Space` but with the string owned by the item.
+    #[cfg(feature = "alloc")]
+    OwnedSpace(Box<str>),
+    /// Numeric item. Can be optionally padded to the maximal length (if any) when formatting;
+    /// the parser simply ignores any padded whitespace and zeroes.
+    Numeric(Numeric, Pad),
+    /// Fixed-format item.
+    Fixed(Fixed),
+    /// Issues a formatting error. Used to signal an invalid format string.
+    Error,
+}
+
+const fn num(numeric: Numeric) -> Item<'static> {
+    Item::Numeric(numeric, Pad::None)
+}
+
+const fn num0(numeric: Numeric) -> Item<'static> {
+    Item::Numeric(numeric, Pad::Zero)
+}
+
+const fn nums(numeric: Numeric) -> Item<'static> {
+    Item::Numeric(numeric, Pad::Space)
+}
+
+const fn fixed(fixed: Fixed) -> Item<'static> {
+    Item::Fixed(fixed)
+}
+
+const fn internal_fixed(val: InternalInternal) -> Item<'static> {
+    Item::Fixed(Fixed::Internal(InternalFixed { val }))
+}
+
+impl Item<'_> {
+    /// Convert items that contain a reference to the format string into an owned variant.
+    #[cfg(any(feature = "alloc", feature = "std"))]
+    pub fn to_owned(self) -> Item<'static> {
+        match self {
+            Item::Literal(s) => Item::OwnedLiteral(Box::from(s)),
+            Item::Space(s) => Item::OwnedSpace(Box::from(s)),
+            Item::Numeric(n, p) => Item::Numeric(n, p),
+            Item::Fixed(f) => Item::Fixed(f),
+            Item::OwnedLiteral(l) => Item::OwnedLiteral(l),
+            Item::OwnedSpace(s) => Item::OwnedSpace(s),
+            Item::Error => Item::Error,
+        }
+    }
+}
+
+/// An error from the `parse` function.
+#[derive(Debug, Clone, PartialEq, Eq, Copy, Hash)]
+pub struct ParseError(ParseErrorKind);
+
+impl ParseError {
+    /// The category of parse error
+    pub const fn kind(&self) -> ParseErrorKind {
+        self.0
+    }
+}
+
+/// The category of parse error
+#[allow(clippy::manual_non_exhaustive)]
+#[derive(Debug, Clone, PartialEq, Eq, Copy, Hash)]
+pub enum ParseErrorKind {
+    /// Given field is out of permitted range.
+    OutOfRange,
+
+    /// There is no possible date and time value with given set of fields.
+    ///
+    /// This does not include the out-of-range conditions, which are trivially invalid.
+    /// It includes the case that there are one or more fields that are inconsistent to each other.
+    Impossible,
+
+    /// Given set of fields is not enough to make a requested date and time value.
+    ///
+    /// Note that there *may* be a case that given fields constrain the possible values so much
+    /// that there is a unique possible value. Chrono only tries to be correct for
+    /// most useful sets of fields however, as such constraint solving can be expensive.
+    NotEnough,
+
+    /// The input string has some invalid character sequence for given formatting items.
+    Invalid,
+
+    /// The input string has been prematurely ended.
+    TooShort,
+
+    /// All formatting items have been read but there is a remaining input.
+    TooLong,
+
+    /// There was an error on the formatting string, or there were non-supported formatting items.
+    BadFormat,
+
+    // TODO: Change this to `#[non_exhaustive]` (on the enum) with the next breaking release.
+    #[doc(hidden)]
+    __Nonexhaustive,
+}
+
+/// Same as `Result<T, ParseError>`.
+pub type ParseResult<T> = Result<T, ParseError>;
+
+impl fmt::Display for ParseError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self.0 {
+            ParseErrorKind::OutOfRange => write!(f, "input is out of range"),
+            ParseErrorKind::Impossible => write!(f, "no possible date and time matching input"),
+            ParseErrorKind::NotEnough => write!(f, "input is not enough for unique date and time"),
+            ParseErrorKind::Invalid => write!(f, "input contains invalid characters"),
+            ParseErrorKind::TooShort => write!(f, "premature end of input"),
+            ParseErrorKind::TooLong => write!(f, "trailing input"),
+            ParseErrorKind::BadFormat => write!(f, "bad or unsupported format string"),
+            _ => unreachable!(),
+        }
+    }
+}
+
+#[cfg(feature = "std")]
+impl Error for ParseError {
+    #[allow(deprecated)]
+    fn description(&self) -> &str {
+        "parser error, see to_string() for details"
+    }
+}
+
+// to be used in this module and submodules
+pub(crate) const OUT_OF_RANGE: ParseError = ParseError(ParseErrorKind::OutOfRange);
+const IMPOSSIBLE: ParseError = ParseError(ParseErrorKind::Impossible);
+const NOT_ENOUGH: ParseError = ParseError(ParseErrorKind::NotEnough);
+const INVALID: ParseError = ParseError(ParseErrorKind::Invalid);
+const TOO_SHORT: ParseError = ParseError(ParseErrorKind::TooShort);
+pub(crate) const TOO_LONG: ParseError = ParseError(ParseErrorKind::TooLong);
+const BAD_FORMAT: ParseError = ParseError(ParseErrorKind::BadFormat);
+
+// this implementation is here only because we need some private code from `scan`
+
+/// Parsing a `str` into a `Weekday` uses the format [`%A`](./format/strftime/index.html).
+///
+/// # Example
+///
+/// ```
+/// use chrono::Weekday;
+///
+/// assert_eq!("Sunday".parse::<Weekday>(), Ok(Weekday::Sun));
+/// assert!("any day".parse::<Weekday>().is_err());
+/// ```
+///
+/// The parsing is case-insensitive.
+///
+/// ```
+/// # use chrono::Weekday;
+/// assert_eq!("mON".parse::<Weekday>(), Ok(Weekday::Mon));
+/// ```
+///
+/// Only the shortest form (e.g. `sun`) and the longest form (e.g. `sunday`) is accepted.
+///
+/// ```
+/// # use chrono::Weekday;
+/// assert!("thurs".parse::<Weekday>().is_err());
+/// ```
+impl FromStr for Weekday {
+    type Err = ParseWeekdayError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if let Ok(("", w)) = scan::short_or_long_weekday(s) {
+            Ok(w)
+        } else {
+            Err(ParseWeekdayError { _dummy: () })
+        }
+    }
+}
+
+/// Parsing a `str` into a `Month` uses the format [`%B`](./format/strftime/index.html).
+///
+/// # Example
+///
+/// ```
+/// use chrono::Month;
+///
+/// assert_eq!("January".parse::<Month>(), Ok(Month::January));
+/// assert!("any day".parse::<Month>().is_err());
+/// ```
+///
+/// The parsing is case-insensitive.
+///
+/// ```
+/// # use chrono::Month;
+/// assert_eq!("fEbruARy".parse::<Month>(), Ok(Month::February));
+/// ```
+///
+/// Only the shortest form (e.g. `jan`) and the longest form (e.g. `january`) is accepted.
+///
+/// ```
+/// # use chrono::Month;
+/// assert!("septem".parse::<Month>().is_err());
+/// assert!("Augustin".parse::<Month>().is_err());
+/// ```
+impl FromStr for Month {
+    type Err = ParseMonthError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if let Ok(("", w)) = scan::short_or_long_month0(s) {
+            match w {
+                0 => Ok(Month::January),
+                1 => Ok(Month::February),
+                2 => Ok(Month::March),
+                3 => Ok(Month::April),
+                4 => Ok(Month::May),
+                5 => Ok(Month::June),
+                6 => Ok(Month::July),
+                7 => Ok(Month::August),
+                8 => Ok(Month::September),
+                9 => Ok(Month::October),
+                10 => Ok(Month::November),
+                11 => Ok(Month::December),
+                _ => Err(ParseMonthError { _dummy: () }),
+            }
+        } else {
+            Err(ParseMonthError { _dummy: () })
+        }
+    }
+}

patch/chrono-0.4.41/src/format/scan.rs

@@ -0,0 +1,431 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+/*!
+ * Various scanning routines for the parser.
+ */
+
+use super::{INVALID, OUT_OF_RANGE, ParseResult, TOO_SHORT};
+use crate::Weekday;
+
+/// Tries to parse the non-negative number from `min` to `max` digits.
+///
+/// The absence of digits at all is an unconditional error.
+/// More than `max` digits are consumed up to the first `max` digits.
+/// Any number that does not fit in `i64` is an error.
+#[inline]
+pub(super) fn number(s: &str, min: usize, max: usize) -> ParseResult<(&str, i64)> {
+    assert!(min <= max);
+
+    // We are only interested in ascii numbers, so we can work with the `str` as bytes. We stop on
+    // the first non-numeric byte, which may be another ascii character or beginning of multi-byte
+    // UTF-8 character.
+    let bytes = s.as_bytes();
+    if bytes.len() < min {
+        return Err(TOO_SHORT);
+    }
+
+    let mut n = 0i64;
+    for (i, c) in bytes.iter().take(max).cloned().enumerate() {
+        // cloned() = copied()
+        if !c.is_ascii_digit() {
+            if i < min {
+                return Err(INVALID);
+            } else {
+                return Ok((&s[i..], n));
+            }
+        }
+
+        n = match n.checked_mul(10).and_then(|n| n.checked_add((c - b'0') as i64)) {
+            Some(n) => n,
+            None => return Err(OUT_OF_RANGE),
+        };
+    }
+
+    Ok((&s[core::cmp::min(max, bytes.len())..], n))
+}
+
+/// Tries to consume at least one digits as a fractional second.
+/// Returns the number of whole nanoseconds (0--999,999,999).
+pub(super) fn nanosecond(s: &str) -> ParseResult<(&str, i64)> {
+    // record the number of digits consumed for later scaling.
+    let origlen = s.len();
+    let (s, v) = number(s, 1, 9)?;
+    let consumed = origlen - s.len();
+
+    // scale the number accordingly.
+    static SCALE: [i64; 10] =
+        [0, 100_000_000, 10_000_000, 1_000_000, 100_000, 10_000, 1_000, 100, 10, 1];
+    let v = v.checked_mul(SCALE[consumed]).ok_or(OUT_OF_RANGE)?;
+
+    // if there are more than 9 digits, skip next digits.
+    let s = s.trim_start_matches(|c: char| c.is_ascii_digit());
+
+    Ok((s, v))
+}
+
+/// Tries to consume a fixed number of digits as a fractional second.
+/// Returns the number of whole nanoseconds (0--999,999,999).
+pub(super) fn nanosecond_fixed(s: &str, digits: usize) -> ParseResult<(&str, i64)> {
+    // record the number of digits consumed for later scaling.
+    let (s, v) = number(s, digits, digits)?;
+
+    // scale the number accordingly.
+    static SCALE: [i64; 10] =
+        [0, 100_000_000, 10_000_000, 1_000_000, 100_000, 10_000, 1_000, 100, 10, 1];
+    let v = v.checked_mul(SCALE[digits]).ok_or(OUT_OF_RANGE)?;
+
+    Ok((s, v))
+}
+
+/// Tries to parse the month index (0 through 11) with the first three ASCII letters.
+pub(super) fn short_month0(s: &str) -> ParseResult<(&str, u8)> {
+    if s.len() < 3 {
+        return Err(TOO_SHORT);
+    }
+    let buf = s.as_bytes();
+    let month0 = match (buf[0] | 32, buf[1] | 32, buf[2] | 32) {
+        (b'j', b'a', b'n') => 0,
+        (b'f', b'e', b'b') => 1,
+        (b'm', b'a', b'r') => 2,
+        (b'a', b'p', b'r') => 3,
+        (b'm', b'a', b'y') => 4,
+        (b'j', b'u', b'n') => 5,
+        (b'j', b'u', b'l') => 6,
+        (b'a', b'u', b'g') => 7,
+        (b's', b'e', b'p') => 8,
+        (b'o', b'c', b't') => 9,
+        (b'n', b'o', b'v') => 10,
+        (b'd', b'e', b'c') => 11,
+        _ => return Err(INVALID),
+    };
+    Ok((&s[3..], month0))
+}
+
+/// Tries to parse the weekday with the first three ASCII letters.
+pub(super) fn short_weekday(s: &str) -> ParseResult<(&str, Weekday)> {
+    if s.len() < 3 {
+        return Err(TOO_SHORT);
+    }
+    let buf = s.as_bytes();
+    let weekday = match (buf[0] | 32, buf[1] | 32, buf[2] | 32) {
+        (b'm', b'o', b'n') => Weekday::Mon,
+        (b't', b'u', b'e') => Weekday::Tue,
+        (b'w', b'e', b'd') => Weekday::Wed,
+        (b't', b'h', b'u') => Weekday::Thu,
+        (b'f', b'r', b'i') => Weekday::Fri,
+        (b's', b'a', b't') => Weekday::Sat,
+        (b's', b'u', b'n') => Weekday::Sun,
+        _ => return Err(INVALID),
+    };
+    Ok((&s[3..], weekday))
+}
+
+/// Tries to parse the month index (0 through 11) with short or long month names.
+/// It prefers long month names to short month names when both are possible.
+pub(super) fn short_or_long_month0(s: &str) -> ParseResult<(&str, u8)> {
+    // lowercased month names, minus first three chars
+    static LONG_MONTH_SUFFIXES: [&[u8]; 12] = [
+        b"uary", b"ruary", b"ch", b"il", b"", b"e", b"y", b"ust", b"tember", b"ober", b"ember",
+        b"ember",
+    ];
+
+    let (mut s, month0) = short_month0(s)?;
+
+    // tries to consume the suffix if possible
+    let suffix = LONG_MONTH_SUFFIXES[month0 as usize];
+    if s.len() >= suffix.len() && s.as_bytes()[..suffix.len()].eq_ignore_ascii_case(suffix) {
+        s = &s[suffix.len()..];
+    }
+
+    Ok((s, month0))
+}
+
+/// Tries to parse the weekday with short or long weekday names.
+/// It prefers long weekday names to short weekday names when both are possible.
+pub(super) fn short_or_long_weekday(s: &str) -> ParseResult<(&str, Weekday)> {
+    // lowercased weekday names, minus first three chars
+    static LONG_WEEKDAY_SUFFIXES: [&[u8]; 7] =
+        [b"day", b"sday", b"nesday", b"rsday", b"day", b"urday", b"day"];
+
+    let (mut s, weekday) = short_weekday(s)?;
+
+    // tries to consume the suffix if possible
+    let suffix = LONG_WEEKDAY_SUFFIXES[weekday.num_days_from_monday() as usize];
+    if s.len() >= suffix.len() && s.as_bytes()[..suffix.len()].eq_ignore_ascii_case(suffix) {
+        s = &s[suffix.len()..];
+    }
+
+    Ok((s, weekday))
+}
+
+/// Tries to consume exactly one given character.
+pub(super) fn char(s: &str, c1: u8) -> ParseResult<&str> {
+    match s.as_bytes().first() {
+        Some(&c) if c == c1 => Ok(&s[1..]),
+        Some(_) => Err(INVALID),
+        None => Err(TOO_SHORT),
+    }
+}
+
+/// Tries to consume one or more whitespace.
+pub(super) fn space(s: &str) -> ParseResult<&str> {
+    let s_ = s.trim_start();
+    if s_.len() < s.len() {
+        Ok(s_)
+    } else if s.is_empty() {
+        Err(TOO_SHORT)
+    } else {
+        Err(INVALID)
+    }
+}
+
+/// Consumes any number (including zero) of colon or spaces.
+pub(crate) fn colon_or_space(s: &str) -> ParseResult<&str> {
+    Ok(s.trim_start_matches(|c: char| c == ':' || c.is_whitespace()))
+}
+
+/// Parse a timezone from `s` and return the offset in seconds.
+///
+/// The `consume_colon` function is used to parse a mandatory or optional `:`
+/// separator between hours offset and minutes offset.
+///
+/// The `allow_missing_minutes` flag allows the timezone minutes offset to be
+/// missing from `s`.
+///
+/// The `allow_tz_minus_sign` flag allows the timezone offset negative character
+/// to also be `−` MINUS SIGN (U+2212) in addition to the typical
+/// ASCII-compatible `-` HYPHEN-MINUS (U+2D).
+/// This is part of [RFC 3339 & ISO 8601].
+///
+/// [RFC 3339 & ISO 8601]: https://en.wikipedia.org/w/index.php?title=ISO_8601&oldid=1114309368#Time_offsets_from_UTC
+pub(crate) fn timezone_offset<F>(
+    mut s: &str,
+    mut consume_colon: F,
+    allow_zulu: bool,
+    allow_missing_minutes: bool,
+    allow_tz_minus_sign: bool,
+) -> ParseResult<(&str, i32)>
+where
+    F: FnMut(&str) -> ParseResult<&str>,
+{
+    if allow_zulu {
+        if let Some(&b'Z' | &b'z') = s.as_bytes().first() {
+            return Ok((&s[1..], 0));
+        }
+    }
+
+    const fn digits(s: &str) -> ParseResult<(u8, u8)> {
+        let b = s.as_bytes();
+        if b.len() < 2 { Err(TOO_SHORT) } else { Ok((b[0], b[1])) }
+    }
+    let negative = match s.chars().next() {
+        Some('+') => {
+            // PLUS SIGN (U+2B)
+            s = &s['+'.len_utf8()..];
+
+            false
+        }
+        Some('-') => {
+            // HYPHEN-MINUS (U+2D)
+            s = &s['-'.len_utf8()..];
+
+            true
+        }
+        Some('−') => {
+            // MINUS SIGN (U+2212)
+            if !allow_tz_minus_sign {
+                return Err(INVALID);
+            }
+            s = &s['−'.len_utf8()..];
+
+            true
+        }
+        Some(_) => return Err(INVALID),
+        None => return Err(TOO_SHORT),
+    };
+
+    // hours (00--99)
+    let hours = match digits(s)? {
+        (h1 @ b'0'..=b'9', h2 @ b'0'..=b'9') => i32::from((h1 - b'0') * 10 + (h2 - b'0')),
+        _ => return Err(INVALID),
+    };
+    s = &s[2..];
+
+    // colons (and possibly other separators)
+    s = consume_colon(s)?;
+
+    // minutes (00--59)
+    // if the next two items are digits then we have to add minutes
+    let minutes = if let Ok(ds) = digits(s) {
+        match ds {
+            (m1 @ b'0'..=b'5', m2 @ b'0'..=b'9') => i32::from((m1 - b'0') * 10 + (m2 - b'0')),
+            (b'6'..=b'9', b'0'..=b'9') => return Err(OUT_OF_RANGE),
+            _ => return Err(INVALID),
+        }
+    } else if allow_missing_minutes {
+        0
+    } else {
+        return Err(TOO_SHORT);
+    };
+    s = match s.len() {
+        len if len >= 2 => &s[2..],
+        0 => s,
+        _ => return Err(TOO_SHORT),
+    };
+
+    let seconds = hours * 3600 + minutes * 60;
+    Ok((s, if negative { -seconds } else { seconds }))
+}
+
+/// Same as `timezone_offset` but also allows for RFC 2822 legacy timezones.
+/// May return `None` which indicates an insufficient offset data (i.e. `-0000`).
+/// See [RFC 2822 Section 4.3].
+///
+/// [RFC 2822 Section 4.3]: https://tools.ietf.org/html/rfc2822#section-4.3
+pub(super) fn timezone_offset_2822(s: &str) -> ParseResult<(&str, i32)> {
+    // tries to parse legacy time zone names
+    let upto = s.as_bytes().iter().position(|&c| !c.is_ascii_alphabetic()).unwrap_or(s.len());
+    if upto > 0 {
+        let name = &s.as_bytes()[..upto];
+        let s = &s[upto..];
+        let offset_hours = |o| Ok((s, o * 3600));
+        // RFC 2822 requires support for some named North America timezones, a small subset of all
+        // named timezones.
+        if name.eq_ignore_ascii_case(b"gmt")
+            || name.eq_ignore_ascii_case(b"ut")
+            || name.eq_ignore_ascii_case(b"z")
+        {
+            return offset_hours(0);
+        } else if name.eq_ignore_ascii_case(b"edt") {
+            return offset_hours(-4);
+        } else if name.eq_ignore_ascii_case(b"est") || name.eq_ignore_ascii_case(b"cdt") {
+            return offset_hours(-5);
+        } else if name.eq_ignore_ascii_case(b"cst") || name.eq_ignore_ascii_case(b"mdt") {
+            return offset_hours(-6);
+        } else if name.eq_ignore_ascii_case(b"mst") || name.eq_ignore_ascii_case(b"pdt") {
+            return offset_hours(-7);
+        } else if name.eq_ignore_ascii_case(b"pst") {
+            return offset_hours(-8);
+        } else if name.len() == 1 {
+            if let b'a'..=b'i' | b'k'..=b'y' | b'A'..=b'I' | b'K'..=b'Y' = name[0] {
+                // recommended by RFC 2822: consume but treat it as -0000
+                return Ok((s, 0));
+            }
+        }
+        Err(INVALID)
+    } else {
+        timezone_offset(s, |s| Ok(s), false, false, false)
+    }
+}
+
+/// Tries to consume an RFC2822 comment including preceding ` `.
+///
+/// Returns the remaining string after the closing parenthesis.
+pub(super) fn comment_2822(s: &str) -> ParseResult<(&str, ())> {
+    use CommentState::*;
+
+    let s = s.trim_start();
+
+    let mut state = Start;
+    for (i, c) in s.bytes().enumerate() {
+        state = match (state, c) {
+            (Start, b'(') => Next(1),
+            (Next(1), b')') => return Ok((&s[i + 1..], ())),
+            (Next(depth), b'\\') => Escape(depth),
+            (Next(depth), b'(') => Next(depth + 1),
+            (Next(depth), b')') => Next(depth - 1),
+            (Next(depth), _) | (Escape(depth), _) => Next(depth),
+            _ => return Err(INVALID),
+        };
+    }
+
+    Err(TOO_SHORT)
+}
+
+enum CommentState {
+    Start,
+    Next(usize),
+    Escape(usize),
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{
+        comment_2822, nanosecond, nanosecond_fixed, short_or_long_month0, short_or_long_weekday,
+        timezone_offset_2822,
+    };
+    use crate::Weekday;
+    use crate::format::{INVALID, TOO_SHORT};
+
+    #[test]
+    fn test_rfc2822_comments() {
+        let testdata = [
+            ("", Err(TOO_SHORT)),
+            (" ", Err(TOO_SHORT)),
+            ("x", Err(INVALID)),
+            ("(", Err(TOO_SHORT)),
+            ("()", Ok("")),
+            (" \r\n\t()", Ok("")),
+            ("() ", Ok(" ")),
+            ("()z", Ok("z")),
+            ("(x)", Ok("")),
+            ("(())", Ok("")),
+            ("((()))", Ok("")),
+            ("(x(x(x)x)x)", Ok("")),
+            ("( x ( x ( x ) x ) x )", Ok("")),
+            (r"(\)", Err(TOO_SHORT)),
+            (r"(\()", Ok("")),
+            (r"(\))", Ok("")),
+            (r"(\\)", Ok("")),
+            ("(()())", Ok("")),
+            ("( x ( x ) x ( x ) x )", Ok("")),
+        ];
+
+        for (test_in, expected) in testdata.iter() {
+            let actual = comment_2822(test_in).map(|(s, _)| s);
+            assert_eq!(
+                *expected, actual,
+                "{test_in:?} expected to produce {expected:?}, but produced {actual:?}."
+            );
+        }
+    }
+
+    #[test]
+    fn test_timezone_offset_2822() {
+        assert_eq!(timezone_offset_2822("cSt").unwrap(), ("", -21600));
+        assert_eq!(timezone_offset_2822("pSt").unwrap(), ("", -28800));
+        assert_eq!(timezone_offset_2822("mSt").unwrap(), ("", -25200));
+        assert_eq!(timezone_offset_2822("-1551").unwrap(), ("", -57060));
+        assert_eq!(timezone_offset_2822("Gp"), Err(INVALID));
+    }
+
+    #[test]
+    fn test_short_or_long_month0() {
+        assert_eq!(short_or_long_month0("JUn").unwrap(), ("", 5));
+        assert_eq!(short_or_long_month0("mAy").unwrap(), ("", 4));
+        assert_eq!(short_or_long_month0("AuG").unwrap(), ("", 7));
+        assert_eq!(short_or_long_month0("Aprâ").unwrap(), ("â", 3));
+        assert_eq!(short_or_long_month0("JUl").unwrap(), ("", 6));
+        assert_eq!(short_or_long_month0("mAr").unwrap(), ("", 2));
+        assert_eq!(short_or_long_month0("Jan").unwrap(), ("", 0));
+    }
+
+    #[test]
+    fn test_short_or_long_weekday() {
+        assert_eq!(short_or_long_weekday("sAtu").unwrap(), ("u", Weekday::Sat));
+        assert_eq!(short_or_long_weekday("thu").unwrap(), ("", Weekday::Thu));
+    }
+
+    #[test]
+    fn test_nanosecond_fixed() {
+        assert_eq!(nanosecond_fixed("", 0usize).unwrap(), ("", 0));
+        assert!(nanosecond_fixed("", 1usize).is_err());
+    }
+
+    #[test]
+    fn test_nanosecond() {
+        assert_eq!(nanosecond("2Ù").unwrap(), ("Ù", 200000000));
+        assert_eq!(nanosecond("8").unwrap(), ("", 800000000));
+    }
+}

patch/chrono-0.4.41/src/lib.rs

@@ -0,0 +1,735 @@
+//! # Chrono: Date and Time for Rust
+//!
+//! Chrono aims to provide all functionality needed to do correct operations on dates and times in
+//! the [proleptic Gregorian calendar]:
+//!
+//! * The [`DateTime`] type is timezone-aware by default, with separate timezone-naive types.
+//! * Operations that may produce an invalid or ambiguous date and time return `Option` or
+//!   [`MappedLocalTime`].
+//! * Configurable parsing and formatting with a `strftime` inspired date and time formatting
+//!   syntax.
+//! * The [`Local`] timezone works with the current timezone of the OS.
+//! * Types and operations are implemented to be reasonably efficient.
+//!
+//! Timezone data is not shipped with chrono by default to limit binary sizes. Use the companion
+//! crate [Chrono-TZ] or [`tzfile`] for full timezone support.
+//!
+//! [proleptic Gregorian calendar]: https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar
+//! [Chrono-TZ]: https://crates.io/crates/chrono-tz
+//! [`tzfile`]: https://crates.io/crates/tzfile
+//!
+//! ### Features
+//!
+//! Chrono supports various runtime environments and operating systems, and has several features
+//! that may be enabled or disabled.
+//!
+//! Default features:
+//!
+//! - `alloc`: Enable features that depend on allocation (primarily string formatting).
+//! - `std`: Enables functionality that depends on the standard library. This is a superset of
+//!   `alloc` and adds interoperation with standard library types and traits.
+//! - `clock`: Enables reading the local timezone (`Local`). This is a superset of `now`.
+//! - `now`: Enables reading the system time (`now`).
+//! - `wasmbind`: Interface with the JS Date API for the `wasm32` target.
+//!
+//! Optional features:
+//!
+//! - `serde`: Enable serialization/deserialization via [serde].
+//! - `rkyv`: Deprecated, use the `rkyv-*` features.
+//! - `rkyv-16`: Enable serialization/deserialization via [rkyv],
+//!   using 16-bit integers for integral `*size` types.
+//! - `rkyv-32`: Enable serialization/deserialization via [rkyv],
+//!   using 32-bit integers for integral `*size` types.
+//! - `rkyv-64`: Enable serialization/deserialization via [rkyv],
+//!   using 64-bit integers for integral `*size` types.
+//! - `rkyv-validation`: Enable rkyv validation support using `bytecheck`.
+//! - `arbitrary`: Construct arbitrary instances of a type with the Arbitrary crate.
+//! - `unstable-locales`: Enable localization. This adds various methods with a `_localized` suffix.
+//!   The implementation and API may change or even be removed in a patch release. Feedback welcome.
+//! - `oldtime`: This feature no longer has any effect; it used to offer compatibility with the
+//!   `time` 0.1 crate.
+//!
+//! Note: The `rkyv{,-16,-32,-64}` features are mutually exclusive.
+//!
+//! See the [cargo docs] for examples of specifying features.
+//!
+//! [serde]: https://github.com/serde-rs/serde
+//! [rkyv]: https://github.com/rkyv/rkyv
+//! [cargo docs]: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#choosing-features
+//!
+//! ## Overview
+//!
+//! ### Time delta / Duration
+//!
+//! Chrono has a [`TimeDelta`] type to represent the magnitude of a time span. This is an "accurate"
+//! duration represented as seconds and nanoseconds, and does not represent "nominal" components
+//! such as days or months.
+//!
+//! The [`TimeDelta`] type was previously named `Duration` (and is still available as a type alias
+//! with that name). A notable difference with the similar [`core::time::Duration`] is that it is a
+//! signed value instead of unsigned.
+//!
+//! Chrono currently only supports a small number of operations with [`core::time::Duration`].
+//! You can convert between both types with the [`TimeDelta::from_std`] and [`TimeDelta::to_std`]
+//! methods.
+//!
+//! ### Date and Time
+//!
+//! Chrono provides a [`DateTime`] type to represent a date and a time in a timezone.
+//!
+//! For more abstract moment-in-time tracking such as internal timekeeping that is unconcerned with
+//! timezones, consider [`std::time::SystemTime`], which tracks your system clock, or
+//! [`std::time::Instant`], which is an opaque but monotonically-increasing representation of a
+//! moment in time.
+//!
+//! [`DateTime`] is timezone-aware and must be constructed from a [`TimeZone`] object, which defines
+//! how the local date is converted to and back from the UTC date.
+//! There are three well-known [`TimeZone`] implementations:
+//!
+//! * [`Utc`] specifies the UTC time zone. It is most efficient.
+//!
+//! * [`Local`] specifies the system local time zone.
+//!
+//! * [`FixedOffset`] specifies an arbitrary, fixed time zone such as UTC+09:00 or UTC-10:30.
+//!   This often results from the parsed textual date and time. Since it stores the most information
+//!   and does not depend on the system environment, you would want to normalize other `TimeZone`s
+//!   into this type.
+//!
+//! [`DateTime`]s with different [`TimeZone`] types are distinct and do not mix, but can be
+//! converted to each other using the [`DateTime::with_timezone`] method.
+//!
+//! You can get the current date and time in the UTC time zone ([`Utc::now()`]) or in the local time
+//! zone ([`Local::now()`]).
+//!
+//! ```
+//! # #[cfg(feature = "now")] {
+//! use chrono::prelude::*;
+//!
+//! let utc: DateTime<Utc> = Utc::now(); // e.g. `2014-11-28T12:45:59.324310806Z`
+//! # let _ = utc;
+//! # }
+//! ```
+//!
+//! ```
+//! # #[cfg(feature = "clock")] {
+//! use chrono::prelude::*;
+//!
+//! let local: DateTime<Local> = Local::now(); // e.g. `2014-11-28T21:45:59.324310806+09:00`
+//! # let _ = local;
+//! # }
+//! ```
+//!
+//! Alternatively, you can create your own date and time. This is a bit verbose due to Rust's lack
+//! of function and method overloading, but in turn we get a rich combination of initialization
+//! methods.
+//!
+//! ```
+//! use chrono::offset::MappedLocalTime;
+//! use chrono::prelude::*;
+//!
+//! # fn doctest() -> Option<()> {
+//!
+//! let dt = Utc.with_ymd_and_hms(2014, 7, 8, 9, 10, 11).unwrap(); // `2014-07-08T09:10:11Z`
+//! assert_eq!(
+//!     dt,
+//!     NaiveDate::from_ymd_opt(2014, 7, 8)?
+//!         .and_hms_opt(9, 10, 11)?
+//!         .and_utc()
+//! );
+//!
+//! // July 8 is 188th day of the year 2014 (`o` for "ordinal")
+//! assert_eq!(dt, NaiveDate::from_yo_opt(2014, 189)?.and_hms_opt(9, 10, 11)?.and_utc());
+//! // July 8 is Tuesday in ISO week 28 of the year 2014.
+//! assert_eq!(
+//!     dt,
+//!     NaiveDate::from_isoywd_opt(2014, 28, Weekday::Tue)?.and_hms_opt(9, 10, 11)?.and_utc()
+//! );
+//!
+//! let dt = NaiveDate::from_ymd_opt(2014, 7, 8)?
+//!     .and_hms_milli_opt(9, 10, 11, 12)?
+//!     .and_utc(); // `2014-07-08T09:10:11.012Z`
+//! assert_eq!(
+//!     dt,
+//!     NaiveDate::from_ymd_opt(2014, 7, 8)?
+//!         .and_hms_micro_opt(9, 10, 11, 12_000)?
+//!         .and_utc()
+//! );
+//! assert_eq!(
+//!     dt,
+//!     NaiveDate::from_ymd_opt(2014, 7, 8)?
+//!         .and_hms_nano_opt(9, 10, 11, 12_000_000)?
+//!         .and_utc()
+//! );
+//!
+//! // dynamic verification
+//! assert_eq!(
+//!     Utc.with_ymd_and_hms(2014, 7, 8, 21, 15, 33),
+//!     MappedLocalTime::Single(
+//!         NaiveDate::from_ymd_opt(2014, 7, 8)?.and_hms_opt(21, 15, 33)?.and_utc()
+//!     )
+//! );
+//! assert_eq!(Utc.with_ymd_and_hms(2014, 7, 8, 80, 15, 33), MappedLocalTime::None);
+//! assert_eq!(Utc.with_ymd_and_hms(2014, 7, 38, 21, 15, 33), MappedLocalTime::None);
+//!
+//! # #[cfg(feature = "clock")] {
+//! // other time zone objects can be used to construct a local datetime.
+//! // obviously, `local_dt` is normally different from `dt`, but `fixed_dt` should be identical.
+//! let local_dt = Local
+//!     .from_local_datetime(
+//!         &NaiveDate::from_ymd_opt(2014, 7, 8).unwrap().and_hms_milli_opt(9, 10, 11, 12).unwrap(),
+//!     )
+//!     .unwrap();
+//! let fixed_dt = FixedOffset::east_opt(9 * 3600)
+//!     .unwrap()
+//!     .from_local_datetime(
+//!         &NaiveDate::from_ymd_opt(2014, 7, 8)
+//!             .unwrap()
+//!             .and_hms_milli_opt(18, 10, 11, 12)
+//!             .unwrap(),
+//!     )
+//!     .unwrap();
+//! assert_eq!(dt, fixed_dt);
+//! # let _ = local_dt;
+//! # }
+//! # Some(())
+//! # }
+//! # doctest().unwrap();
+//! ```
+//!
+//! Various properties are available to the date and time, and can be altered individually. Most of
+//! them are defined in the traits [`Datelike`] and [`Timelike`] which you should `use` before.
+//! Addition and subtraction is also supported.
+//! The following illustrates most supported operations to the date and time:
+//!
+//! ```rust
+//! use chrono::prelude::*;
+//! use chrono::TimeDelta;
+//!
+//! // assume this returned `2014-11-28T21:45:59.324310806+09:00`:
+//! let dt = FixedOffset::east_opt(9 * 3600)
+//!     .unwrap()
+//!     .from_local_datetime(
+//!         &NaiveDate::from_ymd_opt(2014, 11, 28)
+//!             .unwrap()
+//!             .and_hms_nano_opt(21, 45, 59, 324310806)
+//!             .unwrap(),
+//!     )
+//!     .unwrap();
+//!
+//! // property accessors
+//! assert_eq!((dt.year(), dt.month(), dt.day()), (2014, 11, 28));
+//! assert_eq!((dt.month0(), dt.day0()), (10, 27)); // for unfortunate souls
+//! assert_eq!((dt.hour(), dt.minute(), dt.second()), (21, 45, 59));
+//! assert_eq!(dt.weekday(), Weekday::Fri);
+//! assert_eq!(dt.weekday().number_from_monday(), 5); // Mon=1, ..., Sun=7
+//! assert_eq!(dt.ordinal(), 332); // the day of year
+//! assert_eq!(dt.num_days_from_ce(), 735565); // the number of days from and including Jan 1, 1
+//!
+//! // time zone accessor and manipulation
+//! assert_eq!(dt.offset().fix().local_minus_utc(), 9 * 3600);
+//! assert_eq!(dt.timezone(), FixedOffset::east_opt(9 * 3600).unwrap());
+//! assert_eq!(
+//!     dt.with_timezone(&Utc),
+//!     NaiveDate::from_ymd_opt(2014, 11, 28)
+//!         .unwrap()
+//!         .and_hms_nano_opt(12, 45, 59, 324310806)
+//!         .unwrap()
+//!         .and_utc()
+//! );
+//!
+//! // a sample of property manipulations (validates dynamically)
+//! assert_eq!(dt.with_day(29).unwrap().weekday(), Weekday::Sat); // 2014-11-29 is Saturday
+//! assert_eq!(dt.with_day(32), None);
+//! assert_eq!(dt.with_year(-300).unwrap().num_days_from_ce(), -109606); // November 29, 301 BCE
+//!
+//! // arithmetic operations
+//! let dt1 = Utc.with_ymd_and_hms(2014, 11, 14, 8, 9, 10).unwrap();
+//! let dt2 = Utc.with_ymd_and_hms(2014, 11, 14, 10, 9, 8).unwrap();
+//! assert_eq!(dt1.signed_duration_since(dt2), TimeDelta::try_seconds(-2 * 3600 + 2).unwrap());
+//! assert_eq!(dt2.signed_duration_since(dt1), TimeDelta::try_seconds(2 * 3600 - 2).unwrap());
+//! assert_eq!(
+//!     Utc.with_ymd_and_hms(1970, 1, 1, 0, 0, 0).unwrap()
+//!         + TimeDelta::try_seconds(1_000_000_000).unwrap(),
+//!     Utc.with_ymd_and_hms(2001, 9, 9, 1, 46, 40).unwrap()
+//! );
+//! assert_eq!(
+//!     Utc.with_ymd_and_hms(1970, 1, 1, 0, 0, 0).unwrap()
+//!         - TimeDelta::try_seconds(1_000_000_000).unwrap(),
+//!     Utc.with_ymd_and_hms(1938, 4, 24, 22, 13, 20).unwrap()
+//! );
+//! ```
+//!
+//! ### Formatting and Parsing
+//!
+//! Formatting is done via the [`format`](DateTime::format()) method, which format is equivalent to
+//! the familiar `strftime` format.
+//!
+//! See [`format::strftime`](format::strftime#specifiers) documentation for full syntax and list of
+//! specifiers.
+//!
+//! The default `to_string` method and `{:?}` specifier also give a reasonable representation.
+//! Chrono also provides [`to_rfc2822`](DateTime::to_rfc2822) and
+//! [`to_rfc3339`](DateTime::to_rfc3339) methods for well-known formats.
+//!
+//! Chrono now also provides date formatting in almost any language without the help of an
+//! additional C library. This functionality is under the feature `unstable-locales`:
+//!
+//! ```toml
+//! chrono = { version = "0.4", features = ["unstable-locales"] }
+//! ```
+//!
+//! The `unstable-locales` feature requires and implies at least the `alloc` feature.
+//!
+//! ```rust
+//! # #[allow(unused_imports)]
+//! use chrono::prelude::*;
+//!
+//! # #[cfg(all(feature = "unstable-locales", feature = "alloc"))]
+//! # fn test() {
+//! let dt = Utc.with_ymd_and_hms(2014, 11, 28, 12, 0, 9).unwrap();
+//! assert_eq!(dt.format("%Y-%m-%d %H:%M:%S").to_string(), "2014-11-28 12:00:09");
+//! assert_eq!(dt.format("%a %b %e %T %Y").to_string(), "Fri Nov 28 12:00:09 2014");
+//! assert_eq!(
+//!     dt.format_localized("%A %e %B %Y, %T", Locale::fr_BE).to_string(),
+//!     "vendredi 28 novembre 2014, 12:00:09"
+//! );
+//!
+//! assert_eq!(dt.format("%a %b %e %T %Y").to_string(), dt.format("%c").to_string());
+//! assert_eq!(dt.to_string(), "2014-11-28 12:00:09 UTC");
+//! assert_eq!(dt.to_rfc2822(), "Fri, 28 Nov 2014 12:00:09 +0000");
+//! assert_eq!(dt.to_rfc3339(), "2014-11-28T12:00:09+00:00");
+//! assert_eq!(format!("{:?}", dt), "2014-11-28T12:00:09Z");
+//!
+//! // Note that milli/nanoseconds are only printed if they are non-zero
+//! let dt_nano = NaiveDate::from_ymd_opt(2014, 11, 28)
+//!     .unwrap()
+//!     .and_hms_nano_opt(12, 0, 9, 1)
+//!     .unwrap()
+//!     .and_utc();
+//! assert_eq!(format!("{:?}", dt_nano), "2014-11-28T12:00:09.000000001Z");
+//! # }
+//! # #[cfg(not(all(feature = "unstable-locales", feature = "alloc")))]
+//! # fn test() {}
+//! # if cfg!(all(feature = "unstable-locales", feature = "alloc")) {
+//! #    test();
+//! # }
+//! ```
+//!
+//! Parsing can be done with two methods:
+//!
+//! 1. The standard [`FromStr`](std::str::FromStr) trait (and [`parse`](str::parse) method on a
+//!    string) can be used for parsing `DateTime<FixedOffset>`, `DateTime<Utc>` and
+//!    `DateTime<Local>` values. This parses what the `{:?}` ([`std::fmt::Debug`] format specifier
+//!    prints, and requires the offset to be present.
+//!
+//! 2. [`DateTime::parse_from_str`] parses a date and time with offsets and returns
+//!    `DateTime<FixedOffset>`. This should be used when the offset is a part of input and the
+//!    caller cannot guess that. It *cannot* be used when the offset can be missing.
+//!    [`DateTime::parse_from_rfc2822`] and [`DateTime::parse_from_rfc3339`] are similar but for
+//!    well-known formats.
+//!
+//! More detailed control over the parsing process is available via [`format`](mod@format) module.
+//!
+//! ```rust
+//! use chrono::prelude::*;
+//!
+//! let dt = Utc.with_ymd_and_hms(2014, 11, 28, 12, 0, 9).unwrap();
+//! let fixed_dt = dt.with_timezone(&FixedOffset::east_opt(9 * 3600).unwrap());
+//!
+//! // method 1
+//! assert_eq!("2014-11-28T12:00:09Z".parse::<DateTime<Utc>>(), Ok(dt.clone()));
+//! assert_eq!("2014-11-28T21:00:09+09:00".parse::<DateTime<Utc>>(), Ok(dt.clone()));
+//! assert_eq!("2014-11-28T21:00:09+09:00".parse::<DateTime<FixedOffset>>(), Ok(fixed_dt.clone()));
+//!
+//! // method 2
+//! assert_eq!(
+//!     DateTime::parse_from_str("2014-11-28 21:00:09 +09:00", "%Y-%m-%d %H:%M:%S %z"),
+//!     Ok(fixed_dt.clone())
+//! );
+//! assert_eq!(
+//!     DateTime::parse_from_rfc2822("Fri, 28 Nov 2014 21:00:09 +0900"),
+//!     Ok(fixed_dt.clone())
+//! );
+//! assert_eq!(DateTime::parse_from_rfc3339("2014-11-28T21:00:09+09:00"), Ok(fixed_dt.clone()));
+//!
+//! // oops, the year is missing!
+//! assert!(DateTime::parse_from_str("Fri Nov 28 12:00:09", "%a %b %e %T %Y").is_err());
+//! // oops, the format string does not include the year at all!
+//! assert!(DateTime::parse_from_str("Fri Nov 28 12:00:09", "%a %b %e %T").is_err());
+//! // oops, the weekday is incorrect!
+//! assert!(DateTime::parse_from_str("Sat Nov 28 12:00:09 2014", "%a %b %e %T %Y").is_err());
+//! ```
+//!
+//! Again: See [`format::strftime`](format::strftime#specifiers) documentation for full syntax and
+//! list of specifiers.
+//!
+//! ### Conversion from and to EPOCH timestamps
+//!
+//! Use [`DateTime::from_timestamp(seconds, nanoseconds)`](DateTime::from_timestamp)
+//! to construct a [`DateTime<Utc>`] from a UNIX timestamp
+//! (seconds, nanoseconds that passed since January 1st 1970).
+//!
+//! Use [`DateTime.timestamp`](DateTime::timestamp) to get the timestamp (in seconds)
+//! from a [`DateTime`]. Additionally, you can use
+//! [`DateTime.timestamp_subsec_nanos`](DateTime::timestamp_subsec_nanos)
+//! to get the number of additional number of nanoseconds.
+//!
+//! ```
+//! # #[cfg(feature = "alloc")] {
+//! // We need the trait in scope to use Utc::timestamp().
+//! use chrono::{DateTime, Utc};
+//!
+//! // Construct a datetime from epoch:
+//! let dt: DateTime<Utc> = DateTime::from_timestamp(1_500_000_000, 0).unwrap();
+//! assert_eq!(dt.to_rfc2822(), "Fri, 14 Jul 2017 02:40:00 +0000");
+//!
+//! // Get epoch value from a datetime:
+//! let dt = DateTime::parse_from_rfc2822("Fri, 14 Jul 2017 02:40:00 +0000").unwrap();
+//! assert_eq!(dt.timestamp(), 1_500_000_000);
+//! # }
+//! ```
+//!
+//! ### Naive date and time
+//!
+//! Chrono provides naive counterparts to `Date`, (non-existent) `Time` and `DateTime` as
+//! [`NaiveDate`], [`NaiveTime`] and [`NaiveDateTime`] respectively.
+//!
+//! They have almost equivalent interfaces as their timezone-aware twins, but are not associated to
+//! time zones obviously and can be quite low-level. They are mostly useful for building blocks for
+//! higher-level types.
+//!
+//! Timezone-aware `DateTime` and `Date` types have two methods returning naive versions:
+//! [`naive_local`](DateTime::naive_local) returns a view to the naive local time,
+//! and [`naive_utc`](DateTime::naive_utc) returns a view to the naive UTC time.
+//!
+//! ## Limitations
+//!
+//! * Only the proleptic Gregorian calendar (i.e. extended to support older dates) is supported.
+//! * Date types are limited to about +/- 262,000 years from the common epoch.
+//! * Time types are limited to nanosecond accuracy.
+//! * Leap seconds can be represented, but Chrono does not fully support them.
+//!   See [Leap Second Handling](NaiveTime#leap-second-handling).
+//!
+//! ## Rust version requirements
+//!
+//! The Minimum Supported Rust Version (MSRV) is currently **Rust 1.61.0**.
+//!
+//! The MSRV is explicitly tested in CI. It may be bumped in minor releases, but this is not done
+//! lightly.
+//!
+//! ## Relation between chrono and time 0.1
+//!
+//! Rust first had a `time` module added to `std` in its 0.7 release. It later moved to
+//! `libextra`, and then to a `libtime` library shipped alongside the standard library. In 2014
+//! work on chrono started in order to provide a full-featured date and time library in Rust.
+//! Some improvements from chrono made it into the standard library; notably, `chrono::Duration`
+//! was included as `std::time::Duration` ([rust#15934]) in 2014.
+//!
+//! In preparation of Rust 1.0 at the end of 2014 `libtime` was moved out of the Rust distro and
+//! into the `time` crate to eventually be redesigned ([rust#18832], [rust#18858]), like the
+//! `num` and `rand` crates. Of course chrono kept its dependency on this `time` crate. `time`
+//! started re-exporting `std::time::Duration` during this period. Later, the standard library was
+//! changed to have a more limited unsigned `Duration` type ([rust#24920], [RFC 1040]), while the
+//! `time` crate kept the full functionality with `time::Duration`. `time::Duration` had been a
+//! part of chrono's public API.
+//!
+//! By 2016 `time` 0.1 lived under the `rust-lang-deprecated` organisation and was not actively
+//! maintained ([time#136]). chrono absorbed the platform functionality and `Duration` type of the
+//! `time` crate in [chrono#478] (the work started in [chrono#286]). In order to preserve
+//! compatibility with downstream crates depending on `time` and `chrono` sharing a `Duration`
+//! type, chrono kept depending on time 0.1. chrono offered the option to opt out of the `time`
+//! dependency by disabling the `oldtime` feature (swapping it out for an effectively similar
+//! chrono type). In 2019, @jhpratt took over maintenance on the `time` crate and released what
+//! amounts to a new crate as `time` 0.2.
+//!
+//! [rust#15934]: https://github.com/rust-lang/rust/pull/15934
+//! [rust#18832]: https://github.com/rust-lang/rust/pull/18832#issuecomment-62448221
+//! [rust#18858]: https://github.com/rust-lang/rust/pull/18858
+//! [rust#24920]: https://github.com/rust-lang/rust/pull/24920
+//! [RFC 1040]: https://rust-lang.github.io/rfcs/1040-duration-reform.html
+//! [time#136]: https://github.com/time-rs/time/issues/136
+//! [chrono#286]: https://github.com/chronotope/chrono/pull/286
+//! [chrono#478]: https://github.com/chronotope/chrono/pull/478
+//!
+//! ## Security advisories
+//!
+//! In November of 2020 [CVE-2020-26235] and [RUSTSEC-2020-0071] were opened against the `time` crate.
+//! @quininer had found that calls to `localtime_r` may be unsound ([chrono#499]). Eventually, almost
+//! a year later, this was also made into a security advisory against chrono as [RUSTSEC-2020-0159],
+//! which had platform code similar to `time`.
+//!
+//! On Unix-like systems a process is given a timezone id or description via the `TZ` environment
+//! variable. We need this timezone data to calculate the current local time from a value that is
+//! in UTC, such as the time from the system clock. `time` 0.1 and chrono used the POSIX function
+//! `localtime_r` to do the conversion to local time, which reads the `TZ` variable.
+//!
+//! Rust assumes the environment to be writable and uses locks to access it from multiple threads.
+//! Some other programming languages and libraries use similar locking strategies, but these are
+//! typically not shared across languages. More importantly, POSIX declares modifying the
+//! environment in a multi-threaded process as unsafe, and `getenv` in libc can't be changed to
+//! take a lock because it returns a pointer to the data (see [rust#27970] for more discussion).
+//!
+//! Since version 4.20 chrono no longer uses `localtime_r`, instead using Rust code to query the
+//! timezone (from the `TZ` variable or via `iana-time-zone` as a fallback) and work with data
+//! from the system timezone database directly. The code for this was forked from the [tz-rs crate]
+//! by @x-hgg-x. As such, chrono now respects the Rust lock when reading the `TZ` environment
+//! variable. In general, code should avoid modifying the environment.
+//!
+//! [CVE-2020-26235]: https://nvd.nist.gov/vuln/detail/CVE-2020-26235
+//! [RUSTSEC-2020-0071]: https://rustsec.org/advisories/RUSTSEC-2020-0071
+//! [chrono#499]: https://github.com/chronotope/chrono/pull/499
+//! [RUSTSEC-2020-0159]: https://rustsec.org/advisories/RUSTSEC-2020-0159.html
+//! [rust#27970]: https://github.com/rust-lang/rust/issues/27970
+//! [chrono#677]: https://github.com/chronotope/chrono/pull/677
+//! [tz-rs crate]: https://crates.io/crates/tz-rs
+//!
+//! ## Removing time 0.1
+//!
+//! Because time 0.1 has been unmaintained for years, however, the security advisory mentioned
+//! above has not been addressed. While chrono maintainers were careful not to break backwards
+//! compatibility with the `time::Duration` type, there has been a long stream of issues from
+//! users inquiring about the time 0.1 dependency with the vulnerability. We investigated the
+//! potential breakage of removing the time 0.1 dependency in [chrono#1095] using a crater-like
+//! experiment and determined that the potential for breaking (public) dependencies is very low.
+//! We reached out to those few crates that did still depend on compatibility with time 0.1.
+//!
+//! As such, for chrono 0.4.30 we have decided to swap out the time 0.1 `Duration` implementation
+//! for a local one that will offer a strict superset of the existing API going forward. This
+//! will prevent most downstream users from being affected by the security vulnerability in time
+//! 0.1 while minimizing the ecosystem impact of semver-incompatible version churn.
+//!
+//! [chrono#1095]: https://github.com/chronotope/chrono/pull/1095
+
+#![doc(html_root_url = "https://docs.rs/chrono/latest/", test(attr(deny(warnings))))]
+#![deny(missing_docs)]
+#![deny(missing_debug_implementations)]
+#![warn(unreachable_pub)]
+#![deny(clippy::tests_outside_test_module)]
+#![cfg_attr(not(any(feature = "std", test)), no_std)]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+
+#[cfg(feature = "alloc")]
+extern crate alloc;
+
+mod time_delta;
+#[cfg(feature = "std")]
+#[doc(no_inline)]
+pub use time_delta::OutOfRangeError;
+pub use time_delta::TimeDelta;
+
+/// Alias of [`TimeDelta`].
+pub type Duration = TimeDelta;
+
+use core::fmt;
+
+/// A convenience module appropriate for glob imports (`use chrono::prelude::*;`).
+pub mod prelude {
+    #[allow(deprecated)]
+    pub use crate::Date;
+    #[cfg(feature = "clock")]
+    pub use crate::Local;
+    #[cfg(all(feature = "unstable-locales", feature = "alloc"))]
+    pub use crate::Locale;
+    pub use crate::SubsecRound;
+    pub use crate::{DateTime, SecondsFormat};
+    pub use crate::{Datelike, Month, Timelike, Weekday};
+    pub use crate::{FixedOffset, Utc};
+    pub use crate::{NaiveDate, NaiveDateTime, NaiveTime};
+    pub use crate::{Offset, TimeZone};
+}
+
+mod date;
+#[allow(deprecated)]
+pub use date::Date;
+#[doc(no_inline)]
+#[allow(deprecated)]
+pub use date::{MAX_DATE, MIN_DATE};
+
+mod datetime;
+pub use datetime::DateTime;
+#[allow(deprecated)]
+#[doc(no_inline)]
+pub use datetime::{MAX_DATETIME, MIN_DATETIME};
+
+pub mod format;
+/// L10n locales.
+#[cfg(feature = "unstable-locales")]
+pub use format::Locale;
+pub use format::{ParseError, ParseResult, SecondsFormat};
+
+pub mod naive;
+#[doc(inline)]
+pub use naive::{Days, NaiveDate, NaiveDateTime, NaiveTime};
+pub use naive::{IsoWeek, NaiveWeek};
+
+pub mod offset;
+#[cfg(feature = "clock")]
+#[doc(inline)]
+pub use offset::Local;
+#[doc(hidden)]
+pub use offset::LocalResult;
+pub use offset::MappedLocalTime;
+#[doc(inline)]
+pub use offset::{FixedOffset, Offset, TimeZone, Utc};
+
+pub mod round;
+pub use round::{DurationRound, RoundingError, SubsecRound};
+
+mod weekday;
+#[doc(no_inline)]
+pub use weekday::ParseWeekdayError;
+pub use weekday::Weekday;
+
+mod weekday_set;
+pub use weekday_set::WeekdaySet;
+
+mod month;
+#[doc(no_inline)]
+pub use month::ParseMonthError;
+pub use month::{Month, Months};
+
+mod traits;
+pub use traits::{Datelike, Timelike};
+
+#[cfg(feature = "__internal_bench")]
+#[doc(hidden)]
+pub use naive::__BenchYearFlags;
+
+/// Serialization/Deserialization with serde
+///
+/// The [`DateTime`] type has default implementations for (de)serializing to/from the [RFC 3339]
+/// format. This module provides alternatives for serializing to timestamps.
+///
+/// The alternatives are for use with serde's [`with` annotation] combined with the module name.
+/// Alternatively the individual `serialize` and `deserialize` functions in each module can be used
+/// with serde's [`serialize_with`] and [`deserialize_with`] annotations.
+///
+/// *Available on crate feature 'serde' only.*
+///
+/// [RFC 3339]: https://tools.ietf.org/html/rfc3339
+/// [`with` annotation]: https://serde.rs/field-attrs.html#with
+/// [`serialize_with`]: https://serde.rs/field-attrs.html#serialize_with
+/// [`deserialize_with`]: https://serde.rs/field-attrs.html#deserialize_with
+#[cfg(feature = "serde")]
+pub mod serde {
+    use core::fmt;
+    use serde::de;
+
+    pub use super::datetime::serde::*;
+
+    /// Create a custom `de::Error` with `SerdeError::InvalidTimestamp`.
+    pub(crate) fn invalid_ts<E, T>(value: T) -> E
+    where
+        E: de::Error,
+        T: fmt::Display,
+    {
+        E::custom(SerdeError::InvalidTimestamp(value))
+    }
+
+    enum SerdeError<T: fmt::Display> {
+        InvalidTimestamp(T),
+    }
+
+    impl<T: fmt::Display> fmt::Display for SerdeError<T> {
+        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            match self {
+                SerdeError::InvalidTimestamp(ts) => {
+                    write!(f, "value is not a legal timestamp: {ts}")
+                }
+            }
+        }
+    }
+}
+
+/// Zero-copy serialization/deserialization with rkyv.
+///
+/// This module re-exports the `Archived*` versions of chrono's types.
+#[cfg(any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
+pub mod rkyv {
+    pub use crate::datetime::ArchivedDateTime;
+    pub use crate::month::ArchivedMonth;
+    pub use crate::naive::date::ArchivedNaiveDate;
+    pub use crate::naive::datetime::ArchivedNaiveDateTime;
+    pub use crate::naive::isoweek::ArchivedIsoWeek;
+    pub use crate::naive::time::ArchivedNaiveTime;
+    pub use crate::offset::fixed::ArchivedFixedOffset;
+    #[cfg(feature = "clock")]
+    pub use crate::offset::local::ArchivedLocal;
+    pub use crate::offset::utc::ArchivedUtc;
+    pub use crate::time_delta::ArchivedTimeDelta;
+    pub use crate::weekday::ArchivedWeekday;
+
+    /// Alias of [`ArchivedTimeDelta`]
+    pub type ArchivedDuration = ArchivedTimeDelta;
+}
+
+/// Out of range error type used in various converting APIs
+#[derive(Clone, Copy, Hash, PartialEq, Eq)]
+pub struct OutOfRange {
+    _private: (),
+}
+
+impl OutOfRange {
+    const fn new() -> OutOfRange {
+        OutOfRange { _private: () }
+    }
+}
+
+impl fmt::Display for OutOfRange {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "out of range")
+    }
+}
+
+impl fmt::Debug for OutOfRange {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "out of range")
+    }
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for OutOfRange {}
+
+/// Workaround because `?` is not (yet) available in const context.
+#[macro_export]
+#[doc(hidden)]
+macro_rules! try_opt {
+    ($e:expr) => {
+        match $e {
+            Some(v) => v,
+            None => return None,
+        }
+    };
+}
+
+/// Workaround because `.expect()` is not (yet) available in const context.
+pub(crate) const fn expect<T: Copy>(opt: Option<T>, msg: &str) -> T {
+    match opt {
+        Some(val) => val,
+        None => panic!("{}", msg),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[cfg(feature = "clock")]
+    use crate::{DateTime, FixedOffset, Local, NaiveDate, NaiveDateTime, NaiveTime, Utc};
+
+    #[test]
+    #[allow(deprecated)]
+    #[cfg(feature = "clock")]
+    fn test_type_sizes() {
+        use core::mem::size_of;
+        assert_eq!(size_of::<NaiveDate>(), 4);
+        assert_eq!(size_of::<Option<NaiveDate>>(), 4);
+        assert_eq!(size_of::<NaiveTime>(), 8);
+        assert_eq!(size_of::<Option<NaiveTime>>(), 12);
+        assert_eq!(size_of::<NaiveDateTime>(), 12);
+        assert_eq!(size_of::<Option<NaiveDateTime>>(), 12);
+
+        assert_eq!(size_of::<DateTime<Utc>>(), 12);
+        assert_eq!(size_of::<DateTime<FixedOffset>>(), 16);
+        assert_eq!(size_of::<DateTime<Local>>(), 16);
+        assert_eq!(size_of::<Option<DateTime<FixedOffset>>>(), 16);
+    }
+}

patch/chrono-0.4.41/src/month.rs

@@ -0,0 +1,472 @@
+use core::fmt;
+
+#[cfg(any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
+use rkyv::{Archive, Deserialize, Serialize};
+
+use crate::OutOfRange;
+use crate::naive::NaiveDate;
+
+/// The month of the year.
+///
+/// This enum is just a convenience implementation.
+/// The month in dates created by DateLike objects does not return this enum.
+///
+/// It is possible to convert from a date to a month independently
+/// ```
+/// use chrono::prelude::*;
+/// let date = Utc.with_ymd_and_hms(2019, 10, 28, 9, 10, 11).unwrap();
+/// // `2019-10-28T09:10:11Z`
+/// let month = Month::try_from(u8::try_from(date.month()).unwrap()).ok();
+/// assert_eq!(month, Some(Month::October))
+/// ```
+/// Or from a Month to an integer usable by dates
+/// ```
+/// # use chrono::prelude::*;
+/// let month = Month::January;
+/// let dt = Utc.with_ymd_and_hms(2019, month.number_from_month(), 28, 9, 10, 11).unwrap();
+/// assert_eq!((dt.year(), dt.month(), dt.day()), (2019, 1, 28));
+/// ```
+/// Allows mapping from and to month, from 1-January to 12-December.
+/// Can be Serialized/Deserialized with serde
+// Actual implementation is zero-indexed, API intended as 1-indexed for more intuitive behavior.
+#[derive(PartialEq, Eq, Copy, Clone, Debug, Hash, PartialOrd, Ord)]
+#[cfg_attr(
+    any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
+    derive(Archive, Deserialize, Serialize),
+    rkyv(compare(PartialEq, PartialOrd)),
+    rkyv(attr(derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)))
+)]
+#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
+#[cfg_attr(all(feature = "arbitrary", feature = "std"), derive(arbitrary::Arbitrary))]
+pub enum Month {
+    /// January
+    January = 0,
+    /// February
+    February = 1,
+    /// March
+    March = 2,
+    /// April
+    April = 3,
+    /// May
+    May = 4,
+    /// June
+    June = 5,
+    /// July
+    July = 6,
+    /// August
+    August = 7,
+    /// September
+    September = 8,
+    /// October
+    October = 9,
+    /// November
+    November = 10,
+    /// December
+    December = 11,
+}
+
+impl Month {
+    /// The next month.
+    ///
+    /// `m`:        | `January`  | `February` | `...` | `December`
+    /// ----------- | ---------  | ---------- | --- | ---------
+    /// `m.succ()`: | `February` | `March`    | `...` | `January`
+    #[inline]
+    #[must_use]
+    pub const fn succ(&self) -> Month {
+        match *self {
+            Month::January => Month::February,
+            Month::February => Month::March,
+            Month::March => Month::April,
+            Month::April => Month::May,
+            Month::May => Month::June,
+            Month::June => Month::July,
+            Month::July => Month::August,
+            Month::August => Month::September,
+            Month::September => Month::October,
+            Month::October => Month::November,
+            Month::November => Month::December,
+            Month::December => Month::January,
+        }
+    }
+
+    /// The previous month.
+    ///
+    /// `m`:        | `January`  | `February` | `...` | `December`
+    /// ----------- | ---------  | ---------- | --- | ---------
+    /// `m.pred()`: | `December` | `January`  | `...` | `November`
+    #[inline]
+    #[must_use]
+    pub const fn pred(&self) -> Month {
+        match *self {
+            Month::January => Month::December,
+            Month::February => Month::January,
+            Month::March => Month::February,
+            Month::April => Month::March,
+            Month::May => Month::April,
+            Month::June => Month::May,
+            Month::July => Month::June,
+            Month::August => Month::July,
+            Month::September => Month::August,
+            Month::October => Month::September,
+            Month::November => Month::October,
+            Month::December => Month::November,
+        }
+    }
+
+    /// Returns a month-of-year number starting from January = 1.
+    ///
+    /// `m`:                     | `January` | `February` | `...` | `December`
+    /// -------------------------| --------- | ---------- | --- | -----
+    /// `m.number_from_month()`: | 1         | 2          | `...` | 12
+    #[inline]
+    #[must_use]
+    pub const fn number_from_month(&self) -> u32 {
+        match *self {
+            Month::January => 1,
+            Month::February => 2,
+            Month::March => 3,
+            Month::April => 4,
+            Month::May => 5,
+            Month::June => 6,
+            Month::July => 7,
+            Month::August => 8,
+            Month::September => 9,
+            Month::October => 10,
+            Month::November => 11,
+            Month::December => 12,
+        }
+    }
+
+    /// Get the name of the month
+    ///
+    /// ```
+    /// use chrono::Month;
+    ///
+    /// assert_eq!(Month::January.name(), "January")
+    /// ```
+    #[must_use]
+    pub const fn name(&self) -> &'static str {
+        match *self {
+            Month::January => "January",
+            Month::February => "February",
+            Month::March => "March",
+            Month::April => "April",
+            Month::May => "May",
+            Month::June => "June",
+            Month::July => "July",
+            Month::August => "August",
+            Month::September => "September",
+            Month::October => "October",
+            Month::November => "November",
+            Month::December => "December",
+        }
+    }
+
+    /// Get the length in days of the month
+    ///
+    /// Yields `None` if `year` is out of range for `NaiveDate`.
+    pub fn num_days(&self, year: i32) -> Option<u8> {
+        Some(match *self {
+            Month::January => 31,
+            Month::February => match NaiveDate::from_ymd_opt(year, 2, 1)?.leap_year() {
+                true => 29,
+                false => 28,
+            },
+            Month::March => 31,
+            Month::April => 30,
+            Month::May => 31,
+            Month::June => 30,
+            Month::July => 31,
+            Month::August => 31,
+            Month::September => 30,
+            Month::October => 31,
+            Month::November => 30,
+            Month::December => 31,
+        })
+    }
+}
+
+impl TryFrom<u8> for Month {
+    type Error = OutOfRange;
+
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
+        match value {
+            1 => Ok(Month::January),
+            2 => Ok(Month::February),
+            3 => Ok(Month::March),
+            4 => Ok(Month::April),
+            5 => Ok(Month::May),
+            6 => Ok(Month::June),
+            7 => Ok(Month::July),
+            8 => Ok(Month::August),
+            9 => Ok(Month::September),
+            10 => Ok(Month::October),
+            11 => Ok(Month::November),
+            12 => Ok(Month::December),
+            _ => Err(OutOfRange::new()),
+        }
+    }
+}
+
+impl num_traits::FromPrimitive for Month {
+    /// Returns an `Option<Month>` from a i64, assuming a 1-index, January = 1.
+    ///
+    /// `Month::from_i64(n: i64)`: | `1`                  | `2`                   | ... | `12`
+    /// ---------------------------| -------------------- | --------------------- | ... | -----
+    /// ``:                        | Some(Month::January) | Some(Month::February) | ... | Some(Month::December)
+    #[inline]
+    fn from_u64(n: u64) -> Option<Month> {
+        Self::from_u32(n as u32)
+    }
+
+    #[inline]
+    fn from_i64(n: i64) -> Option<Month> {
+        Self::from_u32(n as u32)
+    }
+
+    #[inline]
+    fn from_u32(n: u32) -> Option<Month> {
+        match n {
+            1 => Some(Month::January),
+            2 => Some(Month::February),
+            3 => Some(Month::March),
+            4 => Some(Month::April),
+            5 => Some(Month::May),
+            6 => Some(Month::June),
+            7 => Some(Month::July),
+            8 => Some(Month::August),
+            9 => Some(Month::September),
+            10 => Some(Month::October),
+            11 => Some(Month::November),
+            12 => Some(Month::December),
+            _ => None,
+        }
+    }
+}
+
+/// A duration in calendar months
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, PartialOrd, Ord)]
+#[cfg_attr(all(feature = "arbitrary", feature = "std"), derive(arbitrary::Arbitrary))]
+pub struct Months(pub(crate) u32);
+
+impl Months {
+    /// Construct a new `Months` from a number of months
+    pub const fn new(num: u32) -> Self {
+        Self(num)
+    }
+
+    /// Returns the total number of months in the `Months` instance.
+    #[inline]
+    pub const fn as_u32(&self) -> u32 {
+        self.0
+    }
+}
+
+/// An error resulting from reading `<Month>` value with `FromStr`.
+#[derive(Clone, PartialEq, Eq)]
+pub struct ParseMonthError {
+    pub(crate) _dummy: (),
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for ParseMonthError {}
+
+impl fmt::Display for ParseMonthError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "ParseMonthError {{ .. }}")
+    }
+}
+
+impl fmt::Debug for ParseMonthError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "ParseMonthError {{ .. }}")
+    }
+}
+
+#[cfg(feature = "serde")]
+mod month_serde {
+    use super::Month;
+    use serde::{de, ser};
+
+    use core::fmt;
+
+    impl ser::Serialize for Month {
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: ser::Serializer,
+        {
+            serializer.collect_str(self.name())
+        }
+    }
+
+    struct MonthVisitor;
+
+    impl de::Visitor<'_> for MonthVisitor {
+        type Value = Month;
+
+        fn expecting(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            f.write_str("Month")
+        }
+
+        fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+        where
+            E: de::Error,
+        {
+            value.parse().map_err(|_| E::custom("short (3-letter) or full month names expected"))
+        }
+    }
+
+    impl<'de> de::Deserialize<'de> for Month {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: de::Deserializer<'de>,
+        {
+            deserializer.deserialize_str(MonthVisitor)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Month;
+    use crate::{Datelike, Months, OutOfRange, TimeZone, Utc};
+
+    #[test]
+    fn test_month_enum_try_from() {
+        assert_eq!(Month::try_from(1), Ok(Month::January));
+        assert_eq!(Month::try_from(2), Ok(Month::February));
+        assert_eq!(Month::try_from(12), Ok(Month::December));
+        assert_eq!(Month::try_from(13), Err(OutOfRange::new()));
+
+        let date = Utc.with_ymd_and_hms(2019, 10, 28, 9, 10, 11).unwrap();
+        assert_eq!(Month::try_from(date.month() as u8), Ok(Month::October));
+
+        let month = Month::January;
+        let dt = Utc.with_ymd_and_hms(2019, month.number_from_month(), 28, 9, 10, 11).unwrap();
+        assert_eq!((dt.year(), dt.month(), dt.day()), (2019, 1, 28));
+    }
+
+    #[test]
+    fn test_month_enum_primitive_parse() {
+        use num_traits::FromPrimitive;
+
+        let jan_opt = Month::from_u32(1);
+        let feb_opt = Month::from_u64(2);
+        let dec_opt = Month::from_i64(12);
+        let no_month = Month::from_u32(13);
+        assert_eq!(jan_opt, Some(Month::January));
+        assert_eq!(feb_opt, Some(Month::February));
+        assert_eq!(dec_opt, Some(Month::December));
+        assert_eq!(no_month, None);
+
+        let date = Utc.with_ymd_and_hms(2019, 10, 28, 9, 10, 11).unwrap();
+        assert_eq!(Month::from_u32(date.month()), Some(Month::October));
+
+        let month = Month::January;
+        let dt = Utc.with_ymd_and_hms(2019, month.number_from_month(), 28, 9, 10, 11).unwrap();
+        assert_eq!((dt.year(), dt.month(), dt.day()), (2019, 1, 28));
+    }
+
+    #[test]
+    fn test_month_enum_succ_pred() {
+        assert_eq!(Month::January.succ(), Month::February);
+        assert_eq!(Month::December.succ(), Month::January);
+        assert_eq!(Month::January.pred(), Month::December);
+        assert_eq!(Month::February.pred(), Month::January);
+    }
+
+    #[test]
+    fn test_month_partial_ord() {
+        assert!(Month::January <= Month::January);
+        assert!(Month::January < Month::February);
+        assert!(Month::January < Month::December);
+        assert!(Month::July >= Month::May);
+        assert!(Month::September > Month::March);
+    }
+
+    #[test]
+    fn test_months_as_u32() {
+        assert_eq!(Months::new(0).as_u32(), 0);
+        assert_eq!(Months::new(1).as_u32(), 1);
+        assert_eq!(Months::new(u32::MAX).as_u32(), u32::MAX);
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_serialize() {
+        use Month::*;
+        use serde_json::to_string;
+
+        let cases: Vec<(Month, &str)> = vec![
+            (January, "\"January\""),
+            (February, "\"February\""),
+            (March, "\"March\""),
+            (April, "\"April\""),
+            (May, "\"May\""),
+            (June, "\"June\""),
+            (July, "\"July\""),
+            (August, "\"August\""),
+            (September, "\"September\""),
+            (October, "\"October\""),
+            (November, "\"November\""),
+            (December, "\"December\""),
+        ];
+
+        for (month, expected_str) in cases {
+            let string = to_string(&month).unwrap();
+            assert_eq!(string, expected_str);
+        }
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_deserialize() {
+        use Month::*;
+        use serde_json::from_str;
+
+        let cases: Vec<(&str, Month)> = vec![
+            ("\"january\"", January),
+            ("\"jan\"", January),
+            ("\"FeB\"", February),
+            ("\"MAR\"", March),
+            ("\"mar\"", March),
+            ("\"april\"", April),
+            ("\"may\"", May),
+            ("\"june\"", June),
+            ("\"JULY\"", July),
+            ("\"august\"", August),
+            ("\"september\"", September),
+            ("\"October\"", October),
+            ("\"November\"", November),
+            ("\"DECEmbEr\"", December),
+        ];
+
+        for (string, expected_month) in cases {
+            let month = from_str::<Month>(string).unwrap();
+            assert_eq!(month, expected_month);
+        }
+
+        let errors: Vec<&str> =
+            vec!["\"not a month\"", "\"ja\"", "\"Dece\"", "Dec", "\"Augustin\""];
+
+        for string in errors {
+            from_str::<Month>(string).unwrap_err();
+        }
+    }
+
+    #[test]
+    #[cfg(feature = "rkyv-validation")]
+    fn test_rkyv_validation() {
+        let month = Month::January;
+        let bytes = rkyv::to_bytes::<_, 1>(&month).unwrap();
+        assert_eq!(rkyv::from_bytes::<Month>(&bytes).unwrap(), month);
+    }
+
+    #[test]
+    fn num_days() {
+        assert_eq!(Month::January.num_days(2020), Some(31));
+        assert_eq!(Month::February.num_days(2020), Some(29));
+        assert_eq!(Month::February.num_days(2019), Some(28));
+    }
+}

patch/chrono-0.4.41/src/naive/date/tests.rs

@@ -0,0 +1,875 @@
+use super::{Days, MAX_YEAR, MIN_YEAR, Months, NaiveDate};
+use crate::naive::internals::{A, AG, B, BA, C, CB, D, DC, E, ED, F, FE, G, GF, YearFlags};
+use crate::{Datelike, TimeDelta, Weekday};
+
+// as it is hard to verify year flags in `NaiveDate::MIN` and `NaiveDate::MAX`,
+// we use a separate run-time test.
+#[test]
+fn test_date_bounds() {
+    let calculated_min = NaiveDate::from_ymd_opt(MIN_YEAR, 1, 1).unwrap();
+    let calculated_max = NaiveDate::from_ymd_opt(MAX_YEAR, 12, 31).unwrap();
+    assert!(
+        NaiveDate::MIN == calculated_min,
+        "`NaiveDate::MIN` should have year flag {:?}",
+        calculated_min.year_flags()
+    );
+    assert!(
+        NaiveDate::MAX == calculated_max,
+        "`NaiveDate::MAX` should have year flag {:?} and ordinal {}",
+        calculated_max.year_flags(),
+        calculated_max.ordinal()
+    );
+
+    // let's also check that the entire range do not exceed 2^44 seconds
+    // (sometimes used for bounding `TimeDelta` against overflow)
+    let maxsecs = NaiveDate::MAX.signed_duration_since(NaiveDate::MIN).num_seconds();
+    let maxsecs = maxsecs + 86401; // also take care of DateTime
+    assert!(
+        maxsecs < (1 << MAX_BITS),
+        "The entire `NaiveDate` range somehow exceeds 2^{MAX_BITS} seconds"
+    );
+
+    const BEFORE_MIN: NaiveDate = NaiveDate::BEFORE_MIN;
+    assert_eq!(BEFORE_MIN.year_flags(), YearFlags::from_year(BEFORE_MIN.year()));
+    assert_eq!((BEFORE_MIN.month(), BEFORE_MIN.day()), (12, 31));
+
+    const AFTER_MAX: NaiveDate = NaiveDate::AFTER_MAX;
+    assert_eq!(AFTER_MAX.year_flags(), YearFlags::from_year(AFTER_MAX.year()));
+    assert_eq!((AFTER_MAX.month(), AFTER_MAX.day()), (1, 1));
+}
+
+#[test]
+fn diff_months() {
+    // identity
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 8, 3).unwrap().checked_add_months(Months::new(0)),
+        Some(NaiveDate::from_ymd_opt(2022, 8, 3).unwrap())
+    );
+
+    // add with months exceeding `i32::MAX`
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 8, 3)
+            .unwrap()
+            .checked_add_months(Months::new(i32::MAX as u32 + 1)),
+        None
+    );
+
+    // sub with months exceeding `i32::MIN`
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 8, 3)
+            .unwrap()
+            .checked_sub_months(Months::new(i32::MIN.unsigned_abs() + 1)),
+        None
+    );
+
+    // add overflowing year
+    assert_eq!(NaiveDate::MAX.checked_add_months(Months::new(1)), None);
+
+    // add underflowing year
+    assert_eq!(NaiveDate::MIN.checked_sub_months(Months::new(1)), None);
+
+    // sub crossing year 0 boundary
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 8, 3).unwrap().checked_sub_months(Months::new(2050 * 12)),
+        Some(NaiveDate::from_ymd_opt(-28, 8, 3).unwrap())
+    );
+
+    // add crossing year boundary
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 8, 3).unwrap().checked_add_months(Months::new(6)),
+        Some(NaiveDate::from_ymd_opt(2023, 2, 3).unwrap())
+    );
+
+    // sub crossing year boundary
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 8, 3).unwrap().checked_sub_months(Months::new(10)),
+        Some(NaiveDate::from_ymd_opt(2021, 10, 3).unwrap())
+    );
+
+    // add clamping day, non-leap year
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 1, 29).unwrap().checked_add_months(Months::new(1)),
+        Some(NaiveDate::from_ymd_opt(2022, 2, 28).unwrap())
+    );
+
+    // add to leap day
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 10, 29).unwrap().checked_add_months(Months::new(16)),
+        Some(NaiveDate::from_ymd_opt(2024, 2, 29).unwrap())
+    );
+
+    // add into december
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 10, 31).unwrap().checked_add_months(Months::new(2)),
+        Some(NaiveDate::from_ymd_opt(2022, 12, 31).unwrap())
+    );
+
+    // sub into december
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 10, 31).unwrap().checked_sub_months(Months::new(10)),
+        Some(NaiveDate::from_ymd_opt(2021, 12, 31).unwrap())
+    );
+
+    // add into january
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 8, 3).unwrap().checked_add_months(Months::new(5)),
+        Some(NaiveDate::from_ymd_opt(2023, 1, 3).unwrap())
+    );
+
+    // sub into january
+    assert_eq!(
+        NaiveDate::from_ymd_opt(2022, 8, 3).unwrap().checked_sub_months(Months::new(7)),
+        Some(NaiveDate::from_ymd_opt(2022, 1, 3).unwrap())
+    );
+}
+
+#[test]
+fn test_readme_doomsday() {
+    for y in NaiveDate::MIN.year()..=NaiveDate::MAX.year() {
+        // even months
+        let d4 = NaiveDate::from_ymd_opt(y, 4, 4).unwrap();
+        let d6 = NaiveDate::from_ymd_opt(y, 6, 6).unwrap();
+        let d8 = NaiveDate::from_ymd_opt(y, 8, 8).unwrap();
+        let d10 = NaiveDate::from_ymd_opt(y, 10, 10).unwrap();
+        let d12 = NaiveDate::from_ymd_opt(y, 12, 12).unwrap();
+
+        // nine to five, seven-eleven
+        let d59 = NaiveDate::from_ymd_opt(y, 5, 9).unwrap();
+        let d95 = NaiveDate::from_ymd_opt(y, 9, 5).unwrap();
+        let d711 = NaiveDate::from_ymd_opt(y, 7, 11).unwrap();
+        let d117 = NaiveDate::from_ymd_opt(y, 11, 7).unwrap();
+
+        // "March 0"
+        let d30 = NaiveDate::from_ymd_opt(y, 3, 1).unwrap().pred_opt().unwrap();
+
+        let weekday = d30.weekday();
+        let other_dates = [d4, d6, d8, d10, d12, d59, d95, d711, d117];
+        assert!(other_dates.iter().all(|d| d.weekday() == weekday));
+    }
+}
+
+#[test]
+fn test_date_from_ymd() {
+    let from_ymd = NaiveDate::from_ymd_opt;
+
+    assert!(from_ymd(2012, 0, 1).is_none());
+    assert!(from_ymd(2012, 1, 1).is_some());
+    assert!(from_ymd(2012, 2, 29).is_some());
+    assert!(from_ymd(2014, 2, 29).is_none());
+    assert!(from_ymd(2014, 3, 0).is_none());
+    assert!(from_ymd(2014, 3, 1).is_some());
+    assert!(from_ymd(2014, 3, 31).is_some());
+    assert!(from_ymd(2014, 3, 32).is_none());
+    assert!(from_ymd(2014, 12, 31).is_some());
+    assert!(from_ymd(2014, 13, 1).is_none());
+}
+
+#[test]
+fn test_date_from_yo() {
+    let from_yo = NaiveDate::from_yo_opt;
+    let ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();
+
+    assert_eq!(from_yo(2012, 0), None);
+    assert_eq!(from_yo(2012, 1), Some(ymd(2012, 1, 1)));
+    assert_eq!(from_yo(2012, 2), Some(ymd(2012, 1, 2)));
+    assert_eq!(from_yo(2012, 32), Some(ymd(2012, 2, 1)));
+    assert_eq!(from_yo(2012, 60), Some(ymd(2012, 2, 29)));
+    assert_eq!(from_yo(2012, 61), Some(ymd(2012, 3, 1)));
+    assert_eq!(from_yo(2012, 100), Some(ymd(2012, 4, 9)));
+    assert_eq!(from_yo(2012, 200), Some(ymd(2012, 7, 18)));
+    assert_eq!(from_yo(2012, 300), Some(ymd(2012, 10, 26)));
+    assert_eq!(from_yo(2012, 366), Some(ymd(2012, 12, 31)));
+    assert_eq!(from_yo(2012, 367), None);
+    assert_eq!(from_yo(2012, (1 << 28) | 60), None);
+
+    assert_eq!(from_yo(2014, 0), None);
+    assert_eq!(from_yo(2014, 1), Some(ymd(2014, 1, 1)));
+    assert_eq!(from_yo(2014, 2), Some(ymd(2014, 1, 2)));
+    assert_eq!(from_yo(2014, 32), Some(ymd(2014, 2, 1)));
+    assert_eq!(from_yo(2014, 59), Some(ymd(2014, 2, 28)));
+    assert_eq!(from_yo(2014, 60), Some(ymd(2014, 3, 1)));
+    assert_eq!(from_yo(2014, 100), Some(ymd(2014, 4, 10)));
+    assert_eq!(from_yo(2014, 200), Some(ymd(2014, 7, 19)));
+    assert_eq!(from_yo(2014, 300), Some(ymd(2014, 10, 27)));
+    assert_eq!(from_yo(2014, 365), Some(ymd(2014, 12, 31)));
+    assert_eq!(from_yo(2014, 366), None);
+}
+
+#[test]
+fn test_date_from_isoywd() {
+    let from_isoywd = NaiveDate::from_isoywd_opt;
+    let ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();
+
+    assert_eq!(from_isoywd(2004, 0, Weekday::Sun), None);
+    assert_eq!(from_isoywd(2004, 1, Weekday::Mon), Some(ymd(2003, 12, 29)));
+    assert_eq!(from_isoywd(2004, 1, Weekday::Sun), Some(ymd(2004, 1, 4)));
+    assert_eq!(from_isoywd(2004, 2, Weekday::Mon), Some(ymd(2004, 1, 5)));
+    assert_eq!(from_isoywd(2004, 2, Weekday::Sun), Some(ymd(2004, 1, 11)));
+    assert_eq!(from_isoywd(2004, 52, Weekday::Mon), Some(ymd(2004, 12, 20)));
+    assert_eq!(from_isoywd(2004, 52, Weekday::Sun), Some(ymd(2004, 12, 26)));
+    assert_eq!(from_isoywd(2004, 53, Weekday::Mon), Some(ymd(2004, 12, 27)));
+    assert_eq!(from_isoywd(2004, 53, Weekday::Sun), Some(ymd(2005, 1, 2)));
+    assert_eq!(from_isoywd(2004, 54, Weekday::Mon), None);
+
+    assert_eq!(from_isoywd(2011, 0, Weekday::Sun), None);
+    assert_eq!(from_isoywd(2011, 1, Weekday::Mon), Some(ymd(2011, 1, 3)));
+    assert_eq!(from_isoywd(2011, 1, Weekday::Sun), Some(ymd(2011, 1, 9)));
+    assert_eq!(from_isoywd(2011, 2, Weekday::Mon), Some(ymd(2011, 1, 10)));
+    assert_eq!(from_isoywd(2011, 2, Weekday::Sun), Some(ymd(2011, 1, 16)));
+
+    assert_eq!(from_isoywd(2018, 51, Weekday::Mon), Some(ymd(2018, 12, 17)));
+    assert_eq!(from_isoywd(2018, 51, Weekday::Sun), Some(ymd(2018, 12, 23)));
+    assert_eq!(from_isoywd(2018, 52, Weekday::Mon), Some(ymd(2018, 12, 24)));
+    assert_eq!(from_isoywd(2018, 52, Weekday::Sun), Some(ymd(2018, 12, 30)));
+    assert_eq!(from_isoywd(2018, 53, Weekday::Mon), None);
+}
+
+#[test]
+fn test_date_from_isoywd_and_iso_week() {
+    for year in 2000..2401 {
+        for week in 1..54 {
+            for &weekday in [
+                Weekday::Mon,
+                Weekday::Tue,
+                Weekday::Wed,
+                Weekday::Thu,
+                Weekday::Fri,
+                Weekday::Sat,
+                Weekday::Sun,
+            ]
+            .iter()
+            {
+                let d = NaiveDate::from_isoywd_opt(year, week, weekday);
+                if let Some(d) = d {
+                    assert_eq!(d.weekday(), weekday);
+                    let w = d.iso_week();
+                    assert_eq!(w.year(), year);
+                    assert_eq!(w.week(), week);
+                }
+            }
+        }
+    }
+
+    for year in 2000..2401 {
+        for month in 1..13 {
+            for day in 1..32 {
+                let d = NaiveDate::from_ymd_opt(year, month, day);
+                if let Some(d) = d {
+                    let w = d.iso_week();
+                    let d_ = NaiveDate::from_isoywd_opt(w.year(), w.week(), d.weekday());
+                    assert_eq!(d, d_.unwrap());
+                }
+            }
+        }
+    }
+}
+
+#[test]
+fn test_date_from_num_days_from_ce() {
+    let from_ndays_from_ce = NaiveDate::from_num_days_from_ce_opt;
+    assert_eq!(from_ndays_from_ce(1), Some(NaiveDate::from_ymd_opt(1, 1, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(2), Some(NaiveDate::from_ymd_opt(1, 1, 2).unwrap()));
+    assert_eq!(from_ndays_from_ce(31), Some(NaiveDate::from_ymd_opt(1, 1, 31).unwrap()));
+    assert_eq!(from_ndays_from_ce(32), Some(NaiveDate::from_ymd_opt(1, 2, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(59), Some(NaiveDate::from_ymd_opt(1, 2, 28).unwrap()));
+    assert_eq!(from_ndays_from_ce(60), Some(NaiveDate::from_ymd_opt(1, 3, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(365), Some(NaiveDate::from_ymd_opt(1, 12, 31).unwrap()));
+    assert_eq!(from_ndays_from_ce(365 + 1), Some(NaiveDate::from_ymd_opt(2, 1, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(365 * 2 + 1), Some(NaiveDate::from_ymd_opt(3, 1, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(365 * 3 + 1), Some(NaiveDate::from_ymd_opt(4, 1, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(365 * 4 + 2), Some(NaiveDate::from_ymd_opt(5, 1, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(146097 + 1), Some(NaiveDate::from_ymd_opt(401, 1, 1).unwrap()));
+    assert_eq!(
+        from_ndays_from_ce(146097 * 5 + 1),
+        Some(NaiveDate::from_ymd_opt(2001, 1, 1).unwrap())
+    );
+    assert_eq!(from_ndays_from_ce(719163), Some(NaiveDate::from_ymd_opt(1970, 1, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(0), Some(NaiveDate::from_ymd_opt(0, 12, 31).unwrap())); // 1 BCE
+    assert_eq!(from_ndays_from_ce(-365), Some(NaiveDate::from_ymd_opt(0, 1, 1).unwrap()));
+    assert_eq!(from_ndays_from_ce(-366), Some(NaiveDate::from_ymd_opt(-1, 12, 31).unwrap())); // 2 BCE
+
+    for days in (-9999..10001).map(|x| x * 100) {
+        assert_eq!(from_ndays_from_ce(days).map(|d| d.num_days_from_ce()), Some(days));
+    }
+
+    assert_eq!(from_ndays_from_ce(NaiveDate::MIN.num_days_from_ce()), Some(NaiveDate::MIN));
+    assert_eq!(from_ndays_from_ce(NaiveDate::MIN.num_days_from_ce() - 1), None);
+    assert_eq!(from_ndays_from_ce(NaiveDate::MAX.num_days_from_ce()), Some(NaiveDate::MAX));
+    assert_eq!(from_ndays_from_ce(NaiveDate::MAX.num_days_from_ce() + 1), None);
+
+    assert_eq!(from_ndays_from_ce(i32::MIN), None);
+    assert_eq!(from_ndays_from_ce(i32::MAX), None);
+}
+
+#[test]
+fn test_date_from_weekday_of_month_opt() {
+    let ymwd = NaiveDate::from_weekday_of_month_opt;
+    assert_eq!(ymwd(2018, 8, Weekday::Tue, 0), None);
+    assert_eq!(ymwd(2018, 8, Weekday::Wed, 1), Some(NaiveDate::from_ymd_opt(2018, 8, 1).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Thu, 1), Some(NaiveDate::from_ymd_opt(2018, 8, 2).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Sun, 1), Some(NaiveDate::from_ymd_opt(2018, 8, 5).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Mon, 1), Some(NaiveDate::from_ymd_opt(2018, 8, 6).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Tue, 1), Some(NaiveDate::from_ymd_opt(2018, 8, 7).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Wed, 2), Some(NaiveDate::from_ymd_opt(2018, 8, 8).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Sun, 2), Some(NaiveDate::from_ymd_opt(2018, 8, 12).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Thu, 3), Some(NaiveDate::from_ymd_opt(2018, 8, 16).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Thu, 4), Some(NaiveDate::from_ymd_opt(2018, 8, 23).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Thu, 5), Some(NaiveDate::from_ymd_opt(2018, 8, 30).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Fri, 5), Some(NaiveDate::from_ymd_opt(2018, 8, 31).unwrap()));
+    assert_eq!(ymwd(2018, 8, Weekday::Sat, 5), None);
+}
+
+#[test]
+fn test_date_fields() {
+    fn check(year: i32, month: u32, day: u32, ordinal: u32) {
+        let d1 = NaiveDate::from_ymd_opt(year, month, day).unwrap();
+        assert_eq!(d1.year(), year);
+        assert_eq!(d1.month(), month);
+        assert_eq!(d1.day(), day);
+        assert_eq!(d1.ordinal(), ordinal);
+
+        let d2 = NaiveDate::from_yo_opt(year, ordinal).unwrap();
+        assert_eq!(d2.year(), year);
+        assert_eq!(d2.month(), month);
+        assert_eq!(d2.day(), day);
+        assert_eq!(d2.ordinal(), ordinal);
+
+        assert_eq!(d1, d2);
+    }
+
+    check(2012, 1, 1, 1);
+    check(2012, 1, 2, 2);
+    check(2012, 2, 1, 32);
+    check(2012, 2, 29, 60);
+    check(2012, 3, 1, 61);
+    check(2012, 4, 9, 100);
+    check(2012, 7, 18, 200);
+    check(2012, 10, 26, 300);
+    check(2012, 12, 31, 366);
+
+    check(2014, 1, 1, 1);
+    check(2014, 1, 2, 2);
+    check(2014, 2, 1, 32);
+    check(2014, 2, 28, 59);
+    check(2014, 3, 1, 60);
+    check(2014, 4, 10, 100);
+    check(2014, 7, 19, 200);
+    check(2014, 10, 27, 300);
+    check(2014, 12, 31, 365);
+}
+
+#[test]
+fn test_date_weekday() {
+    assert_eq!(NaiveDate::from_ymd_opt(1582, 10, 15).unwrap().weekday(), Weekday::Fri);
+    // May 20, 1875 = ISO 8601 reference date
+    assert_eq!(NaiveDate::from_ymd_opt(1875, 5, 20).unwrap().weekday(), Weekday::Thu);
+    assert_eq!(NaiveDate::from_ymd_opt(2000, 1, 1).unwrap().weekday(), Weekday::Sat);
+}
+
+#[test]
+fn test_date_with_fields() {
+    let d = NaiveDate::from_ymd_opt(2000, 2, 29).unwrap();
+    assert_eq!(d.with_year(-400), Some(NaiveDate::from_ymd_opt(-400, 2, 29).unwrap()));
+    assert_eq!(d.with_year(-100), None);
+    assert_eq!(d.with_year(1600), Some(NaiveDate::from_ymd_opt(1600, 2, 29).unwrap()));
+    assert_eq!(d.with_year(1900), None);
+    assert_eq!(d.with_year(2000), Some(NaiveDate::from_ymd_opt(2000, 2, 29).unwrap()));
+    assert_eq!(d.with_year(2001), None);
+    assert_eq!(d.with_year(2004), Some(NaiveDate::from_ymd_opt(2004, 2, 29).unwrap()));
+    assert_eq!(d.with_year(i32::MAX), None);
+
+    let d = NaiveDate::from_ymd_opt(2000, 4, 30).unwrap();
+    assert_eq!(d.with_month(0), None);
+    assert_eq!(d.with_month(1), Some(NaiveDate::from_ymd_opt(2000, 1, 30).unwrap()));
+    assert_eq!(d.with_month(2), None);
+    assert_eq!(d.with_month(3), Some(NaiveDate::from_ymd_opt(2000, 3, 30).unwrap()));
+    assert_eq!(d.with_month(4), Some(NaiveDate::from_ymd_opt(2000, 4, 30).unwrap()));
+    assert_eq!(d.with_month(12), Some(NaiveDate::from_ymd_opt(2000, 12, 30).unwrap()));
+    assert_eq!(d.with_month(13), None);
+    assert_eq!(d.with_month(u32::MAX), None);
+
+    let d = NaiveDate::from_ymd_opt(2000, 2, 8).unwrap();
+    assert_eq!(d.with_day(0), None);
+    assert_eq!(d.with_day(1), Some(NaiveDate::from_ymd_opt(2000, 2, 1).unwrap()));
+    assert_eq!(d.with_day(29), Some(NaiveDate::from_ymd_opt(2000, 2, 29).unwrap()));
+    assert_eq!(d.with_day(30), None);
+    assert_eq!(d.with_day(u32::MAX), None);
+}
+
+#[test]
+fn test_date_with_ordinal() {
+    let d = NaiveDate::from_ymd_opt(2000, 5, 5).unwrap();
+    assert_eq!(d.with_ordinal(0), None);
+    assert_eq!(d.with_ordinal(1), Some(NaiveDate::from_ymd_opt(2000, 1, 1).unwrap()));
+    assert_eq!(d.with_ordinal(60), Some(NaiveDate::from_ymd_opt(2000, 2, 29).unwrap()));
+    assert_eq!(d.with_ordinal(61), Some(NaiveDate::from_ymd_opt(2000, 3, 1).unwrap()));
+    assert_eq!(d.with_ordinal(366), Some(NaiveDate::from_ymd_opt(2000, 12, 31).unwrap()));
+    assert_eq!(d.with_ordinal(367), None);
+    assert_eq!(d.with_ordinal((1 << 28) | 60), None);
+    let d = NaiveDate::from_ymd_opt(1999, 5, 5).unwrap();
+    assert_eq!(d.with_ordinal(366), None);
+    assert_eq!(d.with_ordinal(u32::MAX), None);
+}
+
+#[test]
+fn test_date_num_days_from_ce() {
+    assert_eq!(NaiveDate::from_ymd_opt(1, 1, 1).unwrap().num_days_from_ce(), 1);
+
+    for year in -9999..10001 {
+        assert_eq!(
+            NaiveDate::from_ymd_opt(year, 1, 1).unwrap().num_days_from_ce(),
+            NaiveDate::from_ymd_opt(year - 1, 12, 31).unwrap().num_days_from_ce() + 1
+        );
+    }
+}
+
+#[test]
+fn test_date_succ() {
+    let ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();
+    assert_eq!(ymd(2014, 5, 6).succ_opt(), Some(ymd(2014, 5, 7)));
+    assert_eq!(ymd(2014, 5, 31).succ_opt(), Some(ymd(2014, 6, 1)));
+    assert_eq!(ymd(2014, 12, 31).succ_opt(), Some(ymd(2015, 1, 1)));
+    assert_eq!(ymd(2016, 2, 28).succ_opt(), Some(ymd(2016, 2, 29)));
+    assert_eq!(ymd(NaiveDate::MAX.year(), 12, 31).succ_opt(), None);
+}
+
+#[test]
+fn test_date_pred() {
+    let ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();
+    assert_eq!(ymd(2016, 3, 1).pred_opt(), Some(ymd(2016, 2, 29)));
+    assert_eq!(ymd(2015, 1, 1).pred_opt(), Some(ymd(2014, 12, 31)));
+    assert_eq!(ymd(2014, 6, 1).pred_opt(), Some(ymd(2014, 5, 31)));
+    assert_eq!(ymd(2014, 5, 7).pred_opt(), Some(ymd(2014, 5, 6)));
+    assert_eq!(ymd(NaiveDate::MIN.year(), 1, 1).pred_opt(), None);
+}
+
+#[test]
+fn test_date_checked_add_signed() {
+    fn check(lhs: Option<NaiveDate>, delta: TimeDelta, rhs: Option<NaiveDate>) {
+        assert_eq!(lhs.unwrap().checked_add_signed(delta), rhs);
+        assert_eq!(lhs.unwrap().checked_sub_signed(-delta), rhs);
+    }
+    let ymd = NaiveDate::from_ymd_opt;
+
+    check(ymd(2014, 1, 1), TimeDelta::zero(), ymd(2014, 1, 1));
+    check(ymd(2014, 1, 1), TimeDelta::try_seconds(86399).unwrap(), ymd(2014, 1, 1));
+    // always round towards zero
+    check(ymd(2014, 1, 1), TimeDelta::try_seconds(-86399).unwrap(), ymd(2014, 1, 1));
+    check(ymd(2014, 1, 1), TimeDelta::try_days(1).unwrap(), ymd(2014, 1, 2));
+    check(ymd(2014, 1, 1), TimeDelta::try_days(-1).unwrap(), ymd(2013, 12, 31));
+    check(ymd(2014, 1, 1), TimeDelta::try_days(364).unwrap(), ymd(2014, 12, 31));
+    check(ymd(2014, 1, 1), TimeDelta::try_days(365 * 4 + 1).unwrap(), ymd(2018, 1, 1));
+    check(ymd(2014, 1, 1), TimeDelta::try_days(365 * 400 + 97).unwrap(), ymd(2414, 1, 1));
+
+    check(ymd(-7, 1, 1), TimeDelta::try_days(365 * 12 + 3).unwrap(), ymd(5, 1, 1));
+
+    // overflow check
+    check(
+        ymd(0, 1, 1),
+        TimeDelta::try_days(MAX_DAYS_FROM_YEAR_0 as i64).unwrap(),
+        ymd(MAX_YEAR, 12, 31),
+    );
+    check(ymd(0, 1, 1), TimeDelta::try_days(MAX_DAYS_FROM_YEAR_0 as i64 + 1).unwrap(), None);
+    check(ymd(0, 1, 1), TimeDelta::MAX, None);
+    check(
+        ymd(0, 1, 1),
+        TimeDelta::try_days(MIN_DAYS_FROM_YEAR_0 as i64).unwrap(),
+        ymd(MIN_YEAR, 1, 1),
+    );
+    check(ymd(0, 1, 1), TimeDelta::try_days(MIN_DAYS_FROM_YEAR_0 as i64 - 1).unwrap(), None);
+    check(ymd(0, 1, 1), TimeDelta::MIN, None);
+}
+
+#[test]
+fn test_date_signed_duration_since() {
+    fn check(lhs: Option<NaiveDate>, rhs: Option<NaiveDate>, delta: TimeDelta) {
+        assert_eq!(lhs.unwrap().signed_duration_since(rhs.unwrap()), delta);
+        assert_eq!(rhs.unwrap().signed_duration_since(lhs.unwrap()), -delta);
+    }
+    let ymd = NaiveDate::from_ymd_opt;
+
+    check(ymd(2014, 1, 1), ymd(2014, 1, 1), TimeDelta::zero());
+    check(ymd(2014, 1, 2), ymd(2014, 1, 1), TimeDelta::try_days(1).unwrap());
+    check(ymd(2014, 12, 31), ymd(2014, 1, 1), TimeDelta::try_days(364).unwrap());
+    check(ymd(2015, 1, 3), ymd(2014, 1, 1), TimeDelta::try_days(365 + 2).unwrap());
+    check(ymd(2018, 1, 1), ymd(2014, 1, 1), TimeDelta::try_days(365 * 4 + 1).unwrap());
+    check(ymd(2414, 1, 1), ymd(2014, 1, 1), TimeDelta::try_days(365 * 400 + 97).unwrap());
+
+    check(
+        ymd(MAX_YEAR, 12, 31),
+        ymd(0, 1, 1),
+        TimeDelta::try_days(MAX_DAYS_FROM_YEAR_0 as i64).unwrap(),
+    );
+    check(
+        ymd(MIN_YEAR, 1, 1),
+        ymd(0, 1, 1),
+        TimeDelta::try_days(MIN_DAYS_FROM_YEAR_0 as i64).unwrap(),
+    );
+}
+
+#[test]
+fn test_date_add_days() {
+    fn check(lhs: Option<NaiveDate>, days: Days, rhs: Option<NaiveDate>) {
+        assert_eq!(lhs.unwrap().checked_add_days(days), rhs);
+    }
+    let ymd = NaiveDate::from_ymd_opt;
+
+    check(ymd(2014, 1, 1), Days::new(0), ymd(2014, 1, 1));
+    // always round towards zero
+    check(ymd(2014, 1, 1), Days::new(1), ymd(2014, 1, 2));
+    check(ymd(2014, 1, 1), Days::new(364), ymd(2014, 12, 31));
+    check(ymd(2014, 1, 1), Days::new(365 * 4 + 1), ymd(2018, 1, 1));
+    check(ymd(2014, 1, 1), Days::new(365 * 400 + 97), ymd(2414, 1, 1));
+
+    check(ymd(-7, 1, 1), Days::new(365 * 12 + 3), ymd(5, 1, 1));
+
+    // overflow check
+    check(ymd(0, 1, 1), Days::new(MAX_DAYS_FROM_YEAR_0.try_into().unwrap()), ymd(MAX_YEAR, 12, 31));
+    check(ymd(0, 1, 1), Days::new(u64::try_from(MAX_DAYS_FROM_YEAR_0).unwrap() + 1), None);
+}
+
+#[test]
+fn test_date_sub_days() {
+    fn check(lhs: Option<NaiveDate>, days: Days, rhs: Option<NaiveDate>) {
+        assert_eq!(lhs.unwrap().checked_sub_days(days), rhs);
+    }
+    let ymd = NaiveDate::from_ymd_opt;
+
+    check(ymd(2014, 1, 1), Days::new(0), ymd(2014, 1, 1));
+    check(ymd(2014, 1, 2), Days::new(1), ymd(2014, 1, 1));
+    check(ymd(2014, 12, 31), Days::new(364), ymd(2014, 1, 1));
+    check(ymd(2015, 1, 3), Days::new(365 + 2), ymd(2014, 1, 1));
+    check(ymd(2018, 1, 1), Days::new(365 * 4 + 1), ymd(2014, 1, 1));
+    check(ymd(2414, 1, 1), Days::new(365 * 400 + 97), ymd(2014, 1, 1));
+
+    check(ymd(MAX_YEAR, 12, 31), Days::new(MAX_DAYS_FROM_YEAR_0.try_into().unwrap()), ymd(0, 1, 1));
+    check(
+        ymd(0, 1, 1),
+        Days::new((-MIN_DAYS_FROM_YEAR_0).try_into().unwrap()),
+        ymd(MIN_YEAR, 1, 1),
+    );
+}
+
+#[test]
+fn test_date_addassignment() {
+    let ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();
+    let mut date = ymd(2016, 10, 1);
+    date += TimeDelta::try_days(10).unwrap();
+    assert_eq!(date, ymd(2016, 10, 11));
+    date += TimeDelta::try_days(30).unwrap();
+    assert_eq!(date, ymd(2016, 11, 10));
+}
+
+#[test]
+fn test_date_subassignment() {
+    let ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();
+    let mut date = ymd(2016, 10, 11);
+    date -= TimeDelta::try_days(10).unwrap();
+    assert_eq!(date, ymd(2016, 10, 1));
+    date -= TimeDelta::try_days(2).unwrap();
+    assert_eq!(date, ymd(2016, 9, 29));
+}
+
+#[test]
+fn test_date_fmt() {
+    assert_eq!(format!("{:?}", NaiveDate::from_ymd_opt(2012, 3, 4).unwrap()), "2012-03-04");
+    assert_eq!(format!("{:?}", NaiveDate::from_ymd_opt(0, 3, 4).unwrap()), "0000-03-04");
+    assert_eq!(format!("{:?}", NaiveDate::from_ymd_opt(-307, 3, 4).unwrap()), "-0307-03-04");
+    assert_eq!(format!("{:?}", NaiveDate::from_ymd_opt(12345, 3, 4).unwrap()), "+12345-03-04");
+
+    assert_eq!(NaiveDate::from_ymd_opt(2012, 3, 4).unwrap().to_string(), "2012-03-04");
+    assert_eq!(NaiveDate::from_ymd_opt(0, 3, 4).unwrap().to_string(), "0000-03-04");
+    assert_eq!(NaiveDate::from_ymd_opt(-307, 3, 4).unwrap().to_string(), "-0307-03-04");
+    assert_eq!(NaiveDate::from_ymd_opt(12345, 3, 4).unwrap().to_string(), "+12345-03-04");
+
+    // the format specifier should have no effect on `NaiveTime`
+    assert_eq!(format!("{:+30?}", NaiveDate::from_ymd_opt(1234, 5, 6).unwrap()), "1234-05-06");
+    assert_eq!(format!("{:30?}", NaiveDate::from_ymd_opt(12345, 6, 7).unwrap()), "+12345-06-07");
+}
+
+#[test]
+fn test_date_from_str() {
+    // valid cases
+    let valid = [
+        "-0000000123456-1-2",
+        "    -123456 - 1 - 2    ",
+        "-12345-1-2",
+        "-1234-12-31",
+        "-7-6-5",
+        "350-2-28",
+        "360-02-29",
+        "0360-02-29",
+        "2015-2 -18",
+        "2015-02-18",
+        "+70-2-18",
+        "+70000-2-18",
+        "+00007-2-18",
+    ];
+    for &s in &valid {
+        eprintln!("test_date_from_str valid {s:?}");
+        let d = match s.parse::<NaiveDate>() {
+            Ok(d) => d,
+            Err(e) => panic!("parsing `{s}` has failed: {e}"),
+        };
+        eprintln!("d {d:?} (NaiveDate)");
+        let s_ = format!("{d:?}");
+        eprintln!("s_ {s_:?}");
+        // `s` and `s_` may differ, but `s.parse()` and `s_.parse()` must be same
+        let d_ = match s_.parse::<NaiveDate>() {
+            Ok(d) => d,
+            Err(e) => {
+                panic!("`{s}` is parsed into `{d:?}`, but reparsing that has failed: {e}")
+            }
+        };
+        eprintln!("d_ {d_:?} (NaiveDate)");
+        assert!(
+            d == d_,
+            "`{s}` is parsed into `{d:?}`, but reparsed result \
+                            `{d_:?}` does not match"
+        );
+    }
+
+    // some invalid cases
+    // since `ParseErrorKind` is private, all we can do is to check if there was an error
+    let invalid = [
+        "",                     // empty
+        "x",                    // invalid
+        "Fri, 09 Aug 2013 GMT", // valid date, wrong format
+        "Sat Jun 30 2012",      // valid date, wrong format
+        "1441497364.649",       // valid datetime, wrong format
+        "+1441497364.649",      // valid datetime, wrong format
+        "+1441497364",          // valid datetime, wrong format
+        "2014/02/03",           // valid date, wrong format
+        "2014",                 // datetime missing data
+        "2014-01",              // datetime missing data
+        "2014-01-00",           // invalid day
+        "2014-11-32",           // invalid day
+        "2014-13-01",           // invalid month
+        "2014-13-57",           // invalid month, day
+        "9999999-9-9",          // invalid year (out of bounds)
+    ];
+    for &s in &invalid {
+        eprintln!("test_date_from_str invalid {s:?}");
+        assert!(s.parse::<NaiveDate>().is_err());
+    }
+}
+
+#[test]
+fn test_date_parse_from_str() {
+    let ymd = |y, m, d| NaiveDate::from_ymd_opt(y, m, d).unwrap();
+    assert_eq!(
+        NaiveDate::parse_from_str("2014-5-7T12:34:56+09:30", "%Y-%m-%dT%H:%M:%S%z"),
+        Ok(ymd(2014, 5, 7))
+    ); // ignore time and offset
+    assert_eq!(
+        NaiveDate::parse_from_str("2015-W06-1=2015-033 Q1", "%G-W%V-%u = %Y-%j Q%q"),
+        Ok(ymd(2015, 2, 2))
+    );
+    assert_eq!(NaiveDate::parse_from_str("Fri, 09 Aug 13", "%a, %d %b %y"), Ok(ymd(2013, 8, 9)));
+    assert!(NaiveDate::parse_from_str("Sat, 09 Aug 2013", "%a, %d %b %Y").is_err());
+    assert!(NaiveDate::parse_from_str("2014-57", "%Y-%m-%d").is_err());
+    assert!(NaiveDate::parse_from_str("2014", "%Y").is_err()); // insufficient
+
+    assert!(NaiveDate::parse_from_str("2014-5-7 Q3", "%Y-%m-%d Q%q").is_err()); // mismatched quarter
+
+    assert_eq!(
+        NaiveDate::parse_from_str("2020-01-0", "%Y-%W-%w").ok(),
+        NaiveDate::from_ymd_opt(2020, 1, 12),
+    );
+
+    assert_eq!(
+        NaiveDate::parse_from_str("2019-01-0", "%Y-%W-%w").ok(),
+        NaiveDate::from_ymd_opt(2019, 1, 13),
+    );
+}
+
+#[test]
+fn test_day_iterator_limit() {
+    assert_eq!(NaiveDate::from_ymd_opt(MAX_YEAR, 12, 29).unwrap().iter_days().take(4).count(), 2);
+    assert_eq!(
+        NaiveDate::from_ymd_opt(MIN_YEAR, 1, 3).unwrap().iter_days().rev().take(4).count(),
+        2
+    );
+}
+
+#[test]
+fn test_week_iterator_limit() {
+    assert_eq!(NaiveDate::from_ymd_opt(MAX_YEAR, 12, 12).unwrap().iter_weeks().take(4).count(), 2);
+    assert_eq!(
+        NaiveDate::from_ymd_opt(MIN_YEAR, 1, 15).unwrap().iter_weeks().rev().take(4).count(),
+        2
+    );
+}
+
+#[test]
+fn test_weeks_from() {
+    // tests per: https://github.com/chronotope/chrono/issues/961
+    // these internally use `weeks_from` via the parsing infrastructure
+    assert_eq!(
+        NaiveDate::parse_from_str("2020-01-0", "%Y-%W-%w").ok(),
+        NaiveDate::from_ymd_opt(2020, 1, 12),
+    );
+    assert_eq!(
+        NaiveDate::parse_from_str("2019-01-0", "%Y-%W-%w").ok(),
+        NaiveDate::from_ymd_opt(2019, 1, 13),
+    );
+
+    // direct tests
+    for (y, starts_on) in &[
+        (2019, Weekday::Tue),
+        (2020, Weekday::Wed),
+        (2021, Weekday::Fri),
+        (2022, Weekday::Sat),
+        (2023, Weekday::Sun),
+        (2024, Weekday::Mon),
+        (2025, Weekday::Wed),
+        (2026, Weekday::Thu),
+    ] {
+        for day in &[
+            Weekday::Mon,
+            Weekday::Tue,
+            Weekday::Wed,
+            Weekday::Thu,
+            Weekday::Fri,
+            Weekday::Sat,
+            Weekday::Sun,
+        ] {
+            assert_eq!(
+                NaiveDate::from_ymd_opt(*y, 1, 1).map(|d| d.weeks_from(*day)),
+                Some(if day == starts_on { 1 } else { 0 })
+            );
+
+            // last day must always be in week 52 or 53
+            assert!(
+                [52, 53].contains(&NaiveDate::from_ymd_opt(*y, 12, 31).unwrap().weeks_from(*day)),
+            );
+        }
+    }
+
+    let base = NaiveDate::from_ymd_opt(2019, 1, 1).unwrap();
+
+    // 400 years covers all year types
+    for day in &[
+        Weekday::Mon,
+        Weekday::Tue,
+        Weekday::Wed,
+        Weekday::Thu,
+        Weekday::Fri,
+        Weekday::Sat,
+        Weekday::Sun,
+    ] {
+        // must always be below 54
+        for dplus in 1..(400 * 366) {
+            assert!((base + Days::new(dplus)).weeks_from(*day) < 54)
+        }
+    }
+}
+
+#[test]
+fn test_with_0_overflow() {
+    let dt = NaiveDate::from_ymd_opt(2023, 4, 18).unwrap();
+    assert!(dt.with_month0(4294967295).is_none());
+    assert!(dt.with_day0(4294967295).is_none());
+    assert!(dt.with_ordinal0(4294967295).is_none());
+}
+
+#[test]
+fn test_leap_year() {
+    for year in 0..=MAX_YEAR {
+        let date = NaiveDate::from_ymd_opt(year, 1, 1).unwrap();
+        let is_leap = year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
+        assert_eq!(date.leap_year(), is_leap);
+        assert_eq!(date.leap_year(), date.with_ordinal(366).is_some());
+    }
+}
+
+#[test]
+fn test_date_yearflags() {
+    for (year, year_flags, _) in YEAR_FLAGS {
+        assert_eq!(NaiveDate::from_yo_opt(year, 1).unwrap().year_flags(), year_flags);
+    }
+}
+
+#[test]
+fn test_weekday_with_yearflags() {
+    for (year, year_flags, first_weekday) in YEAR_FLAGS {
+        let first_day_of_year = NaiveDate::from_yo_opt(year, 1).unwrap();
+        dbg!(year);
+        assert_eq!(first_day_of_year.year_flags(), year_flags);
+        assert_eq!(first_day_of_year.weekday(), first_weekday);
+
+        let mut prev = first_day_of_year.weekday();
+        for ordinal in 2u32..=year_flags.ndays() {
+            let date = NaiveDate::from_yo_opt(year, ordinal).unwrap();
+            let expected = prev.succ();
+            assert_eq!(date.weekday(), expected);
+            prev = expected;
+        }
+    }
+}
+
+#[test]
+fn test_isoweekdate_with_yearflags() {
+    for (year, year_flags, _) in YEAR_FLAGS {
+        // January 4 should be in the first week
+        let jan4 = NaiveDate::from_ymd_opt(year, 1, 4).unwrap();
+        let iso_week = jan4.iso_week();
+        assert_eq!(jan4.year_flags(), year_flags);
+        assert_eq!(iso_week.week(), 1);
+    }
+}
+
+#[test]
+fn test_date_to_mdf_to_date() {
+    for (year, year_flags, _) in YEAR_FLAGS {
+        for ordinal in 1..=year_flags.ndays() {
+            let date = NaiveDate::from_yo_opt(year, ordinal).unwrap();
+            assert_eq!(date, NaiveDate::from_mdf(date.year(), date.mdf()).unwrap());
+        }
+    }
+}
+
+// Used for testing some methods with all combinations of `YearFlags`.
+// (year, flags, first weekday of year)
+const YEAR_FLAGS: [(i32, YearFlags, Weekday); 14] = [
+    (2006, A, Weekday::Sun),
+    (2005, B, Weekday::Sat),
+    (2010, C, Weekday::Fri),
+    (2009, D, Weekday::Thu),
+    (2003, E, Weekday::Wed),
+    (2002, F, Weekday::Tue),
+    (2001, G, Weekday::Mon),
+    (2012, AG, Weekday::Sun),
+    (2000, BA, Weekday::Sat),
+    (2016, CB, Weekday::Fri),
+    (2004, DC, Weekday::Thu),
+    (2020, ED, Weekday::Wed),
+    (2008, FE, Weekday::Tue),
+    (2024, GF, Weekday::Mon),
+];
+
+#[test]
+#[cfg(feature = "rkyv-validation")]
+fn test_rkyv_validation() {
+    let date_min = NaiveDate::MIN;
+    let bytes = rkyv::to_bytes::<_, 4>(&date_min).unwrap();
+    assert_eq!(rkyv::from_bytes::<NaiveDate>(&bytes).unwrap(), date_min);
+
+    let date_max = NaiveDate::MAX;
+    let bytes = rkyv::to_bytes::<_, 4>(&date_max).unwrap();
+    assert_eq!(rkyv::from_bytes::<NaiveDate>(&bytes).unwrap(), date_max);
+}
+
+//   MAX_YEAR-12-31 minus 0000-01-01
+// = (MAX_YEAR-12-31 minus 0000-12-31) + (0000-12-31 - 0000-01-01)
+// = MAX_YEAR * 365 + (# of leap years from 0001 to MAX_YEAR) + 365
+// = (MAX_YEAR + 1) * 365 + (# of leap years from 0001 to MAX_YEAR)
+const MAX_DAYS_FROM_YEAR_0: i32 =
+    (MAX_YEAR + 1) * 365 + MAX_YEAR / 4 - MAX_YEAR / 100 + MAX_YEAR / 400;
+
+//   MIN_YEAR-01-01 minus 0000-01-01
+// = MIN_YEAR * 365 + (# of leap years from MIN_YEAR to 0000)
+const MIN_DAYS_FROM_YEAR_0: i32 = MIN_YEAR * 365 + MIN_YEAR / 4 - MIN_YEAR / 100 + MIN_YEAR / 400;
+
+// only used for testing, but duplicated in naive::datetime
+const MAX_BITS: usize = 44;

patch/chrono-0.4.41/src/naive/datetime/tests.rs

@@ -0,0 +1,405 @@
+use super::NaiveDateTime;
+use crate::{Datelike, FixedOffset, MappedLocalTime, NaiveDate, TimeDelta, Utc};
+
+#[test]
+fn test_datetime_add() {
+    fn check(
+        (y, m, d, h, n, s): (i32, u32, u32, u32, u32, u32),
+        rhs: TimeDelta,
+        result: Option<(i32, u32, u32, u32, u32, u32)>,
+    ) {
+        let lhs = NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_opt(h, n, s).unwrap();
+        let sum = result.map(|(y, m, d, h, n, s)| {
+            NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_opt(h, n, s).unwrap()
+        });
+        assert_eq!(lhs.checked_add_signed(rhs), sum);
+        assert_eq!(lhs.checked_sub_signed(-rhs), sum);
+    }
+    let seconds = |s| TimeDelta::try_seconds(s).unwrap();
+
+    check((2014, 5, 6, 7, 8, 9), seconds(3600 + 60 + 1), Some((2014, 5, 6, 8, 9, 10)));
+    check((2014, 5, 6, 7, 8, 9), seconds(-(3600 + 60 + 1)), Some((2014, 5, 6, 6, 7, 8)));
+    check((2014, 5, 6, 7, 8, 9), seconds(86399), Some((2014, 5, 7, 7, 8, 8)));
+    check((2014, 5, 6, 7, 8, 9), seconds(86_400 * 10), Some((2014, 5, 16, 7, 8, 9)));
+    check((2014, 5, 6, 7, 8, 9), seconds(-86_400 * 10), Some((2014, 4, 26, 7, 8, 9)));
+    check((2014, 5, 6, 7, 8, 9), seconds(86_400 * 10), Some((2014, 5, 16, 7, 8, 9)));
+
+    // overflow check
+    // assumes that we have correct values for MAX/MIN_DAYS_FROM_YEAR_0 from `naive::date`.
+    // (they are private constants, but the equivalence is tested in that module.)
+    let max_days_from_year_0 =
+        NaiveDate::MAX.signed_duration_since(NaiveDate::from_ymd_opt(0, 1, 1).unwrap());
+    check((0, 1, 1, 0, 0, 0), max_days_from_year_0, Some((NaiveDate::MAX.year(), 12, 31, 0, 0, 0)));
+    check(
+        (0, 1, 1, 0, 0, 0),
+        max_days_from_year_0 + seconds(86399),
+        Some((NaiveDate::MAX.year(), 12, 31, 23, 59, 59)),
+    );
+    check((0, 1, 1, 0, 0, 0), max_days_from_year_0 + seconds(86_400), None);
+    check((0, 1, 1, 0, 0, 0), TimeDelta::MAX, None);
+
+    let min_days_from_year_0 =
+        NaiveDate::MIN.signed_duration_since(NaiveDate::from_ymd_opt(0, 1, 1).unwrap());
+    check((0, 1, 1, 0, 0, 0), min_days_from_year_0, Some((NaiveDate::MIN.year(), 1, 1, 0, 0, 0)));
+    check((0, 1, 1, 0, 0, 0), min_days_from_year_0 - seconds(1), None);
+    check((0, 1, 1, 0, 0, 0), TimeDelta::MIN, None);
+}
+
+#[test]
+fn test_datetime_sub() {
+    let ymdhms =
+        |y, m, d, h, n, s| NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_opt(h, n, s).unwrap();
+    let since = NaiveDateTime::signed_duration_since;
+    assert_eq!(since(ymdhms(2014, 5, 6, 7, 8, 9), ymdhms(2014, 5, 6, 7, 8, 9)), TimeDelta::zero());
+    assert_eq!(
+        since(ymdhms(2014, 5, 6, 7, 8, 10), ymdhms(2014, 5, 6, 7, 8, 9)),
+        TimeDelta::try_seconds(1).unwrap()
+    );
+    assert_eq!(
+        since(ymdhms(2014, 5, 6, 7, 8, 9), ymdhms(2014, 5, 6, 7, 8, 10)),
+        TimeDelta::try_seconds(-1).unwrap()
+    );
+    assert_eq!(
+        since(ymdhms(2014, 5, 7, 7, 8, 9), ymdhms(2014, 5, 6, 7, 8, 10)),
+        TimeDelta::try_seconds(86399).unwrap()
+    );
+    assert_eq!(
+        since(ymdhms(2001, 9, 9, 1, 46, 39), ymdhms(1970, 1, 1, 0, 0, 0)),
+        TimeDelta::try_seconds(999_999_999).unwrap()
+    );
+}
+
+#[test]
+fn test_datetime_addassignment() {
+    let ymdhms =
+        |y, m, d, h, n, s| NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_opt(h, n, s).unwrap();
+    let mut date = ymdhms(2016, 10, 1, 10, 10, 10);
+    date += TimeDelta::try_minutes(10_000_000).unwrap();
+    assert_eq!(date, ymdhms(2035, 10, 6, 20, 50, 10));
+    date += TimeDelta::try_days(10).unwrap();
+    assert_eq!(date, ymdhms(2035, 10, 16, 20, 50, 10));
+}
+
+#[test]
+fn test_datetime_subassignment() {
+    let ymdhms =
+        |y, m, d, h, n, s| NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_opt(h, n, s).unwrap();
+    let mut date = ymdhms(2016, 10, 1, 10, 10, 10);
+    date -= TimeDelta::try_minutes(10_000_000).unwrap();
+    assert_eq!(date, ymdhms(1997, 9, 26, 23, 30, 10));
+    date -= TimeDelta::try_days(10).unwrap();
+    assert_eq!(date, ymdhms(1997, 9, 16, 23, 30, 10));
+}
+
+#[test]
+fn test_core_duration_ops() {
+    use core::time::Duration;
+
+    let mut dt = NaiveDate::from_ymd_opt(2023, 8, 29).unwrap().and_hms_opt(11, 34, 12).unwrap();
+    let same = dt + Duration::ZERO;
+    assert_eq!(dt, same);
+
+    dt += Duration::new(3600, 0);
+    assert_eq!(dt, NaiveDate::from_ymd_opt(2023, 8, 29).unwrap().and_hms_opt(12, 34, 12).unwrap());
+}
+
+#[test]
+#[should_panic]
+fn test_core_duration_max() {
+    use core::time::Duration;
+
+    let mut utc_dt = NaiveDate::from_ymd_opt(2023, 8, 29).unwrap().and_hms_opt(11, 34, 12).unwrap();
+    utc_dt += Duration::MAX;
+}
+
+#[test]
+fn test_datetime_from_str() {
+    // valid cases
+    let valid = [
+        "2001-02-03T04:05:06",
+        "2012-12-12T12:12:12",
+        "2015-02-18T23:16:09.153",
+        "2015-2-18T23:16:09.153",
+        "-77-02-18T23:16:09",
+        "+82701-05-6T15:9:60.898989898989",
+        "  +82701  -  05  -  6  T  15  :  9  : 60.898989898989   ",
+    ];
+    for &s in &valid {
+        eprintln!("test_parse_naivedatetime valid {s:?}");
+        let d = match s.parse::<NaiveDateTime>() {
+            Ok(d) => d,
+            Err(e) => panic!("parsing `{s}` has failed: {e}"),
+        };
+        let s_ = format!("{d:?}");
+        // `s` and `s_` may differ, but `s.parse()` and `s_.parse()` must be same
+        let d_ = match s_.parse::<NaiveDateTime>() {
+            Ok(d) => d,
+            Err(e) => {
+                panic!("`{s}` is parsed into `{d:?}`, but reparsing that has failed: {e}")
+            }
+        };
+        assert!(
+            d == d_,
+            "`{s}` is parsed into `{d:?}`, but reparsed result \
+             `{d_:?}` does not match"
+        );
+    }
+
+    // some invalid cases
+    // since `ParseErrorKind` is private, all we can do is to check if there was an error
+    let invalid = [
+        "",                              // empty
+        "x",                             // invalid / missing data
+        "15",                            // missing data
+        "15:8:9",                        // looks like a time (invalid date)
+        "15-8-9",                        // looks like a date (invalid)
+        "Fri, 09 Aug 2013 23:54:35 GMT", // valid date, wrong format
+        "Sat Jun 30 23:59:60 2012",      // valid date, wrong format
+        "1441497364.649",                // valid date, wrong format
+        "+1441497364.649",               // valid date, wrong format
+        "+1441497364",                   // valid date, wrong format
+        "2014/02/03 04:05:06",           // valid date, wrong format
+        "2015-15-15T15:15:15",           // invalid date
+        "2012-12-12T12:12:12x",          // bad timezone / trailing literal
+        "2012-12-12T12:12:12+00:00",     // unexpected timezone / trailing literal
+        "2012-12-12T12:12:12 +00:00",    // unexpected timezone / trailing literal
+        "2012-12-12T12:12:12 GMT",       // unexpected timezone / trailing literal
+        "2012-123-12T12:12:12",          // invalid month
+        "2012-12-12t12:12:12",           // bad divider 't'
+        "2012-12-12 12:12:12",           // missing divider 'T'
+        "2012-12-12T12:12:12Z",          // trailing char 'Z'
+        "+ 82701-123-12T12:12:12",       // strange year, invalid month
+        "+802701-123-12T12:12:12",       // out-of-bound year, invalid month
+    ];
+    for &s in &invalid {
+        eprintln!("test_datetime_from_str invalid {s:?}");
+        assert!(s.parse::<NaiveDateTime>().is_err());
+    }
+}
+
+#[test]
+fn test_datetime_parse_from_str() {
+    let ymdhms =
+        |y, m, d, h, n, s| NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_opt(h, n, s).unwrap();
+    let ymdhmsn = |y, m, d, h, n, s, nano| {
+        NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_nano_opt(h, n, s, nano).unwrap()
+    };
+    assert_eq!(
+        NaiveDateTime::parse_from_str("2014-5-7T12:34:56+09:30", "%Y-%m-%dT%H:%M:%S%z"),
+        Ok(ymdhms(2014, 5, 7, 12, 34, 56))
+    ); // ignore offset
+    assert_eq!(
+        NaiveDateTime::parse_from_str("2015-W06-1 000000", "%G-W%V-%u%H%M%S"),
+        Ok(ymdhms(2015, 2, 2, 0, 0, 0))
+    );
+    assert_eq!(
+        NaiveDateTime::parse_from_str("Fri, 09 Aug 2013 23:54:35 GMT", "%a, %d %b %Y %H:%M:%S GMT"),
+        Ok(ymdhms(2013, 8, 9, 23, 54, 35))
+    );
+    assert!(
+        NaiveDateTime::parse_from_str("Sat, 09 Aug 2013 23:54:35 GMT", "%a, %d %b %Y %H:%M:%S GMT")
+            .is_err()
+    );
+    assert!(NaiveDateTime::parse_from_str("2014-5-7 Q2 12:3456", "%Y-%m-%d Q%q %H:%M:%S").is_err());
+    assert!(NaiveDateTime::parse_from_str("12:34:56", "%H:%M:%S").is_err()); // insufficient
+    assert_eq!(
+        NaiveDateTime::parse_from_str("1441497364", "%s"),
+        Ok(ymdhms(2015, 9, 5, 23, 56, 4))
+    );
+    assert_eq!(
+        NaiveDateTime::parse_from_str("1283929614.1234", "%s.%f"),
+        Ok(ymdhmsn(2010, 9, 8, 7, 6, 54, 1234))
+    );
+    assert_eq!(
+        NaiveDateTime::parse_from_str("1441497364.649", "%s%.3f"),
+        Ok(ymdhmsn(2015, 9, 5, 23, 56, 4, 649000000))
+    );
+    assert_eq!(
+        NaiveDateTime::parse_from_str("1497854303.087654", "%s%.6f"),
+        Ok(ymdhmsn(2017, 6, 19, 6, 38, 23, 87654000))
+    );
+    assert_eq!(
+        NaiveDateTime::parse_from_str("1437742189.918273645", "%s%.9f"),
+        Ok(ymdhmsn(2015, 7, 24, 12, 49, 49, 918273645))
+    );
+}
+
+#[test]
+fn test_datetime_parse_from_str_with_spaces() {
+    let parse_from_str = NaiveDateTime::parse_from_str;
+    let dt = NaiveDate::from_ymd_opt(2013, 8, 9).unwrap().and_hms_opt(23, 54, 35).unwrap();
+    // with varying spaces - should succeed
+    assert_eq!(parse_from_str(" Aug 09 2013 23:54:35", " %b %d %Y %H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("Aug 09 2013 23:54:35 ", "%b %d %Y %H:%M:%S "), Ok(dt));
+    assert_eq!(parse_from_str(" Aug 09 2013  23:54:35 ", " %b %d %Y  %H:%M:%S "), Ok(dt));
+    assert_eq!(parse_from_str("  Aug 09 2013 23:54:35", "  %b %d %Y %H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("   Aug 09 2013 23:54:35", "   %b %d %Y %H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("\n\tAug 09 2013 23:54:35  ", "\n\t%b %d %Y %H:%M:%S  "), Ok(dt));
+    assert_eq!(parse_from_str("\tAug 09 2013 23:54:35\t", "\t%b %d %Y %H:%M:%S\t"), Ok(dt));
+    assert_eq!(parse_from_str("Aug  09 2013 23:54:35", "%b  %d %Y %H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("Aug    09 2013 23:54:35", "%b    %d %Y %H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("Aug  09 2013\t23:54:35", "%b  %d %Y\t%H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("Aug  09 2013\t\t23:54:35", "%b  %d %Y\t\t%H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("Aug 09 2013 23:54:35 ", "%b %d %Y %H:%M:%S\n"), Ok(dt));
+    assert_eq!(parse_from_str("Aug 09 2013 23:54:35", "%b %d %Y\t%H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("Aug 09 2013 23:54:35", "%b %d %Y %H:%M:%S "), Ok(dt));
+    assert_eq!(parse_from_str("Aug 09 2013 23:54:35", " %b %d %Y %H:%M:%S"), Ok(dt));
+    assert_eq!(parse_from_str("Aug 09 2013 23:54:35", "%b %d %Y %H:%M:%S\n"), Ok(dt));
+    // with varying spaces - should fail
+    // leading space in data
+    assert!(parse_from_str(" Aug 09 2013 23:54:35", "%b %d %Y %H:%M:%S").is_err());
+    // trailing space in data
+    assert!(parse_from_str("Aug 09 2013 23:54:35 ", "%b %d %Y %H:%M:%S").is_err());
+    // trailing tab in data
+    assert!(parse_from_str("Aug 09 2013 23:54:35\t", "%b %d %Y %H:%M:%S").is_err());
+    // mismatched newlines
+    assert!(parse_from_str("\nAug 09 2013 23:54:35", "%b %d %Y %H:%M:%S\n").is_err());
+    // trailing literal in data
+    assert!(parse_from_str("Aug 09 2013 23:54:35 !!!", "%b %d %Y %H:%M:%S ").is_err());
+}
+
+#[test]
+fn test_datetime_add_sub_invariant() {
+    // issue #37
+    let base = NaiveDate::from_ymd_opt(2000, 1, 1).unwrap().and_hms_opt(0, 0, 0).unwrap();
+    let t = -946684799990000;
+    let time = base + TimeDelta::microseconds(t);
+    assert_eq!(t, time.signed_duration_since(base).num_microseconds().unwrap());
+}
+
+#[test]
+fn test_and_local_timezone() {
+    let ndt = NaiveDate::from_ymd_opt(2022, 6, 15).unwrap().and_hms_opt(18, 59, 36).unwrap();
+    let dt_utc = ndt.and_utc();
+    assert_eq!(dt_utc.naive_local(), ndt);
+    assert_eq!(dt_utc.timezone(), Utc);
+
+    let offset_tz = FixedOffset::west_opt(4 * 3600).unwrap();
+    let dt_offset = ndt.and_local_timezone(offset_tz).unwrap();
+    assert_eq!(dt_offset.naive_local(), ndt);
+    assert_eq!(dt_offset.timezone(), offset_tz);
+}
+
+#[test]
+fn test_and_utc() {
+    let ndt = NaiveDate::from_ymd_opt(2023, 1, 30).unwrap().and_hms_opt(19, 32, 33).unwrap();
+    let dt_utc = ndt.and_utc();
+    assert_eq!(dt_utc.naive_local(), ndt);
+    assert_eq!(dt_utc.timezone(), Utc);
+}
+
+#[test]
+fn test_checked_add_offset() {
+    let ymdhmsm = |y, m, d, h, mn, s, mi| {
+        NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_milli_opt(h, mn, s, mi)
+    };
+
+    let positive_offset = FixedOffset::east_opt(2 * 60 * 60).unwrap();
+    // regular date
+    let dt = ymdhmsm(2023, 5, 5, 20, 10, 0, 0).unwrap();
+    assert_eq!(dt.checked_add_offset(positive_offset), ymdhmsm(2023, 5, 5, 22, 10, 0, 0));
+    // leap second is preserved
+    let dt = ymdhmsm(2023, 6, 30, 23, 59, 59, 1_000).unwrap();
+    assert_eq!(dt.checked_add_offset(positive_offset), ymdhmsm(2023, 7, 1, 1, 59, 59, 1_000));
+    // out of range
+    assert!(NaiveDateTime::MAX.checked_add_offset(positive_offset).is_none());
+
+    let negative_offset = FixedOffset::west_opt(2 * 60 * 60).unwrap();
+    // regular date
+    let dt = ymdhmsm(2023, 5, 5, 20, 10, 0, 0).unwrap();
+    assert_eq!(dt.checked_add_offset(negative_offset), ymdhmsm(2023, 5, 5, 18, 10, 0, 0));
+    // leap second is preserved
+    let dt = ymdhmsm(2023, 6, 30, 23, 59, 59, 1_000).unwrap();
+    assert_eq!(dt.checked_add_offset(negative_offset), ymdhmsm(2023, 6, 30, 21, 59, 59, 1_000));
+    // out of range
+    assert!(NaiveDateTime::MIN.checked_add_offset(negative_offset).is_none());
+}
+
+#[test]
+fn test_checked_sub_offset() {
+    let ymdhmsm = |y, m, d, h, mn, s, mi| {
+        NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_milli_opt(h, mn, s, mi)
+    };
+
+    let positive_offset = FixedOffset::east_opt(2 * 60 * 60).unwrap();
+    // regular date
+    let dt = ymdhmsm(2023, 5, 5, 20, 10, 0, 0).unwrap();
+    assert_eq!(dt.checked_sub_offset(positive_offset), ymdhmsm(2023, 5, 5, 18, 10, 0, 0));
+    // leap second is preserved
+    let dt = ymdhmsm(2023, 6, 30, 23, 59, 59, 1_000).unwrap();
+    assert_eq!(dt.checked_sub_offset(positive_offset), ymdhmsm(2023, 6, 30, 21, 59, 59, 1_000));
+    // out of range
+    assert!(NaiveDateTime::MIN.checked_sub_offset(positive_offset).is_none());
+
+    let negative_offset = FixedOffset::west_opt(2 * 60 * 60).unwrap();
+    // regular date
+    let dt = ymdhmsm(2023, 5, 5, 20, 10, 0, 0).unwrap();
+    assert_eq!(dt.checked_sub_offset(negative_offset), ymdhmsm(2023, 5, 5, 22, 10, 0, 0));
+    // leap second is preserved
+    let dt = ymdhmsm(2023, 6, 30, 23, 59, 59, 1_000).unwrap();
+    assert_eq!(dt.checked_sub_offset(negative_offset), ymdhmsm(2023, 7, 1, 1, 59, 59, 1_000));
+    // out of range
+    assert!(NaiveDateTime::MAX.checked_sub_offset(negative_offset).is_none());
+
+    assert_eq!(dt.checked_add_offset(positive_offset), Some(dt + positive_offset));
+    assert_eq!(dt.checked_sub_offset(positive_offset), Some(dt - positive_offset));
+}
+
+#[test]
+fn test_overflowing_add_offset() {
+    let ymdhmsm = |y, m, d, h, mn, s, mi| {
+        NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_milli_opt(h, mn, s, mi).unwrap()
+    };
+    let positive_offset = FixedOffset::east_opt(2 * 60 * 60).unwrap();
+    // regular date
+    let dt = ymdhmsm(2023, 5, 5, 20, 10, 0, 0);
+    assert_eq!(dt.overflowing_add_offset(positive_offset), ymdhmsm(2023, 5, 5, 22, 10, 0, 0));
+    // leap second is preserved
+    let dt = ymdhmsm(2023, 6, 30, 23, 59, 59, 1_000);
+    assert_eq!(dt.overflowing_add_offset(positive_offset), ymdhmsm(2023, 7, 1, 1, 59, 59, 1_000));
+    // out of range
+    assert!(NaiveDateTime::MAX.overflowing_add_offset(positive_offset) > NaiveDateTime::MAX);
+
+    let negative_offset = FixedOffset::west_opt(2 * 60 * 60).unwrap();
+    // regular date
+    let dt = ymdhmsm(2023, 5, 5, 20, 10, 0, 0);
+    assert_eq!(dt.overflowing_add_offset(negative_offset), ymdhmsm(2023, 5, 5, 18, 10, 0, 0));
+    // leap second is preserved
+    let dt = ymdhmsm(2023, 6, 30, 23, 59, 59, 1_000);
+    assert_eq!(dt.overflowing_add_offset(negative_offset), ymdhmsm(2023, 6, 30, 21, 59, 59, 1_000));
+    // out of range
+    assert!(NaiveDateTime::MIN.overflowing_add_offset(negative_offset) < NaiveDateTime::MIN);
+}
+
+#[test]
+fn test_and_timezone_min_max_dates() {
+    for offset_hour in -23..=23 {
+        dbg!(offset_hour);
+        let offset = FixedOffset::east_opt(offset_hour * 60 * 60).unwrap();
+
+        let local_max = NaiveDateTime::MAX.and_local_timezone(offset);
+        if offset_hour >= 0 {
+            assert_eq!(local_max.unwrap().naive_local(), NaiveDateTime::MAX);
+        } else {
+            assert_eq!(local_max, MappedLocalTime::None);
+        }
+        let local_min = NaiveDateTime::MIN.and_local_timezone(offset);
+        if offset_hour <= 0 {
+            assert_eq!(local_min.unwrap().naive_local(), NaiveDateTime::MIN);
+        } else {
+            assert_eq!(local_min, MappedLocalTime::None);
+        }
+    }
+}
+
+#[test]
+#[cfg(feature = "rkyv-validation")]
+fn test_rkyv_validation() {
+    let dt_min = NaiveDateTime::MIN;
+    let bytes = rkyv::to_bytes::<_, 12>(&dt_min).unwrap();
+    assert_eq!(rkyv::from_bytes::<NaiveDateTime>(&bytes).unwrap(), dt_min);
+
+    let dt_max = NaiveDateTime::MAX;
+    let bytes = rkyv::to_bytes::<_, 12>(&dt_max).unwrap();
+    assert_eq!(rkyv::from_bytes::<NaiveDateTime>(&bytes).unwrap(), dt_max);
+}

patch/chrono-0.4.41/src/naive/internals.rs

@@ -0,0 +1,591 @@
+//! Internal helper types for working with dates.
+
+#![cfg_attr(feature = "__internal_bench", allow(missing_docs))]
+
+use core::fmt;
+
+/// Year flags (aka the dominical letter).
+///
+/// `YearFlags` are used as the last four bits of `NaiveDate`, `Mdf` and `IsoWeek`.
+///
+/// There are 14 possible classes of year in the Gregorian calendar:
+/// common and leap years starting with Monday through Sunday.
+///
+/// The `YearFlags` stores this information into 4 bits `LWWW`. `L` is the leap year flag, with `1`
+/// for the common year (this simplifies validating an ordinal in `NaiveDate`). `WWW` is a non-zero
+/// `Weekday` of the last day in the preceding year.
+#[allow(unreachable_pub)] // public as an alias for benchmarks only
+#[derive(PartialEq, Eq, Copy, Clone, Hash)]
+pub struct YearFlags(pub(super) u8);
+
+// Weekday of the last day in the preceding year.
+// Allows for quick day of week calculation from the 1-based ordinal.
+const YEAR_STARTS_AFTER_MONDAY: u8 = 7; // non-zero to allow use with `NonZero*`.
+const YEAR_STARTS_AFTER_THUESDAY: u8 = 1;
+const YEAR_STARTS_AFTER_WEDNESDAY: u8 = 2;
+const YEAR_STARTS_AFTER_THURSDAY: u8 = 3;
+const YEAR_STARTS_AFTER_FRIDAY: u8 = 4;
+const YEAR_STARTS_AFTER_SATURDAY: u8 = 5;
+const YEAR_STARTS_AFTER_SUNDAY: u8 = 6;
+
+const COMMON_YEAR: u8 = 1 << 3;
+const LEAP_YEAR: u8 = 0 << 3;
+
+pub(super) const A: YearFlags = YearFlags(COMMON_YEAR | YEAR_STARTS_AFTER_SATURDAY);
+pub(super) const AG: YearFlags = YearFlags(LEAP_YEAR | YEAR_STARTS_AFTER_SATURDAY);
+pub(super) const B: YearFlags = YearFlags(COMMON_YEAR | YEAR_STARTS_AFTER_FRIDAY);
+pub(super) const BA: YearFlags = YearFlags(LEAP_YEAR | YEAR_STARTS_AFTER_FRIDAY);
+pub(super) const C: YearFlags = YearFlags(COMMON_YEAR | YEAR_STARTS_AFTER_THURSDAY);
+pub(super) const CB: YearFlags = YearFlags(LEAP_YEAR | YEAR_STARTS_AFTER_THURSDAY);
+pub(super) const D: YearFlags = YearFlags(COMMON_YEAR | YEAR_STARTS_AFTER_WEDNESDAY);
+pub(super) const DC: YearFlags = YearFlags(LEAP_YEAR | YEAR_STARTS_AFTER_WEDNESDAY);
+pub(super) const E: YearFlags = YearFlags(COMMON_YEAR | YEAR_STARTS_AFTER_THUESDAY);
+pub(super) const ED: YearFlags = YearFlags(LEAP_YEAR | YEAR_STARTS_AFTER_THUESDAY);
+pub(super) const F: YearFlags = YearFlags(COMMON_YEAR | YEAR_STARTS_AFTER_MONDAY);
+pub(super) const FE: YearFlags = YearFlags(LEAP_YEAR | YEAR_STARTS_AFTER_MONDAY);
+pub(super) const G: YearFlags = YearFlags(COMMON_YEAR | YEAR_STARTS_AFTER_SUNDAY);
+pub(super) const GF: YearFlags = YearFlags(LEAP_YEAR | YEAR_STARTS_AFTER_SUNDAY);
+
+const YEAR_TO_FLAGS: &[YearFlags; 400] = &[
+    BA, G, F, E, DC, B, A, G, FE, D, C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA,
+    G, F, E, DC, B, A, G, FE, D, C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G,
+    F, E, DC, B, A, G, FE, D, C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F,
+    E, DC, B, A, G, FE, D, C, B, AG, F, E, D, // 100
+    C, B, A, G, FE, D, C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC,
+    B, A, G, FE, D, C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC, B,
+    A, G, FE, D, C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC, B, A,
+    G, FE, D, C, B, AG, F, E, D, CB, A, G, F, // 200
+    E, D, C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC, B, A, G, FE,
+    D, C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC, B, A, G, FE, D,
+    C, B, AG, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC, B, A, G, FE, D, C,
+    B, AG, F, E, D, CB, A, G, F, ED, C, B, A, // 300
+    G, F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC, B, A, G, FE, D, C, B, AG,
+    F, E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC, B, A, G, FE, D, C, B, AG, F,
+    E, D, CB, A, G, F, ED, C, B, A, GF, E, D, C, BA, G, F, E, DC, B, A, G, FE, D, C, B, AG, F, E,
+    D, CB, A, G, F, ED, C, B, A, GF, E, D, C, // 400
+];
+
+impl YearFlags {
+    #[allow(unreachable_pub)] // public as an alias for benchmarks only
+    #[doc(hidden)] // for benchmarks only
+    #[inline]
+    #[must_use]
+    pub const fn from_year(year: i32) -> YearFlags {
+        let year = year.rem_euclid(400);
+        YearFlags::from_year_mod_400(year)
+    }
+
+    #[inline]
+    pub(super) const fn from_year_mod_400(year: i32) -> YearFlags {
+        YEAR_TO_FLAGS[year as usize]
+    }
+
+    #[inline]
+    pub(super) const fn ndays(&self) -> u32 {
+        let YearFlags(flags) = *self;
+        366 - (flags >> 3) as u32
+    }
+
+    #[inline]
+    pub(super) const fn isoweek_delta(&self) -> u32 {
+        let YearFlags(flags) = *self;
+        let mut delta = (flags & 0b0111) as u32;
+        if delta < 3 {
+            delta += 7;
+        }
+        delta
+    }
+
+    #[inline]
+    pub(super) const fn nisoweeks(&self) -> u32 {
+        let YearFlags(flags) = *self;
+        52 + ((0b0000_0100_0000_0110 >> flags as usize) & 1)
+    }
+}
+
+impl fmt::Debug for YearFlags {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let YearFlags(flags) = *self;
+        match flags {
+            0o15 => "A".fmt(f),
+            0o05 => "AG".fmt(f),
+            0o14 => "B".fmt(f),
+            0o04 => "BA".fmt(f),
+            0o13 => "C".fmt(f),
+            0o03 => "CB".fmt(f),
+            0o12 => "D".fmt(f),
+            0o02 => "DC".fmt(f),
+            0o11 => "E".fmt(f),
+            0o01 => "ED".fmt(f),
+            0o10 => "F?".fmt(f),
+            0o00 => "FE?".fmt(f), // non-canonical
+            0o17 => "F".fmt(f),
+            0o07 => "FE".fmt(f),
+            0o16 => "G".fmt(f),
+            0o06 => "GF".fmt(f),
+            _ => write!(f, "YearFlags({flags})"),
+        }
+    }
+}
+
+// OL: (ordinal << 1) | leap year flag
+const MAX_OL: u32 = 366 << 1; // `(366 << 1) | 1` would be day 366 in a non-leap year
+const MAX_MDL: u32 = (12 << 6) | (31 << 1) | 1;
+
+// The next table are adjustment values to convert a date encoded as month-day-leapyear to
+// ordinal-leapyear. OL = MDL - adjustment.
+// Dates that do not exist are encoded as `XX`.
+const XX: i8 = 0;
+const MDL_TO_OL: &[i8; MAX_MDL as usize + 1] = &[
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX,
+    XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, // 0
+    XX, XX, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, // 1
+    XX, XX, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
+    66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
+    66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, XX, XX, XX, XX, XX, // 2
+    XX, XX, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74,
+    72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74,
+    72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, // 3
+    XX, XX, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76,
+    74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76,
+    74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, XX, XX, // 4
+    XX, XX, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80,
+    78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80,
+    78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, // 5
+    XX, XX, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82,
+    80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82,
+    80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, XX, XX, // 6
+    XX, XX, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86,
+    84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86,
+    84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, // 7
+    XX, XX, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88,
+    86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88,
+    86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, // 8
+    XX, XX, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90,
+    88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90,
+    88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, XX, XX, // 9
+    XX, XX, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94,
+    92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94,
+    92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, // 10
+    XX, XX, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96,
+    94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96,
+    94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, XX, XX, // 11
+    XX, XX, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98,
+    100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100,
+    98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98,
+    100, // 12
+];
+
+const OL_TO_MDL: &[u8; MAX_OL as usize + 1] = &[
+    0, 0, // 0
+    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
+    64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, // 1
+    66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
+    66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66,
+    66, 66, 66, 66, 66, 66, 66, 66, 66, // 2
+    74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72,
+    74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72,
+    74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, 74, 72, // 3
+    76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74,
+    76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74,
+    76, 74, 76, 74, 76, 74, 76, 74, 76, 74, 76, 74, // 4
+    80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78,
+    80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78,
+    80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, 80, 78, // 5
+    82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80,
+    82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80,
+    82, 80, 82, 80, 82, 80, 82, 80, 82, 80, 82, 80, // 6
+    86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84,
+    86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84,
+    86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, 86, 84, // 7
+    88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86,
+    88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86,
+    88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, 88, 86, // 8
+    90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88,
+    90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88,
+    90, 88, 90, 88, 90, 88, 90, 88, 90, 88, 90, 88, // 9
+    94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92,
+    94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92,
+    94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, 94, 92, // 10
+    96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94,
+    96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94,
+    96, 94, 96, 94, 96, 94, 96, 94, 96, 94, 96, 94, // 11
+    100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100,
+    98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98,
+    100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100, 98, 100,
+    98, // 12
+];
+
+/// Month, day of month and year flags: `(month << 9) | (day << 4) | flags`
+/// `M_MMMD_DDDD_LFFF`
+///
+/// The whole bits except for the least 3 bits are referred as `Mdl` (month, day of month, and leap
+/// year flag), which is an index to the `MDL_TO_OL` lookup table.
+///
+/// The conversion between the packed calendar date (`Mdf`) and the ordinal date (`NaiveDate`) is
+/// based on the moderately-sized lookup table (~1.5KB) and the packed representation is chosen for
+/// efficient lookup.
+///
+/// The methods of `Mdf` validate their inputs as late as possible. Dates that can't exist, like
+/// February 30, can still be represented. This allows the validation to be combined with the final
+/// table lookup, which is good for performance.
+#[derive(PartialEq, PartialOrd, Copy, Clone)]
+pub(super) struct Mdf(u32);
+
+impl Mdf {
+    /// Makes a new `Mdf` value from month, day and `YearFlags`.
+    ///
+    /// This method doesn't fully validate the range of the `month` and `day` parameters, only as
+    /// much as what can't be deferred until later. The year `flags` are trusted to be correct.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` if `month > 12` or `day > 31`.
+    #[inline]
+    pub(super) const fn new(month: u32, day: u32, YearFlags(flags): YearFlags) -> Option<Mdf> {
+        match month <= 12 && day <= 31 {
+            true => Some(Mdf((month << 9) | (day << 4) | flags as u32)),
+            false => None,
+        }
+    }
+
+    /// Makes a new `Mdf` value from an `i32` with an ordinal and a leap year flag, and year
+    /// `flags`.
+    ///
+    /// The `ol` is trusted to be valid, and the `flags` are trusted to match it.
+    #[inline]
+    pub(super) const fn from_ol(ol: i32, YearFlags(flags): YearFlags) -> Mdf {
+        debug_assert!(ol > 1 && ol <= MAX_OL as i32);
+        // Array is indexed from `[2..=MAX_OL]`, with a `0` index having a meaningless value.
+        Mdf(((ol as u32 + OL_TO_MDL[ol as usize] as u32) << 3) | flags as u32)
+    }
+
+    /// Returns the month of this `Mdf`.
+    #[inline]
+    pub(super) const fn month(&self) -> u32 {
+        let Mdf(mdf) = *self;
+        mdf >> 9
+    }
+
+    /// Replaces the month of this `Mdf`, keeping the day and flags.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` if `month > 12`.
+    #[inline]
+    pub(super) const fn with_month(&self, month: u32) -> Option<Mdf> {
+        if month > 12 {
+            return None;
+        }
+
+        let Mdf(mdf) = *self;
+        Some(Mdf((mdf & 0b1_1111_1111) | (month << 9)))
+    }
+
+    /// Returns the day of this `Mdf`.
+    #[inline]
+    pub(super) const fn day(&self) -> u32 {
+        let Mdf(mdf) = *self;
+        (mdf >> 4) & 0b1_1111
+    }
+
+    /// Replaces the day of this `Mdf`, keeping the month and flags.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` if `day > 31`.
+    #[inline]
+    pub(super) const fn with_day(&self, day: u32) -> Option<Mdf> {
+        if day > 31 {
+            return None;
+        }
+
+        let Mdf(mdf) = *self;
+        Some(Mdf((mdf & !0b1_1111_0000) | (day << 4)))
+    }
+
+    /// Replaces the flags of this `Mdf`, keeping the month and day.
+    #[inline]
+    pub(super) const fn with_flags(&self, YearFlags(flags): YearFlags) -> Mdf {
+        let Mdf(mdf) = *self;
+        Mdf((mdf & !0b1111) | flags as u32)
+    }
+
+    /// Returns the ordinal that corresponds to this `Mdf`.
+    ///
+    /// This does a table lookup to calculate the corresponding ordinal. It will return an error if
+    /// the `Mdl` turns out not to be a valid date.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` if `month == 0` or `day == 0`, or if a the given day does not exist in the
+    /// given month.
+    #[inline]
+    pub(super) const fn ordinal(&self) -> Option<u32> {
+        let mdl = self.0 >> 3;
+        match MDL_TO_OL[mdl as usize] {
+            XX => None,
+            v => Some((mdl - v as u8 as u32) >> 1),
+        }
+    }
+
+    /// Returns the year flags of this `Mdf`.
+    #[inline]
+    pub(super) const fn year_flags(&self) -> YearFlags {
+        YearFlags((self.0 & 0b1111) as u8)
+    }
+
+    /// Returns the ordinal that corresponds to this `Mdf`, encoded as a value including year flags.
+    ///
+    /// This does a table lookup to calculate the corresponding ordinal. It will return an error if
+    /// the `Mdl` turns out not to be a valid date.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` if `month == 0` or `day == 0`, or if a the given day does not exist in the
+    /// given month.
+    #[inline]
+    pub(super) const fn ordinal_and_flags(&self) -> Option<i32> {
+        let mdl = self.0 >> 3;
+        match MDL_TO_OL[mdl as usize] {
+            XX => None,
+            v => Some(self.0 as i32 - ((v as i32) << 3)),
+        }
+    }
+
+    #[cfg(test)]
+    fn valid(&self) -> bool {
+        let mdl = self.0 >> 3;
+        MDL_TO_OL[mdl as usize] > 0
+    }
+}
+
+impl fmt::Debug for Mdf {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let Mdf(mdf) = *self;
+        write!(
+            f,
+            "Mdf(({} << 9) | ({} << 4) | {:#04o} /*{:?}*/)",
+            mdf >> 9,
+            (mdf >> 4) & 0b1_1111,
+            mdf & 0b1111,
+            YearFlags((mdf & 0b1111) as u8)
+        )
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Mdf;
+    use super::{A, AG, B, BA, C, CB, D, DC, E, ED, F, FE, G, GF, YearFlags};
+
+    const NONLEAP_FLAGS: [YearFlags; 7] = [A, B, C, D, E, F, G];
+    const LEAP_FLAGS: [YearFlags; 7] = [AG, BA, CB, DC, ED, FE, GF];
+    const FLAGS: [YearFlags; 14] = [A, B, C, D, E, F, G, AG, BA, CB, DC, ED, FE, GF];
+
+    #[test]
+    fn test_year_flags_ndays_from_year() {
+        assert_eq!(YearFlags::from_year(2014).ndays(), 365);
+        assert_eq!(YearFlags::from_year(2012).ndays(), 366);
+        assert_eq!(YearFlags::from_year(2000).ndays(), 366);
+        assert_eq!(YearFlags::from_year(1900).ndays(), 365);
+        assert_eq!(YearFlags::from_year(1600).ndays(), 366);
+        assert_eq!(YearFlags::from_year(1).ndays(), 365);
+        assert_eq!(YearFlags::from_year(0).ndays(), 366); // 1 BCE (proleptic Gregorian)
+        assert_eq!(YearFlags::from_year(-1).ndays(), 365); // 2 BCE
+        assert_eq!(YearFlags::from_year(-4).ndays(), 366); // 5 BCE
+        assert_eq!(YearFlags::from_year(-99).ndays(), 365); // 100 BCE
+        assert_eq!(YearFlags::from_year(-100).ndays(), 365); // 101 BCE
+        assert_eq!(YearFlags::from_year(-399).ndays(), 365); // 400 BCE
+        assert_eq!(YearFlags::from_year(-400).ndays(), 366); // 401 BCE
+    }
+
+    #[test]
+    fn test_year_flags_nisoweeks() {
+        assert_eq!(A.nisoweeks(), 52);
+        assert_eq!(B.nisoweeks(), 52);
+        assert_eq!(C.nisoweeks(), 52);
+        assert_eq!(D.nisoweeks(), 53);
+        assert_eq!(E.nisoweeks(), 52);
+        assert_eq!(F.nisoweeks(), 52);
+        assert_eq!(G.nisoweeks(), 52);
+        assert_eq!(AG.nisoweeks(), 52);
+        assert_eq!(BA.nisoweeks(), 52);
+        assert_eq!(CB.nisoweeks(), 52);
+        assert_eq!(DC.nisoweeks(), 53);
+        assert_eq!(ED.nisoweeks(), 53);
+        assert_eq!(FE.nisoweeks(), 52);
+        assert_eq!(GF.nisoweeks(), 52);
+    }
+
+    #[test]
+    fn test_mdf_valid() {
+        fn check(expected: bool, flags: YearFlags, month1: u32, day1: u32, month2: u32, day2: u32) {
+            for month in month1..=month2 {
+                for day in day1..=day2 {
+                    let mdf = match Mdf::new(month, day, flags) {
+                        Some(mdf) => mdf,
+                        None if !expected => continue,
+                        None => panic!("Mdf::new({month}, {day}, {flags:?}) returned None"),
+                    };
+
+                    assert!(
+                        mdf.valid() == expected,
+                        "month {} day {} = {:?} should be {} for dominical year {:?}",
+                        month,
+                        day,
+                        mdf,
+                        if expected { "valid" } else { "invalid" },
+                        flags
+                    );
+                }
+            }
+        }
+
+        for &flags in NONLEAP_FLAGS.iter() {
+            check(false, flags, 0, 0, 0, 1024);
+            check(false, flags, 0, 0, 16, 0);
+            check(true, flags, 1, 1, 1, 31);
+            check(false, flags, 1, 32, 1, 1024);
+            check(true, flags, 2, 1, 2, 28);
+            check(false, flags, 2, 29, 2, 1024);
+            check(true, flags, 3, 1, 3, 31);
+            check(false, flags, 3, 32, 3, 1024);
+            check(true, flags, 4, 1, 4, 30);
+            check(false, flags, 4, 31, 4, 1024);
+            check(true, flags, 5, 1, 5, 31);
+            check(false, flags, 5, 32, 5, 1024);
+            check(true, flags, 6, 1, 6, 30);
+            check(false, flags, 6, 31, 6, 1024);
+            check(true, flags, 7, 1, 7, 31);
+            check(false, flags, 7, 32, 7, 1024);
+            check(true, flags, 8, 1, 8, 31);
+            check(false, flags, 8, 32, 8, 1024);
+            check(true, flags, 9, 1, 9, 30);
+            check(false, flags, 9, 31, 9, 1024);
+            check(true, flags, 10, 1, 10, 31);
+            check(false, flags, 10, 32, 10, 1024);
+            check(true, flags, 11, 1, 11, 30);
+            check(false, flags, 11, 31, 11, 1024);
+            check(true, flags, 12, 1, 12, 31);
+            check(false, flags, 12, 32, 12, 1024);
+            check(false, flags, 13, 0, 16, 1024);
+            check(false, flags, u32::MAX, 0, u32::MAX, 1024);
+            check(false, flags, 0, u32::MAX, 16, u32::MAX);
+            check(false, flags, u32::MAX, u32::MAX, u32::MAX, u32::MAX);
+        }
+
+        for &flags in LEAP_FLAGS.iter() {
+            check(false, flags, 0, 0, 0, 1024);
+            check(false, flags, 0, 0, 16, 0);
+            check(true, flags, 1, 1, 1, 31);
+            check(false, flags, 1, 32, 1, 1024);
+            check(true, flags, 2, 1, 2, 29);
+            check(false, flags, 2, 30, 2, 1024);
+            check(true, flags, 3, 1, 3, 31);
+            check(false, flags, 3, 32, 3, 1024);
+            check(true, flags, 4, 1, 4, 30);
+            check(false, flags, 4, 31, 4, 1024);
+            check(true, flags, 5, 1, 5, 31);
+            check(false, flags, 5, 32, 5, 1024);
+            check(true, flags, 6, 1, 6, 30);
+            check(false, flags, 6, 31, 6, 1024);
+            check(true, flags, 7, 1, 7, 31);
+            check(false, flags, 7, 32, 7, 1024);
+            check(true, flags, 8, 1, 8, 31);
+            check(false, flags, 8, 32, 8, 1024);
+            check(true, flags, 9, 1, 9, 30);
+            check(false, flags, 9, 31, 9, 1024);
+            check(true, flags, 10, 1, 10, 31);
+            check(false, flags, 10, 32, 10, 1024);
+            check(true, flags, 11, 1, 11, 30);
+            check(false, flags, 11, 31, 11, 1024);
+            check(true, flags, 12, 1, 12, 31);
+            check(false, flags, 12, 32, 12, 1024);
+            check(false, flags, 13, 0, 16, 1024);
+            check(false, flags, u32::MAX, 0, u32::MAX, 1024);
+            check(false, flags, 0, u32::MAX, 16, u32::MAX);
+            check(false, flags, u32::MAX, u32::MAX, u32::MAX, u32::MAX);
+        }
+    }
+
+    #[test]
+    fn test_mdf_fields() {
+        for &flags in FLAGS.iter() {
+            for month in 1u32..=12 {
+                for day in 1u32..31 {
+                    let mdf = match Mdf::new(month, day, flags) {
+                        Some(mdf) => mdf,
+                        None => continue,
+                    };
+
+                    if mdf.valid() {
+                        assert_eq!(mdf.month(), month);
+                        assert_eq!(mdf.day(), day);
+                    }
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn test_mdf_with_fields() {
+        fn check(flags: YearFlags, month: u32, day: u32) {
+            let mdf = Mdf::new(month, day, flags).unwrap();
+
+            for month in 0u32..=16 {
+                let mdf = match mdf.with_month(month) {
+                    Some(mdf) => mdf,
+                    None if month > 12 => continue,
+                    None => panic!("failed to create Mdf with month {month}"),
+                };
+
+                if mdf.valid() {
+                    assert_eq!(mdf.month(), month);
+                    assert_eq!(mdf.day(), day);
+                }
+            }
+
+            for day in 0u32..=1024 {
+                let mdf = match mdf.with_day(day) {
+                    Some(mdf) => mdf,
+                    None if day > 31 => continue,
+                    None => panic!("failed to create Mdf with month {month}"),
+                };
+
+                if mdf.valid() {
+                    assert_eq!(mdf.month(), month);
+                    assert_eq!(mdf.day(), day);
+                }
+            }
+        }
+
+        for &flags in NONLEAP_FLAGS.iter() {
+            check(flags, 1, 1);
+            check(flags, 1, 31);
+            check(flags, 2, 1);
+            check(flags, 2, 28);
+            check(flags, 2, 29);
+            check(flags, 12, 31);
+        }
+        for &flags in LEAP_FLAGS.iter() {
+            check(flags, 1, 1);
+            check(flags, 1, 31);
+            check(flags, 2, 1);
+            check(flags, 2, 29);
+            check(flags, 2, 30);
+            check(flags, 12, 31);
+        }
+    }
+
+    #[test]
+    fn test_mdf_new_range() {
+        let flags = YearFlags::from_year(2023);
+        assert!(Mdf::new(13, 1, flags).is_none());
+        assert!(Mdf::new(1, 32, flags).is_none());
+    }
+}

patch/chrono-0.4.41/src/naive/isoweek.rs

@@ -0,0 +1,233 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+//! ISO 8601 week.
+
+use core::fmt;
+
+use super::internals::YearFlags;
+
+#[cfg(any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
+use rkyv::{Archive, Deserialize, Serialize};
+
+/// ISO 8601 week.
+///
+/// This type, combined with [`Weekday`](../enum.Weekday.html),
+/// constitutes the ISO 8601 [week date](./struct.NaiveDate.html#week-date).
+/// One can retrieve this type from the existing [`Datelike`](../trait.Datelike.html) types
+/// via the [`Datelike::iso_week`](../trait.Datelike.html#tymethod.iso_week) method.
+#[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Hash)]
+#[cfg_attr(
+    any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
+    derive(Archive, Deserialize, Serialize),
+    rkyv(compare(PartialEq, PartialOrd)),
+    rkyv(attr(derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)))
+)]
+#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
+pub struct IsoWeek {
+    // Note that this allows for larger year range than `NaiveDate`.
+    // This is crucial because we have an edge case for the first and last week supported,
+    // which year number might not match the calendar year number.
+    ywf: i32, // (year << 10) | (week << 4) | flag
+}
+
+impl IsoWeek {
+    /// Returns the corresponding `IsoWeek` from the year and the `Of` internal value.
+    //
+    // Internal use only. We don't expose the public constructor for `IsoWeek` for now
+    // because the year range for the week date and the calendar date do not match, and
+    // it is confusing to have a date that is out of range in one and not in another.
+    // Currently we sidestep this issue by making `IsoWeek` fully dependent of `Datelike`.
+    pub(super) fn from_yof(year: i32, ordinal: u32, year_flags: YearFlags) -> Self {
+        let rawweek = (ordinal + year_flags.isoweek_delta()) / 7;
+        let (year, week) = if rawweek < 1 {
+            // previous year
+            let prevlastweek = YearFlags::from_year(year - 1).nisoweeks();
+            (year - 1, prevlastweek)
+        } else {
+            let lastweek = year_flags.nisoweeks();
+            if rawweek > lastweek {
+                // next year
+                (year + 1, 1)
+            } else {
+                (year, rawweek)
+            }
+        };
+        let flags = YearFlags::from_year(year);
+        IsoWeek { ywf: (year << 10) | (week << 4) as i32 | i32::from(flags.0) }
+    }
+
+    /// Returns the year number for this ISO week.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use chrono::{Datelike, NaiveDate, Weekday};
+    ///
+    /// let d = NaiveDate::from_isoywd_opt(2015, 1, Weekday::Mon).unwrap();
+    /// assert_eq!(d.iso_week().year(), 2015);
+    /// ```
+    ///
+    /// This year number might not match the calendar year number.
+    /// Continuing the example...
+    ///
+    /// ```
+    /// # use chrono::{NaiveDate, Datelike, Weekday};
+    /// # let d = NaiveDate::from_isoywd_opt(2015, 1, Weekday::Mon).unwrap();
+    /// assert_eq!(d.year(), 2014);
+    /// assert_eq!(d, NaiveDate::from_ymd_opt(2014, 12, 29).unwrap());
+    /// ```
+    #[inline]
+    pub const fn year(&self) -> i32 {
+        self.ywf >> 10
+    }
+
+    /// Returns the ISO week number starting from 1.
+    ///
+    /// The return value ranges from 1 to 53. (The last week of year differs by years.)
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use chrono::{Datelike, NaiveDate, Weekday};
+    ///
+    /// let d = NaiveDate::from_isoywd_opt(2015, 15, Weekday::Mon).unwrap();
+    /// assert_eq!(d.iso_week().week(), 15);
+    /// ```
+    #[inline]
+    pub const fn week(&self) -> u32 {
+        ((self.ywf >> 4) & 0x3f) as u32
+    }
+
+    /// Returns the ISO week number starting from 0.
+    ///
+    /// The return value ranges from 0 to 52. (The last week of year differs by years.)
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use chrono::{Datelike, NaiveDate, Weekday};
+    ///
+    /// let d = NaiveDate::from_isoywd_opt(2015, 15, Weekday::Mon).unwrap();
+    /// assert_eq!(d.iso_week().week0(), 14);
+    /// ```
+    #[inline]
+    pub const fn week0(&self) -> u32 {
+        ((self.ywf >> 4) & 0x3f) as u32 - 1
+    }
+}
+
+/// The `Debug` output of the ISO week `w` is the same as
+/// [`d.format("%G-W%V")`](../format/strftime/index.html)
+/// where `d` is any `NaiveDate` value in that week.
+///
+/// # Example
+///
+/// ```
+/// use chrono::{Datelike, NaiveDate};
+///
+/// assert_eq!(
+///     format!("{:?}", NaiveDate::from_ymd_opt(2015, 9, 5).unwrap().iso_week()),
+///     "2015-W36"
+/// );
+/// assert_eq!(format!("{:?}", NaiveDate::from_ymd_opt(0, 1, 3).unwrap().iso_week()), "0000-W01");
+/// assert_eq!(
+///     format!("{:?}", NaiveDate::from_ymd_opt(9999, 12, 31).unwrap().iso_week()),
+///     "9999-W52"
+/// );
+/// ```
+///
+/// ISO 8601 requires an explicit sign for years before 1 BCE or after 9999 CE.
+///
+/// ```
+/// # use chrono::{NaiveDate, Datelike};
+/// assert_eq!(format!("{:?}", NaiveDate::from_ymd_opt(0, 1, 2).unwrap().iso_week()), "-0001-W52");
+/// assert_eq!(
+///     format!("{:?}", NaiveDate::from_ymd_opt(10000, 12, 31).unwrap().iso_week()),
+///     "+10000-W52"
+/// );
+/// ```
+impl fmt::Debug for IsoWeek {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let year = self.year();
+        let week = self.week();
+        if (0..=9999).contains(&year) {
+            write!(f, "{year:04}-W{week:02}")
+        } else {
+            // ISO 8601 requires the explicit sign for out-of-range years
+            write!(f, "{year:+05}-W{week:02}")
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    #[cfg(feature = "rkyv-validation")]
+    use super::IsoWeek;
+    use crate::Datelike;
+    use crate::naive::date::{self, NaiveDate};
+
+    #[test]
+    fn test_iso_week_extremes() {
+        let minweek = NaiveDate::MIN.iso_week();
+        let maxweek = NaiveDate::MAX.iso_week();
+
+        assert_eq!(minweek.year(), date::MIN_YEAR);
+        assert_eq!(minweek.week(), 1);
+        assert_eq!(minweek.week0(), 0);
+        #[cfg(feature = "alloc")]
+        assert_eq!(format!("{:?}", minweek), NaiveDate::MIN.format("%G-W%V").to_string());
+
+        assert_eq!(maxweek.year(), date::MAX_YEAR + 1);
+        assert_eq!(maxweek.week(), 1);
+        assert_eq!(maxweek.week0(), 0);
+        #[cfg(feature = "alloc")]
+        assert_eq!(format!("{:?}", maxweek), NaiveDate::MAX.format("%G-W%V").to_string());
+    }
+
+    #[test]
+    fn test_iso_week_equivalence_for_first_week() {
+        let monday = NaiveDate::from_ymd_opt(2024, 12, 30).unwrap();
+        let friday = NaiveDate::from_ymd_opt(2025, 1, 3).unwrap();
+
+        assert_eq!(monday.iso_week(), friday.iso_week());
+    }
+
+    #[test]
+    fn test_iso_week_equivalence_for_last_week() {
+        let monday = NaiveDate::from_ymd_opt(2026, 12, 28).unwrap();
+        let friday = NaiveDate::from_ymd_opt(2027, 1, 1).unwrap();
+
+        assert_eq!(monday.iso_week(), friday.iso_week());
+    }
+
+    #[test]
+    fn test_iso_week_ordering_for_first_week() {
+        let monday = NaiveDate::from_ymd_opt(2024, 12, 30).unwrap();
+        let friday = NaiveDate::from_ymd_opt(2025, 1, 3).unwrap();
+
+        assert!(monday.iso_week() >= friday.iso_week());
+        assert!(monday.iso_week() <= friday.iso_week());
+    }
+
+    #[test]
+    fn test_iso_week_ordering_for_last_week() {
+        let monday = NaiveDate::from_ymd_opt(2026, 12, 28).unwrap();
+        let friday = NaiveDate::from_ymd_opt(2027, 1, 1).unwrap();
+
+        assert!(monday.iso_week() >= friday.iso_week());
+        assert!(monday.iso_week() <= friday.iso_week());
+    }
+
+    #[test]
+    #[cfg(feature = "rkyv-validation")]
+    fn test_rkyv_validation() {
+        let minweek = NaiveDate::MIN.iso_week();
+        let bytes = rkyv::to_bytes::<_, 4>(&minweek).unwrap();
+        assert_eq!(rkyv::from_bytes::<IsoWeek>(&bytes).unwrap(), minweek);
+
+        let maxweek = NaiveDate::MAX.iso_week();
+        let bytes = rkyv::to_bytes::<_, 4>(&maxweek).unwrap();
+        assert_eq!(rkyv::from_bytes::<IsoWeek>(&bytes).unwrap(), maxweek);
+    }
+}

patch/chrono-0.4.41/src/naive/mod.rs

@@ -0,0 +1,335 @@
+//! Date and time types unconcerned with timezones.
+//!
+//! They are primarily building blocks for other types
+//! (e.g. [`TimeZone`](../offset/trait.TimeZone.html)),
+//! but can be also used for the simpler date and time handling.
+
+use core::hash::{Hash, Hasher};
+use core::ops::RangeInclusive;
+
+use crate::Weekday;
+use crate::expect;
+
+pub(crate) mod date;
+pub(crate) mod datetime;
+mod internals;
+pub(crate) mod isoweek;
+pub(crate) mod time;
+
+#[allow(deprecated)]
+pub use self::date::{MAX_DATE, MIN_DATE};
+pub use self::date::{NaiveDate, NaiveDateDaysIterator, NaiveDateWeeksIterator};
+#[allow(deprecated)]
+pub use self::datetime::{MAX_DATETIME, MIN_DATETIME, NaiveDateTime};
+pub use self::isoweek::IsoWeek;
+pub use self::time::NaiveTime;
+
+#[cfg(feature = "__internal_bench")]
+#[doc(hidden)]
+pub use self::internals::YearFlags as __BenchYearFlags;
+
+/// A week represented by a [`NaiveDate`] and a [`Weekday`] which is the first
+/// day of the week.
+#[derive(Clone, Copy, Debug, Eq)]
+pub struct NaiveWeek {
+    date: NaiveDate,
+    start: Weekday,
+}
+
+impl NaiveWeek {
+    /// Create a new `NaiveWeek`
+    pub(crate) const fn new(date: NaiveDate, start: Weekday) -> Self {
+        Self { date, start }
+    }
+
+    /// Returns a date representing the first day of the week.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the first day of the week happens to fall just out of range of `NaiveDate`
+    /// (more than ca. 262,000 years away from common era).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{NaiveDate, Weekday};
+    ///
+    /// let date = NaiveDate::from_ymd_opt(2022, 4, 18).unwrap();
+    /// let week = date.week(Weekday::Mon);
+    /// assert!(week.first_day() <= date);
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn first_day(&self) -> NaiveDate {
+        expect(self.checked_first_day(), "first weekday out of range for `NaiveDate`")
+    }
+
+    /// Returns a date representing the first day of the week or
+    /// `None` if the date is out of `NaiveDate`'s range
+    /// (more than ca. 262,000 years away from common era).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{NaiveDate, Weekday};
+    ///
+    /// let date = NaiveDate::MIN;
+    /// let week = date.week(Weekday::Mon);
+    /// if let Some(first_day) = week.checked_first_day() {
+    ///     assert!(first_day == date);
+    /// } else {
+    ///     // error handling code
+    ///     return;
+    /// };
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn checked_first_day(&self) -> Option<NaiveDate> {
+        let start = self.start.num_days_from_monday() as i32;
+        let ref_day = self.date.weekday().num_days_from_monday() as i32;
+        // Calculate the number of days to subtract from `self.date`.
+        // Do not construct an intermediate date beyond `self.date`, because that may be out of
+        // range if `date` is close to `NaiveDate::MAX`.
+        let days = start - ref_day - if start > ref_day { 7 } else { 0 };
+        self.date.add_days(days)
+    }
+
+    /// Returns a date representing the last day of the week.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the last day of the week happens to fall just out of range of `NaiveDate`
+    /// (more than ca. 262,000 years away from common era).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{NaiveDate, Weekday};
+    ///
+    /// let date = NaiveDate::from_ymd_opt(2022, 4, 18).unwrap();
+    /// let week = date.week(Weekday::Mon);
+    /// assert!(week.last_day() >= date);
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn last_day(&self) -> NaiveDate {
+        expect(self.checked_last_day(), "last weekday out of range for `NaiveDate`")
+    }
+
+    /// Returns a date representing the last day of the week or
+    /// `None` if the date is out of `NaiveDate`'s range
+    /// (more than ca. 262,000 years away from common era).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{NaiveDate, Weekday};
+    ///
+    /// let date = NaiveDate::MAX;
+    /// let week = date.week(Weekday::Mon);
+    /// if let Some(last_day) = week.checked_last_day() {
+    ///     assert!(last_day == date);
+    /// } else {
+    ///     // error handling code
+    ///     return;
+    /// };
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn checked_last_day(&self) -> Option<NaiveDate> {
+        let end = self.start.pred().num_days_from_monday() as i32;
+        let ref_day = self.date.weekday().num_days_from_monday() as i32;
+        // Calculate the number of days to add to `self.date`.
+        // Do not construct an intermediate date before `self.date` (like with `first_day()`),
+        // because that may be out of range if `date` is close to `NaiveDate::MIN`.
+        let days = end - ref_day + if end < ref_day { 7 } else { 0 };
+        self.date.add_days(days)
+    }
+
+    /// Returns a [`RangeInclusive<T>`] representing the whole week bounded by
+    /// [first_day](NaiveWeek::first_day) and [last_day](NaiveWeek::last_day) functions.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the either the first or last day of the week happens to fall just out of range of
+    /// `NaiveDate` (more than ca. 262,000 years away from common era).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{NaiveDate, Weekday};
+    ///
+    /// let date = NaiveDate::from_ymd_opt(2022, 4, 18).unwrap();
+    /// let week = date.week(Weekday::Mon);
+    /// let days = week.days();
+    /// assert!(days.contains(&date));
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn days(&self) -> RangeInclusive<NaiveDate> {
+        // `expect` doesn't work because `RangeInclusive` is not `Copy`
+        match self.checked_days() {
+            Some(val) => val,
+            None => panic!("{}", "first or last weekday is out of range for `NaiveDate`"),
+        }
+    }
+
+    /// Returns an [`Option<RangeInclusive<T>>`] representing the whole week bounded by
+    /// [checked_first_day](NaiveWeek::checked_first_day) and
+    /// [checked_last_day](NaiveWeek::checked_last_day) functions.
+    ///
+    /// Returns `None` if either of the boundaries are out of `NaiveDate`'s range
+    /// (more than ca. 262,000 years away from common era).
+    ///
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{NaiveDate, Weekday};
+    ///
+    /// let date = NaiveDate::MAX;
+    /// let week = date.week(Weekday::Mon);
+    /// let _days = match week.checked_days() {
+    ///     Some(d) => d,
+    ///     None => {
+    ///         // error handling code
+    ///         return;
+    ///     }
+    /// };
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn checked_days(&self) -> Option<RangeInclusive<NaiveDate>> {
+        match (self.checked_first_day(), self.checked_last_day()) {
+            (Some(first), Some(last)) => Some(first..=last),
+            (_, _) => None,
+        }
+    }
+}
+
+impl PartialEq for NaiveWeek {
+    fn eq(&self, other: &Self) -> bool {
+        self.first_day() == other.first_day()
+    }
+}
+
+impl Hash for NaiveWeek {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.first_day().hash(state);
+    }
+}
+
+/// A duration in calendar days.
+///
+/// This is useful because when using `TimeDelta` it is possible that adding `TimeDelta::days(1)`
+/// doesn't increment the day value as expected due to it being a fixed number of seconds. This
+/// difference applies only when dealing with `DateTime<TimeZone>` data types and in other cases
+/// `TimeDelta::days(n)` and `Days::new(n)` are equivalent.
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq, PartialOrd, Ord)]
+pub struct Days(pub(crate) u64);
+
+impl Days {
+    /// Construct a new `Days` from a number of days
+    pub const fn new(num: u64) -> Self {
+        Self(num)
+    }
+}
+
+/// Serialization/Deserialization of `NaiveDateTime` in alternate formats
+///
+/// The various modules in here are intended to be used with serde's [`with` annotation] to
+/// serialize as something other than the default ISO 8601 format.
+///
+/// [`with` annotation]: https://serde.rs/field-attrs.html#with
+#[cfg(feature = "serde")]
+pub mod serde {
+    pub use super::datetime::serde::*;
+}
+
+#[cfg(test)]
+mod test {
+    use crate::{NaiveDate, NaiveWeek, Weekday};
+    use std::hash::{DefaultHasher, Hash, Hasher};
+    #[test]
+    fn test_naiveweek() {
+        let date = NaiveDate::from_ymd_opt(2022, 5, 18).unwrap();
+        let asserts = [
+            (Weekday::Mon, "Mon 2022-05-16", "Sun 2022-05-22"),
+            (Weekday::Tue, "Tue 2022-05-17", "Mon 2022-05-23"),
+            (Weekday::Wed, "Wed 2022-05-18", "Tue 2022-05-24"),
+            (Weekday::Thu, "Thu 2022-05-12", "Wed 2022-05-18"),
+            (Weekday::Fri, "Fri 2022-05-13", "Thu 2022-05-19"),
+            (Weekday::Sat, "Sat 2022-05-14", "Fri 2022-05-20"),
+            (Weekday::Sun, "Sun 2022-05-15", "Sat 2022-05-21"),
+        ];
+        for (start, first_day, last_day) in asserts {
+            let week = date.week(start);
+            let days = week.days();
+            assert_eq!(Ok(week.first_day()), NaiveDate::parse_from_str(first_day, "%a %Y-%m-%d"));
+            assert_eq!(Ok(week.last_day()), NaiveDate::parse_from_str(last_day, "%a %Y-%m-%d"));
+            assert!(days.contains(&date));
+        }
+    }
+
+    #[test]
+    fn test_naiveweek_min_max() {
+        let date_max = NaiveDate::MAX;
+        assert!(date_max.week(Weekday::Mon).first_day() <= date_max);
+        let date_min = NaiveDate::MIN;
+        assert!(date_min.week(Weekday::Mon).last_day() >= date_min);
+    }
+
+    #[test]
+    fn test_naiveweek_checked_no_panic() {
+        let date_max = NaiveDate::MAX;
+        if let Some(last) = date_max.week(Weekday::Mon).checked_last_day() {
+            assert!(last == date_max);
+        }
+        let date_min = NaiveDate::MIN;
+        if let Some(first) = date_min.week(Weekday::Mon).checked_first_day() {
+            assert!(first == date_min);
+        }
+        let _ = date_min.week(Weekday::Mon).checked_days();
+        let _ = date_max.week(Weekday::Mon).checked_days();
+    }
+
+    #[test]
+    fn test_naiveweek_eq() {
+        let a =
+            NaiveWeek { date: NaiveDate::from_ymd_opt(2025, 4, 3).unwrap(), start: Weekday::Mon };
+        let b =
+            NaiveWeek { date: NaiveDate::from_ymd_opt(2025, 4, 4).unwrap(), start: Weekday::Mon };
+        assert_eq!(a, b);
+
+        let c =
+            NaiveWeek { date: NaiveDate::from_ymd_opt(2025, 4, 3).unwrap(), start: Weekday::Sun };
+        assert_ne!(a, c);
+        assert_ne!(b, c);
+    }
+
+    #[test]
+    fn test_naiveweek_hash() {
+        let a =
+            NaiveWeek { date: NaiveDate::from_ymd_opt(2025, 4, 3).unwrap(), start: Weekday::Mon };
+        let b =
+            NaiveWeek { date: NaiveDate::from_ymd_opt(2025, 4, 4).unwrap(), start: Weekday::Mon };
+        let c =
+            NaiveWeek { date: NaiveDate::from_ymd_opt(2025, 4, 3).unwrap(), start: Weekday::Sun };
+
+        let mut hasher = DefaultHasher::default();
+        a.hash(&mut hasher);
+        let a_hash = hasher.finish();
+
+        hasher = DefaultHasher::default();
+        b.hash(&mut hasher);
+        let b_hash = hasher.finish();
+
+        hasher = DefaultHasher::default();
+        c.hash(&mut hasher);
+        let c_hash = hasher.finish();
+
+        assert_eq!(a_hash, b_hash);
+        assert_ne!(b_hash, c_hash);
+        assert_ne!(a_hash, c_hash);
+    }
+}

patch/chrono-0.4.41/src/naive/time/serde.rs

@@ -0,0 +1,143 @@
+use super::NaiveTime;
+use core::fmt;
+use serde::{de, ser};
+
+// TODO not very optimized for space (binary formats would want something better)
+// TODO round-trip for general leap seconds (not just those with second = 60)
+
+impl ser::Serialize for NaiveTime {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: ser::Serializer,
+    {
+        serializer.collect_str(&self)
+    }
+}
+
+struct NaiveTimeVisitor;
+
+impl de::Visitor<'_> for NaiveTimeVisitor {
+    type Value = NaiveTime;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("a formatted time string")
+    }
+
+    fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+    where
+        E: de::Error,
+    {
+        value.parse().map_err(E::custom)
+    }
+}
+
+impl<'de> de::Deserialize<'de> for NaiveTime {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: de::Deserializer<'de>,
+    {
+        deserializer.deserialize_str(NaiveTimeVisitor)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::NaiveTime;
+
+    #[test]
+    fn test_serde_serialize() {
+        assert_eq!(
+            serde_json::to_string(&NaiveTime::from_hms_opt(0, 0, 0).unwrap()).ok(),
+            Some(r#""00:00:00""#.into())
+        );
+        assert_eq!(
+            serde_json::to_string(&NaiveTime::from_hms_milli_opt(0, 0, 0, 950).unwrap()).ok(),
+            Some(r#""00:00:00.950""#.into())
+        );
+        assert_eq!(
+            serde_json::to_string(&NaiveTime::from_hms_milli_opt(0, 0, 59, 1_000).unwrap()).ok(),
+            Some(r#""00:00:60""#.into())
+        );
+        assert_eq!(
+            serde_json::to_string(&NaiveTime::from_hms_opt(0, 1, 2).unwrap()).ok(),
+            Some(r#""00:01:02""#.into())
+        );
+        assert_eq!(
+            serde_json::to_string(&NaiveTime::from_hms_nano_opt(3, 5, 7, 98765432).unwrap()).ok(),
+            Some(r#""03:05:07.098765432""#.into())
+        );
+        assert_eq!(
+            serde_json::to_string(&NaiveTime::from_hms_opt(7, 8, 9).unwrap()).ok(),
+            Some(r#""07:08:09""#.into())
+        );
+        assert_eq!(
+            serde_json::to_string(&NaiveTime::from_hms_micro_opt(12, 34, 56, 789).unwrap()).ok(),
+            Some(r#""12:34:56.000789""#.into())
+        );
+        let leap = NaiveTime::from_hms_nano_opt(23, 59, 59, 1_999_999_999).unwrap();
+        assert_eq!(serde_json::to_string(&leap).ok(), Some(r#""23:59:60.999999999""#.into()));
+    }
+
+    #[test]
+    fn test_serde_deserialize() {
+        let from_str = serde_json::from_str::<NaiveTime>;
+
+        assert_eq!(from_str(r#""00:00:00""#).ok(), Some(NaiveTime::from_hms_opt(0, 0, 0).unwrap()));
+        assert_eq!(from_str(r#""0:0:0""#).ok(), Some(NaiveTime::from_hms_opt(0, 0, 0).unwrap()));
+        assert_eq!(
+            from_str(r#""00:00:00.950""#).ok(),
+            Some(NaiveTime::from_hms_milli_opt(0, 0, 0, 950).unwrap())
+        );
+        assert_eq!(
+            from_str(r#""0:0:0.95""#).ok(),
+            Some(NaiveTime::from_hms_milli_opt(0, 0, 0, 950).unwrap())
+        );
+        assert_eq!(
+            from_str(r#""00:00:60""#).ok(),
+            Some(NaiveTime::from_hms_milli_opt(0, 0, 59, 1_000).unwrap())
+        );
+        assert_eq!(from_str(r#""00:01:02""#).ok(), Some(NaiveTime::from_hms_opt(0, 1, 2).unwrap()));
+        assert_eq!(
+            from_str(r#""03:05:07.098765432""#).ok(),
+            Some(NaiveTime::from_hms_nano_opt(3, 5, 7, 98765432).unwrap())
+        );
+        assert_eq!(from_str(r#""07:08:09""#).ok(), Some(NaiveTime::from_hms_opt(7, 8, 9).unwrap()));
+        assert_eq!(
+            from_str(r#""12:34:56.000789""#).ok(),
+            Some(NaiveTime::from_hms_micro_opt(12, 34, 56, 789).unwrap())
+        );
+        assert_eq!(
+            from_str(r#""23:59:60.999999999""#).ok(),
+            Some(NaiveTime::from_hms_nano_opt(23, 59, 59, 1_999_999_999).unwrap())
+        );
+        assert_eq!(
+            from_str(r#""23:59:60.9999999999997""#).ok(), // excess digits are ignored
+            Some(NaiveTime::from_hms_nano_opt(23, 59, 59, 1_999_999_999).unwrap())
+        );
+
+        // bad formats
+        assert!(from_str(r#""""#).is_err());
+        assert!(from_str(r#""000000""#).is_err());
+        assert!(from_str(r#""00:00:61""#).is_err());
+        assert!(from_str(r#""00:60:00""#).is_err());
+        assert!(from_str(r#""24:00:00""#).is_err());
+        assert!(from_str(r#""23:59:59,1""#).is_err());
+        assert!(from_str(r#""012:34:56""#).is_err());
+        assert!(from_str(r#""hh:mm:ss""#).is_err());
+        assert!(from_str(r#"0"#).is_err());
+        assert!(from_str(r#"86399"#).is_err());
+        assert!(from_str(r#"{}"#).is_err());
+    }
+
+    #[test]
+    fn test_serde_bincode() {
+        // Bincode is relevant to test separately from JSON because
+        // it is not self-describing.
+        use bincode::{deserialize, serialize};
+
+        let t = NaiveTime::from_hms_nano_opt(3, 5, 7, 98765432).unwrap();
+        let encoded = serialize(&t).unwrap();
+        let decoded: NaiveTime = deserialize(&encoded).unwrap();
+        assert_eq!(t, decoded);
+    }
+}

patch/chrono-0.4.41/src/naive/time/tests.rs

@@ -0,0 +1,393 @@
+use super::NaiveTime;
+use crate::{FixedOffset, TimeDelta, Timelike};
+
+#[test]
+fn test_time_from_hms_milli() {
+    assert_eq!(
+        NaiveTime::from_hms_milli_opt(3, 5, 7, 0),
+        Some(NaiveTime::from_hms_nano_opt(3, 5, 7, 0).unwrap())
+    );
+    assert_eq!(
+        NaiveTime::from_hms_milli_opt(3, 5, 7, 777),
+        Some(NaiveTime::from_hms_nano_opt(3, 5, 7, 777_000_000).unwrap())
+    );
+    assert_eq!(
+        NaiveTime::from_hms_milli_opt(3, 5, 59, 1_999),
+        Some(NaiveTime::from_hms_nano_opt(3, 5, 59, 1_999_000_000).unwrap())
+    );
+    assert_eq!(NaiveTime::from_hms_milli_opt(3, 5, 59, 2_000), None);
+    assert_eq!(NaiveTime::from_hms_milli_opt(3, 5, 59, 5_000), None); // overflow check
+    assert_eq!(NaiveTime::from_hms_milli_opt(3, 5, 59, u32::MAX), None);
+}
+
+#[test]
+fn test_time_from_hms_micro() {
+    assert_eq!(
+        NaiveTime::from_hms_micro_opt(3, 5, 7, 0),
+        Some(NaiveTime::from_hms_nano_opt(3, 5, 7, 0).unwrap())
+    );
+    assert_eq!(
+        NaiveTime::from_hms_micro_opt(3, 5, 7, 333),
+        Some(NaiveTime::from_hms_nano_opt(3, 5, 7, 333_000).unwrap())
+    );
+    assert_eq!(
+        NaiveTime::from_hms_micro_opt(3, 5, 7, 777_777),
+        Some(NaiveTime::from_hms_nano_opt(3, 5, 7, 777_777_000).unwrap())
+    );
+    assert_eq!(
+        NaiveTime::from_hms_micro_opt(3, 5, 59, 1_999_999),
+        Some(NaiveTime::from_hms_nano_opt(3, 5, 59, 1_999_999_000).unwrap())
+    );
+    assert_eq!(NaiveTime::from_hms_micro_opt(3, 5, 59, 2_000_000), None);
+    assert_eq!(NaiveTime::from_hms_micro_opt(3, 5, 59, 5_000_000), None); // overflow check
+    assert_eq!(NaiveTime::from_hms_micro_opt(3, 5, 59, u32::MAX), None);
+}
+
+#[test]
+fn test_time_hms() {
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().hour(), 3);
+    assert_eq!(
+        NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_hour(0),
+        Some(NaiveTime::from_hms_opt(0, 5, 7).unwrap())
+    );
+    assert_eq!(
+        NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_hour(23),
+        Some(NaiveTime::from_hms_opt(23, 5, 7).unwrap())
+    );
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_hour(24), None);
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_hour(u32::MAX), None);
+
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().minute(), 5);
+    assert_eq!(
+        NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_minute(0),
+        Some(NaiveTime::from_hms_opt(3, 0, 7).unwrap())
+    );
+    assert_eq!(
+        NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_minute(59),
+        Some(NaiveTime::from_hms_opt(3, 59, 7).unwrap())
+    );
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_minute(60), None);
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_minute(u32::MAX), None);
+
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().second(), 7);
+    assert_eq!(
+        NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_second(0),
+        Some(NaiveTime::from_hms_opt(3, 5, 0).unwrap())
+    );
+    assert_eq!(
+        NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_second(59),
+        Some(NaiveTime::from_hms_opt(3, 5, 59).unwrap())
+    );
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_second(60), None);
+    assert_eq!(NaiveTime::from_hms_opt(3, 5, 7).unwrap().with_second(u32::MAX), None);
+}
+
+#[test]
+fn test_time_add() {
+    macro_rules! check {
+        ($lhs:expr, $rhs:expr, $sum:expr) => {{
+            assert_eq!($lhs + $rhs, $sum);
+            //assert_eq!($rhs + $lhs, $sum);
+        }};
+    }
+
+    let hmsm = |h, m, s, ms| NaiveTime::from_hms_milli_opt(h, m, s, ms).unwrap();
+
+    check!(hmsm(3, 5, 59, 900), TimeDelta::zero(), hmsm(3, 5, 59, 900));
+    check!(hmsm(3, 5, 59, 900), TimeDelta::try_milliseconds(100).unwrap(), hmsm(3, 6, 0, 0));
+    check!(hmsm(3, 5, 59, 1_300), TimeDelta::try_milliseconds(-1800).unwrap(), hmsm(3, 5, 58, 500));
+    check!(hmsm(3, 5, 59, 1_300), TimeDelta::try_milliseconds(-800).unwrap(), hmsm(3, 5, 59, 500));
+    check!(
+        hmsm(3, 5, 59, 1_300),
+        TimeDelta::try_milliseconds(-100).unwrap(),
+        hmsm(3, 5, 59, 1_200)
+    );
+    check!(hmsm(3, 5, 59, 1_300), TimeDelta::try_milliseconds(100).unwrap(), hmsm(3, 5, 59, 1_400));
+    check!(hmsm(3, 5, 59, 1_300), TimeDelta::try_milliseconds(800).unwrap(), hmsm(3, 6, 0, 100));
+    check!(hmsm(3, 5, 59, 1_300), TimeDelta::try_milliseconds(1800).unwrap(), hmsm(3, 6, 1, 100));
+    check!(hmsm(3, 5, 59, 900), TimeDelta::try_seconds(86399).unwrap(), hmsm(3, 5, 58, 900)); // overwrap
+    check!(hmsm(3, 5, 59, 900), TimeDelta::try_seconds(-86399).unwrap(), hmsm(3, 6, 0, 900));
+    check!(hmsm(3, 5, 59, 900), TimeDelta::try_days(12345).unwrap(), hmsm(3, 5, 59, 900));
+    check!(hmsm(3, 5, 59, 1_300), TimeDelta::try_days(1).unwrap(), hmsm(3, 5, 59, 300));
+    check!(hmsm(3, 5, 59, 1_300), TimeDelta::try_days(-1).unwrap(), hmsm(3, 6, 0, 300));
+
+    // regression tests for #37
+    check!(hmsm(0, 0, 0, 0), TimeDelta::try_milliseconds(-990).unwrap(), hmsm(23, 59, 59, 10));
+    check!(hmsm(0, 0, 0, 0), TimeDelta::try_milliseconds(-9990).unwrap(), hmsm(23, 59, 50, 10));
+}
+
+#[test]
+fn test_time_overflowing_add() {
+    let hmsm = |h, m, s, ms| NaiveTime::from_hms_milli_opt(h, m, s, ms).unwrap();
+
+    assert_eq!(
+        hmsm(3, 4, 5, 678).overflowing_add_signed(TimeDelta::try_hours(11).unwrap()),
+        (hmsm(14, 4, 5, 678), 0)
+    );
+    assert_eq!(
+        hmsm(3, 4, 5, 678).overflowing_add_signed(TimeDelta::try_hours(23).unwrap()),
+        (hmsm(2, 4, 5, 678), 86_400)
+    );
+    assert_eq!(
+        hmsm(3, 4, 5, 678).overflowing_add_signed(TimeDelta::try_hours(-7).unwrap()),
+        (hmsm(20, 4, 5, 678), -86_400)
+    );
+
+    // overflowing_add_signed with leap seconds may be counter-intuitive
+    assert_eq!(
+        hmsm(3, 4, 59, 1_678).overflowing_add_signed(TimeDelta::try_days(1).unwrap()),
+        (hmsm(3, 4, 59, 678), 86_400)
+    );
+    assert_eq!(
+        hmsm(3, 4, 59, 1_678).overflowing_add_signed(TimeDelta::try_days(-1).unwrap()),
+        (hmsm(3, 5, 0, 678), -86_400)
+    );
+}
+
+#[test]
+fn test_time_addassignment() {
+    let hms = |h, m, s| NaiveTime::from_hms_opt(h, m, s).unwrap();
+    let mut time = hms(12, 12, 12);
+    time += TimeDelta::try_hours(10).unwrap();
+    assert_eq!(time, hms(22, 12, 12));
+    time += TimeDelta::try_hours(10).unwrap();
+    assert_eq!(time, hms(8, 12, 12));
+}
+
+#[test]
+fn test_time_subassignment() {
+    let hms = |h, m, s| NaiveTime::from_hms_opt(h, m, s).unwrap();
+    let mut time = hms(12, 12, 12);
+    time -= TimeDelta::try_hours(10).unwrap();
+    assert_eq!(time, hms(2, 12, 12));
+    time -= TimeDelta::try_hours(10).unwrap();
+    assert_eq!(time, hms(16, 12, 12));
+}
+
+#[test]
+fn test_time_sub() {
+    macro_rules! check {
+        ($lhs:expr, $rhs:expr, $diff:expr) => {{
+            // `time1 - time2 = duration` is equivalent to `time2 - time1 = -duration`
+            assert_eq!($lhs.signed_duration_since($rhs), $diff);
+            assert_eq!($rhs.signed_duration_since($lhs), -$diff);
+        }};
+    }
+
+    let hmsm = |h, m, s, ms| NaiveTime::from_hms_milli_opt(h, m, s, ms).unwrap();
+
+    check!(hmsm(3, 5, 7, 900), hmsm(3, 5, 7, 900), TimeDelta::zero());
+    check!(hmsm(3, 5, 7, 900), hmsm(3, 5, 7, 600), TimeDelta::try_milliseconds(300).unwrap());
+    check!(hmsm(3, 5, 7, 200), hmsm(2, 4, 6, 200), TimeDelta::try_seconds(3600 + 60 + 1).unwrap());
+    check!(
+        hmsm(3, 5, 7, 200),
+        hmsm(2, 4, 6, 300),
+        TimeDelta::try_seconds(3600 + 60).unwrap() + TimeDelta::try_milliseconds(900).unwrap()
+    );
+
+    // treats the leap second as if it coincides with the prior non-leap second,
+    // as required by `time1 - time2 = duration` and `time2 - time1 = -duration` equivalence.
+    check!(hmsm(3, 6, 0, 200), hmsm(3, 5, 59, 1_800), TimeDelta::try_milliseconds(400).unwrap());
+    //check!(hmsm(3, 5, 7, 1_200), hmsm(3, 5, 6, 1_800), TimeDelta::try_milliseconds(1400).unwrap());
+    //check!(hmsm(3, 5, 7, 1_200), hmsm(3, 5, 6, 800), TimeDelta::try_milliseconds(1400).unwrap());
+
+    // additional equality: `time1 + duration = time2` is equivalent to
+    // `time2 - time1 = duration` IF AND ONLY IF `time2` represents a non-leap second.
+    assert_eq!(hmsm(3, 5, 6, 800) + TimeDelta::try_milliseconds(400).unwrap(), hmsm(3, 5, 7, 200));
+    //assert_eq!(hmsm(3, 5, 6, 1_800) + TimeDelta::try_milliseconds(400).unwrap(), hmsm(3, 5, 7, 200));
+}
+
+#[test]
+fn test_core_duration_ops() {
+    use core::time::Duration;
+
+    let mut t = NaiveTime::from_hms_opt(11, 34, 23).unwrap();
+    let same = t + Duration::ZERO;
+    assert_eq!(t, same);
+
+    t += Duration::new(3600, 0);
+    assert_eq!(t, NaiveTime::from_hms_opt(12, 34, 23).unwrap());
+
+    t -= Duration::new(7200, 0);
+    assert_eq!(t, NaiveTime::from_hms_opt(10, 34, 23).unwrap());
+}
+
+#[test]
+fn test_time_fmt() {
+    assert_eq!(
+        format!("{}", NaiveTime::from_hms_milli_opt(23, 59, 59, 999).unwrap()),
+        "23:59:59.999"
+    );
+    assert_eq!(
+        format!("{}", NaiveTime::from_hms_milli_opt(23, 59, 59, 1_000).unwrap()),
+        "23:59:60"
+    );
+    assert_eq!(
+        format!("{}", NaiveTime::from_hms_milli_opt(23, 59, 59, 1_001).unwrap()),
+        "23:59:60.001"
+    );
+    assert_eq!(
+        format!("{}", NaiveTime::from_hms_micro_opt(0, 0, 0, 43210).unwrap()),
+        "00:00:00.043210"
+    );
+    assert_eq!(
+        format!("{}", NaiveTime::from_hms_nano_opt(0, 0, 0, 6543210).unwrap()),
+        "00:00:00.006543210"
+    );
+
+    // the format specifier should have no effect on `NaiveTime`
+    assert_eq!(
+        format!("{:30}", NaiveTime::from_hms_milli_opt(3, 5, 7, 9).unwrap()),
+        "03:05:07.009"
+    );
+}
+
+#[test]
+fn test_time_from_str() {
+    // valid cases
+    let valid = [
+        "0:0:0",
+        "0:0:0.0000000",
+        "0:0:0.0000003",
+        " 4 : 3 : 2.1 ",
+        " 09:08:07 ",
+        " 09:08 ",
+        " 9:8:07 ",
+        "01:02:03",
+        "4:3:2.1",
+        "9:8:7",
+        "09:8:7",
+        "9:08:7",
+        "9:8:07",
+        "09:08:7",
+        "09:8:07",
+        "09:08:7",
+        "9:08:07",
+        "09:08:07",
+        "9:8:07.123",
+        "9:08:7.123",
+        "09:8:7.123",
+        "09:08:7.123",
+        "9:08:07.123",
+        "09:8:07.123",
+        "09:08:07.123",
+        "09:08:07.123",
+        "09:08:07.1234",
+        "09:08:07.12345",
+        "09:08:07.123456",
+        "09:08:07.1234567",
+        "09:08:07.12345678",
+        "09:08:07.123456789",
+        "09:08:07.1234567891",
+        "09:08:07.12345678912",
+        "23:59:60.373929310237",
+    ];
+    for &s in &valid {
+        eprintln!("test_time_parse_from_str valid {:?}", s);
+        let d = match s.parse::<NaiveTime>() {
+            Ok(d) => d,
+            Err(e) => panic!("parsing `{}` has failed: {}", s, e),
+        };
+        let s_ = format!("{:?}", d);
+        // `s` and `s_` may differ, but `s.parse()` and `s_.parse()` must be same
+        let d_ = match s_.parse::<NaiveTime>() {
+            Ok(d) => d,
+            Err(e) => {
+                panic!("`{}` is parsed into `{:?}`, but reparsing that has failed: {}", s, d, e)
+            }
+        };
+        assert!(
+            d == d_,
+            "`{}` is parsed into `{:?}`, but reparsed result \
+                              `{:?}` does not match",
+            s,
+            d,
+            d_
+        );
+    }
+
+    // some invalid cases
+    // since `ParseErrorKind` is private, all we can do is to check if there was an error
+    let invalid = [
+        "",                  // empty
+        "x",                 // invalid
+        "15",                // missing data
+        "15:8:",             // trailing colon
+        "15:8:x",            // invalid data
+        "15:8:9x",           // invalid data
+        "23:59:61",          // invalid second (out of bounds)
+        "23:54:35 GMT",      // invalid (timezone non-sensical for NaiveTime)
+        "23:54:35 +0000",    // invalid (timezone non-sensical for NaiveTime)
+        "1441497364.649",    // valid datetime, not a NaiveTime
+        "+1441497364.649",   // valid datetime, not a NaiveTime
+        "+1441497364",       // valid datetime, not a NaiveTime
+        "001:02:03",         // invalid hour
+        "01:002:03",         // invalid minute
+        "01:02:003",         // invalid second
+        "12:34:56.x",        // invalid fraction
+        "12:34:56. 0",       // invalid fraction format
+        "09:08:00000000007", // invalid second / invalid fraction format
+    ];
+    for &s in &invalid {
+        eprintln!("test_time_parse_from_str invalid {:?}", s);
+        assert!(s.parse::<NaiveTime>().is_err());
+    }
+}
+
+#[test]
+fn test_time_parse_from_str() {
+    let hms = |h, m, s| NaiveTime::from_hms_opt(h, m, s).unwrap();
+    assert_eq!(
+        NaiveTime::parse_from_str("2014-5-7T12:34:56+09:30", "%Y-%m-%dT%H:%M:%S%z"),
+        Ok(hms(12, 34, 56))
+    ); // ignore date and offset
+    assert_eq!(NaiveTime::parse_from_str("PM 12:59", "%P %H:%M"), Ok(hms(12, 59, 0)));
+    assert_eq!(NaiveTime::parse_from_str("12:59 \n\t PM", "%H:%M \n\t %P"), Ok(hms(12, 59, 0)));
+    assert_eq!(NaiveTime::parse_from_str("\t\t12:59\tPM\t", "\t\t%H:%M\t%P\t"), Ok(hms(12, 59, 0)));
+    assert_eq!(
+        NaiveTime::parse_from_str("\t\t1259\t\tPM\t", "\t\t%H%M\t\t%P\t"),
+        Ok(hms(12, 59, 0))
+    );
+    assert!(NaiveTime::parse_from_str("12:59 PM", "%H:%M\t%P").is_ok());
+    assert!(NaiveTime::parse_from_str("\t\t12:59 PM\t", "\t\t%H:%M\t%P\t").is_ok());
+    assert!(NaiveTime::parse_from_str("12:59  PM", "%H:%M %P").is_ok());
+    assert!(NaiveTime::parse_from_str("12:3456", "%H:%M:%S").is_err());
+}
+
+#[test]
+fn test_overflowing_offset() {
+    let hmsm = |h, m, s, n| NaiveTime::from_hms_milli_opt(h, m, s, n).unwrap();
+
+    let positive_offset = FixedOffset::east_opt(4 * 60 * 60).unwrap();
+    // regular time
+    let t = hmsm(5, 6, 7, 890);
+    assert_eq!(t.overflowing_add_offset(positive_offset), (hmsm(9, 6, 7, 890), 0));
+    assert_eq!(t.overflowing_sub_offset(positive_offset), (hmsm(1, 6, 7, 890), 0));
+    // leap second is preserved, and wrap to next day
+    let t = hmsm(23, 59, 59, 1_000);
+    assert_eq!(t.overflowing_add_offset(positive_offset), (hmsm(3, 59, 59, 1_000), 1));
+    assert_eq!(t.overflowing_sub_offset(positive_offset), (hmsm(19, 59, 59, 1_000), 0));
+    // wrap to previous day
+    let t = hmsm(1, 2, 3, 456);
+    assert_eq!(t.overflowing_sub_offset(positive_offset), (hmsm(21, 2, 3, 456), -1));
+    // an odd offset
+    let negative_offset = FixedOffset::west_opt(((2 * 60) + 3) * 60 + 4).unwrap();
+    let t = hmsm(5, 6, 7, 890);
+    assert_eq!(t.overflowing_add_offset(negative_offset), (hmsm(3, 3, 3, 890), 0));
+    assert_eq!(t.overflowing_sub_offset(negative_offset), (hmsm(7, 9, 11, 890), 0));
+
+    assert_eq!(t.overflowing_add_offset(positive_offset).0, t + positive_offset);
+    assert_eq!(t.overflowing_sub_offset(positive_offset).0, t - positive_offset);
+}
+
+#[test]
+#[cfg(feature = "rkyv-validation")]
+fn test_rkyv_validation() {
+    let t_min = NaiveTime::MIN;
+    let bytes = rkyv::to_bytes::<_, 8>(&t_min).unwrap();
+    assert_eq!(rkyv::from_bytes::<NaiveTime>(&bytes).unwrap(), t_min);
+
+    let t_max = NaiveTime::MAX;
+    let bytes = rkyv::to_bytes::<_, 8>(&t_max).unwrap();
+    assert_eq!(rkyv::from_bytes::<NaiveTime>(&bytes).unwrap(), t_max);
+}

patch/chrono-0.4.41/src/offset/fixed.rs

@@ -0,0 +1,236 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+//! The time zone which has a fixed offset from UTC.
+
+use core::fmt;
+use core::str::FromStr;
+
+#[cfg(any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
+use rkyv::{Archive, Deserialize, Serialize};
+
+use super::{MappedLocalTime, Offset, TimeZone};
+use crate::format::{OUT_OF_RANGE, ParseError, scan};
+use crate::naive::{NaiveDate, NaiveDateTime};
+
+/// The time zone with fixed offset, from UTC-23:59:59 to UTC+23:59:59.
+///
+/// Using the [`TimeZone`](./trait.TimeZone.html) methods
+/// on a `FixedOffset` struct is the preferred way to construct
+/// `DateTime<FixedOffset>` instances. See the [`east_opt`](#method.east_opt) and
+/// [`west_opt`](#method.west_opt) methods for examples.
+#[derive(PartialEq, Eq, Hash, Copy, Clone)]
+#[cfg_attr(
+    any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
+    derive(Archive, Deserialize, Serialize),
+    rkyv(compare(PartialEq)),
+    rkyv(attr(derive(Clone, Copy, PartialEq, Eq, Hash, Debug)))
+)]
+#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
+pub struct FixedOffset {
+    local_minus_utc: i32,
+}
+
+impl FixedOffset {
+    /// Makes a new `FixedOffset` for the Eastern Hemisphere with given timezone difference.
+    /// The negative `secs` means the Western Hemisphere.
+    ///
+    /// Panics on the out-of-bound `secs`.
+    #[deprecated(since = "0.4.23", note = "use `east_opt()` instead")]
+    #[must_use]
+    pub fn east(secs: i32) -> FixedOffset {
+        FixedOffset::east_opt(secs).expect("FixedOffset::east out of bounds")
+    }
+
+    /// Makes a new `FixedOffset` for the Eastern Hemisphere with given timezone difference.
+    /// The negative `secs` means the Western Hemisphere.
+    ///
+    /// Returns `None` on the out-of-bound `secs`.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # #[cfg(feature = "alloc")] {
+    /// use chrono::{FixedOffset, TimeZone};
+    /// let hour = 3600;
+    /// let datetime =
+    ///     FixedOffset::east_opt(5 * hour).unwrap().with_ymd_and_hms(2016, 11, 08, 0, 0, 0).unwrap();
+    /// assert_eq!(&datetime.to_rfc3339(), "2016-11-08T00:00:00+05:00")
+    /// # }
+    /// ```
+    #[must_use]
+    pub const fn east_opt(secs: i32) -> Option<FixedOffset> {
+        if -86_400 < secs && secs < 86_400 {
+            Some(FixedOffset { local_minus_utc: secs })
+        } else {
+            None
+        }
+    }
+
+    /// Makes a new `FixedOffset` for the Western Hemisphere with given timezone difference.
+    /// The negative `secs` means the Eastern Hemisphere.
+    ///
+    /// Panics on the out-of-bound `secs`.
+    #[deprecated(since = "0.4.23", note = "use `west_opt()` instead")]
+    #[must_use]
+    pub fn west(secs: i32) -> FixedOffset {
+        FixedOffset::west_opt(secs).expect("FixedOffset::west out of bounds")
+    }
+
+    /// Makes a new `FixedOffset` for the Western Hemisphere with given timezone difference.
+    /// The negative `secs` means the Eastern Hemisphere.
+    ///
+    /// Returns `None` on the out-of-bound `secs`.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # #[cfg(feature = "alloc")] {
+    /// use chrono::{FixedOffset, TimeZone};
+    /// let hour = 3600;
+    /// let datetime =
+    ///     FixedOffset::west_opt(5 * hour).unwrap().with_ymd_and_hms(2016, 11, 08, 0, 0, 0).unwrap();
+    /// assert_eq!(&datetime.to_rfc3339(), "2016-11-08T00:00:00-05:00")
+    /// # }
+    /// ```
+    #[must_use]
+    pub const fn west_opt(secs: i32) -> Option<FixedOffset> {
+        if -86_400 < secs && secs < 86_400 {
+            Some(FixedOffset { local_minus_utc: -secs })
+        } else {
+            None
+        }
+    }
+
+    /// Returns the number of seconds to add to convert from UTC to the local time.
+    #[inline]
+    pub const fn local_minus_utc(&self) -> i32 {
+        self.local_minus_utc
+    }
+
+    /// Returns the number of seconds to add to convert from the local time to UTC.
+    #[inline]
+    pub const fn utc_minus_local(&self) -> i32 {
+        -self.local_minus_utc
+    }
+}
+
+/// Parsing a `str` into a `FixedOffset` uses the format [`%z`](crate::format::strftime).
+impl FromStr for FixedOffset {
+    type Err = ParseError;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let (_, offset) = scan::timezone_offset(s, scan::colon_or_space, false, false, true)?;
+        Self::east_opt(offset).ok_or(OUT_OF_RANGE)
+    }
+}
+
+impl TimeZone for FixedOffset {
+    type Offset = FixedOffset;
+
+    fn from_offset(offset: &FixedOffset) -> FixedOffset {
+        *offset
+    }
+
+    fn offset_from_local_date(&self, _local: &NaiveDate) -> MappedLocalTime<FixedOffset> {
+        MappedLocalTime::Single(*self)
+    }
+    fn offset_from_local_datetime(&self, _local: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
+        MappedLocalTime::Single(*self)
+    }
+
+    fn offset_from_utc_date(&self, _utc: &NaiveDate) -> FixedOffset {
+        *self
+    }
+    fn offset_from_utc_datetime(&self, _utc: &NaiveDateTime) -> FixedOffset {
+        *self
+    }
+}
+
+impl Offset for FixedOffset {
+    fn fix(&self) -> FixedOffset {
+        *self
+    }
+}
+
+impl fmt::Debug for FixedOffset {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let offset = self.local_minus_utc;
+        let (sign, offset) = if offset < 0 { ('-', -offset) } else { ('+', offset) };
+        let sec = offset.rem_euclid(60);
+        let mins = offset.div_euclid(60);
+        let min = mins.rem_euclid(60);
+        let hour = mins.div_euclid(60);
+        if sec == 0 {
+            write!(f, "{sign}{hour:02}:{min:02}")
+        } else {
+            write!(f, "{sign}{hour:02}:{min:02}:{sec:02}")
+        }
+    }
+}
+
+impl fmt::Display for FixedOffset {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(self, f)
+    }
+}
+
+#[cfg(all(feature = "arbitrary", feature = "std"))]
+impl arbitrary::Arbitrary<'_> for FixedOffset {
+    fn arbitrary(u: &mut arbitrary::Unstructured) -> arbitrary::Result<FixedOffset> {
+        let secs = u.int_in_range(-86_399..=86_399)?;
+        let fixed_offset = FixedOffset::east_opt(secs)
+            .expect("Could not generate a valid chrono::FixedOffset. It looks like implementation of Arbitrary for FixedOffset is erroneous.");
+        Ok(fixed_offset)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::FixedOffset;
+    use crate::offset::TimeZone;
+    use std::str::FromStr;
+
+    #[test]
+    fn test_date_extreme_offset() {
+        // starting from 0.3 we don't have an offset exceeding one day.
+        // this makes everything easier!
+        let offset = FixedOffset::east_opt(86399).unwrap();
+        assert_eq!(
+            format!("{:?}", offset.with_ymd_and_hms(2012, 2, 29, 5, 6, 7).unwrap()),
+            "2012-02-29T05:06:07+23:59:59"
+        );
+        let offset = FixedOffset::east_opt(-86399).unwrap();
+        assert_eq!(
+            format!("{:?}", offset.with_ymd_and_hms(2012, 2, 29, 5, 6, 7).unwrap()),
+            "2012-02-29T05:06:07-23:59:59"
+        );
+        let offset = FixedOffset::west_opt(86399).unwrap();
+        assert_eq!(
+            format!("{:?}", offset.with_ymd_and_hms(2012, 3, 4, 5, 6, 7).unwrap()),
+            "2012-03-04T05:06:07-23:59:59"
+        );
+        let offset = FixedOffset::west_opt(-86399).unwrap();
+        assert_eq!(
+            format!("{:?}", offset.with_ymd_and_hms(2012, 3, 4, 5, 6, 7).unwrap()),
+            "2012-03-04T05:06:07+23:59:59"
+        );
+    }
+
+    #[test]
+    fn test_parse_offset() {
+        let offset = FixedOffset::from_str("-0500").unwrap();
+        assert_eq!(offset.local_minus_utc, -5 * 3600);
+        let offset = FixedOffset::from_str("-08:00").unwrap();
+        assert_eq!(offset.local_minus_utc, -8 * 3600);
+        let offset = FixedOffset::from_str("+06:30").unwrap();
+        assert_eq!(offset.local_minus_utc, (6 * 3600) + 1800);
+    }
+
+    #[test]
+    #[cfg(feature = "rkyv-validation")]
+    fn test_rkyv_validation() {
+        let offset = FixedOffset::from_str("-0500").unwrap();
+        let bytes = rkyv::to_bytes::<_, 4>(&offset).unwrap();
+        assert_eq!(rkyv::from_bytes::<FixedOffset>(&bytes).unwrap(), offset);
+    }
+}

patch/chrono-0.4.41/src/offset/local/mod.rs

@@ -0,0 +1,544 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+//! The local (system) time zone.
+
+#[cfg(windows)]
+use std::cmp::Ordering;
+
+#[cfg(any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
+use rkyv::{Archive, Deserialize, Serialize};
+
+use super::fixed::FixedOffset;
+use super::{MappedLocalTime, TimeZone};
+#[allow(deprecated)]
+use crate::Date;
+use crate::naive::{NaiveDate, NaiveDateTime, NaiveTime};
+use crate::{DateTime, Utc};
+
+#[cfg(unix)]
+#[path = "unix.rs"]
+mod inner;
+
+#[cfg(windows)]
+#[path = "windows.rs"]
+mod inner;
+
+#[cfg(all(windows, feature = "clock"))]
+#[allow(unreachable_pub)]
+mod win_bindings;
+
+#[cfg(all(any(target_os = "android", target_env = "ohos", test), feature = "clock"))]
+mod tz_data;
+
+#[cfg(all(
+    not(unix),
+    not(windows),
+    not(all(
+        target_arch = "wasm32",
+        feature = "wasmbind",
+        not(any(target_os = "emscripten", target_os = "wasi"))
+    ))
+))]
+mod inner {
+    use crate::{FixedOffset, MappedLocalTime, NaiveDateTime};
+
+    pub(super) fn offset_from_utc_datetime(
+        _utc_time: &NaiveDateTime,
+    ) -> MappedLocalTime<FixedOffset> {
+        MappedLocalTime::Single(FixedOffset::east_opt(0).unwrap())
+    }
+
+    pub(super) fn offset_from_local_datetime(
+        _local_time: &NaiveDateTime,
+    ) -> MappedLocalTime<FixedOffset> {
+        MappedLocalTime::Single(FixedOffset::east_opt(0).unwrap())
+    }
+}
+
+#[cfg(all(
+    target_arch = "wasm32",
+    feature = "wasmbind",
+    not(any(target_os = "emscripten", target_os = "wasi", target_os = "linux"))
+))]
+mod inner {
+    use crate::{Datelike, FixedOffset, MappedLocalTime, NaiveDateTime, Timelike};
+
+    pub(super) fn offset_from_utc_datetime(utc: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
+        let offset = js_sys::Date::from(utc.and_utc()).get_timezone_offset();
+        MappedLocalTime::Single(FixedOffset::west_opt((offset as i32) * 60).unwrap())
+    }
+
+    pub(super) fn offset_from_local_datetime(
+        local: &NaiveDateTime,
+    ) -> MappedLocalTime<FixedOffset> {
+        let mut year = local.year();
+        if year < 100 {
+            // The API in `js_sys` does not let us create a `Date` with negative years.
+            // And values for years from `0` to `99` map to the years `1900` to `1999`.
+            // Shift the value by a multiple of 400 years until it is `>= 100`.
+            let shift_cycles = (year - 100).div_euclid(400);
+            year -= shift_cycles * 400;
+        }
+        let js_date = js_sys::Date::new_with_year_month_day_hr_min_sec(
+            year as u32,
+            local.month0() as i32,
+            local.day() as i32,
+            local.hour() as i32,
+            local.minute() as i32,
+            local.second() as i32,
+            // ignore milliseconds, our representation of leap seconds may be problematic
+        );
+        let offset = js_date.get_timezone_offset();
+        // We always get a result, even if this time does not exist or is ambiguous.
+        MappedLocalTime::Single(FixedOffset::west_opt((offset as i32) * 60).unwrap())
+    }
+}
+
+#[cfg(unix)]
+mod tz_info;
+
+/// The local timescale.
+///
+/// Using the [`TimeZone`](./trait.TimeZone.html) methods
+/// on the Local struct is the preferred way to construct `DateTime<Local>`
+/// instances.
+///
+/// # Example
+///
+/// ```
+/// use chrono::{DateTime, Local, TimeZone};
+///
+/// let dt1: DateTime<Local> = Local::now();
+/// let dt2: DateTime<Local> = Local.timestamp_opt(0, 0).unwrap();
+/// assert!(dt1 >= dt2);
+/// ```
+#[derive(Copy, Clone, Debug)]
+#[cfg_attr(
+    any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
+    derive(Archive, Deserialize, Serialize),
+    rkyv(compare(PartialEq)),
+    rkyv(attr(derive(Clone, Copy, Debug)))
+)]
+#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
+pub struct Local;
+
+impl Local {
+    /// Returns a `Date` which corresponds to the current date.
+    #[deprecated(since = "0.4.23", note = "use `Local::now()` instead")]
+    #[allow(deprecated)]
+    #[must_use]
+    pub fn today() -> Date<Local> {
+        Local::now().date()
+    }
+
+    /// Returns a `DateTime<Local>` which corresponds to the current date, time and offset from
+    /// UTC.
+    ///
+    /// See also the similar [`Utc::now()`] which returns `DateTime<Utc>`, i.e. without the local
+    /// offset.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # #![allow(unused_variables)]
+    /// # use chrono::{DateTime, FixedOffset, Local};
+    /// // Current local time
+    /// let now = Local::now();
+    ///
+    /// // Current local date
+    /// let today = now.date_naive();
+    ///
+    /// // Current local time, converted to `DateTime<FixedOffset>`
+    /// let now_fixed_offset = Local::now().fixed_offset();
+    /// // or
+    /// let now_fixed_offset: DateTime<FixedOffset> = Local::now().into();
+    ///
+    /// // Current time in some timezone (let's use +05:00)
+    /// // Note that it is usually more efficient to use `Utc::now` for this use case.
+    /// let offset = FixedOffset::east_opt(5 * 60 * 60).unwrap();
+    /// let now_with_offset = Local::now().with_timezone(&offset);
+    /// ```
+    pub fn now() -> DateTime<Local> {
+        Utc::now().with_timezone(&Local)
+    }
+}
+
+impl TimeZone for Local {
+    type Offset = FixedOffset;
+
+    fn from_offset(_offset: &FixedOffset) -> Local {
+        Local
+    }
+
+    #[allow(deprecated)]
+    fn offset_from_local_date(&self, local: &NaiveDate) -> MappedLocalTime<FixedOffset> {
+        // Get the offset at local midnight.
+        self.offset_from_local_datetime(&local.and_time(NaiveTime::MIN))
+    }
+
+    fn offset_from_local_datetime(&self, local: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
+        inner::offset_from_local_datetime(local)
+    }
+
+    #[allow(deprecated)]
+    fn offset_from_utc_date(&self, utc: &NaiveDate) -> FixedOffset {
+        // Get the offset at midnight.
+        self.offset_from_utc_datetime(&utc.and_time(NaiveTime::MIN))
+    }
+
+    fn offset_from_utc_datetime(&self, utc: &NaiveDateTime) -> FixedOffset {
+        inner::offset_from_utc_datetime(utc).unwrap()
+    }
+}
+
+#[cfg(windows)]
+#[derive(Copy, Clone, Eq, PartialEq)]
+struct Transition {
+    transition_utc: NaiveDateTime,
+    offset_before: FixedOffset,
+    offset_after: FixedOffset,
+}
+
+#[cfg(windows)]
+impl Transition {
+    fn new(
+        transition_local: NaiveDateTime,
+        offset_before: FixedOffset,
+        offset_after: FixedOffset,
+    ) -> Transition {
+        // It is no problem if the transition time in UTC falls a couple of hours inside the buffer
+        // space around the `NaiveDateTime` range (although it is very theoretical to have a
+        // transition at midnight around `NaiveDate::(MIN|MAX)`.
+        let transition_utc = transition_local.overflowing_sub_offset(offset_before);
+        Transition { transition_utc, offset_before, offset_after }
+    }
+}
+
+#[cfg(windows)]
+impl PartialOrd for Transition {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.transition_utc.cmp(&other.transition_utc))
+    }
+}
+
+#[cfg(windows)]
+impl Ord for Transition {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.transition_utc.cmp(&other.transition_utc)
+    }
+}
+
+// Calculate the time in UTC given a local time and transitions.
+// `transitions` must be sorted.
+#[cfg(windows)]
+fn lookup_with_dst_transitions(
+    transitions: &[Transition],
+    dt: NaiveDateTime,
+) -> MappedLocalTime<FixedOffset> {
+    for t in transitions.iter() {
+        // A transition can result in the wall clock time going forward (creating a gap) or going
+        // backward (creating a fold). We are interested in the earliest and latest wall time of the
+        // transition, as this are the times between which `dt` does may not exist or is ambiguous.
+        //
+        // It is no problem if the transition times falls a couple of hours inside the buffer
+        // space around the `NaiveDateTime` range (although it is very theoretical to have a
+        // transition at midnight around `NaiveDate::(MIN|MAX)`.
+        let (offset_min, offset_max) =
+            match t.offset_after.local_minus_utc() > t.offset_before.local_minus_utc() {
+                true => (t.offset_before, t.offset_after),
+                false => (t.offset_after, t.offset_before),
+            };
+        let wall_earliest = t.transition_utc.overflowing_add_offset(offset_min);
+        let wall_latest = t.transition_utc.overflowing_add_offset(offset_max);
+
+        if dt < wall_earliest {
+            return MappedLocalTime::Single(t.offset_before);
+        } else if dt <= wall_latest {
+            return match t.offset_after.local_minus_utc().cmp(&t.offset_before.local_minus_utc()) {
+                Ordering::Equal => MappedLocalTime::Single(t.offset_before),
+                Ordering::Less => MappedLocalTime::Ambiguous(t.offset_before, t.offset_after),
+                Ordering::Greater => {
+                    if dt == wall_earliest {
+                        MappedLocalTime::Single(t.offset_before)
+                    } else if dt == wall_latest {
+                        MappedLocalTime::Single(t.offset_after)
+                    } else {
+                        MappedLocalTime::None
+                    }
+                }
+            };
+        }
+    }
+    MappedLocalTime::Single(transitions.last().unwrap().offset_after)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Local;
+    use crate::offset::TimeZone;
+    #[cfg(windows)]
+    use crate::offset::local::{Transition, lookup_with_dst_transitions};
+    use crate::{Datelike, Days, Utc};
+    #[cfg(windows)]
+    use crate::{FixedOffset, MappedLocalTime, NaiveDate, NaiveDateTime};
+
+    #[test]
+    fn verify_correct_offsets() {
+        let now = Local::now();
+        let from_local = Local.from_local_datetime(&now.naive_local()).unwrap();
+        let from_utc = Local.from_utc_datetime(&now.naive_utc());
+
+        assert_eq!(now.offset().local_minus_utc(), from_local.offset().local_minus_utc());
+        assert_eq!(now.offset().local_minus_utc(), from_utc.offset().local_minus_utc());
+
+        assert_eq!(now, from_local);
+        assert_eq!(now, from_utc);
+    }
+
+    #[test]
+    fn verify_correct_offsets_distant_past() {
+        let distant_past = Local::now() - Days::new(365 * 500);
+        let from_local = Local.from_local_datetime(&distant_past.naive_local()).unwrap();
+        let from_utc = Local.from_utc_datetime(&distant_past.naive_utc());
+
+        assert_eq!(distant_past.offset().local_minus_utc(), from_local.offset().local_minus_utc());
+        assert_eq!(distant_past.offset().local_minus_utc(), from_utc.offset().local_minus_utc());
+
+        assert_eq!(distant_past, from_local);
+        assert_eq!(distant_past, from_utc);
+    }
+
+    #[test]
+    fn verify_correct_offsets_distant_future() {
+        let distant_future = Local::now() + Days::new(365 * 35000);
+        let from_local = Local.from_local_datetime(&distant_future.naive_local()).unwrap();
+        let from_utc = Local.from_utc_datetime(&distant_future.naive_utc());
+
+        assert_eq!(
+            distant_future.offset().local_minus_utc(),
+            from_local.offset().local_minus_utc()
+        );
+        assert_eq!(distant_future.offset().local_minus_utc(), from_utc.offset().local_minus_utc());
+
+        assert_eq!(distant_future, from_local);
+        assert_eq!(distant_future, from_utc);
+    }
+
+    #[test]
+    fn test_local_date_sanity_check() {
+        // issue #27
+        assert_eq!(Local.with_ymd_and_hms(2999, 12, 28, 0, 0, 0).unwrap().day(), 28);
+    }
+
+    #[test]
+    fn test_leap_second() {
+        // issue #123
+        let today = Utc::now().date_naive();
+
+        if let Some(dt) = today.and_hms_milli_opt(15, 2, 59, 1000) {
+            let timestr = dt.time().to_string();
+            // the OS API may or may not support the leap second,
+            // but there are only two sensible options.
+            assert!(
+                timestr == "15:02:60" || timestr == "15:03:00",
+                "unexpected timestr {:?}",
+                timestr
+            );
+        }
+
+        if let Some(dt) = today.and_hms_milli_opt(15, 2, 3, 1234) {
+            let timestr = dt.time().to_string();
+            assert!(
+                timestr == "15:02:03.234" || timestr == "15:02:04.234",
+                "unexpected timestr {:?}",
+                timestr
+            );
+        }
+    }
+
+    #[test]
+    #[cfg(windows)]
+    fn test_lookup_with_dst_transitions() {
+        let ymdhms = |y, m, d, h, n, s| {
+            NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_opt(h, n, s).unwrap()
+        };
+
+        #[track_caller]
+        #[allow(clippy::too_many_arguments)]
+        fn compare_lookup(
+            transitions: &[Transition],
+            y: i32,
+            m: u32,
+            d: u32,
+            h: u32,
+            n: u32,
+            s: u32,
+            result: MappedLocalTime<FixedOffset>,
+        ) {
+            let dt = NaiveDate::from_ymd_opt(y, m, d).unwrap().and_hms_opt(h, n, s).unwrap();
+            assert_eq!(lookup_with_dst_transitions(transitions, dt), result);
+        }
+
+        // dst transition before std transition
+        // dst offset > std offset
+        let std = FixedOffset::east_opt(3 * 60 * 60).unwrap();
+        let dst = FixedOffset::east_opt(4 * 60 * 60).unwrap();
+        let transitions = [
+            Transition::new(ymdhms(2023, 3, 26, 2, 0, 0), std, dst),
+            Transition::new(ymdhms(2023, 10, 29, 3, 0, 0), dst, std),
+        ];
+        compare_lookup(&transitions, 2023, 3, 26, 1, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 3, 26, 2, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 3, 26, 2, 30, 0, MappedLocalTime::None);
+        compare_lookup(&transitions, 2023, 3, 26, 3, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 3, 26, 4, 0, 0, MappedLocalTime::Single(dst));
+
+        compare_lookup(&transitions, 2023, 10, 29, 1, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 10, 29, 2, 0, 0, MappedLocalTime::Ambiguous(dst, std));
+        compare_lookup(&transitions, 2023, 10, 29, 2, 30, 0, MappedLocalTime::Ambiguous(dst, std));
+        compare_lookup(&transitions, 2023, 10, 29, 3, 0, 0, MappedLocalTime::Ambiguous(dst, std));
+        compare_lookup(&transitions, 2023, 10, 29, 4, 0, 0, MappedLocalTime::Single(std));
+
+        // std transition before dst transition
+        // dst offset > std offset
+        let std = FixedOffset::east_opt(-5 * 60 * 60).unwrap();
+        let dst = FixedOffset::east_opt(-4 * 60 * 60).unwrap();
+        let transitions = [
+            Transition::new(ymdhms(2023, 3, 24, 3, 0, 0), dst, std),
+            Transition::new(ymdhms(2023, 10, 27, 2, 0, 0), std, dst),
+        ];
+        compare_lookup(&transitions, 2023, 3, 24, 1, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 3, 24, 2, 0, 0, MappedLocalTime::Ambiguous(dst, std));
+        compare_lookup(&transitions, 2023, 3, 24, 2, 30, 0, MappedLocalTime::Ambiguous(dst, std));
+        compare_lookup(&transitions, 2023, 3, 24, 3, 0, 0, MappedLocalTime::Ambiguous(dst, std));
+        compare_lookup(&transitions, 2023, 3, 24, 4, 0, 0, MappedLocalTime::Single(std));
+
+        compare_lookup(&transitions, 2023, 10, 27, 1, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 10, 27, 2, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 10, 27, 2, 30, 0, MappedLocalTime::None);
+        compare_lookup(&transitions, 2023, 10, 27, 3, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 10, 27, 4, 0, 0, MappedLocalTime::Single(dst));
+
+        // dst transition before std transition
+        // dst offset < std offset
+        let std = FixedOffset::east_opt(3 * 60 * 60).unwrap();
+        let dst = FixedOffset::east_opt((2 * 60 + 30) * 60).unwrap();
+        let transitions = [
+            Transition::new(ymdhms(2023, 3, 26, 2, 30, 0), std, dst),
+            Transition::new(ymdhms(2023, 10, 29, 2, 0, 0), dst, std),
+        ];
+        compare_lookup(&transitions, 2023, 3, 26, 1, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 3, 26, 2, 0, 0, MappedLocalTime::Ambiguous(std, dst));
+        compare_lookup(&transitions, 2023, 3, 26, 2, 15, 0, MappedLocalTime::Ambiguous(std, dst));
+        compare_lookup(&transitions, 2023, 3, 26, 2, 30, 0, MappedLocalTime::Ambiguous(std, dst));
+        compare_lookup(&transitions, 2023, 3, 26, 3, 0, 0, MappedLocalTime::Single(dst));
+
+        compare_lookup(&transitions, 2023, 10, 29, 1, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 10, 29, 2, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 10, 29, 2, 15, 0, MappedLocalTime::None);
+        compare_lookup(&transitions, 2023, 10, 29, 2, 30, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 10, 29, 3, 0, 0, MappedLocalTime::Single(std));
+
+        // std transition before dst transition
+        // dst offset < std offset
+        let std = FixedOffset::east_opt(-(4 * 60 + 30) * 60).unwrap();
+        let dst = FixedOffset::east_opt(-5 * 60 * 60).unwrap();
+        let transitions = [
+            Transition::new(ymdhms(2023, 3, 24, 2, 0, 0), dst, std),
+            Transition::new(ymdhms(2023, 10, 27, 2, 30, 0), std, dst),
+        ];
+        compare_lookup(&transitions, 2023, 3, 24, 1, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 3, 24, 2, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 3, 24, 2, 15, 0, MappedLocalTime::None);
+        compare_lookup(&transitions, 2023, 3, 24, 2, 30, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 3, 24, 3, 0, 0, MappedLocalTime::Single(std));
+
+        compare_lookup(&transitions, 2023, 10, 27, 1, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 10, 27, 2, 0, 0, MappedLocalTime::Ambiguous(std, dst));
+        compare_lookup(&transitions, 2023, 10, 27, 2, 15, 0, MappedLocalTime::Ambiguous(std, dst));
+        compare_lookup(&transitions, 2023, 10, 27, 2, 30, 0, MappedLocalTime::Ambiguous(std, dst));
+        compare_lookup(&transitions, 2023, 10, 27, 3, 0, 0, MappedLocalTime::Single(dst));
+
+        // offset stays the same
+        let std = FixedOffset::east_opt(3 * 60 * 60).unwrap();
+        let transitions = [
+            Transition::new(ymdhms(2023, 3, 26, 2, 0, 0), std, std),
+            Transition::new(ymdhms(2023, 10, 29, 3, 0, 0), std, std),
+        ];
+        compare_lookup(&transitions, 2023, 3, 26, 2, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 10, 29, 3, 0, 0, MappedLocalTime::Single(std));
+
+        // single transition
+        let std = FixedOffset::east_opt(3 * 60 * 60).unwrap();
+        let dst = FixedOffset::east_opt(4 * 60 * 60).unwrap();
+        let transitions = [Transition::new(ymdhms(2023, 3, 26, 2, 0, 0), std, dst)];
+        compare_lookup(&transitions, 2023, 3, 26, 1, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 3, 26, 2, 0, 0, MappedLocalTime::Single(std));
+        compare_lookup(&transitions, 2023, 3, 26, 2, 30, 0, MappedLocalTime::None);
+        compare_lookup(&transitions, 2023, 3, 26, 3, 0, 0, MappedLocalTime::Single(dst));
+        compare_lookup(&transitions, 2023, 3, 26, 4, 0, 0, MappedLocalTime::Single(dst));
+    }
+
+    #[test]
+    #[cfg(windows)]
+    fn test_lookup_with_dst_transitions_limits() {
+        // Transition beyond UTC year end doesn't panic in year of `NaiveDate::MAX`
+        let std = FixedOffset::east_opt(3 * 60 * 60).unwrap();
+        let dst = FixedOffset::east_opt(4 * 60 * 60).unwrap();
+        let transitions = [
+            Transition::new(NaiveDateTime::MAX.with_month(7).unwrap(), std, dst),
+            Transition::new(NaiveDateTime::MAX, dst, std),
+        ];
+        assert_eq!(
+            lookup_with_dst_transitions(&transitions, NaiveDateTime::MAX.with_month(3).unwrap()),
+            MappedLocalTime::Single(std)
+        );
+        assert_eq!(
+            lookup_with_dst_transitions(&transitions, NaiveDateTime::MAX.with_month(8).unwrap()),
+            MappedLocalTime::Single(dst)
+        );
+        // Doesn't panic with `NaiveDateTime::MAX` as argument (which would be out of range when
+        // converted to UTC).
+        assert_eq!(
+            lookup_with_dst_transitions(&transitions, NaiveDateTime::MAX),
+            MappedLocalTime::Ambiguous(dst, std)
+        );
+
+        // Transition before UTC year end doesn't panic in year of `NaiveDate::MIN`
+        let std = FixedOffset::west_opt(3 * 60 * 60).unwrap();
+        let dst = FixedOffset::west_opt(4 * 60 * 60).unwrap();
+        let transitions = [
+            Transition::new(NaiveDateTime::MIN, std, dst),
+            Transition::new(NaiveDateTime::MIN.with_month(6).unwrap(), dst, std),
+        ];
+        assert_eq!(
+            lookup_with_dst_transitions(&transitions, NaiveDateTime::MIN.with_month(3).unwrap()),
+            MappedLocalTime::Single(dst)
+        );
+        assert_eq!(
+            lookup_with_dst_transitions(&transitions, NaiveDateTime::MIN.with_month(8).unwrap()),
+            MappedLocalTime::Single(std)
+        );
+        // Doesn't panic with `NaiveDateTime::MIN` as argument (which would be out of range when
+        // converted to UTC).
+        assert_eq!(
+            lookup_with_dst_transitions(&transitions, NaiveDateTime::MIN),
+            MappedLocalTime::Ambiguous(std, dst)
+        );
+    }
+
+    #[test]
+    #[cfg(feature = "rkyv-validation")]
+    fn test_rkyv_validation() {
+        let local = Local;
+        // Local is a ZST and serializes to 0 bytes
+        let bytes = rkyv::to_bytes::<_, 0>(&local).unwrap();
+        assert_eq!(bytes.len(), 0);
+
+        // but is deserialized to an archived variant without a
+        // wrapping object
+        assert_eq!(rkyv::from_bytes::<Local>(&bytes).unwrap(), super::ArchivedLocal);
+    }
+}

patch/chrono-0.4.41/src/offset/local/tz_data.rs

@@ -0,0 +1,267 @@
+//! Rust parser of ZoneInfoDb(`tzdata`) on Android and OpenHarmony
+//!
+//! Ported from: https://android.googlesource.com/platform/prebuilts/fullsdk/sources/+/refs/heads/androidx-appcompat-release/android-34/com/android/i18n/timezone/ZoneInfoDb.java
+use std::{
+    ffi::CStr,
+    fmt::Debug,
+    fs::File,
+    io::{Error, ErrorKind, Read, Result, Seek, SeekFrom},
+};
+
+/// Get timezone data from the `tzdata` file of HarmonyOS NEXT.
+#[cfg(target_env = "ohos")]
+pub(crate) fn for_zone(tz_string: &str) -> Result<Option<Vec<u8>>> {
+    let mut file = File::open("/system/etc/zoneinfo/tzdata")?;
+    find_tz_data::<OHOS_ENTRY_LEN>(&mut file, tz_string.as_bytes())
+}
+
+/// Get timezone data from the `tzdata` file of Android.
+#[cfg(target_os = "android")]
+pub(crate) fn for_zone(tz_string: &str) -> Result<Option<Vec<u8>>> {
+    let mut file = open_android_tz_data_file()?;
+    find_tz_data::<ANDROID_ENTRY_LEN>(&mut file, tz_string.as_bytes())
+}
+
+/// Open the `tzdata` file of Android from the environment variables.
+#[cfg(target_os = "android")]
+fn open_android_tz_data_file() -> Result<File> {
+    for (env_var, path) in
+        [("ANDROID_DATA", "/misc/zoneinfo"), ("ANDROID_ROOT", "/usr/share/zoneinfo")]
+    {
+        if let Ok(env_value) = std::env::var(env_var) {
+            if let Ok(file) = File::open(format!("{}{}/tzdata", env_value, path)) {
+                return Ok(file);
+            }
+        }
+    }
+    Err(Error::from(ErrorKind::NotFound))
+}
+
+/// Get timezone data from the `tzdata` file reader
+#[cfg(any(test, target_env = "ohos", target_os = "android"))]
+fn find_tz_data<const ENTRY_LEN: usize>(
+    mut reader: impl Read + Seek,
+    tz_name: &[u8],
+) -> Result<Option<Vec<u8>>> {
+    let header = TzDataHeader::new(&mut reader)?;
+    let index = TzDataIndexes::new::<ENTRY_LEN>(&mut reader, &header)?;
+    Ok(if let Some(entry) = index.find_timezone(tz_name) {
+        Some(index.find_tzdata(reader, &header, entry)?)
+    } else {
+        None
+    })
+}
+
+/// Header of the `tzdata` file.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct TzDataHeader {
+    version: [u8; 5],
+    index_offset: u32,
+    data_offset: u32,
+    zonetab_offset: u32,
+}
+
+impl TzDataHeader {
+    /// Parse the header of the `tzdata` file.
+    fn new(mut data: impl Read) -> Result<Self> {
+        let version = {
+            let mut magic = [0; TZDATA_VERSION_LEN];
+            data.read_exact(&mut magic)?;
+            if !magic.starts_with(b"tzdata") || magic[TZDATA_VERSION_LEN - 1] != 0 {
+                return Err(Error::new(ErrorKind::Other, "invalid tzdata header magic"));
+            }
+            let mut version = [0; 5];
+            version.copy_from_slice(&magic[6..11]);
+            version
+        };
+
+        let mut offset = [0; 4];
+        data.read_exact(&mut offset)?;
+        let index_offset = u32::from_be_bytes(offset);
+        data.read_exact(&mut offset)?;
+        let data_offset = u32::from_be_bytes(offset);
+        data.read_exact(&mut offset)?;
+        let zonetab_offset = u32::from_be_bytes(offset);
+
+        Ok(Self { version, index_offset, data_offset, zonetab_offset })
+    }
+}
+
+/// Indexes of the `tzdata` file.
+struct TzDataIndexes {
+    indexes: Vec<TzDataIndex>,
+}
+
+impl TzDataIndexes {
+    /// Create a new `TzDataIndexes` from the `tzdata` file reader.
+    fn new<const ENTRY_LEN: usize>(mut reader: impl Read, header: &TzDataHeader) -> Result<Self> {
+        let mut buf = vec![0; header.data_offset.saturating_sub(header.index_offset) as usize];
+        reader.read_exact(&mut buf)?;
+        // replace chunks with array_chunks when it's stable
+        Ok(TzDataIndexes {
+            indexes: buf
+                .chunks(ENTRY_LEN)
+                .filter_map(|chunk| {
+                    from_bytes_until_nul(&chunk[..TZ_NAME_LEN]).map(|name| {
+                        let name = name.to_bytes().to_vec().into_boxed_slice();
+                        let offset = u32::from_be_bytes(
+                            chunk[TZ_NAME_LEN..TZ_NAME_LEN + 4].try_into().unwrap(),
+                        );
+                        let length = u32::from_be_bytes(
+                            chunk[TZ_NAME_LEN + 4..TZ_NAME_LEN + 8].try_into().unwrap(),
+                        );
+                        TzDataIndex { name, offset, length }
+                    })
+                })
+                .collect(),
+        })
+    }
+
+    /// Find a timezone by name.
+    fn find_timezone(&self, timezone: &[u8]) -> Option<&TzDataIndex> {
+        // timezones in tzdata are sorted by name.
+        self.indexes.binary_search_by_key(&timezone, |x| &x.name).map(|x| &self.indexes[x]).ok()
+    }
+
+    /// Retrieve a chunk of timezone data by the index.
+    fn find_tzdata(
+        &self,
+        mut reader: impl Read + Seek,
+        header: &TzDataHeader,
+        index: &TzDataIndex,
+    ) -> Result<Vec<u8>> {
+        reader.seek(SeekFrom::Start(index.offset as u64 + header.data_offset as u64))?;
+        let mut buffer = vec![0; index.length as usize];
+        reader.read_exact(&mut buffer)?;
+        Ok(buffer)
+    }
+}
+
+/// Index entry of the `tzdata` file.
+struct TzDataIndex {
+    name: Box<[u8]>,
+    offset: u32,
+    length: u32,
+}
+
+/// TODO: Change this `CStr::from_bytes_until_nul` once MSRV was bumped above 1.72.0
+fn from_bytes_until_nul(bytes: &[u8]) -> Option<&CStr> {
+    let nul_pos = bytes.iter().position(|&b| b == 0)?;
+    // SAFETY:
+    // 1. nul_pos + 1 <= bytes.len()
+    // 2. We know there is a nul byte at nul_pos, so this slice (ending at the nul byte) is a well-formed C string.
+    Some(unsafe { CStr::from_bytes_with_nul_unchecked(&bytes[..=nul_pos]) })
+}
+
+/// Ohos tzdata index entry size: `name + offset + length`
+#[cfg(any(test, target_env = "ohos"))]
+const OHOS_ENTRY_LEN: usize = TZ_NAME_LEN + 2 * size_of::<u32>();
+/// Android tzdata index entry size: `name + offset + length + raw_utc_offset(legacy)`:
+/// [reference](https://android.googlesource.com/platform/prebuilts/fullsdk/sources/+/refs/heads/androidx-appcompat-release/android-34/com/android/i18n/timezone/ZoneInfoDb.java#271)
+#[cfg(any(test, target_os = "android"))]
+const ANDROID_ENTRY_LEN: usize = TZ_NAME_LEN + 3 * size_of::<u32>();
+/// The database reserves 40 bytes for each id.
+const TZ_NAME_LEN: usize = 40;
+/// Size of the version string in the header of `tzdata` file.
+/// e.g. `tzdata2024b\0`
+const TZDATA_VERSION_LEN: usize = 12;
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_ohos_tzdata_header_and_index() {
+        let file = File::open("./tests/ohos/tzdata").unwrap();
+        let header = TzDataHeader::new(&file).unwrap();
+        assert_eq!(header.version, *b"2024a");
+        assert_eq!(header.index_offset, 24);
+        assert_eq!(header.data_offset, 21240);
+        assert_eq!(header.zonetab_offset, 272428);
+
+        let iter = TzDataIndexes::new::<OHOS_ENTRY_LEN>(&file, &header).unwrap();
+        assert_eq!(iter.indexes.len(), 442);
+        assert!(iter.find_timezone(b"Asia/Shanghai").is_some());
+        assert!(iter.find_timezone(b"Pacific/Noumea").is_some());
+    }
+
+    #[test]
+    fn test_ohos_tzdata_loading() {
+        let file = File::open("./tests/ohos/tzdata").unwrap();
+        let header = TzDataHeader::new(&file).unwrap();
+        let iter = TzDataIndexes::new::<OHOS_ENTRY_LEN>(&file, &header).unwrap();
+        let timezone = iter.find_timezone(b"Asia/Shanghai").unwrap();
+        let tzdata = iter.find_tzdata(&file, &header, timezone).unwrap();
+        assert_eq!(tzdata.len(), 393);
+    }
+
+    #[test]
+    fn test_invalid_tzdata_header() {
+        TzDataHeader::new(&b"tzdaaa2024aaaaaaaaaaaaaaa\0"[..]).unwrap_err();
+    }
+
+    #[test]
+    fn test_android_tzdata_header_and_index() {
+        let file = File::open("./tests/android/tzdata").unwrap();
+        let header = TzDataHeader::new(&file).unwrap();
+        assert_eq!(header.version, *b"2021a");
+        assert_eq!(header.index_offset, 24);
+        assert_eq!(header.data_offset, 30860);
+        assert_eq!(header.zonetab_offset, 491837);
+
+        let iter = TzDataIndexes::new::<ANDROID_ENTRY_LEN>(&file, &header).unwrap();
+        assert_eq!(iter.indexes.len(), 593);
+        assert!(iter.find_timezone(b"Asia/Shanghai").is_some());
+        assert!(iter.find_timezone(b"Pacific/Noumea").is_some());
+    }
+
+    #[test]
+    fn test_android_tzdata_loading() {
+        let file = File::open("./tests/android/tzdata").unwrap();
+        let header = TzDataHeader::new(&file).unwrap();
+        let iter = TzDataIndexes::new::<ANDROID_ENTRY_LEN>(&file, &header).unwrap();
+        let timezone = iter.find_timezone(b"Asia/Shanghai").unwrap();
+        let tzdata = iter.find_tzdata(&file, &header, timezone).unwrap();
+        assert_eq!(tzdata.len(), 573);
+    }
+
+    #[test]
+    fn test_ohos_tzdata_find() {
+        let file = File::open("./tests/ohos/tzdata").unwrap();
+        let tzdata = find_tz_data::<OHOS_ENTRY_LEN>(file, b"Asia/Shanghai").unwrap().unwrap();
+        assert_eq!(tzdata.len(), 393);
+    }
+
+    #[test]
+    fn test_ohos_tzdata_find_missing() {
+        let file = File::open("./tests/ohos/tzdata").unwrap();
+        assert!(find_tz_data::<OHOS_ENTRY_LEN>(file, b"Asia/Sjasdfai").unwrap().is_none());
+    }
+
+    #[test]
+    fn test_android_tzdata_find() {
+        let file = File::open("./tests/android/tzdata").unwrap();
+        let tzdata = find_tz_data::<ANDROID_ENTRY_LEN>(file, b"Asia/Shanghai").unwrap().unwrap();
+        assert_eq!(tzdata.len(), 573);
+    }
+
+    #[test]
+    fn test_android_tzdata_find_missing() {
+        let file = File::open("./tests/android/tzdata").unwrap();
+        assert!(find_tz_data::<ANDROID_ENTRY_LEN>(file, b"Asia/S000000i").unwrap().is_none());
+    }
+
+    #[cfg(target_env = "ohos")]
+    #[test]
+    fn test_ohos_machine_tz_data_loading() {
+        let tzdata = for_zone(b"Asia/Shanghai").unwrap().unwrap();
+        assert!(!tzdata.is_empty());
+    }
+
+    #[cfg(target_os = "android")]
+    #[test]
+    fn test_android_machine_tz_data_loading() {
+        let tzdata = for_zone(b"Asia/Shanghai").unwrap().unwrap();
+        assert!(!tzdata.is_empty());
+    }
+}

patch/chrono-0.4.41/src/offset/local/tz_info/mod.rs

@@ -0,0 +1,116 @@
+#![deny(missing_docs)]
+#![allow(dead_code)]
+#![warn(unreachable_pub)]
+
+use std::num::ParseIntError;
+use std::str::Utf8Error;
+use std::time::SystemTimeError;
+use std::{error, fmt, io};
+
+mod timezone;
+pub(crate) use timezone::TimeZone;
+
+mod parser;
+mod rule;
+
+/// Unified error type for everything in the crate
+#[derive(Debug)]
+pub(crate) enum Error {
+    /// Date time error
+    DateTime(&'static str),
+    /// Local time type search error
+    FindLocalTimeType(&'static str),
+    /// Local time type error
+    LocalTimeType(&'static str),
+    /// Invalid slice for integer conversion
+    InvalidSlice(&'static str),
+    /// Invalid Tzif file
+    InvalidTzFile(&'static str),
+    /// Invalid TZ string
+    InvalidTzString(&'static str),
+    /// I/O error
+    Io(io::Error),
+    /// Out of range error
+    OutOfRange(&'static str),
+    /// Integer parsing error
+    ParseInt(ParseIntError),
+    /// Date time projection error
+    ProjectDateTime(&'static str),
+    /// System time error
+    SystemTime(SystemTimeError),
+    /// Time zone error
+    TimeZone(&'static str),
+    /// Transition rule error
+    TransitionRule(&'static str),
+    /// Unsupported Tzif file
+    UnsupportedTzFile(&'static str),
+    /// Unsupported TZ string
+    UnsupportedTzString(&'static str),
+    /// UTF-8 error
+    Utf8(Utf8Error),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use Error::*;
+        match self {
+            DateTime(error) => write!(f, "invalid date time: {error}"),
+            FindLocalTimeType(error) => error.fmt(f),
+            LocalTimeType(error) => write!(f, "invalid local time type: {error}"),
+            InvalidSlice(error) => error.fmt(f),
+            InvalidTzString(error) => write!(f, "invalid TZ string: {error}"),
+            InvalidTzFile(error) => error.fmt(f),
+            Io(error) => error.fmt(f),
+            OutOfRange(error) => error.fmt(f),
+            ParseInt(error) => error.fmt(f),
+            ProjectDateTime(error) => error.fmt(f),
+            SystemTime(error) => error.fmt(f),
+            TransitionRule(error) => write!(f, "invalid transition rule: {error}"),
+            TimeZone(error) => write!(f, "invalid time zone: {error}"),
+            UnsupportedTzFile(error) => error.fmt(f),
+            UnsupportedTzString(error) => write!(f, "unsupported TZ string: {error}"),
+            Utf8(error) => error.fmt(f),
+        }
+    }
+}
+
+impl error::Error for Error {}
+
+impl From<io::Error> for Error {
+    fn from(error: io::Error) -> Self {
+        Error::Io(error)
+    }
+}
+
+impl From<ParseIntError> for Error {
+    fn from(error: ParseIntError) -> Self {
+        Error::ParseInt(error)
+    }
+}
+
+impl From<SystemTimeError> for Error {
+    fn from(error: SystemTimeError) -> Self {
+        Error::SystemTime(error)
+    }
+}
+
+impl From<Utf8Error> for Error {
+    fn from(error: Utf8Error) -> Self {
+        Error::Utf8(error)
+    }
+}
+
+/// Number of hours in one day
+const HOURS_PER_DAY: i64 = 24;
+/// Number of seconds in one hour
+const SECONDS_PER_HOUR: i64 = 3600;
+/// Number of seconds in one day
+const SECONDS_PER_DAY: i64 = SECONDS_PER_HOUR * HOURS_PER_DAY;
+/// Number of days in one week
+const DAYS_PER_WEEK: i64 = 7;
+
+/// Month days in a normal year
+const DAY_IN_MONTHS_NORMAL_YEAR: [i64; 12] = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
+/// Cumulated month days in a normal year
+const CUMUL_DAY_IN_MONTHS_NORMAL_YEAR: [i64; 12] =
+    [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334];

patch/chrono-0.4.41/src/offset/local/tz_info/parser.rs

@@ -0,0 +1,348 @@
+use std::io::{self, ErrorKind};
+use std::iter;
+use std::num::ParseIntError;
+use std::str::{self, FromStr};
+
+use super::Error;
+use super::rule::TransitionRule;
+use super::timezone::{LeapSecond, LocalTimeType, TimeZone, Transition};
+
+pub(super) fn parse(bytes: &[u8]) -> Result<TimeZone, Error> {
+    let mut cursor = Cursor::new(bytes);
+    let state = State::new(&mut cursor, true)?;
+    let (state, footer) = match state.header.version {
+        Version::V1 => match cursor.is_empty() {
+            true => (state, None),
+            false => {
+                return Err(Error::InvalidTzFile("remaining data after end of TZif v1 data block"));
+            }
+        },
+        Version::V2 | Version::V3 => {
+            let state = State::new(&mut cursor, false)?;
+            (state, Some(cursor.remaining()))
+        }
+    };
+
+    let mut transitions = Vec::with_capacity(state.header.transition_count);
+    for (arr_time, &local_time_type_index) in
+        state.transition_times.chunks_exact(state.time_size).zip(state.transition_types)
+    {
+        let unix_leap_time =
+            state.parse_time(&arr_time[0..state.time_size], state.header.version)?;
+        let local_time_type_index = local_time_type_index as usize;
+        transitions.push(Transition::new(unix_leap_time, local_time_type_index));
+    }
+
+    let mut local_time_types = Vec::with_capacity(state.header.type_count);
+    for arr in state.local_time_types.chunks_exact(6) {
+        let ut_offset = read_be_i32(&arr[..4])?;
+
+        let is_dst = match arr[4] {
+            0 => false,
+            1 => true,
+            _ => return Err(Error::InvalidTzFile("invalid DST indicator")),
+        };
+
+        let char_index = arr[5] as usize;
+        if char_index >= state.header.char_count {
+            return Err(Error::InvalidTzFile("invalid time zone name char index"));
+        }
+
+        let position = match state.names[char_index..].iter().position(|&c| c == b'\0') {
+            Some(position) => position,
+            None => return Err(Error::InvalidTzFile("invalid time zone name char index")),
+        };
+
+        let name = &state.names[char_index..char_index + position];
+        let name = if !name.is_empty() { Some(name) } else { None };
+        local_time_types.push(LocalTimeType::new(ut_offset, is_dst, name)?);
+    }
+
+    let mut leap_seconds = Vec::with_capacity(state.header.leap_count);
+    for arr in state.leap_seconds.chunks_exact(state.time_size + 4) {
+        let unix_leap_time = state.parse_time(&arr[0..state.time_size], state.header.version)?;
+        let correction = read_be_i32(&arr[state.time_size..state.time_size + 4])?;
+        leap_seconds.push(LeapSecond::new(unix_leap_time, correction));
+    }
+
+    let std_walls_iter = state.std_walls.iter().copied().chain(iter::repeat(0));
+    let ut_locals_iter = state.ut_locals.iter().copied().chain(iter::repeat(0));
+    if std_walls_iter.zip(ut_locals_iter).take(state.header.type_count).any(|pair| pair == (0, 1)) {
+        return Err(Error::InvalidTzFile(
+            "invalid couple of standard/wall and UT/local indicators",
+        ));
+    }
+
+    let extra_rule = match footer {
+        Some(footer) => {
+            let footer = str::from_utf8(footer)?;
+            if !(footer.starts_with('\n') && footer.ends_with('\n')) {
+                return Err(Error::InvalidTzFile("invalid footer"));
+            }
+
+            let tz_string = footer.trim_matches(|c: char| c.is_ascii_whitespace());
+            if tz_string.starts_with(':') || tz_string.contains('\0') {
+                return Err(Error::InvalidTzFile("invalid footer"));
+            }
+
+            match tz_string.is_empty() {
+                true => None,
+                false => Some(TransitionRule::from_tz_string(
+                    tz_string.as_bytes(),
+                    state.header.version == Version::V3,
+                )?),
+            }
+        }
+        None => None,
+    };
+
+    TimeZone::new(transitions, local_time_types, leap_seconds, extra_rule)
+}
+
+/// TZif data blocks
+struct State<'a> {
+    header: Header,
+    /// Time size in bytes
+    time_size: usize,
+    /// Transition times data block
+    transition_times: &'a [u8],
+    /// Transition types data block
+    transition_types: &'a [u8],
+    /// Local time types data block
+    local_time_types: &'a [u8],
+    /// Time zone names data block
+    names: &'a [u8],
+    /// Leap seconds data block
+    leap_seconds: &'a [u8],
+    /// UT/local indicators data block
+    std_walls: &'a [u8],
+    /// Standard/wall indicators data block
+    ut_locals: &'a [u8],
+}
+
+impl<'a> State<'a> {
+    /// Read TZif data blocks
+    fn new(cursor: &mut Cursor<'a>, first: bool) -> Result<Self, Error> {
+        let header = Header::new(cursor)?;
+        let time_size = match first {
+            true => 4, // We always parse V1 first
+            false => 8,
+        };
+
+        Ok(Self {
+            time_size,
+            transition_times: cursor.read_exact(header.transition_count * time_size)?,
+            transition_types: cursor.read_exact(header.transition_count)?,
+            local_time_types: cursor.read_exact(header.type_count * 6)?,
+            names: cursor.read_exact(header.char_count)?,
+            leap_seconds: cursor.read_exact(header.leap_count * (time_size + 4))?,
+            std_walls: cursor.read_exact(header.std_wall_count)?,
+            ut_locals: cursor.read_exact(header.ut_local_count)?,
+            header,
+        })
+    }
+
+    /// Parse time values
+    fn parse_time(&self, arr: &[u8], version: Version) -> Result<i64, Error> {
+        match version {
+            Version::V1 => Ok(read_be_i32(&arr[..4])?.into()),
+            Version::V2 | Version::V3 => read_be_i64(arr),
+        }
+    }
+}
+
+/// TZif header
+#[derive(Debug)]
+struct Header {
+    /// TZif version
+    version: Version,
+    /// Number of UT/local indicators
+    ut_local_count: usize,
+    /// Number of standard/wall indicators
+    std_wall_count: usize,
+    /// Number of leap-second records
+    leap_count: usize,
+    /// Number of transition times
+    transition_count: usize,
+    /// Number of local time type records
+    type_count: usize,
+    /// Number of time zone names bytes
+    char_count: usize,
+}
+
+impl Header {
+    fn new(cursor: &mut Cursor) -> Result<Self, Error> {
+        let magic = cursor.read_exact(4)?;
+        if magic != *b"TZif" {
+            return Err(Error::InvalidTzFile("invalid magic number"));
+        }
+
+        let version = match cursor.read_exact(1)? {
+            [0x00] => Version::V1,
+            [0x32] => Version::V2,
+            [0x33] => Version::V3,
+            _ => return Err(Error::UnsupportedTzFile("unsupported TZif version")),
+        };
+
+        cursor.read_exact(15)?;
+        let ut_local_count = cursor.read_be_u32()?;
+        let std_wall_count = cursor.read_be_u32()?;
+        let leap_count = cursor.read_be_u32()?;
+        let transition_count = cursor.read_be_u32()?;
+        let type_count = cursor.read_be_u32()?;
+        let char_count = cursor.read_be_u32()?;
+
+        if !(type_count != 0
+            && char_count != 0
+            && (ut_local_count == 0 || ut_local_count == type_count)
+            && (std_wall_count == 0 || std_wall_count == type_count))
+        {
+            return Err(Error::InvalidTzFile("invalid header"));
+        }
+
+        Ok(Self {
+            version,
+            ut_local_count: ut_local_count as usize,
+            std_wall_count: std_wall_count as usize,
+            leap_count: leap_count as usize,
+            transition_count: transition_count as usize,
+            type_count: type_count as usize,
+            char_count: char_count as usize,
+        })
+    }
+}
+
+/// A `Cursor` contains a slice of a buffer and a read count.
+#[derive(Debug, Eq, PartialEq)]
+pub(crate) struct Cursor<'a> {
+    /// Slice representing the remaining data to be read
+    remaining: &'a [u8],
+    /// Number of already read bytes
+    read_count: usize,
+}
+
+impl<'a> Cursor<'a> {
+    /// Construct a new `Cursor` from remaining data
+    pub(crate) const fn new(remaining: &'a [u8]) -> Self {
+        Self { remaining, read_count: 0 }
+    }
+
+    pub(crate) fn peek(&self) -> Option<&u8> {
+        self.remaining().first()
+    }
+
+    /// Returns remaining data
+    pub(crate) const fn remaining(&self) -> &'a [u8] {
+        self.remaining
+    }
+
+    /// Returns `true` if data is remaining
+    pub(crate) const fn is_empty(&self) -> bool {
+        self.remaining.is_empty()
+    }
+
+    pub(crate) fn read_be_u32(&mut self) -> Result<u32, Error> {
+        let mut buf = [0; 4];
+        buf.copy_from_slice(self.read_exact(4)?);
+        Ok(u32::from_be_bytes(buf))
+    }
+
+    #[cfg(target_env = "ohos")]
+    pub(crate) fn seek_after(&mut self, offset: usize) -> Result<usize, io::Error> {
+        if offset < self.read_count {
+            return Err(io::Error::from(ErrorKind::UnexpectedEof));
+        }
+        match self.remaining.get((offset - self.read_count)..) {
+            Some(remaining) => {
+                self.remaining = remaining;
+                self.read_count = offset;
+                Ok(offset)
+            }
+            _ => Err(io::Error::from(ErrorKind::UnexpectedEof)),
+        }
+    }
+
+    /// Read exactly `count` bytes, reducing remaining data and incrementing read count
+    pub(crate) fn read_exact(&mut self, count: usize) -> Result<&'a [u8], io::Error> {
+        match (self.remaining.get(..count), self.remaining.get(count..)) {
+            (Some(result), Some(remaining)) => {
+                self.remaining = remaining;
+                self.read_count += count;
+                Ok(result)
+            }
+            _ => Err(io::Error::from(ErrorKind::UnexpectedEof)),
+        }
+    }
+
+    /// Read bytes and compare them to the provided tag
+    pub(crate) fn read_tag(&mut self, tag: &[u8]) -> Result<(), io::Error> {
+        if self.read_exact(tag.len())? == tag {
+            Ok(())
+        } else {
+            Err(io::Error::from(ErrorKind::InvalidData))
+        }
+    }
+
+    /// Read bytes if the remaining data is prefixed by the provided tag
+    pub(crate) fn read_optional_tag(&mut self, tag: &[u8]) -> Result<bool, io::Error> {
+        if self.remaining.starts_with(tag) {
+            self.read_exact(tag.len())?;
+            Ok(true)
+        } else {
+            Ok(false)
+        }
+    }
+
+    /// Read bytes as long as the provided predicate is true
+    pub(crate) fn read_while<F: Fn(&u8) -> bool>(&mut self, f: F) -> Result<&'a [u8], io::Error> {
+        match self.remaining.iter().position(|x| !f(x)) {
+            None => self.read_exact(self.remaining.len()),
+            Some(position) => self.read_exact(position),
+        }
+    }
+
+    // Parse an integer out of the ASCII digits
+    pub(crate) fn read_int<T: FromStr<Err = ParseIntError>>(&mut self) -> Result<T, Error> {
+        let bytes = self.read_while(u8::is_ascii_digit)?;
+        Ok(str::from_utf8(bytes)?.parse()?)
+    }
+
+    /// Read bytes until the provided predicate is true
+    pub(crate) fn read_until<F: Fn(&u8) -> bool>(&mut self, f: F) -> Result<&'a [u8], io::Error> {
+        match self.remaining.iter().position(f) {
+            None => self.read_exact(self.remaining.len()),
+            Some(position) => self.read_exact(position),
+        }
+    }
+}
+
+pub(crate) fn read_be_i32(bytes: &[u8]) -> Result<i32, Error> {
+    if bytes.len() != 4 {
+        return Err(Error::InvalidSlice("too short for i32"));
+    }
+
+    let mut buf = [0; 4];
+    buf.copy_from_slice(bytes);
+    Ok(i32::from_be_bytes(buf))
+}
+
+pub(crate) fn read_be_i64(bytes: &[u8]) -> Result<i64, Error> {
+    if bytes.len() != 8 {
+        return Err(Error::InvalidSlice("too short for i64"));
+    }
+
+    let mut buf = [0; 8];
+    buf.copy_from_slice(bytes);
+    Ok(i64::from_be_bytes(buf))
+}
+
+/// TZif version
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+enum Version {
+    /// Version 1
+    V1,
+    /// Version 2
+    V2,
+    /// Version 3
+    V3,
+}

patch/chrono-0.4.41/src/offset/local/tz_info/timezone.rs

@@ -0,0 +1,948 @@
+//! Types related to a time zone.
+
+use std::fs::{self, File};
+use std::io::{self, Read};
+use std::path::{Path, PathBuf};
+use std::{cmp::Ordering, fmt, str};
+
+use super::rule::{AlternateTime, TransitionRule};
+use super::{DAYS_PER_WEEK, Error, SECONDS_PER_DAY, parser};
+use crate::NaiveDateTime;
+
+/// Time zone
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub(crate) struct TimeZone {
+    /// List of transitions
+    transitions: Vec<Transition>,
+    /// List of local time types (cannot be empty)
+    local_time_types: Vec<LocalTimeType>,
+    /// List of leap seconds
+    leap_seconds: Vec<LeapSecond>,
+    /// Extra transition rule applicable after the last transition
+    extra_rule: Option<TransitionRule>,
+}
+
+impl TimeZone {
+    /// Returns local time zone.
+    ///
+    /// This method in not supported on non-UNIX platforms, and returns the UTC time zone instead.
+    pub(crate) fn local(env_tz: Option<&str>) -> Result<Self, Error> {
+        match env_tz {
+            Some(tz) => Self::from_posix_tz(tz),
+            None => Self::from_posix_tz("localtime"),
+        }
+    }
+
+    /// Construct a time zone from a POSIX TZ string, as described in [the POSIX documentation of the `TZ` environment variable](https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html).
+    fn from_posix_tz(tz_string: &str) -> Result<Self, Error> {
+        // It is commonly agreed (but not standard) that setting an empty `TZ=` uses UTC.
+        if tz_string.is_empty() {
+            return Ok(Self::utc());
+        }
+
+        if tz_string == "localtime" {
+            return Self::from_tz_data(&fs::read("/etc/localtime")?);
+        }
+
+        // attributes are not allowed on if blocks in Rust 1.38
+        #[cfg(any(target_os = "android", target_env = "ohos"))]
+        {
+            if let Ok(Some(bytes)) = crate::offset::local::tz_data::for_zone(tz_string) {
+                return Self::from_tz_data(&bytes);
+            }
+        }
+
+        let mut chars = tz_string.chars();
+        if chars.next() == Some(':') {
+            return Self::from_file(&mut find_tz_file(chars.as_str())?);
+        }
+
+        if let Ok(mut file) = find_tz_file(tz_string) {
+            return Self::from_file(&mut file);
+        }
+
+        // TZ string extensions are not allowed
+        let tz_string = tz_string.trim_matches(|c: char| c.is_ascii_whitespace());
+        let rule = TransitionRule::from_tz_string(tz_string.as_bytes(), false)?;
+        Self::new(
+            vec![],
+            match rule {
+                TransitionRule::Fixed(local_time_type) => vec![local_time_type],
+                TransitionRule::Alternate(AlternateTime { std, dst, .. }) => vec![std, dst],
+            },
+            vec![],
+            Some(rule),
+        )
+    }
+
+    /// Construct a time zone
+    pub(super) fn new(
+        transitions: Vec<Transition>,
+        local_time_types: Vec<LocalTimeType>,
+        leap_seconds: Vec<LeapSecond>,
+        extra_rule: Option<TransitionRule>,
+    ) -> Result<Self, Error> {
+        let new = Self { transitions, local_time_types, leap_seconds, extra_rule };
+        new.as_ref().validate()?;
+        Ok(new)
+    }
+
+    /// Construct a time zone from the contents of a time zone file
+    fn from_file(file: &mut File) -> Result<Self, Error> {
+        let mut bytes = Vec::new();
+        file.read_to_end(&mut bytes)?;
+        Self::from_tz_data(&bytes)
+    }
+
+    /// Construct a time zone from the contents of a time zone file
+    ///
+    /// Parse TZif data as described in [RFC 8536](https://datatracker.ietf.org/doc/html/rfc8536).
+    pub(crate) fn from_tz_data(bytes: &[u8]) -> Result<Self, Error> {
+        parser::parse(bytes)
+    }
+
+    /// Construct a time zone with the specified UTC offset in seconds
+    fn fixed(ut_offset: i32) -> Result<Self, Error> {
+        Ok(Self {
+            transitions: Vec::new(),
+            local_time_types: vec![LocalTimeType::with_offset(ut_offset)?],
+            leap_seconds: Vec::new(),
+            extra_rule: None,
+        })
+    }
+
+    /// Construct the time zone associated to UTC
+    pub(crate) fn utc() -> Self {
+        Self {
+            transitions: Vec::new(),
+            local_time_types: vec![LocalTimeType::UTC],
+            leap_seconds: Vec::new(),
+            extra_rule: None,
+        }
+    }
+
+    /// Find the local time type associated to the time zone at the specified Unix time in seconds
+    pub(crate) fn find_local_time_type(&self, unix_time: i64) -> Result<&LocalTimeType, Error> {
+        self.as_ref().find_local_time_type(unix_time)
+    }
+
+    pub(crate) fn find_local_time_type_from_local(
+        &self,
+        local_time: NaiveDateTime,
+    ) -> Result<crate::MappedLocalTime<LocalTimeType>, Error> {
+        self.as_ref().find_local_time_type_from_local(local_time)
+    }
+
+    /// Returns a reference to the time zone
+    fn as_ref(&'_ self) -> TimeZoneRef<'_> {
+        TimeZoneRef {
+            transitions: &self.transitions,
+            local_time_types: &self.local_time_types,
+            leap_seconds: &self.leap_seconds,
+            extra_rule: &self.extra_rule,
+        }
+    }
+}
+
+/// Reference to a time zone
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub(crate) struct TimeZoneRef<'a> {
+    /// List of transitions
+    transitions: &'a [Transition],
+    /// List of local time types (cannot be empty)
+    local_time_types: &'a [LocalTimeType],
+    /// List of leap seconds
+    leap_seconds: &'a [LeapSecond],
+    /// Extra transition rule applicable after the last transition
+    extra_rule: &'a Option<TransitionRule>,
+}
+
+impl<'a> TimeZoneRef<'a> {
+    /// Find the local time type associated to the time zone at the specified Unix time in seconds
+    pub(crate) fn find_local_time_type(&self, unix_time: i64) -> Result<&'a LocalTimeType, Error> {
+        let extra_rule = match self.transitions.last() {
+            None => match self.extra_rule {
+                Some(extra_rule) => extra_rule,
+                None => return Ok(&self.local_time_types[0]),
+            },
+            Some(last_transition) => {
+                let unix_leap_time = match self.unix_time_to_unix_leap_time(unix_time) {
+                    Ok(unix_leap_time) => unix_leap_time,
+                    Err(Error::OutOfRange(error)) => return Err(Error::FindLocalTimeType(error)),
+                    Err(err) => return Err(err),
+                };
+
+                if unix_leap_time >= last_transition.unix_leap_time {
+                    match self.extra_rule {
+                        Some(extra_rule) => extra_rule,
+                        None => {
+                            // RFC 8536 3.2:
+                            // "Local time for timestamps on or after the last transition is
+                            // specified by the TZ string in the footer (Section 3.3) if present
+                            // and nonempty; otherwise, it is unspecified."
+                            //
+                            // Older versions of macOS (1.12 and before?) have TZif file with a
+                            // missing TZ string, and use the offset given by the last transition.
+                            return Ok(
+                                &self.local_time_types[last_transition.local_time_type_index]
+                            );
+                        }
+                    }
+                } else {
+                    let index = match self
+                        .transitions
+                        .binary_search_by_key(&unix_leap_time, Transition::unix_leap_time)
+                    {
+                        Ok(x) => x + 1,
+                        Err(x) => x,
+                    };
+
+                    let local_time_type_index = if index > 0 {
+                        self.transitions[index - 1].local_time_type_index
+                    } else {
+                        0
+                    };
+                    return Ok(&self.local_time_types[local_time_type_index]);
+                }
+            }
+        };
+
+        match extra_rule.find_local_time_type(unix_time) {
+            Ok(local_time_type) => Ok(local_time_type),
+            Err(Error::OutOfRange(error)) => Err(Error::FindLocalTimeType(error)),
+            err => err,
+        }
+    }
+
+    pub(crate) fn find_local_time_type_from_local(
+        &self,
+        local_time: NaiveDateTime,
+    ) -> Result<crate::MappedLocalTime<LocalTimeType>, Error> {
+        // #TODO: this is wrong as we need 'local_time_to_local_leap_time ?
+        // but ... does the local time even include leap seconds ??
+        // let unix_leap_time = match self.unix_time_to_unix_leap_time(local_time) {
+        //     Ok(unix_leap_time) => unix_leap_time,
+        //     Err(Error::OutOfRange(error)) => return Err(Error::FindLocalTimeType(error)),
+        //     Err(err) => return Err(err),
+        // };
+        let local_leap_time = local_time.and_utc().timestamp();
+
+        // if we have at least one transition,
+        // we must check _all_ of them, in case of any Overlapping (MappedLocalTime::Ambiguous) or Skipping (MappedLocalTime::None) transitions
+        let offset_after_last = if !self.transitions.is_empty() {
+            let mut prev = self.local_time_types[0];
+
+            for transition in self.transitions {
+                let after_ltt = self.local_time_types[transition.local_time_type_index];
+
+                // the end and start here refers to where the time starts prior to the transition
+                // and where it ends up after. not the temporal relationship.
+                let transition_end = transition.unix_leap_time + i64::from(after_ltt.ut_offset);
+                let transition_start = transition.unix_leap_time + i64::from(prev.ut_offset);
+
+                match transition_start.cmp(&transition_end) {
+                    Ordering::Greater => {
+                        // backwards transition, eg from DST to regular
+                        // this means a given local time could have one of two possible offsets
+                        if local_leap_time < transition_end {
+                            return Ok(crate::MappedLocalTime::Single(prev));
+                        } else if local_leap_time >= transition_end
+                            && local_leap_time <= transition_start
+                        {
+                            if prev.ut_offset < after_ltt.ut_offset {
+                                return Ok(crate::MappedLocalTime::Ambiguous(prev, after_ltt));
+                            } else {
+                                return Ok(crate::MappedLocalTime::Ambiguous(after_ltt, prev));
+                            }
+                        }
+                    }
+                    Ordering::Equal => {
+                        // should this ever happen? presumably we have to handle it anyway.
+                        if local_leap_time < transition_start {
+                            return Ok(crate::MappedLocalTime::Single(prev));
+                        } else if local_leap_time == transition_end {
+                            if prev.ut_offset < after_ltt.ut_offset {
+                                return Ok(crate::MappedLocalTime::Ambiguous(prev, after_ltt));
+                            } else {
+                                return Ok(crate::MappedLocalTime::Ambiguous(after_ltt, prev));
+                            }
+                        }
+                    }
+                    Ordering::Less => {
+                        // forwards transition, eg from regular to DST
+                        // this means that times that are skipped are invalid local times
+                        if local_leap_time <= transition_start {
+                            return Ok(crate::MappedLocalTime::Single(prev));
+                        } else if local_leap_time < transition_end {
+                            return Ok(crate::MappedLocalTime::None);
+                        } else if local_leap_time == transition_end {
+                            return Ok(crate::MappedLocalTime::Single(after_ltt));
+                        }
+                    }
+                }
+
+                // try the next transition, we are fully after this one
+                prev = after_ltt;
+            }
+
+            prev
+        } else {
+            self.local_time_types[0]
+        };
+
+        if let Some(extra_rule) = self.extra_rule {
+            match extra_rule.find_local_time_type_from_local(local_time) {
+                Ok(local_time_type) => Ok(local_time_type),
+                Err(Error::OutOfRange(error)) => Err(Error::FindLocalTimeType(error)),
+                err => err,
+            }
+        } else {
+            Ok(crate::MappedLocalTime::Single(offset_after_last))
+        }
+    }
+
+    /// Check time zone inputs
+    fn validate(&self) -> Result<(), Error> {
+        // Check local time types
+        let local_time_types_size = self.local_time_types.len();
+        if local_time_types_size == 0 {
+            return Err(Error::TimeZone("list of local time types must not be empty"));
+        }
+
+        // Check transitions
+        let mut i_transition = 0;
+        while i_transition < self.transitions.len() {
+            if self.transitions[i_transition].local_time_type_index >= local_time_types_size {
+                return Err(Error::TimeZone("invalid local time type index"));
+            }
+
+            if i_transition + 1 < self.transitions.len()
+                && self.transitions[i_transition].unix_leap_time
+                    >= self.transitions[i_transition + 1].unix_leap_time
+            {
+                return Err(Error::TimeZone("invalid transition"));
+            }
+
+            i_transition += 1;
+        }
+
+        // Check leap seconds
+        if !(self.leap_seconds.is_empty()
+            || self.leap_seconds[0].unix_leap_time >= 0
+                && self.leap_seconds[0].correction.saturating_abs() == 1)
+        {
+            return Err(Error::TimeZone("invalid leap second"));
+        }
+
+        let min_interval = SECONDS_PER_28_DAYS - 1;
+
+        let mut i_leap_second = 0;
+        while i_leap_second < self.leap_seconds.len() {
+            if i_leap_second + 1 < self.leap_seconds.len() {
+                let x0 = &self.leap_seconds[i_leap_second];
+                let x1 = &self.leap_seconds[i_leap_second + 1];
+
+                let diff_unix_leap_time = x1.unix_leap_time.saturating_sub(x0.unix_leap_time);
+                let abs_diff_correction =
+                    x1.correction.saturating_sub(x0.correction).saturating_abs();
+
+                if !(diff_unix_leap_time >= min_interval && abs_diff_correction == 1) {
+                    return Err(Error::TimeZone("invalid leap second"));
+                }
+            }
+            i_leap_second += 1;
+        }
+
+        // Check extra rule
+        let (extra_rule, last_transition) = match (&self.extra_rule, self.transitions.last()) {
+            (Some(rule), Some(trans)) => (rule, trans),
+            _ => return Ok(()),
+        };
+
+        let last_local_time_type = &self.local_time_types[last_transition.local_time_type_index];
+        let unix_time = match self.unix_leap_time_to_unix_time(last_transition.unix_leap_time) {
+            Ok(unix_time) => unix_time,
+            Err(Error::OutOfRange(error)) => return Err(Error::TimeZone(error)),
+            Err(err) => return Err(err),
+        };
+
+        let rule_local_time_type = match extra_rule.find_local_time_type(unix_time) {
+            Ok(rule_local_time_type) => rule_local_time_type,
+            Err(Error::OutOfRange(error)) => return Err(Error::TimeZone(error)),
+            Err(err) => return Err(err),
+        };
+
+        let check = last_local_time_type.ut_offset == rule_local_time_type.ut_offset
+            && last_local_time_type.is_dst == rule_local_time_type.is_dst
+            && match (&last_local_time_type.name, &rule_local_time_type.name) {
+                (Some(x), Some(y)) => x.equal(y),
+                (None, None) => true,
+                _ => false,
+            };
+
+        if !check {
+            return Err(Error::TimeZone(
+                "extra transition rule is inconsistent with the last transition",
+            ));
+        }
+
+        Ok(())
+    }
+
+    /// Convert Unix time to Unix leap time, from the list of leap seconds in a time zone
+    const fn unix_time_to_unix_leap_time(&self, unix_time: i64) -> Result<i64, Error> {
+        let mut unix_leap_time = unix_time;
+
+        let mut i = 0;
+        while i < self.leap_seconds.len() {
+            let leap_second = &self.leap_seconds[i];
+
+            if unix_leap_time < leap_second.unix_leap_time {
+                break;
+            }
+
+            unix_leap_time = match unix_time.checked_add(leap_second.correction as i64) {
+                Some(unix_leap_time) => unix_leap_time,
+                None => return Err(Error::OutOfRange("out of range operation")),
+            };
+
+            i += 1;
+        }
+
+        Ok(unix_leap_time)
+    }
+
+    /// Convert Unix leap time to Unix time, from the list of leap seconds in a time zone
+    fn unix_leap_time_to_unix_time(&self, unix_leap_time: i64) -> Result<i64, Error> {
+        if unix_leap_time == i64::MIN {
+            return Err(Error::OutOfRange("out of range operation"));
+        }
+
+        let index = match self
+            .leap_seconds
+            .binary_search_by_key(&(unix_leap_time - 1), LeapSecond::unix_leap_time)
+        {
+            Ok(x) => x + 1,
+            Err(x) => x,
+        };
+
+        let correction = if index > 0 { self.leap_seconds[index - 1].correction } else { 0 };
+
+        match unix_leap_time.checked_sub(correction as i64) {
+            Some(unix_time) => Ok(unix_time),
+            None => Err(Error::OutOfRange("out of range operation")),
+        }
+    }
+
+    /// The UTC time zone
+    const UTC: TimeZoneRef<'static> = TimeZoneRef {
+        transitions: &[],
+        local_time_types: &[LocalTimeType::UTC],
+        leap_seconds: &[],
+        extra_rule: &None,
+    };
+}
+
+/// Transition of a TZif file
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub(super) struct Transition {
+    /// Unix leap time
+    unix_leap_time: i64,
+    /// Index specifying the local time type of the transition
+    local_time_type_index: usize,
+}
+
+impl Transition {
+    /// Construct a TZif file transition
+    pub(super) const fn new(unix_leap_time: i64, local_time_type_index: usize) -> Self {
+        Self { unix_leap_time, local_time_type_index }
+    }
+
+    /// Returns Unix leap time
+    const fn unix_leap_time(&self) -> i64 {
+        self.unix_leap_time
+    }
+}
+
+/// Leap second of a TZif file
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub(super) struct LeapSecond {
+    /// Unix leap time
+    unix_leap_time: i64,
+    /// Leap second correction
+    correction: i32,
+}
+
+impl LeapSecond {
+    /// Construct a TZif file leap second
+    pub(super) const fn new(unix_leap_time: i64, correction: i32) -> Self {
+        Self { unix_leap_time, correction }
+    }
+
+    /// Returns Unix leap time
+    const fn unix_leap_time(&self) -> i64 {
+        self.unix_leap_time
+    }
+}
+
+/// ASCII-encoded fixed-capacity string, used for storing time zone names
+#[derive(Copy, Clone, Eq, PartialEq)]
+struct TimeZoneName {
+    /// Length-prefixed string buffer
+    bytes: [u8; 8],
+}
+
+impl TimeZoneName {
+    /// Construct a time zone name
+    ///
+    /// man tzfile(5):
+    /// Time zone designations should consist of at least three (3) and no more than six (6) ASCII
+    /// characters from the set of alphanumerics, “-”, and “+”. This is for compatibility with
+    /// POSIX requirements for time zone abbreviations.
+    fn new(input: &[u8]) -> Result<Self, Error> {
+        let len = input.len();
+
+        if !(3..=7).contains(&len) {
+            return Err(Error::LocalTimeType(
+                "time zone name must have between 3 and 7 characters",
+            ));
+        }
+
+        let mut bytes = [0; 8];
+        bytes[0] = input.len() as u8;
+
+        let mut i = 0;
+        while i < len {
+            let b = input[i];
+            match b {
+                b'0'..=b'9' | b'A'..=b'Z' | b'a'..=b'z' | b'+' | b'-' => {}
+                _ => return Err(Error::LocalTimeType("invalid characters in time zone name")),
+            }
+
+            bytes[i + 1] = b;
+            i += 1;
+        }
+
+        Ok(Self { bytes })
+    }
+
+    /// Returns time zone name as a byte slice
+    fn as_bytes(&self) -> &[u8] {
+        match self.bytes[0] {
+            3 => &self.bytes[1..4],
+            4 => &self.bytes[1..5],
+            5 => &self.bytes[1..6],
+            6 => &self.bytes[1..7],
+            7 => &self.bytes[1..8],
+            _ => unreachable!(),
+        }
+    }
+
+    /// Check if two time zone names are equal
+    fn equal(&self, other: &Self) -> bool {
+        self.bytes == other.bytes
+    }
+}
+
+impl AsRef<str> for TimeZoneName {
+    fn as_ref(&self) -> &str {
+        // SAFETY: ASCII is valid UTF-8
+        unsafe { str::from_utf8_unchecked(self.as_bytes()) }
+    }
+}
+
+impl fmt::Debug for TimeZoneName {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.as_ref().fmt(f)
+    }
+}
+
+/// Local time type associated to a time zone
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub(crate) struct LocalTimeType {
+    /// Offset from UTC in seconds
+    pub(super) ut_offset: i32,
+    /// Daylight Saving Time indicator
+    is_dst: bool,
+    /// Time zone name
+    name: Option<TimeZoneName>,
+}
+
+impl LocalTimeType {
+    /// Construct a local time type
+    pub(super) fn new(ut_offset: i32, is_dst: bool, name: Option<&[u8]>) -> Result<Self, Error> {
+        if ut_offset == i32::MIN {
+            return Err(Error::LocalTimeType("invalid UTC offset"));
+        }
+
+        let name = match name {
+            Some(name) => TimeZoneName::new(name)?,
+            None => return Ok(Self { ut_offset, is_dst, name: None }),
+        };
+
+        Ok(Self { ut_offset, is_dst, name: Some(name) })
+    }
+
+    /// Construct a local time type with the specified UTC offset in seconds
+    pub(super) const fn with_offset(ut_offset: i32) -> Result<Self, Error> {
+        if ut_offset == i32::MIN {
+            return Err(Error::LocalTimeType("invalid UTC offset"));
+        }
+
+        Ok(Self { ut_offset, is_dst: false, name: None })
+    }
+
+    /// Returns offset from UTC in seconds
+    pub(crate) const fn offset(&self) -> i32 {
+        self.ut_offset
+    }
+
+    /// Returns daylight saving time indicator
+    pub(super) const fn is_dst(&self) -> bool {
+        self.is_dst
+    }
+
+    pub(super) const UTC: LocalTimeType = Self { ut_offset: 0, is_dst: false, name: None };
+}
+
+/// Open the TZif file corresponding to a TZ string
+fn find_tz_file(path: impl AsRef<Path>) -> Result<File, Error> {
+    // Don't check system timezone directories on non-UNIX platforms
+    #[cfg(not(unix))]
+    return Ok(File::open(path)?);
+
+    #[cfg(unix)]
+    {
+        let path = path.as_ref();
+        if path.is_absolute() {
+            return Ok(File::open(path)?);
+        }
+
+        for folder in &ZONE_INFO_DIRECTORIES {
+            if let Ok(file) = File::open(PathBuf::from(folder).join(path)) {
+                return Ok(file);
+            }
+        }
+
+        Err(Error::Io(io::ErrorKind::NotFound.into()))
+    }
+}
+
+// Possible system timezone directories
+#[cfg(unix)]
+const ZONE_INFO_DIRECTORIES: [&str; 4] =
+    ["/usr/share/zoneinfo", "/share/zoneinfo", "/etc/zoneinfo", "/usr/share/lib/zoneinfo"];
+
+/// Number of seconds in one week
+pub(crate) const SECONDS_PER_WEEK: i64 = SECONDS_PER_DAY * DAYS_PER_WEEK;
+/// Number of seconds in 28 days
+const SECONDS_PER_28_DAYS: i64 = SECONDS_PER_DAY * 28;
+
+#[cfg(test)]
+mod tests {
+    use super::super::Error;
+    use super::{LeapSecond, LocalTimeType, TimeZone, TimeZoneName, Transition, TransitionRule};
+
+    #[test]
+    fn test_no_dst() -> Result<(), Error> {
+        let tz_string = b"HST10";
+        let transition_rule = TransitionRule::from_tz_string(tz_string, false)?;
+        assert_eq!(transition_rule, LocalTimeType::new(-36000, false, Some(b"HST"))?.into());
+        Ok(())
+    }
+
+    #[test]
+    fn test_error() -> Result<(), Error> {
+        assert!(matches!(
+            TransitionRule::from_tz_string(b"IST-1GMT0", false),
+            Err(Error::UnsupportedTzString(_))
+        ));
+        assert!(matches!(
+            TransitionRule::from_tz_string(b"EET-2EEST", false),
+            Err(Error::UnsupportedTzString(_))
+        ));
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_v1_file_with_leap_seconds() -> Result<(), Error> {
+        let bytes = b"TZif\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x01\0\0\0\x01\0\0\0\x1b\0\0\0\0\0\0\0\x01\0\0\0\x04\0\0\0\0\0\0UTC\0\x04\xb2\x58\0\0\0\0\x01\x05\xa4\xec\x01\0\0\0\x02\x07\x86\x1f\x82\0\0\0\x03\x09\x67\x53\x03\0\0\0\x04\x0b\x48\x86\x84\0\0\0\x05\x0d\x2b\x0b\x85\0\0\0\x06\x0f\x0c\x3f\x06\0\0\0\x07\x10\xed\x72\x87\0\0\0\x08\x12\xce\xa6\x08\0\0\0\x09\x15\x9f\xca\x89\0\0\0\x0a\x17\x80\xfe\x0a\0\0\0\x0b\x19\x62\x31\x8b\0\0\0\x0c\x1d\x25\xea\x0c\0\0\0\x0d\x21\xda\xe5\x0d\0\0\0\x0e\x25\x9e\x9d\x8e\0\0\0\x0f\x27\x7f\xd1\x0f\0\0\0\x10\x2a\x50\xf5\x90\0\0\0\x11\x2c\x32\x29\x11\0\0\0\x12\x2e\x13\x5c\x92\0\0\0\x13\x30\xe7\x24\x13\0\0\0\x14\x33\xb8\x48\x94\0\0\0\x15\x36\x8c\x10\x15\0\0\0\x16\x43\xb7\x1b\x96\0\0\0\x17\x49\x5c\x07\x97\0\0\0\x18\x4f\xef\x93\x18\0\0\0\x19\x55\x93\x2d\x99\0\0\0\x1a\x58\x68\x46\x9a\0\0\0\x1b\0\0";
+
+        let time_zone = TimeZone::from_tz_data(bytes)?;
+
+        let time_zone_result = TimeZone::new(
+            Vec::new(),
+            vec![LocalTimeType::new(0, false, Some(b"UTC"))?],
+            vec![
+                LeapSecond::new(78796800, 1),
+                LeapSecond::new(94694401, 2),
+                LeapSecond::new(126230402, 3),
+                LeapSecond::new(157766403, 4),
+                LeapSecond::new(189302404, 5),
+                LeapSecond::new(220924805, 6),
+                LeapSecond::new(252460806, 7),
+                LeapSecond::new(283996807, 8),
+                LeapSecond::new(315532808, 9),
+                LeapSecond::new(362793609, 10),
+                LeapSecond::new(394329610, 11),
+                LeapSecond::new(425865611, 12),
+                LeapSecond::new(489024012, 13),
+                LeapSecond::new(567993613, 14),
+                LeapSecond::new(631152014, 15),
+                LeapSecond::new(662688015, 16),
+                LeapSecond::new(709948816, 17),
+                LeapSecond::new(741484817, 18),
+                LeapSecond::new(773020818, 19),
+                LeapSecond::new(820454419, 20),
+                LeapSecond::new(867715220, 21),
+                LeapSecond::new(915148821, 22),
+                LeapSecond::new(1136073622, 23),
+                LeapSecond::new(1230768023, 24),
+                LeapSecond::new(1341100824, 25),
+                LeapSecond::new(1435708825, 26),
+                LeapSecond::new(1483228826, 27),
+            ],
+            None,
+        )?;
+
+        assert_eq!(time_zone, time_zone_result);
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_v2_file() -> Result<(), Error> {
+        let bytes = b"TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x06\0\0\0\x06\0\0\0\0\0\0\0\x07\0\0\0\x06\0\0\0\x14\x80\0\0\0\xbb\x05\x43\x48\xbb\x21\x71\x58\xcb\x89\x3d\xc8\xd2\x23\xf4\x70\xd2\x61\x49\x38\xd5\x8d\x73\x48\x01\x02\x01\x03\x04\x01\x05\xff\xff\x6c\x02\0\0\xff\xff\x6c\x58\0\x04\xff\xff\x7a\x68\x01\x08\xff\xff\x7a\x68\x01\x0c\xff\xff\x7a\x68\x01\x10\xff\xff\x73\x60\0\x04LMT\0HST\0HDT\0HWT\0HPT\0\0\0\0\0\x01\0\0\0\0\0\x01\0TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x06\0\0\0\x06\0\0\0\0\0\0\0\x07\0\0\0\x06\0\0\0\x14\xff\xff\xff\xff\x74\xe0\x70\xbe\xff\xff\xff\xff\xbb\x05\x43\x48\xff\xff\xff\xff\xbb\x21\x71\x58\xff\xff\xff\xff\xcb\x89\x3d\xc8\xff\xff\xff\xff\xd2\x23\xf4\x70\xff\xff\xff\xff\xd2\x61\x49\x38\xff\xff\xff\xff\xd5\x8d\x73\x48\x01\x02\x01\x03\x04\x01\x05\xff\xff\x6c\x02\0\0\xff\xff\x6c\x58\0\x04\xff\xff\x7a\x68\x01\x08\xff\xff\x7a\x68\x01\x0c\xff\xff\x7a\x68\x01\x10\xff\xff\x73\x60\0\x04LMT\0HST\0HDT\0HWT\0HPT\0\0\0\0\0\x01\0\0\0\0\0\x01\0\x0aHST10\x0a";
+
+        let time_zone = TimeZone::from_tz_data(bytes)?;
+
+        let time_zone_result = TimeZone::new(
+            vec![
+                Transition::new(-2334101314, 1),
+                Transition::new(-1157283000, 2),
+                Transition::new(-1155436200, 1),
+                Transition::new(-880198200, 3),
+                Transition::new(-769395600, 4),
+                Transition::new(-765376200, 1),
+                Transition::new(-712150200, 5),
+            ],
+            vec![
+                LocalTimeType::new(-37886, false, Some(b"LMT"))?,
+                LocalTimeType::new(-37800, false, Some(b"HST"))?,
+                LocalTimeType::new(-34200, true, Some(b"HDT"))?,
+                LocalTimeType::new(-34200, true, Some(b"HWT"))?,
+                LocalTimeType::new(-34200, true, Some(b"HPT"))?,
+                LocalTimeType::new(-36000, false, Some(b"HST"))?,
+            ],
+            Vec::new(),
+            Some(TransitionRule::from(LocalTimeType::new(-36000, false, Some(b"HST"))?)),
+        )?;
+
+        assert_eq!(time_zone, time_zone_result);
+
+        assert_eq!(
+            *time_zone.find_local_time_type(-1156939200)?,
+            LocalTimeType::new(-34200, true, Some(b"HDT"))?
+        );
+        assert_eq!(
+            *time_zone.find_local_time_type(1546300800)?,
+            LocalTimeType::new(-36000, false, Some(b"HST"))?
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_no_tz_string() -> Result<(), Error> {
+        // Guayaquil from macOS 10.11
+        let bytes = b"TZif\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x02\0\0\0\x02\0\0\0\0\0\0\0\x01\0\0\0\x02\0\0\0\x08\xb6\xa4B\x18\x01\xff\xff\xb6h\0\0\xff\xff\xb9\xb0\0\x04QMT\0ECT\0\0\0\0\0";
+
+        let time_zone = TimeZone::from_tz_data(bytes)?;
+        dbg!(&time_zone);
+
+        let time_zone_result = TimeZone::new(
+            vec![Transition::new(-1230749160, 1)],
+            vec![
+                LocalTimeType::new(-18840, false, Some(b"QMT"))?,
+                LocalTimeType::new(-18000, false, Some(b"ECT"))?,
+            ],
+            Vec::new(),
+            None,
+        )?;
+
+        assert_eq!(time_zone, time_zone_result);
+
+        assert_eq!(
+            *time_zone.find_local_time_type(-1500000000)?,
+            LocalTimeType::new(-18840, false, Some(b"QMT"))?
+        );
+        assert_eq!(
+            *time_zone.find_local_time_type(0)?,
+            LocalTimeType::new(-18000, false, Some(b"ECT"))?
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_tz_ascii_str() -> Result<(), Error> {
+        assert!(matches!(TimeZoneName::new(b""), Err(Error::LocalTimeType(_))));
+        assert!(matches!(TimeZoneName::new(b"A"), Err(Error::LocalTimeType(_))));
+        assert!(matches!(TimeZoneName::new(b"AB"), Err(Error::LocalTimeType(_))));
+        assert_eq!(TimeZoneName::new(b"CET")?.as_bytes(), b"CET");
+        assert_eq!(TimeZoneName::new(b"CHADT")?.as_bytes(), b"CHADT");
+        assert_eq!(TimeZoneName::new(b"abcdefg")?.as_bytes(), b"abcdefg");
+        assert_eq!(TimeZoneName::new(b"UTC+02")?.as_bytes(), b"UTC+02");
+        assert_eq!(TimeZoneName::new(b"-1230")?.as_bytes(), b"-1230");
+        assert!(matches!(TimeZoneName::new("−0330".as_bytes()), Err(Error::LocalTimeType(_)))); // MINUS SIGN (U+2212)
+        assert!(matches!(TimeZoneName::new(b"\x00123"), Err(Error::LocalTimeType(_))));
+        assert!(matches!(TimeZoneName::new(b"12345678"), Err(Error::LocalTimeType(_))));
+        assert!(matches!(TimeZoneName::new(b"GMT\0\0\0"), Err(Error::LocalTimeType(_))));
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_time_zone() -> Result<(), Error> {
+        let utc = LocalTimeType::UTC;
+        let cet = LocalTimeType::with_offset(3600)?;
+
+        let utc_local_time_types = vec![utc];
+        let fixed_extra_rule = TransitionRule::from(cet);
+
+        let time_zone_1 = TimeZone::new(vec![], utc_local_time_types.clone(), vec![], None)?;
+        let time_zone_2 =
+            TimeZone::new(vec![], utc_local_time_types.clone(), vec![], Some(fixed_extra_rule))?;
+        let time_zone_3 =
+            TimeZone::new(vec![Transition::new(0, 0)], utc_local_time_types.clone(), vec![], None)?;
+        let time_zone_4 = TimeZone::new(
+            vec![Transition::new(i32::MIN.into(), 0), Transition::new(0, 1)],
+            vec![utc, cet],
+            Vec::new(),
+            Some(fixed_extra_rule),
+        )?;
+
+        assert_eq!(*time_zone_1.find_local_time_type(0)?, utc);
+        assert_eq!(*time_zone_2.find_local_time_type(0)?, cet);
+
+        assert_eq!(*time_zone_3.find_local_time_type(-1)?, utc);
+        assert_eq!(*time_zone_3.find_local_time_type(0)?, utc);
+
+        assert_eq!(*time_zone_4.find_local_time_type(-1)?, utc);
+        assert_eq!(*time_zone_4.find_local_time_type(0)?, cet);
+
+        let time_zone_err = TimeZone::new(
+            vec![Transition::new(0, 0)],
+            utc_local_time_types,
+            vec![],
+            Some(fixed_extra_rule),
+        );
+        assert!(time_zone_err.is_err());
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_time_zone_from_posix_tz() -> Result<(), Error> {
+        #[cfg(unix)]
+        {
+            // if the TZ var is set, this essentially _overrides_ the
+            // time set by the localtime symlink
+            // so just ensure that ::local() acts as expected
+            // in this case
+            if let Ok(tz) = std::env::var("TZ") {
+                let time_zone_local = TimeZone::local(Some(tz.as_str()))?;
+                let time_zone_local_1 = TimeZone::from_posix_tz(&tz)?;
+                assert_eq!(time_zone_local, time_zone_local_1);
+            }
+
+            // `TimeZone::from_posix_tz("UTC")` will return `Error` if the environment does not have
+            // a time zone database, like for example some docker containers.
+            // In that case skip the test.
+            if let Ok(time_zone_utc) = TimeZone::from_posix_tz("UTC") {
+                assert_eq!(time_zone_utc.find_local_time_type(0)?.offset(), 0);
+            }
+        }
+
+        assert!(TimeZone::from_posix_tz("EST5EDT,0/0,J365/25").is_err());
+        assert_eq!(TimeZone::from_posix_tz("").unwrap().find_local_time_type(0)?.offset(), 0);
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_leap_seconds() -> Result<(), Error> {
+        let time_zone = TimeZone::new(
+            Vec::new(),
+            vec![LocalTimeType::new(0, false, Some(b"UTC"))?],
+            vec![
+                LeapSecond::new(78796800, 1),
+                LeapSecond::new(94694401, 2),
+                LeapSecond::new(126230402, 3),
+                LeapSecond::new(157766403, 4),
+                LeapSecond::new(189302404, 5),
+                LeapSecond::new(220924805, 6),
+                LeapSecond::new(252460806, 7),
+                LeapSecond::new(283996807, 8),
+                LeapSecond::new(315532808, 9),
+                LeapSecond::new(362793609, 10),
+                LeapSecond::new(394329610, 11),
+                LeapSecond::new(425865611, 12),
+                LeapSecond::new(489024012, 13),
+                LeapSecond::new(567993613, 14),
+                LeapSecond::new(631152014, 15),
+                LeapSecond::new(662688015, 16),
+                LeapSecond::new(709948816, 17),
+                LeapSecond::new(741484817, 18),
+                LeapSecond::new(773020818, 19),
+                LeapSecond::new(820454419, 20),
+                LeapSecond::new(867715220, 21),
+                LeapSecond::new(915148821, 22),
+                LeapSecond::new(1136073622, 23),
+                LeapSecond::new(1230768023, 24),
+                LeapSecond::new(1341100824, 25),
+                LeapSecond::new(1435708825, 26),
+                LeapSecond::new(1483228826, 27),
+            ],
+            None,
+        )?;
+
+        let time_zone_ref = time_zone.as_ref();
+
+        assert!(matches!(time_zone_ref.unix_leap_time_to_unix_time(1136073621), Ok(1136073599)));
+        assert!(matches!(time_zone_ref.unix_leap_time_to_unix_time(1136073622), Ok(1136073600)));
+        assert!(matches!(time_zone_ref.unix_leap_time_to_unix_time(1136073623), Ok(1136073600)));
+        assert!(matches!(time_zone_ref.unix_leap_time_to_unix_time(1136073624), Ok(1136073601)));
+
+        assert!(matches!(time_zone_ref.unix_time_to_unix_leap_time(1136073599), Ok(1136073621)));
+        assert!(matches!(time_zone_ref.unix_time_to_unix_leap_time(1136073600), Ok(1136073623)));
+        assert!(matches!(time_zone_ref.unix_time_to_unix_leap_time(1136073601), Ok(1136073624)));
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_leap_seconds_overflow() -> Result<(), Error> {
+        let time_zone_err = TimeZone::new(
+            vec![Transition::new(i64::MIN, 0)],
+            vec![LocalTimeType::UTC],
+            vec![LeapSecond::new(0, 1)],
+            Some(TransitionRule::from(LocalTimeType::UTC)),
+        );
+        assert!(time_zone_err.is_err());
+
+        let time_zone = TimeZone::new(
+            vec![Transition::new(i64::MAX, 0)],
+            vec![LocalTimeType::UTC],
+            vec![LeapSecond::new(0, 1)],
+            None,
+        )?;
+        assert!(matches!(
+            time_zone.find_local_time_type(i64::MAX),
+            Err(Error::FindLocalTimeType(_))
+        ));
+
+        Ok(())
+    }
+}

patch/chrono-0.4.41/src/offset/local/unix.rs

@@ -0,0 +1,171 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::{cell::RefCell, collections::hash_map, env, fs, hash::Hasher, time::SystemTime};
+
+use super::tz_info::TimeZone;
+use super::{FixedOffset, NaiveDateTime};
+use crate::MappedLocalTime;
+
+pub(super) fn offset_from_utc_datetime(utc: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
+    offset(utc, false)
+}
+
+pub(super) fn offset_from_local_datetime(local: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
+    offset(local, true)
+}
+
+fn offset(d: &NaiveDateTime, local: bool) -> MappedLocalTime<FixedOffset> {
+    TZ_INFO.with(|maybe_cache| {
+        maybe_cache.borrow_mut().get_or_insert_with(Cache::default).offset(*d, local)
+    })
+}
+
+// we have to store the `Cache` in an option as it can't
+// be initialized in a static context.
+thread_local! {
+    static TZ_INFO: RefCell<Option<Cache>> = Default::default();
+}
+
+enum Source {
+    LocalTime { mtime: SystemTime },
+    Environment { hash: u64 },
+}
+
+impl Source {
+    fn new(env_tz: Option<&str>) -> Source {
+        match env_tz {
+            Some(tz) => {
+                let mut hasher = hash_map::DefaultHasher::new();
+                hasher.write(tz.as_bytes());
+                let hash = hasher.finish();
+                Source::Environment { hash }
+            }
+            None => match fs::symlink_metadata("/etc/localtime") {
+                Ok(data) => Source::LocalTime {
+                    // we have to pick a sensible default when the mtime fails
+                    // by picking SystemTime::now() we raise the probability of
+                    // the cache being invalidated if/when the mtime starts working
+                    mtime: data.modified().unwrap_or_else(|_| SystemTime::now()),
+                },
+                Err(_) => {
+                    // as above, now() should be a better default than some constant
+                    // TODO: see if we can improve caching in the case where the fallback is a valid timezone
+                    Source::LocalTime { mtime: SystemTime::now() }
+                }
+            },
+        }
+    }
+}
+
+struct Cache {
+    zone: TimeZone,
+    source: Source,
+    last_checked: SystemTime,
+}
+
+#[cfg(target_os = "aix")]
+const TZDB_LOCATION: &str = "/usr/share/lib/zoneinfo";
+
+#[cfg(not(any(target_os = "android", target_os = "aix", target_env = "ohos")))]
+const TZDB_LOCATION: &str = "/usr/share/zoneinfo";
+
+fn fallback_timezone() -> Option<TimeZone> {
+    let tz_name = iana_time_zone::get_timezone().ok()?;
+    #[cfg(not(any(target_os = "android", target_env = "ohos")))]
+    let bytes = fs::read(format!("{TZDB_LOCATION}/{tz_name}")).ok()?;
+    #[cfg(any(target_os = "android", target_env = "ohos"))]
+    let bytes = crate::offset::local::tz_data::for_zone(&tz_name).ok()??;
+    TimeZone::from_tz_data(&bytes).ok()
+}
+
+impl Default for Cache {
+    fn default() -> Cache {
+        // default to UTC if no local timezone can be found
+        let env_tz = env::var("TZ").ok();
+        let env_ref = env_tz.as_deref();
+        Cache {
+            last_checked: SystemTime::now(),
+            source: Source::new(env_ref),
+            zone: current_zone(env_ref),
+        }
+    }
+}
+
+fn current_zone(var: Option<&str>) -> TimeZone {
+    TimeZone::local(var).ok().or_else(fallback_timezone).unwrap_or_else(TimeZone::utc)
+}
+
+impl Cache {
+    fn offset(&mut self, d: NaiveDateTime, local: bool) -> MappedLocalTime<FixedOffset> {
+        let now = SystemTime::now();
+
+        match now.duration_since(self.last_checked) {
+            // If the cache has been around for less than a second then we reuse it
+            // unconditionally. This is a reasonable tradeoff because the timezone
+            // generally won't be changing _that_ often, but if the time zone does
+            // change, it will reflect sufficiently quickly from an application
+            // user's perspective.
+            Ok(d) if d.as_secs() < 1 => (),
+            Ok(_) | Err(_) => {
+                let env_tz = env::var("TZ").ok();
+                let env_ref = env_tz.as_deref();
+                let new_source = Source::new(env_ref);
+
+                let out_of_date = match (&self.source, &new_source) {
+                    // change from env to file or file to env, must recreate the zone
+                    (Source::Environment { .. }, Source::LocalTime { .. })
+                    | (Source::LocalTime { .. }, Source::Environment { .. }) => true,
+                    // stay as file, but mtime has changed
+                    (Source::LocalTime { mtime: old_mtime }, Source::LocalTime { mtime })
+                        if old_mtime != mtime =>
+                    {
+                        true
+                    }
+                    // stay as env, but hash of variable has changed
+                    (Source::Environment { hash: old_hash }, Source::Environment { hash })
+                        if old_hash != hash =>
+                    {
+                        true
+                    }
+                    // cache can be reused
+                    _ => false,
+                };
+
+                if out_of_date {
+                    self.zone = current_zone(env_ref);
+                }
+
+                self.last_checked = now;
+                self.source = new_source;
+            }
+        }
+
+        if !local {
+            let offset = self
+                .zone
+                .find_local_time_type(d.and_utc().timestamp())
+                .expect("unable to select local time type")
+                .offset();
+
+            return match FixedOffset::east_opt(offset) {
+                Some(offset) => MappedLocalTime::Single(offset),
+                None => MappedLocalTime::None,
+            };
+        }
+
+        // we pass through the year as the year of a local point in time must either be valid in that locale, or
+        // the entire time was skipped in which case we will return MappedLocalTime::None anyway.
+        self.zone
+            .find_local_time_type_from_local(d)
+            .expect("unable to select local time type")
+            .and_then(|o| FixedOffset::east_opt(o.offset()))
+    }
+}

patch/chrono-0.4.41/src/offset/local/win_bindings.rs

@@ -0,0 +1,59 @@
+#![allow(non_snake_case, non_upper_case_globals, non_camel_case_types, dead_code, clippy::all)]
+
+windows_link::link!("kernel32.dll" "system" fn GetTimeZoneInformationForYear(wyear : u16, pdtzi : *const DYNAMIC_TIME_ZONE_INFORMATION, ptzi : *mut TIME_ZONE_INFORMATION) -> BOOL);
+windows_link::link!("kernel32.dll" "system" fn SystemTimeToFileTime(lpsystemtime : *const SYSTEMTIME, lpfiletime : *mut FILETIME) -> BOOL);
+windows_link::link!("kernel32.dll" "system" fn SystemTimeToTzSpecificLocalTime(lptimezoneinformation : *const TIME_ZONE_INFORMATION, lpuniversaltime : *const SYSTEMTIME, lplocaltime : *mut SYSTEMTIME) -> BOOL);
+windows_link::link!("kernel32.dll" "system" fn TzSpecificLocalTimeToSystemTime(lptimezoneinformation : *const TIME_ZONE_INFORMATION, lplocaltime : *const SYSTEMTIME, lpuniversaltime : *mut SYSTEMTIME) -> BOOL);
+pub type BOOL = i32;
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct DYNAMIC_TIME_ZONE_INFORMATION {
+    pub Bias: i32,
+    pub StandardName: [u16; 32],
+    pub StandardDate: SYSTEMTIME,
+    pub StandardBias: i32,
+    pub DaylightName: [u16; 32],
+    pub DaylightDate: SYSTEMTIME,
+    pub DaylightBias: i32,
+    pub TimeZoneKeyName: [u16; 128],
+    pub DynamicDaylightTimeDisabled: bool,
+}
+impl Default for DYNAMIC_TIME_ZONE_INFORMATION {
+    fn default() -> Self {
+        unsafe { core::mem::zeroed() }
+    }
+}
+#[repr(C)]
+#[derive(Clone, Copy, Default)]
+pub struct FILETIME {
+    pub dwLowDateTime: u32,
+    pub dwHighDateTime: u32,
+}
+#[repr(C)]
+#[derive(Clone, Copy, Default)]
+pub struct SYSTEMTIME {
+    pub wYear: u16,
+    pub wMonth: u16,
+    pub wDayOfWeek: u16,
+    pub wDay: u16,
+    pub wHour: u16,
+    pub wMinute: u16,
+    pub wSecond: u16,
+    pub wMilliseconds: u16,
+}
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct TIME_ZONE_INFORMATION {
+    pub Bias: i32,
+    pub StandardName: [u16; 32],
+    pub StandardDate: SYSTEMTIME,
+    pub StandardBias: i32,
+    pub DaylightName: [u16; 32],
+    pub DaylightDate: SYSTEMTIME,
+    pub DaylightBias: i32,
+}
+impl Default for TIME_ZONE_INFORMATION {
+    fn default() -> Self {
+        unsafe { core::mem::zeroed() }
+    }
+}

patch/chrono-0.4.41/src/offset/local/win_bindings.txt

@@ -0,0 +1,7 @@
+--out src/offset/local/win_bindings.rs
+--flat --sys --no-comment
+--filter
+    GetTimeZoneInformationForYear
+    SystemTimeToFileTime
+    SystemTimeToTzSpecificLocalTime
+    TzSpecificLocalTimeToSystemTime

patch/chrono-0.4.41/src/offset/local/windows.rs

@@ -0,0 +1,293 @@
+// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::cmp::Ordering;
+use std::mem::MaybeUninit;
+use std::ptr;
+
+use super::win_bindings::{GetTimeZoneInformationForYear, SYSTEMTIME, TIME_ZONE_INFORMATION};
+
+use crate::offset::local::{Transition, lookup_with_dst_transitions};
+use crate::{Datelike, FixedOffset, MappedLocalTime, NaiveDate, NaiveDateTime, NaiveTime, Weekday};
+
+// We don't use `SystemTimeToTzSpecificLocalTime` because it doesn't support the same range of dates
+// as Chrono. Also it really isn't that difficult to work out the correct offset from the provided
+// DST rules.
+//
+// This method uses `overflowing_sub_offset` because it is no problem if the transition time in UTC
+// falls a couple of hours inside the buffer space around the `NaiveDateTime` range (although it is
+// very theoretical to have a transition at midnight around `NaiveDate::(MIN|MAX)`.
+pub(super) fn offset_from_utc_datetime(utc: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
+    // Using a `TzInfo` based on the year of an UTC datetime is technically wrong, we should be
+    // using the rules for the year of the corresponding local time. But this matches what
+    // `SystemTimeToTzSpecificLocalTime` is documented to do.
+    let tz_info = match TzInfo::for_year(utc.year()) {
+        Some(tz_info) => tz_info,
+        None => return MappedLocalTime::None,
+    };
+    let offset = match (tz_info.std_transition, tz_info.dst_transition) {
+        (Some(std_transition), Some(dst_transition)) => {
+            let std_transition_utc = std_transition.overflowing_sub_offset(tz_info.dst_offset);
+            let dst_transition_utc = dst_transition.overflowing_sub_offset(tz_info.std_offset);
+            if dst_transition_utc < std_transition_utc {
+                match utc >= &dst_transition_utc && utc < &std_transition_utc {
+                    true => tz_info.dst_offset,
+                    false => tz_info.std_offset,
+                }
+            } else {
+                match utc >= &std_transition_utc && utc < &dst_transition_utc {
+                    true => tz_info.std_offset,
+                    false => tz_info.dst_offset,
+                }
+            }
+        }
+        (Some(std_transition), None) => {
+            let std_transition_utc = std_transition.overflowing_sub_offset(tz_info.dst_offset);
+            match utc < &std_transition_utc {
+                true => tz_info.dst_offset,
+                false => tz_info.std_offset,
+            }
+        }
+        (None, Some(dst_transition)) => {
+            let dst_transition_utc = dst_transition.overflowing_sub_offset(tz_info.std_offset);
+            match utc < &dst_transition_utc {
+                true => tz_info.std_offset,
+                false => tz_info.dst_offset,
+            }
+        }
+        (None, None) => tz_info.std_offset,
+    };
+    MappedLocalTime::Single(offset)
+}
+
+// We don't use `TzSpecificLocalTimeToSystemTime` because it doesn't let us choose how to handle
+// ambiguous cases (during a DST transition). Instead we get the timezone information for the
+// current year and compute it ourselves, like we do on Unix.
+pub(super) fn offset_from_local_datetime(local: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
+    let tz_info = match TzInfo::for_year(local.year()) {
+        Some(tz_info) => tz_info,
+        None => return MappedLocalTime::None,
+    };
+    // Create a sorted slice of transitions and use `lookup_with_dst_transitions`.
+    match (tz_info.std_transition, tz_info.dst_transition) {
+        (Some(std_transition), Some(dst_transition)) => {
+            let std_transition =
+                Transition::new(std_transition, tz_info.dst_offset, tz_info.std_offset);
+            let dst_transition =
+                Transition::new(dst_transition, tz_info.std_offset, tz_info.dst_offset);
+            let transitions = match std_transition.cmp(&dst_transition) {
+                Ordering::Less => [std_transition, dst_transition],
+                Ordering::Greater => [dst_transition, std_transition],
+                Ordering::Equal => {
+                    // This doesn't make sense. Let's just return the standard offset.
+                    return MappedLocalTime::Single(tz_info.std_offset);
+                }
+            };
+            lookup_with_dst_transitions(&transitions, *local)
+        }
+        (Some(std_transition), None) => {
+            let transitions =
+                [Transition::new(std_transition, tz_info.dst_offset, tz_info.std_offset)];
+            lookup_with_dst_transitions(&transitions, *local)
+        }
+        (None, Some(dst_transition)) => {
+            let transitions =
+                [Transition::new(dst_transition, tz_info.std_offset, tz_info.dst_offset)];
+            lookup_with_dst_transitions(&transitions, *local)
+        }
+        (None, None) => MappedLocalTime::Single(tz_info.std_offset),
+    }
+}
+
+// The basis for Windows timezone and DST support has been in place since Windows 2000. It does not
+// allow for complex rules like the IANA timezone database:
+// - A timezone has the same base offset the whole year.
+// - There seem to be either zero or two DST transitions (but we support having just one).
+// - As of Vista(?) only years from 2004 until a few years into the future are supported.
+// - All other years get the base settings, which seem to be that of the current year.
+//
+// These details don't matter much, we just work with the offsets and transition dates Windows
+// returns through `GetTimeZoneInformationForYear` for a particular year.
+struct TzInfo {
+    // Offset from UTC during standard time.
+    std_offset: FixedOffset,
+    // Offset from UTC during daylight saving time.
+    dst_offset: FixedOffset,
+    // Transition from standard time to daylight saving time, given in local standard time.
+    std_transition: Option<NaiveDateTime>,
+    // Transition from daylight saving time to standard time, given in local daylight saving time.
+    dst_transition: Option<NaiveDateTime>,
+}
+
+impl TzInfo {
+    fn for_year(year: i32) -> Option<TzInfo> {
+        // The API limits years to 1601..=30827.
+        // Working with timezones and daylight saving time this far into the past or future makes
+        // little sense. But whatever is extrapolated for 1601 or 30827 is what can be extrapolated
+        // for years beyond.
+        let ref_year = year.clamp(1601, 30827) as u16;
+        let tz_info = unsafe {
+            let mut tz_info = MaybeUninit::<TIME_ZONE_INFORMATION>::uninit();
+            if GetTimeZoneInformationForYear(ref_year, ptr::null_mut(), tz_info.as_mut_ptr()) == 0 {
+                return None;
+            }
+            tz_info.assume_init()
+        };
+        let std_offset = (tz_info.Bias)
+            .checked_add(tz_info.StandardBias)
+            .and_then(|o| o.checked_mul(60))
+            .and_then(FixedOffset::west_opt)?;
+        let dst_offset = (tz_info.Bias)
+            .checked_add(tz_info.DaylightBias)
+            .and_then(|o| o.checked_mul(60))
+            .and_then(FixedOffset::west_opt)?;
+        Some(TzInfo {
+            std_offset,
+            dst_offset,
+            std_transition: naive_date_time_from_system_time(tz_info.StandardDate, year).ok()?,
+            dst_transition: naive_date_time_from_system_time(tz_info.DaylightDate, year).ok()?,
+        })
+    }
+}
+
+/// Resolve a `SYSTEMTIME` object to an `Option<NaiveDateTime>`.
+///
+/// A `SYSTEMTIME` within a `TIME_ZONE_INFORMATION` struct can be zero to indicate there is no
+/// transition.
+/// If it has year, month and day values it is a concrete date.
+/// If the year is missing the `SYSTEMTIME` is a rule, which this method resolves for the provided
+/// year. A rule has a month, weekday, and nth weekday of the month as components.
+///
+/// Returns `Err` if any of the values is invalid, which should never happen.
+fn naive_date_time_from_system_time(
+    st: SYSTEMTIME,
+    year: i32,
+) -> Result<Option<NaiveDateTime>, ()> {
+    if st.wYear == 0 && st.wMonth == 0 {
+        return Ok(None);
+    }
+    let time = NaiveTime::from_hms_milli_opt(
+        st.wHour as u32,
+        st.wMinute as u32,
+        st.wSecond as u32,
+        st.wMilliseconds as u32,
+    )
+    .ok_or(())?;
+
+    if st.wYear != 0 {
+        // We have a concrete date.
+        let date =
+            NaiveDate::from_ymd_opt(st.wYear as i32, st.wMonth as u32, st.wDay as u32).ok_or(())?;
+        return Ok(Some(date.and_time(time)));
+    }
+
+    // Resolve a rule with month, weekday, and nth weekday of the month to a date in the current
+    // year.
+    let weekday = match st.wDayOfWeek {
+        0 => Weekday::Sun,
+        1 => Weekday::Mon,
+        2 => Weekday::Tue,
+        3 => Weekday::Wed,
+        4 => Weekday::Thu,
+        5 => Weekday::Fri,
+        6 => Weekday::Sat,
+        _ => return Err(()),
+    };
+    let nth_day = match st.wDay {
+        1..=5 => st.wDay as u8,
+        _ => return Err(()),
+    };
+    let date = NaiveDate::from_weekday_of_month_opt(year, st.wMonth as u32, weekday, nth_day)
+        .or_else(|| NaiveDate::from_weekday_of_month_opt(year, st.wMonth as u32, weekday, 4))
+        .ok_or(())?; // `st.wMonth` must be invalid
+    Ok(Some(date.and_time(time)))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::offset::local::win_bindings::{
+        FILETIME, SYSTEMTIME, SystemTimeToFileTime, TzSpecificLocalTimeToSystemTime,
+    };
+    use crate::{DateTime, FixedOffset, Local, NaiveDate, NaiveDateTime, TimeDelta};
+    use crate::{Datelike, TimeZone, Timelike};
+    use std::mem::MaybeUninit;
+    use std::ptr;
+
+    #[test]
+    fn verify_against_tz_specific_local_time_to_system_time() {
+        // The implementation in Windows itself is the source of truth on how to work with the OS
+        // timezone information. This test compares for every hour over a period of 125 years our
+        // implementation to `TzSpecificLocalTimeToSystemTime`.
+        //
+        // This uses parts of a previous Windows `Local` implementation in chrono.
+        fn from_local_time(dt: &NaiveDateTime) -> DateTime<Local> {
+            let st = system_time_from_naive_date_time(dt);
+            let utc_time = local_to_utc_time(&st);
+            let utc_secs = system_time_as_unix_seconds(&utc_time);
+            let local_secs = system_time_as_unix_seconds(&st);
+            let offset = (local_secs - utc_secs) as i32;
+            let offset = FixedOffset::east_opt(offset).unwrap();
+            DateTime::from_naive_utc_and_offset(*dt - offset, offset)
+        }
+        fn system_time_from_naive_date_time(dt: &NaiveDateTime) -> SYSTEMTIME {
+            SYSTEMTIME {
+                // Valid values: 1601-30827
+                wYear: dt.year() as u16,
+                // Valid values:1-12
+                wMonth: dt.month() as u16,
+                // Valid values: 0-6, starting Sunday.
+                // NOTE: enum returns 1-7, starting Monday, so we are
+                // off here, but this is not currently used in local.
+                wDayOfWeek: dt.weekday() as u16,
+                // Valid values: 1-31
+                wDay: dt.day() as u16,
+                // Valid values: 0-23
+                wHour: dt.hour() as u16,
+                // Valid values: 0-59
+                wMinute: dt.minute() as u16,
+                // Valid values: 0-59
+                wSecond: dt.second() as u16,
+                // Valid values: 0-999
+                wMilliseconds: 0,
+            }
+        }
+        fn local_to_utc_time(local: &SYSTEMTIME) -> SYSTEMTIME {
+            let mut sys_time = MaybeUninit::<SYSTEMTIME>::uninit();
+            unsafe { TzSpecificLocalTimeToSystemTime(ptr::null(), local, sys_time.as_mut_ptr()) };
+            // SAFETY: TzSpecificLocalTimeToSystemTime must have succeeded at this point, so we can
+            // assume the value is initialized.
+            unsafe { sys_time.assume_init() }
+        }
+        const HECTONANOSECS_IN_SEC: i64 = 10_000_000;
+        const HECTONANOSEC_TO_UNIX_EPOCH: i64 = 11_644_473_600 * HECTONANOSECS_IN_SEC;
+        fn system_time_as_unix_seconds(st: &SYSTEMTIME) -> i64 {
+            let mut init = MaybeUninit::<FILETIME>::uninit();
+            unsafe {
+                SystemTimeToFileTime(st, init.as_mut_ptr());
+            }
+            // SystemTimeToFileTime must have succeeded at this point, so we can assume the value is
+            // initialized.
+            let filetime = unsafe { init.assume_init() };
+            let bit_shift =
+                ((filetime.dwHighDateTime as u64) << 32) | (filetime.dwLowDateTime as u64);
+            (bit_shift as i64 - HECTONANOSEC_TO_UNIX_EPOCH) / HECTONANOSECS_IN_SEC
+        }
+
+        let mut date = NaiveDate::from_ymd_opt(1975, 1, 1).unwrap().and_hms_opt(0, 30, 0).unwrap();
+
+        while date.year() < 2078 {
+            // Windows doesn't handle non-existing dates, it just treats it as valid.
+            if let Some(our_result) = Local.from_local_datetime(&date).earliest() {
+                assert_eq!(from_local_time(&date), our_result);
+            }
+            date += TimeDelta::try_hours(1).unwrap();
+        }
+    }
+}

patch/chrono-0.4.41/src/offset/mod.rs

@@ -0,0 +1,715 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+//! The time zone, which calculates offsets from the local time to UTC.
+//!
+//! There are four operations provided by the `TimeZone` trait:
+//!
+//! 1. Converting the local `NaiveDateTime` to `DateTime<Tz>`
+//! 2. Converting the UTC `NaiveDateTime` to `DateTime<Tz>`
+//! 3. Converting `DateTime<Tz>` to the local `NaiveDateTime`
+//! 4. Constructing `DateTime<Tz>` objects from various offsets
+//!
+//! 1 is used for constructors. 2 is used for the `with_timezone` method of date and time types.
+//! 3 is used for other methods, e.g. `year()` or `format()`, and provided by an associated type
+//! which implements `Offset` (which then passed to `TimeZone` for actual implementations).
+//! Technically speaking `TimeZone` has a total knowledge about given timescale,
+//! but `Offset` is used as a cache to avoid the repeated conversion
+//! and provides implementations for 1 and 3.
+//! An `TimeZone` instance can be reconstructed from the corresponding `Offset` instance.
+
+use core::fmt;
+
+use crate::Weekday;
+use crate::format::{ParseResult, Parsed, StrftimeItems, parse};
+use crate::naive::{NaiveDate, NaiveDateTime, NaiveTime};
+#[allow(deprecated)]
+use crate::{Date, DateTime};
+
+pub(crate) mod fixed;
+pub use self::fixed::FixedOffset;
+
+#[cfg(feature = "clock")]
+pub(crate) mod local;
+#[cfg(feature = "clock")]
+pub use self::local::Local;
+
+pub(crate) mod utc;
+pub use self::utc::Utc;
+
+/// The result of mapping a local time to a concrete instant in a given time zone.
+///
+/// The calculation to go from a local time (wall clock time) to an instant in UTC can end up in
+/// three cases:
+/// * A single, simple result.
+/// * An ambiguous result when the clock is turned backwards during a transition due to for example
+///   DST.
+/// * No result when the clock is turned forwards during a transition due to for example DST.
+///
+/// <div class="warning">
+///
+/// In wasm, when using [`Local`], only the [`LocalResult::Single`] variant is returned.
+/// Specifically:
+///
+/// * When the clock is turned backwards, where `Ambiguous(earliest, latest)` would be expected,
+///   `Single(earliest)` is returned instead.
+/// * When the clock is turned forwards, where `None` would be expected, `Single(t)` is returned,
+///   with `t` being the requested local time represented as though there is no transition on that
+///   day (i.e. still "summer time")
+///
+/// This is caused because of limitations in the JavaScript
+/// [`Date`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date)
+/// API, which always parses a local time as a single, valid time - even for an
+/// input which describes a nonexistent or ambiguous time.
+///
+/// See further discussion and workarounds in <https://github.com/chronotope/chrono/issues/1701>.
+///
+/// </div>
+///
+/// When the clock is turned backwards it creates a _fold_ in local time, during which the local
+/// time is _ambiguous_. When the clock is turned forwards it creates a _gap_ in local time, during
+/// which the local time is _missing_, or does not exist.
+///
+/// Chrono does not return a default choice or invalid data during time zone transitions, but has
+/// the `MappedLocalTime` type to help deal with the result correctly.
+///
+/// The type of `T` is usually a [`DateTime`] but may also be only an offset.
+pub type MappedLocalTime<T> = LocalResult<T>;
+#[derive(Clone, PartialEq, Debug, Copy, Eq, Hash)]
+
+/// Old name of [`MappedLocalTime`]. See that type for more documentation.
+pub enum LocalResult<T> {
+    /// The local time maps to a single unique result.
+    Single(T),
+
+    /// The local time is _ambiguous_ because there is a _fold_ in the local time.
+    ///
+    /// This variant contains the two possible results, in the order `(earliest, latest)`.
+    Ambiguous(T, T),
+
+    /// The local time does not exist because there is a _gap_ in the local time.
+    ///
+    /// This variant may also be returned if there was an error while resolving the local time,
+    /// caused by for example missing time zone data files, an error in an OS API, or overflow.
+    None,
+}
+
+impl<T> MappedLocalTime<T> {
+    /// Returns `Some` if the time zone mapping has a single result.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` if local time falls in a _fold_ or _gap_ in the local time, or if there was
+    /// an error.
+    #[must_use]
+    pub fn single(self) -> Option<T> {
+        match self {
+            MappedLocalTime::Single(t) => Some(t),
+            _ => None,
+        }
+    }
+
+    /// Returns the earliest possible result of the time zone mapping.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` if local time falls in a _gap_ in the local time, or if there was an error.
+    #[must_use]
+    pub fn earliest(self) -> Option<T> {
+        match self {
+            MappedLocalTime::Single(t) | MappedLocalTime::Ambiguous(t, _) => Some(t),
+            _ => None,
+        }
+    }
+
+    /// Returns the latest possible result of the time zone mapping.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` if local time falls in a _gap_ in the local time, or if there was an error.
+    #[must_use]
+    pub fn latest(self) -> Option<T> {
+        match self {
+            MappedLocalTime::Single(t) | MappedLocalTime::Ambiguous(_, t) => Some(t),
+            _ => None,
+        }
+    }
+
+    /// Maps a `MappedLocalTime<T>` into `MappedLocalTime<U>` with given function.
+    #[must_use]
+    pub fn map<U, F: FnMut(T) -> U>(self, mut f: F) -> MappedLocalTime<U> {
+        match self {
+            MappedLocalTime::None => MappedLocalTime::None,
+            MappedLocalTime::Single(v) => MappedLocalTime::Single(f(v)),
+            MappedLocalTime::Ambiguous(min, max) => MappedLocalTime::Ambiguous(f(min), f(max)),
+        }
+    }
+
+    /// Maps a `MappedLocalTime<T>` into `MappedLocalTime<U>` with given function.
+    ///
+    /// Returns `MappedLocalTime::None` if the function returns `None`.
+    #[must_use]
+    pub(crate) fn and_then<U, F: FnMut(T) -> Option<U>>(self, mut f: F) -> MappedLocalTime<U> {
+        match self {
+            MappedLocalTime::None => MappedLocalTime::None,
+            MappedLocalTime::Single(v) => match f(v) {
+                Some(new) => MappedLocalTime::Single(new),
+                None => MappedLocalTime::None,
+            },
+            MappedLocalTime::Ambiguous(min, max) => match (f(min), f(max)) {
+                (Some(min), Some(max)) => MappedLocalTime::Ambiguous(min, max),
+                _ => MappedLocalTime::None,
+            },
+        }
+    }
+}
+
+#[allow(deprecated)]
+impl<Tz: TimeZone> MappedLocalTime<Date<Tz>> {
+    /// Makes a new `DateTime` from the current date and given `NaiveTime`.
+    /// The offset in the current date is preserved.
+    ///
+    /// Propagates any error. Ambiguous result would be discarded.
+    #[inline]
+    #[must_use]
+    pub fn and_time(self, time: NaiveTime) -> MappedLocalTime<DateTime<Tz>> {
+        match self {
+            MappedLocalTime::Single(d) => {
+                d.and_time(time).map_or(MappedLocalTime::None, MappedLocalTime::Single)
+            }
+            _ => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute and second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Propagates any error. Ambiguous result would be discarded.
+    #[inline]
+    #[must_use]
+    pub fn and_hms_opt(self, hour: u32, min: u32, sec: u32) -> MappedLocalTime<DateTime<Tz>> {
+        match self {
+            MappedLocalTime::Single(d) => {
+                d.and_hms_opt(hour, min, sec).map_or(MappedLocalTime::None, MappedLocalTime::Single)
+            }
+            _ => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and millisecond.
+    /// The millisecond part can exceed 1,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Propagates any error. Ambiguous result would be discarded.
+    #[inline]
+    #[must_use]
+    pub fn and_hms_milli_opt(
+        self,
+        hour: u32,
+        min: u32,
+        sec: u32,
+        milli: u32,
+    ) -> MappedLocalTime<DateTime<Tz>> {
+        match self {
+            MappedLocalTime::Single(d) => d
+                .and_hms_milli_opt(hour, min, sec, milli)
+                .map_or(MappedLocalTime::None, MappedLocalTime::Single),
+            _ => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and microsecond.
+    /// The microsecond part can exceed 1,000,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Propagates any error. Ambiguous result would be discarded.
+    #[inline]
+    #[must_use]
+    pub fn and_hms_micro_opt(
+        self,
+        hour: u32,
+        min: u32,
+        sec: u32,
+        micro: u32,
+    ) -> MappedLocalTime<DateTime<Tz>> {
+        match self {
+            MappedLocalTime::Single(d) => d
+                .and_hms_micro_opt(hour, min, sec, micro)
+                .map_or(MappedLocalTime::None, MappedLocalTime::Single),
+            _ => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `DateTime` from the current date, hour, minute, second and nanosecond.
+    /// The nanosecond part can exceed 1,000,000,000 in order to represent the leap second.
+    /// The offset in the current date is preserved.
+    ///
+    /// Propagates any error. Ambiguous result would be discarded.
+    #[inline]
+    #[must_use]
+    pub fn and_hms_nano_opt(
+        self,
+        hour: u32,
+        min: u32,
+        sec: u32,
+        nano: u32,
+    ) -> MappedLocalTime<DateTime<Tz>> {
+        match self {
+            MappedLocalTime::Single(d) => d
+                .and_hms_nano_opt(hour, min, sec, nano)
+                .map_or(MappedLocalTime::None, MappedLocalTime::Single),
+            _ => MappedLocalTime::None,
+        }
+    }
+}
+
+impl<T: fmt::Debug> MappedLocalTime<T> {
+    /// Returns a single unique conversion result or panics.
+    ///
+    /// `unwrap()` is best combined with time zone types where the mapping can never fail like
+    /// [`Utc`] and [`FixedOffset`]. Note that for [`FixedOffset`] there is a rare case where a
+    /// resulting [`DateTime`] can be out of range.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the local time falls within a _fold_ or a _gap_ in the local time, and on any
+    /// error that may have been returned by the type implementing [`TimeZone`].
+    #[must_use]
+    #[track_caller]
+    pub fn unwrap(self) -> T {
+        match self {
+            MappedLocalTime::None => panic!("No such local time"),
+            MappedLocalTime::Single(t) => t,
+            MappedLocalTime::Ambiguous(t1, t2) => {
+                panic!("Ambiguous local time, ranging from {t1:?} to {t2:?}")
+            }
+        }
+    }
+}
+
+/// The offset from the local time to UTC.
+pub trait Offset: Sized + Clone + fmt::Debug {
+    /// Returns the fixed offset from UTC to the local time stored.
+    fn fix(&self) -> FixedOffset;
+}
+
+/// The time zone.
+///
+/// The methods here are the primary constructors for the [`DateTime`] type.
+pub trait TimeZone: Sized + Clone {
+    /// An associated offset type.
+    /// This type is used to store the actual offset in date and time types.
+    /// The original `TimeZone` value can be recovered via `TimeZone::from_offset`.
+    type Offset: Offset;
+
+    /// Make a new `DateTime` from year, month, day, time components and current time zone.
+    ///
+    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
+    ///
+    /// Returns `MappedLocalTime::None` on invalid input data.
+    fn with_ymd_and_hms(
+        &self,
+        year: i32,
+        month: u32,
+        day: u32,
+        hour: u32,
+        min: u32,
+        sec: u32,
+    ) -> MappedLocalTime<DateTime<Self>> {
+        match NaiveDate::from_ymd_opt(year, month, day).and_then(|d| d.and_hms_opt(hour, min, sec))
+        {
+            Some(dt) => self.from_local_datetime(&dt),
+            None => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `Date` from year, month, day and the current time zone.
+    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
+    ///
+    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
+    /// but it will propagate to the `DateTime` values constructed via this date.
+    ///
+    /// Panics on the out-of-range date, invalid month and/or day.
+    #[deprecated(since = "0.4.23", note = "use `with_ymd_and_hms()` instead")]
+    #[allow(deprecated)]
+    fn ymd(&self, year: i32, month: u32, day: u32) -> Date<Self> {
+        self.ymd_opt(year, month, day).unwrap()
+    }
+
+    /// Makes a new `Date` from year, month, day and the current time zone.
+    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
+    ///
+    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
+    /// but it will propagate to the `DateTime` values constructed via this date.
+    ///
+    /// Returns `None` on the out-of-range date, invalid month and/or day.
+    #[deprecated(since = "0.4.23", note = "use `with_ymd_and_hms()` instead")]
+    #[allow(deprecated)]
+    fn ymd_opt(&self, year: i32, month: u32, day: u32) -> MappedLocalTime<Date<Self>> {
+        match NaiveDate::from_ymd_opt(year, month, day) {
+            Some(d) => self.from_local_date(&d),
+            None => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `Date` from year, day of year (DOY or "ordinal") and the current time zone.
+    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
+    ///
+    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
+    /// but it will propagate to the `DateTime` values constructed via this date.
+    ///
+    /// Panics on the out-of-range date and/or invalid DOY.
+    #[deprecated(
+        since = "0.4.23",
+        note = "use `from_local_datetime()` with a `NaiveDateTime` instead"
+    )]
+    #[allow(deprecated)]
+    fn yo(&self, year: i32, ordinal: u32) -> Date<Self> {
+        self.yo_opt(year, ordinal).unwrap()
+    }
+
+    /// Makes a new `Date` from year, day of year (DOY or "ordinal") and the current time zone.
+    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
+    ///
+    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
+    /// but it will propagate to the `DateTime` values constructed via this date.
+    ///
+    /// Returns `None` on the out-of-range date and/or invalid DOY.
+    #[deprecated(
+        since = "0.4.23",
+        note = "use `from_local_datetime()` with a `NaiveDateTime` instead"
+    )]
+    #[allow(deprecated)]
+    fn yo_opt(&self, year: i32, ordinal: u32) -> MappedLocalTime<Date<Self>> {
+        match NaiveDate::from_yo_opt(year, ordinal) {
+            Some(d) => self.from_local_date(&d),
+            None => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `Date` from ISO week date (year and week number), day of the week (DOW) and
+    /// the current time zone.
+    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
+    /// The resulting `Date` may have a different year from the input year.
+    ///
+    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
+    /// but it will propagate to the `DateTime` values constructed via this date.
+    ///
+    /// Panics on the out-of-range date and/or invalid week number.
+    #[deprecated(
+        since = "0.4.23",
+        note = "use `from_local_datetime()` with a `NaiveDateTime` instead"
+    )]
+    #[allow(deprecated)]
+    fn isoywd(&self, year: i32, week: u32, weekday: Weekday) -> Date<Self> {
+        self.isoywd_opt(year, week, weekday).unwrap()
+    }
+
+    /// Makes a new `Date` from ISO week date (year and week number), day of the week (DOW) and
+    /// the current time zone.
+    /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE.
+    /// The resulting `Date` may have a different year from the input year.
+    ///
+    /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24),
+    /// but it will propagate to the `DateTime` values constructed via this date.
+    ///
+    /// Returns `None` on the out-of-range date and/or invalid week number.
+    #[deprecated(
+        since = "0.4.23",
+        note = "use `from_local_datetime()` with a `NaiveDateTime` instead"
+    )]
+    #[allow(deprecated)]
+    fn isoywd_opt(&self, year: i32, week: u32, weekday: Weekday) -> MappedLocalTime<Date<Self>> {
+        match NaiveDate::from_isoywd_opt(year, week, weekday) {
+            Some(d) => self.from_local_date(&d),
+            None => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `DateTime` from the number of non-leap seconds
+    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp")
+    /// and the number of nanoseconds since the last whole non-leap second.
+    ///
+    /// The nanosecond part can exceed 1,000,000,000 in order to represent a
+    /// [leap second](crate::NaiveTime#leap-second-handling), but only when `secs % 60 == 59`.
+    /// (The true "UNIX timestamp" cannot represent a leap second unambiguously.)
+    ///
+    /// # Panics
+    ///
+    /// Panics on the out-of-range number of seconds and/or invalid nanosecond,
+    /// for a non-panicking version see [`timestamp_opt`](#method.timestamp_opt).
+    #[deprecated(since = "0.4.23", note = "use `timestamp_opt()` instead")]
+    fn timestamp(&self, secs: i64, nsecs: u32) -> DateTime<Self> {
+        self.timestamp_opt(secs, nsecs).unwrap()
+    }
+
+    /// Makes a new `DateTime` from the number of non-leap seconds
+    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp")
+    /// and the number of nanoseconds since the last whole non-leap second.
+    ///
+    /// The nanosecond part can exceed 1,000,000,000 in order to represent a
+    /// [leap second](crate::NaiveTime#leap-second-handling), but only when `secs % 60 == 59`.
+    /// (The true "UNIX timestamp" cannot represent a leap second unambiguously.)
+    ///
+    /// # Errors
+    ///
+    /// Returns `MappedLocalTime::None` on out-of-range number of seconds and/or
+    /// invalid nanosecond, otherwise always returns `MappedLocalTime::Single`.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use chrono::{TimeZone, Utc};
+    ///
+    /// assert_eq!(Utc.timestamp_opt(1431648000, 0).unwrap().to_string(), "2015-05-15 00:00:00 UTC");
+    /// ```
+    fn timestamp_opt(&self, secs: i64, nsecs: u32) -> MappedLocalTime<DateTime<Self>> {
+        match DateTime::from_timestamp(secs, nsecs) {
+            Some(dt) => MappedLocalTime::Single(self.from_utc_datetime(&dt.naive_utc())),
+            None => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `DateTime` from the number of non-leap milliseconds
+    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp").
+    ///
+    /// Panics on out-of-range number of milliseconds for a non-panicking
+    /// version see [`timestamp_millis_opt`](#method.timestamp_millis_opt).
+    #[deprecated(since = "0.4.23", note = "use `timestamp_millis_opt()` instead")]
+    fn timestamp_millis(&self, millis: i64) -> DateTime<Self> {
+        self.timestamp_millis_opt(millis).unwrap()
+    }
+
+    /// Makes a new `DateTime` from the number of non-leap milliseconds
+    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp").
+    ///
+    ///
+    /// Returns `MappedLocalTime::None` on out-of-range number of milliseconds
+    /// and/or invalid nanosecond, otherwise always returns
+    /// `MappedLocalTime::Single`.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use chrono::{MappedLocalTime, TimeZone, Utc};
+    /// match Utc.timestamp_millis_opt(1431648000) {
+    ///     MappedLocalTime::Single(dt) => assert_eq!(dt.timestamp(), 1431648),
+    ///     _ => panic!("Incorrect timestamp_millis"),
+    /// };
+    /// ```
+    fn timestamp_millis_opt(&self, millis: i64) -> MappedLocalTime<DateTime<Self>> {
+        match DateTime::from_timestamp_millis(millis) {
+            Some(dt) => MappedLocalTime::Single(self.from_utc_datetime(&dt.naive_utc())),
+            None => MappedLocalTime::None,
+        }
+    }
+
+    /// Makes a new `DateTime` from the number of non-leap nanoseconds
+    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp").
+    ///
+    /// Unlike [`timestamp_millis_opt`](#method.timestamp_millis_opt), this never fails.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use chrono::{TimeZone, Utc};
+    ///
+    /// assert_eq!(Utc.timestamp_nanos(1431648000000000).timestamp(), 1431648);
+    /// ```
+    fn timestamp_nanos(&self, nanos: i64) -> DateTime<Self> {
+        self.from_utc_datetime(&DateTime::from_timestamp_nanos(nanos).naive_utc())
+    }
+
+    /// Makes a new `DateTime` from the number of non-leap microseconds
+    /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp").
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use chrono::{TimeZone, Utc};
+    ///
+    /// assert_eq!(Utc.timestamp_micros(1431648000000).unwrap().timestamp(), 1431648);
+    /// ```
+    fn timestamp_micros(&self, micros: i64) -> MappedLocalTime<DateTime<Self>> {
+        match DateTime::from_timestamp_micros(micros) {
+            Some(dt) => MappedLocalTime::Single(self.from_utc_datetime(&dt.naive_utc())),
+            None => MappedLocalTime::None,
+        }
+    }
+
+    /// Parses a string with the specified format string and returns a
+    /// `DateTime` with the current offset.
+    ///
+    /// See the [`crate::format::strftime`] module on the
+    /// supported escape sequences.
+    ///
+    /// If the to-be-parsed string includes an offset, it *must* match the
+    /// offset of the TimeZone, otherwise an error will be returned.
+    ///
+    /// See also [`DateTime::parse_from_str`] which gives a [`DateTime`] with
+    /// parsed [`FixedOffset`].
+    ///
+    /// See also [`NaiveDateTime::parse_from_str`] which gives a [`NaiveDateTime`] without
+    /// an offset, but can be converted to a [`DateTime`] with [`NaiveDateTime::and_utc`] or
+    /// [`NaiveDateTime::and_local_timezone`].
+    #[deprecated(
+        since = "0.4.29",
+        note = "use `DateTime::parse_from_str` or `NaiveDateTime::parse_from_str` with `and_utc()` or `and_local_timezone()` instead"
+    )]
+    fn datetime_from_str(&self, s: &str, fmt: &str) -> ParseResult<DateTime<Self>> {
+        let mut parsed = Parsed::new();
+        parse(&mut parsed, s, StrftimeItems::new(fmt))?;
+        parsed.to_datetime_with_timezone(self)
+    }
+
+    /// Reconstructs the time zone from the offset.
+    fn from_offset(offset: &Self::Offset) -> Self;
+
+    /// Creates the offset(s) for given local `NaiveDate` if possible.
+    fn offset_from_local_date(&self, local: &NaiveDate) -> MappedLocalTime<Self::Offset>;
+
+    /// Creates the offset(s) for given local `NaiveDateTime` if possible.
+    fn offset_from_local_datetime(&self, local: &NaiveDateTime) -> MappedLocalTime<Self::Offset>;
+
+    /// Converts the local `NaiveDate` to the timezone-aware `Date` if possible.
+    #[allow(clippy::wrong_self_convention)]
+    #[deprecated(since = "0.4.23", note = "use `from_local_datetime()` instead")]
+    #[allow(deprecated)]
+    fn from_local_date(&self, local: &NaiveDate) -> MappedLocalTime<Date<Self>> {
+        self.offset_from_local_date(local).map(|offset| {
+            // since FixedOffset is within +/- 1 day, the date is never affected
+            Date::from_utc(*local, offset)
+        })
+    }
+
+    /// Converts the local `NaiveDateTime` to the timezone-aware `DateTime` if possible.
+    #[allow(clippy::wrong_self_convention)]
+    fn from_local_datetime(&self, local: &NaiveDateTime) -> MappedLocalTime<DateTime<Self>> {
+        self.offset_from_local_datetime(local).and_then(|off| {
+            local
+                .checked_sub_offset(off.fix())
+                .map(|dt| DateTime::from_naive_utc_and_offset(dt, off))
+        })
+    }
+
+    /// Creates the offset for given UTC `NaiveDate`. This cannot fail.
+    fn offset_from_utc_date(&self, utc: &NaiveDate) -> Self::Offset;
+
+    /// Creates the offset for given UTC `NaiveDateTime`. This cannot fail.
+    fn offset_from_utc_datetime(&self, utc: &NaiveDateTime) -> Self::Offset;
+
+    /// Converts the UTC `NaiveDate` to the local time.
+    /// The UTC is continuous and thus this cannot fail (but can give the duplicate local time).
+    #[allow(clippy::wrong_self_convention)]
+    #[deprecated(since = "0.4.23", note = "use `from_utc_datetime()` instead")]
+    #[allow(deprecated)]
+    fn from_utc_date(&self, utc: &NaiveDate) -> Date<Self> {
+        Date::from_utc(*utc, self.offset_from_utc_date(utc))
+    }
+
+    /// Converts the UTC `NaiveDateTime` to the local time.
+    /// The UTC is continuous and thus this cannot fail (but can give the duplicate local time).
+    #[allow(clippy::wrong_self_convention)]
+    fn from_utc_datetime(&self, utc: &NaiveDateTime) -> DateTime<Self> {
+        DateTime::from_naive_utc_and_offset(*utc, self.offset_from_utc_datetime(utc))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_fixed_offset_min_max_dates() {
+        for offset_hour in -23..=23 {
+            dbg!(offset_hour);
+            let offset = FixedOffset::east_opt(offset_hour * 60 * 60).unwrap();
+
+            let local_max = offset.from_utc_datetime(&NaiveDateTime::MAX);
+            assert_eq!(local_max.naive_utc(), NaiveDateTime::MAX);
+            let local_min = offset.from_utc_datetime(&NaiveDateTime::MIN);
+            assert_eq!(local_min.naive_utc(), NaiveDateTime::MIN);
+
+            let local_max = offset.from_local_datetime(&NaiveDateTime::MAX);
+            if offset_hour >= 0 {
+                assert_eq!(local_max.unwrap().naive_local(), NaiveDateTime::MAX);
+            } else {
+                assert_eq!(local_max, MappedLocalTime::None);
+            }
+            let local_min = offset.from_local_datetime(&NaiveDateTime::MIN);
+            if offset_hour <= 0 {
+                assert_eq!(local_min.unwrap().naive_local(), NaiveDateTime::MIN);
+            } else {
+                assert_eq!(local_min, MappedLocalTime::None);
+            }
+        }
+    }
+
+    #[test]
+    fn test_negative_millis() {
+        let dt = Utc.timestamp_millis_opt(-1000).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59 UTC");
+        let dt = Utc.timestamp_millis_opt(-7000).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:53 UTC");
+        let dt = Utc.timestamp_millis_opt(-7001).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:52.999 UTC");
+        let dt = Utc.timestamp_millis_opt(-7003).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:52.997 UTC");
+        let dt = Utc.timestamp_millis_opt(-999).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.001 UTC");
+        let dt = Utc.timestamp_millis_opt(-1).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.999 UTC");
+        let dt = Utc.timestamp_millis_opt(-60000).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:00 UTC");
+        let dt = Utc.timestamp_millis_opt(-3600000).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:00:00 UTC");
+
+        for (millis, expected) in &[
+            (-7000, "1969-12-31 23:59:53 UTC"),
+            (-7001, "1969-12-31 23:59:52.999 UTC"),
+            (-7003, "1969-12-31 23:59:52.997 UTC"),
+        ] {
+            match Utc.timestamp_millis_opt(*millis) {
+                MappedLocalTime::Single(dt) => {
+                    assert_eq!(dt.to_string(), *expected);
+                }
+                e => panic!("Got {:?} instead of an okay answer", e),
+            }
+        }
+    }
+
+    #[test]
+    fn test_negative_nanos() {
+        let dt = Utc.timestamp_nanos(-1_000_000_000);
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59 UTC");
+        let dt = Utc.timestamp_nanos(-999_999_999);
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.000000001 UTC");
+        let dt = Utc.timestamp_nanos(-1);
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.999999999 UTC");
+        let dt = Utc.timestamp_nanos(-60_000_000_000);
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:00 UTC");
+        let dt = Utc.timestamp_nanos(-3_600_000_000_000);
+        assert_eq!(dt.to_string(), "1969-12-31 23:00:00 UTC");
+    }
+
+    #[test]
+    fn test_nanos_never_panics() {
+        Utc.timestamp_nanos(i64::MAX);
+        Utc.timestamp_nanos(i64::default());
+        Utc.timestamp_nanos(i64::MIN);
+    }
+
+    #[test]
+    fn test_negative_micros() {
+        let dt = Utc.timestamp_micros(-1_000_000).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59 UTC");
+        let dt = Utc.timestamp_micros(-999_999).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.000001 UTC");
+        let dt = Utc.timestamp_micros(-1).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:59.999999 UTC");
+        let dt = Utc.timestamp_micros(-60_000_000).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:59:00 UTC");
+        let dt = Utc.timestamp_micros(-3_600_000_000).unwrap();
+        assert_eq!(dt.to_string(), "1969-12-31 23:00:00 UTC");
+    }
+}

patch/chrono-0.4.41/src/offset/utc.rs

@@ -0,0 +1,152 @@
+// This is a part of Chrono.
+// See README.md and LICENSE.txt for details.
+
+//! The UTC (Coordinated Universal Time) time zone.
+
+use core::fmt;
+#[cfg(all(
+    feature = "now",
+    not(all(
+        target_arch = "wasm32",
+        feature = "wasmbind",
+        not(any(target_os = "emscripten", target_os = "wasi", target_os = "linux"))
+    ))
+))]
+use std::time::{SystemTime, UNIX_EPOCH};
+
+#[cfg(any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
+use rkyv::{Archive, Deserialize, Serialize};
+
+use super::{FixedOffset, MappedLocalTime, Offset, TimeZone};
+use crate::naive::{NaiveDate, NaiveDateTime};
+#[cfg(feature = "now")]
+#[allow(deprecated)]
+use crate::{Date, DateTime};
+
+/// The UTC time zone. This is the most efficient time zone when you don't need the local time.
+/// It is also used as an offset (which is also a dummy type).
+///
+/// Using the [`TimeZone`](./trait.TimeZone.html) methods
+/// on the UTC struct is the preferred way to construct `DateTime<Utc>`
+/// instances.
+///
+/// # Example
+///
+/// ```
+/// use chrono::{DateTime, TimeZone, Utc};
+///
+/// let dt = DateTime::from_timestamp(61, 0).unwrap();
+///
+/// assert_eq!(Utc.timestamp_opt(61, 0).unwrap(), dt);
+/// assert_eq!(Utc.with_ymd_and_hms(1970, 1, 1, 0, 1, 1).unwrap(), dt);
+/// ```
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+#[cfg_attr(
+    any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
+    derive(Archive, Deserialize, Serialize),
+    rkyv(compare(PartialEq)),
+    rkyv(attr(derive(Clone, Copy, PartialEq, Eq, Debug, Hash)))
+)]
+#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
+#[cfg_attr(all(feature = "arbitrary", feature = "std"), derive(arbitrary::Arbitrary))]
+pub struct Utc;
+
+#[cfg(feature = "now")]
+impl Utc {
+    /// Returns a `Date` which corresponds to the current date.
+    #[deprecated(
+        since = "0.4.23",
+        note = "use `Utc::now()` instead, potentially with `.date_naive()`"
+    )]
+    #[allow(deprecated)]
+    #[must_use]
+    pub fn today() -> Date<Utc> {
+        Utc::now().date()
+    }
+
+    /// Returns a `DateTime<Utc>` which corresponds to the current date and time in UTC.
+    ///
+    /// See also the similar [`Local::now()`] which returns `DateTime<Local>`, i.e. the local date
+    /// and time including offset from UTC.
+    ///
+    /// [`Local::now()`]: crate::Local::now
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # #![allow(unused_variables)]
+    /// # use chrono::{FixedOffset, Utc};
+    /// // Current time in UTC
+    /// let now_utc = Utc::now();
+    ///
+    /// // Current date in UTC
+    /// let today_utc = now_utc.date_naive();
+    ///
+    /// // Current time in some timezone (let's use +05:00)
+    /// let offset = FixedOffset::east_opt(5 * 60 * 60).unwrap();
+    /// let now_with_offset = Utc::now().with_timezone(&offset);
+    /// ```
+    #[cfg(not(all(
+        target_arch = "wasm32",
+        feature = "wasmbind",
+        not(any(target_os = "emscripten", target_os = "wasi", target_os = "linux"))
+    )))]
+    #[must_use]
+    pub fn now() -> DateTime<Utc> {
+        let now =
+            SystemTime::now().duration_since(UNIX_EPOCH).expect("system time before Unix epoch");
+        DateTime::from_timestamp(now.as_secs() as i64, now.subsec_nanos()).unwrap()
+    }
+
+    /// Returns a `DateTime` which corresponds to the current date and time.
+    #[cfg(all(
+        target_arch = "wasm32",
+        feature = "wasmbind",
+        not(any(target_os = "emscripten", target_os = "wasi", target_os = "linux"))
+    ))]
+    #[must_use]
+    pub fn now() -> DateTime<Utc> {
+        let now = js_sys::Date::new_0();
+        DateTime::<Utc>::from(now)
+    }
+}
+
+impl TimeZone for Utc {
+    type Offset = Utc;
+
+    fn from_offset(_state: &Utc) -> Utc {
+        Utc
+    }
+
+    fn offset_from_local_date(&self, _local: &NaiveDate) -> MappedLocalTime<Utc> {
+        MappedLocalTime::Single(Utc)
+    }
+    fn offset_from_local_datetime(&self, _local: &NaiveDateTime) -> MappedLocalTime<Utc> {
+        MappedLocalTime::Single(Utc)
+    }
+
+    fn offset_from_utc_date(&self, _utc: &NaiveDate) -> Utc {
+        Utc
+    }
+    fn offset_from_utc_datetime(&self, _utc: &NaiveDateTime) -> Utc {
+        Utc
+    }
+}
+
+impl Offset for Utc {
+    fn fix(&self) -> FixedOffset {
+        FixedOffset::east_opt(0).unwrap()
+    }
+}
+
+impl fmt::Debug for Utc {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Z")
+    }
+}
+
+impl fmt::Display for Utc {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "UTC")
+    }
+}

patch/chrono-0.4.41/src/traits.rs

@@ -0,0 +1,415 @@
+use crate::{IsoWeek, Month, Weekday};
+
+/// The common set of methods for date component.
+///
+/// Methods such as [`year`], [`month`], [`day`] and [`weekday`] can be used to get basic
+/// information about the date.
+///
+/// The `with_*` methods can change the date.
+///
+/// # Warning
+///
+/// The `with_*` methods can be convenient to change a single component of a date, but they must be
+/// used with some care. Examples to watch out for:
+///
+/// - [`with_year`] changes the year component of a year-month-day value. Don't use this method if
+///   you want the ordinal to stay the same after changing the year, of if you want the week and
+///   weekday values to stay the same.
+/// - Don't combine two `with_*` methods to change two components of the date. For example to
+///   change both the year and month components of a date. This could fail because an intermediate
+///   value does not exist, while the final date would be valid.
+///
+/// For more complex changes to a date, it is best to use the methods on [`NaiveDate`] to create a
+/// new value instead of altering an existing date.
+///
+/// [`year`]: Datelike::year
+/// [`month`]: Datelike::month
+/// [`day`]: Datelike::day
+/// [`weekday`]: Datelike::weekday
+/// [`with_year`]: Datelike::with_year
+/// [`NaiveDate`]: crate::NaiveDate
+pub trait Datelike: Sized {
+    /// Returns the year number in the [calendar date](./naive/struct.NaiveDate.html#calendar-date).
+    fn year(&self) -> i32;
+
+    /// Returns the absolute year number starting from 1 with a boolean flag,
+    /// which is false when the year predates the epoch (BCE/BC) and true otherwise (CE/AD).
+    #[inline]
+    fn year_ce(&self) -> (bool, u32) {
+        let year = self.year();
+        if year < 1 { (false, (1 - year) as u32) } else { (true, year as u32) }
+    }
+
+    /// Returns the quarter number starting from 1.
+    ///
+    /// The return value ranges from 1 to 4.
+    #[inline]
+    fn quarter(&self) -> u32 {
+        (self.month() - 1).div_euclid(3) + 1
+    }
+
+    /// Returns the month number starting from 1.
+    ///
+    /// The return value ranges from 1 to 12.
+    fn month(&self) -> u32;
+
+    /// Returns the month number starting from 0.
+    ///
+    /// The return value ranges from 0 to 11.
+    fn month0(&self) -> u32;
+
+    /// Returns the day of month starting from 1.
+    ///
+    /// The return value ranges from 1 to 31. (The last day of month differs by months.)
+    fn day(&self) -> u32;
+
+    /// Returns the day of month starting from 0.
+    ///
+    /// The return value ranges from 0 to 30. (The last day of month differs by months.)
+    fn day0(&self) -> u32;
+
+    /// Returns the day of year starting from 1.
+    ///
+    /// The return value ranges from 1 to 366. (The last day of year differs by years.)
+    fn ordinal(&self) -> u32;
+
+    /// Returns the day of year starting from 0.
+    ///
+    /// The return value ranges from 0 to 365. (The last day of year differs by years.)
+    fn ordinal0(&self) -> u32;
+
+    /// Returns the day of week.
+    fn weekday(&self) -> Weekday;
+
+    /// Returns the ISO week.
+    fn iso_week(&self) -> IsoWeek;
+
+    /// Makes a new value with the year number changed, while keeping the same month and day.
+    ///
+    /// This method assumes you want to work on the date as a year-month-day value. Don't use it if
+    /// you want the ordinal to stay the same after changing the year, of if you want the week and
+    /// weekday values to stay the same.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` when:
+    ///
+    /// - The resulting date does not exist (February 29 in a non-leap year).
+    /// - The year is out of range for [`NaiveDate`].
+    /// - In case of [`DateTime<Tz>`] if the resulting date and time fall within a timezone
+    ///   transition such as from DST to standard time.
+    ///
+    /// [`NaiveDate`]: crate::NaiveDate
+    /// [`DateTime<Tz>`]: crate::DateTime
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{Datelike, NaiveDate};
+    ///
+    /// assert_eq!(
+    ///     NaiveDate::from_ymd_opt(2020, 5, 13).unwrap().with_year(2023).unwrap(),
+    ///     NaiveDate::from_ymd_opt(2023, 5, 13).unwrap()
+    /// );
+    /// // Resulting date 2023-02-29 does not exist:
+    /// assert!(NaiveDate::from_ymd_opt(2020, 2, 29).unwrap().with_year(2023).is_none());
+    ///
+    /// // Don't use `with_year` if you want the ordinal date to stay the same:
+    /// assert_ne!(
+    ///     NaiveDate::from_yo_opt(2020, 100).unwrap().with_year(2023).unwrap(),
+    ///     NaiveDate::from_yo_opt(2023, 100).unwrap() // result is 2023-101
+    /// );
+    /// ```
+    fn with_year(&self, year: i32) -> Option<Self>;
+
+    /// Makes a new value with the month number (starting from 1) changed.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` when:
+    ///
+    /// - The resulting date does not exist (for example `month(4)` when day of the month is 31).
+    /// - In case of [`DateTime<Tz>`] if the resulting date and time fall within a timezone
+    ///   transition such as from DST to standard time.
+    /// - The value for `month` is out of range.
+    ///
+    /// [`DateTime<Tz>`]: crate::DateTime
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{Datelike, NaiveDate};
+    ///
+    /// assert_eq!(
+    ///     NaiveDate::from_ymd_opt(2023, 5, 12).unwrap().with_month(9).unwrap(),
+    ///     NaiveDate::from_ymd_opt(2023, 9, 12).unwrap()
+    /// );
+    /// // Resulting date 2023-09-31 does not exist:
+    /// assert!(NaiveDate::from_ymd_opt(2023, 5, 31).unwrap().with_month(9).is_none());
+    /// ```
+    ///
+    /// Don't combine multiple `Datelike::with_*` methods. The intermediate value may not exist.
+    /// ```
+    /// use chrono::{Datelike, NaiveDate};
+    ///
+    /// fn with_year_month(date: NaiveDate, year: i32, month: u32) -> Option<NaiveDate> {
+    ///     date.with_year(year)?.with_month(month)
+    /// }
+    /// let d = NaiveDate::from_ymd_opt(2020, 2, 29).unwrap();
+    /// assert!(with_year_month(d, 2019, 1).is_none()); // fails because of invalid intermediate value
+    ///
+    /// // Correct version:
+    /// fn with_year_month_fixed(date: NaiveDate, year: i32, month: u32) -> Option<NaiveDate> {
+    ///     NaiveDate::from_ymd_opt(year, month, date.day())
+    /// }
+    /// let d = NaiveDate::from_ymd_opt(2020, 2, 29).unwrap();
+    /// assert_eq!(with_year_month_fixed(d, 2019, 1), NaiveDate::from_ymd_opt(2019, 1, 29));
+    /// ```
+    fn with_month(&self, month: u32) -> Option<Self>;
+
+    /// Makes a new value with the month number (starting from 0) changed.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` when:
+    ///
+    /// - The resulting date does not exist (for example `month0(3)` when day of the month is 31).
+    /// - In case of [`DateTime<Tz>`] if the resulting date and time fall within a timezone
+    ///   transition such as from DST to standard time.
+    /// - The value for `month0` is out of range.
+    ///
+    /// [`DateTime<Tz>`]: crate::DateTime
+    fn with_month0(&self, month0: u32) -> Option<Self>;
+
+    /// Makes a new value with the day of month (starting from 1) changed.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` when:
+    ///
+    /// - The resulting date does not exist (for example `day(31)` in April).
+    /// - In case of [`DateTime<Tz>`] if the resulting date and time fall within a timezone
+    ///   transition such as from DST to standard time.
+    /// - The value for `day` is out of range.
+    ///
+    /// [`DateTime<Tz>`]: crate::DateTime
+    fn with_day(&self, day: u32) -> Option<Self>;
+
+    /// Makes a new value with the day of month (starting from 0) changed.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` when:
+    ///
+    /// - The resulting date does not exist (for example `day0(30)` in April).
+    /// - In case of [`DateTime<Tz>`] if the resulting date and time fall within a timezone
+    ///   transition such as from DST to standard time.
+    /// - The value for `day0` is out of range.
+    ///
+    /// [`DateTime<Tz>`]: crate::DateTime
+    fn with_day0(&self, day0: u32) -> Option<Self>;
+
+    /// Makes a new value with the day of year (starting from 1) changed.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` when:
+    ///
+    /// - The resulting date does not exist (`with_ordinal(366)` in a non-leap year).
+    /// - In case of [`DateTime<Tz>`] if the resulting date and time fall within a timezone
+    ///   transition such as from DST to standard time.
+    /// - The value for `ordinal` is out of range.
+    ///
+    /// [`DateTime<Tz>`]: crate::DateTime
+    fn with_ordinal(&self, ordinal: u32) -> Option<Self>;
+
+    /// Makes a new value with the day of year (starting from 0) changed.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` when:
+    ///
+    /// - The resulting date does not exist (`with_ordinal0(365)` in a non-leap year).
+    /// - In case of [`DateTime<Tz>`] if the resulting date and time fall within a timezone
+    ///   transition such as from DST to standard time.
+    /// - The value for `ordinal0` is out of range.
+    ///
+    /// [`DateTime<Tz>`]: crate::DateTime
+    fn with_ordinal0(&self, ordinal0: u32) -> Option<Self>;
+
+    /// Counts the days in the proleptic Gregorian calendar, with January 1, Year 1 (CE) as day 1.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::{Datelike, NaiveDate};
+    ///
+    /// assert_eq!(NaiveDate::from_ymd_opt(1970, 1, 1).unwrap().num_days_from_ce(), 719_163);
+    /// assert_eq!(NaiveDate::from_ymd_opt(2, 1, 1).unwrap().num_days_from_ce(), 366);
+    /// assert_eq!(NaiveDate::from_ymd_opt(1, 1, 1).unwrap().num_days_from_ce(), 1);
+    /// assert_eq!(NaiveDate::from_ymd_opt(0, 1, 1).unwrap().num_days_from_ce(), -365);
+    /// ```
+    fn num_days_from_ce(&self) -> i32 {
+        // See test_num_days_from_ce_against_alternative_impl below for a more straightforward
+        // implementation.
+
+        // we know this wouldn't overflow since year is limited to 1/2^13 of i32's full range.
+        let mut year = self.year() - 1;
+        let mut ndays = 0;
+        if year < 0 {
+            let excess = 1 + (-year) / 400;
+            year += excess * 400;
+            ndays -= excess * 146_097;
+        }
+        let div_100 = year / 100;
+        ndays += ((year * 1461) >> 2) - div_100 + (div_100 >> 2);
+        ndays + self.ordinal() as i32
+    }
+
+    /// Get the length in days of the month
+    fn num_days_in_month(&self) -> u8 {
+        use num_traits::FromPrimitive;
+        // The value returned from `self.month()` is guaranteed to be in the
+        // range [1,12], which will never result in a `None` value here.
+        let month = Month::from_u32(self.month()).unwrap();
+        // `Month::num_days` will only return `None` if the provided year is out
+        // of range. Since we are passing it directly from a verified date, we
+        // know it is in range, and the result will never be `None`.
+        month.num_days(self.year()).unwrap()
+    }
+}
+
+/// The common set of methods for time component.
+pub trait Timelike: Sized {
+    /// Returns the hour number from 0 to 23.
+    fn hour(&self) -> u32;
+
+    /// Returns the hour number from 1 to 12 with a boolean flag,
+    /// which is false for AM and true for PM.
+    #[inline]
+    fn hour12(&self) -> (bool, u32) {
+        let hour = self.hour();
+        let mut hour12 = hour % 12;
+        if hour12 == 0 {
+            hour12 = 12;
+        }
+        (hour >= 12, hour12)
+    }
+
+    /// Returns the minute number from 0 to 59.
+    fn minute(&self) -> u32;
+
+    /// Returns the second number from 0 to 59.
+    fn second(&self) -> u32;
+
+    /// Returns the number of nanoseconds since the whole non-leap second.
+    /// The range from 1,000,000,000 to 1,999,999,999 represents
+    /// the [leap second](./naive/struct.NaiveTime.html#leap-second-handling).
+    fn nanosecond(&self) -> u32;
+
+    /// Makes a new value with the hour number changed.
+    ///
+    /// Returns `None` when the resulting value would be invalid.
+    fn with_hour(&self, hour: u32) -> Option<Self>;
+
+    /// Makes a new value with the minute number changed.
+    ///
+    /// Returns `None` when the resulting value would be invalid.
+    fn with_minute(&self, min: u32) -> Option<Self>;
+
+    /// Makes a new value with the second number changed.
+    ///
+    /// Returns `None` when the resulting value would be invalid.
+    /// As with the [`second`](#tymethod.second) method,
+    /// the input range is restricted to 0 through 59.
+    fn with_second(&self, sec: u32) -> Option<Self>;
+
+    /// Makes a new value with nanoseconds since the whole non-leap second changed.
+    ///
+    /// Returns `None` when the resulting value would be invalid.
+    /// As with the [`nanosecond`](#tymethod.nanosecond) method,
+    /// the input range can exceed 1,000,000,000 for leap seconds.
+    fn with_nanosecond(&self, nano: u32) -> Option<Self>;
+
+    /// Returns the number of non-leap seconds past the last midnight.
+    ///
+    /// Every value in 00:00:00-23:59:59 maps to an integer in 0-86399.
+    ///
+    /// This method is not intended to provide the real number of seconds since midnight on a given
+    /// day. It does not take things like DST transitions into account.
+    #[inline]
+    fn num_seconds_from_midnight(&self) -> u32 {
+        self.hour() * 3600 + self.minute() * 60 + self.second()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Datelike;
+    use crate::{Days, NaiveDate};
+
+    /// Tests `Datelike::num_days_from_ce` against an alternative implementation.
+    ///
+    /// The alternative implementation is not as short as the current one but it is simpler to
+    /// understand, with less unexplained magic constants.
+    #[test]
+    fn test_num_days_from_ce_against_alternative_impl() {
+        /// Returns the number of multiples of `div` in the range `start..end`.
+        ///
+        /// If the range `start..end` is back-to-front, i.e. `start` is greater than `end`, the
+        /// behaviour is defined by the following equation:
+        /// `in_between(start, end, div) == - in_between(end, start, div)`.
+        ///
+        /// When `div` is 1, this is equivalent to `end - start`, i.e. the length of `start..end`.
+        ///
+        /// # Panics
+        ///
+        /// Panics if `div` is not positive.
+        fn in_between(start: i32, end: i32, div: i32) -> i32 {
+            assert!(div > 0, "in_between: nonpositive div = {}", div);
+            let start = (start.div_euclid(div), start.rem_euclid(div));
+            let end = (end.div_euclid(div), end.rem_euclid(div));
+            // The lowest multiple of `div` greater than or equal to `start`, divided.
+            let start = start.0 + (start.1 != 0) as i32;
+            // The lowest multiple of `div` greater than or equal to   `end`, divided.
+            let end = end.0 + (end.1 != 0) as i32;
+            end - start
+        }
+
+        /// Alternative implementation to `Datelike::num_days_from_ce`
+        fn num_days_from_ce<Date: Datelike>(date: &Date) -> i32 {
+            let year = date.year();
+            let diff = move |div| in_between(1, year, div);
+            // 365 days a year, one more in leap years. In the gregorian calendar, leap years are all
+            // the multiples of 4 except multiples of 100 but including multiples of 400.
+            date.ordinal() as i32 + 365 * diff(1) + diff(4) - diff(100) + diff(400)
+        }
+
+        for year in NaiveDate::MIN.year()..=NaiveDate::MAX.year() {
+            let jan1_year = NaiveDate::from_ymd_opt(year, 1, 1).unwrap();
+            assert_eq!(
+                jan1_year.num_days_from_ce(),
+                num_days_from_ce(&jan1_year),
+                "on {:?}",
+                jan1_year
+            );
+            let mid_year = jan1_year + Days::new(133);
+            assert_eq!(
+                mid_year.num_days_from_ce(),
+                num_days_from_ce(&mid_year),
+                "on {:?}",
+                mid_year
+            );
+        }
+    }
+
+    #[test]
+    fn test_num_days_in_month() {
+        let feb_leap_year = NaiveDate::from_ymd_opt(2004, 2, 1).unwrap();
+        assert_eq!(feb_leap_year.num_days_in_month(), 29);
+        let feb = feb_leap_year.with_year(2005).unwrap();
+        assert_eq!(feb.num_days_in_month(), 28);
+        let march = feb.with_month(3).unwrap();
+        assert_eq!(march.num_days_in_month(), 31);
+    }
+}

patch/chrono-0.4.41/src/weekday.rs

@@ -0,0 +1,408 @@
+use core::fmt;
+
+#[cfg(any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
+use rkyv::{Archive, Deserialize, Serialize};
+
+use crate::OutOfRange;
+
+/// The day of week.
+///
+/// The order of the days of week depends on the context.
+/// (This is why this type does *not* implement `PartialOrd` or `Ord` traits.)
+/// One should prefer `*_from_monday` or `*_from_sunday` methods to get the correct result.
+///
+/// # Example
+/// ```
+/// use chrono::Weekday;
+///
+/// let monday = "Monday".parse::<Weekday>().unwrap();
+/// assert_eq!(monday, Weekday::Mon);
+///
+/// let sunday = Weekday::try_from(6).unwrap();
+/// assert_eq!(sunday, Weekday::Sun);
+///
+/// assert_eq!(sunday.num_days_from_monday(), 6); // starts counting with Monday = 0
+/// assert_eq!(sunday.number_from_monday(), 7); // starts counting with Monday = 1
+/// assert_eq!(sunday.num_days_from_sunday(), 0); // starts counting with Sunday = 0
+/// assert_eq!(sunday.number_from_sunday(), 1); // starts counting with Sunday = 1
+///
+/// assert_eq!(sunday.succ(), monday);
+/// assert_eq!(sunday.pred(), Weekday::Sat);
+/// ```
+#[derive(PartialEq, Eq, Copy, Clone, Debug, Hash)]
+#[cfg_attr(
+    any(feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
+    derive(Archive, Deserialize, Serialize),
+    rkyv(compare(PartialEq)),
+    rkyv(attr(derive(Clone, Copy, PartialEq, Eq, Debug, Hash)))
+)]
+#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
+#[cfg_attr(all(feature = "arbitrary", feature = "std"), derive(arbitrary::Arbitrary))]
+pub enum Weekday {
+    /// Monday.
+    Mon = 0,
+    /// Tuesday.
+    Tue = 1,
+    /// Wednesday.
+    Wed = 2,
+    /// Thursday.
+    Thu = 3,
+    /// Friday.
+    Fri = 4,
+    /// Saturday.
+    Sat = 5,
+    /// Sunday.
+    Sun = 6,
+}
+
+impl Weekday {
+    /// The next day in the week.
+    ///
+    /// `w`:        | `Mon` | `Tue` | `Wed` | `Thu` | `Fri` | `Sat` | `Sun`
+    /// ----------- | ----- | ----- | ----- | ----- | ----- | ----- | -----
+    /// `w.succ()`: | `Tue` | `Wed` | `Thu` | `Fri` | `Sat` | `Sun` | `Mon`
+    #[inline]
+    #[must_use]
+    pub const fn succ(&self) -> Weekday {
+        match *self {
+            Weekday::Mon => Weekday::Tue,
+            Weekday::Tue => Weekday::Wed,
+            Weekday::Wed => Weekday::Thu,
+            Weekday::Thu => Weekday::Fri,
+            Weekday::Fri => Weekday::Sat,
+            Weekday::Sat => Weekday::Sun,
+            Weekday::Sun => Weekday::Mon,
+        }
+    }
+
+    /// The previous day in the week.
+    ///
+    /// `w`:        | `Mon` | `Tue` | `Wed` | `Thu` | `Fri` | `Sat` | `Sun`
+    /// ----------- | ----- | ----- | ----- | ----- | ----- | ----- | -----
+    /// `w.pred()`: | `Sun` | `Mon` | `Tue` | `Wed` | `Thu` | `Fri` | `Sat`
+    #[inline]
+    #[must_use]
+    pub const fn pred(&self) -> Weekday {
+        match *self {
+            Weekday::Mon => Weekday::Sun,
+            Weekday::Tue => Weekday::Mon,
+            Weekday::Wed => Weekday::Tue,
+            Weekday::Thu => Weekday::Wed,
+            Weekday::Fri => Weekday::Thu,
+            Weekday::Sat => Weekday::Fri,
+            Weekday::Sun => Weekday::Sat,
+        }
+    }
+
+    /// Returns a day-of-week number starting from Monday = 1. (ISO 8601 weekday number)
+    ///
+    /// `w`:                      | `Mon` | `Tue` | `Wed` | `Thu` | `Fri` | `Sat` | `Sun`
+    /// ------------------------- | ----- | ----- | ----- | ----- | ----- | ----- | -----
+    /// `w.number_from_monday()`: | 1     | 2     | 3     | 4     | 5     | 6     | 7
+    #[inline]
+    pub const fn number_from_monday(&self) -> u32 {
+        self.days_since(Weekday::Mon) + 1
+    }
+
+    /// Returns a day-of-week number starting from Sunday = 1.
+    ///
+    /// `w`:                      | `Mon` | `Tue` | `Wed` | `Thu` | `Fri` | `Sat` | `Sun`
+    /// ------------------------- | ----- | ----- | ----- | ----- | ----- | ----- | -----
+    /// `w.number_from_sunday()`: | 2     | 3     | 4     | 5     | 6     | 7     | 1
+    #[inline]
+    pub const fn number_from_sunday(&self) -> u32 {
+        self.days_since(Weekday::Sun) + 1
+    }
+
+    /// Returns a day-of-week number starting from Monday = 0.
+    ///
+    /// `w`:                        | `Mon` | `Tue` | `Wed` | `Thu` | `Fri` | `Sat` | `Sun`
+    /// --------------------------- | ----- | ----- | ----- | ----- | ----- | ----- | -----
+    /// `w.num_days_from_monday()`: | 0     | 1     | 2     | 3     | 4     | 5     | 6
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # #[cfg(feature = "clock")] {
+    /// # use chrono::{Local, Datelike};
+    /// // MTWRFSU is occasionally used as a single-letter abbreviation of the weekdays.
+    /// // Use `num_days_from_monday` to index into the array.
+    /// const MTWRFSU: [char; 7] = ['M', 'T', 'W', 'R', 'F', 'S', 'U'];
+    ///
+    /// let today = Local::now().weekday();
+    /// println!("{}", MTWRFSU[today.num_days_from_monday() as usize]);
+    /// # }
+    /// ```
+    #[inline]
+    pub const fn num_days_from_monday(&self) -> u32 {
+        self.days_since(Weekday::Mon)
+    }
+
+    /// Returns a day-of-week number starting from Sunday = 0.
+    ///
+    /// `w`:                        | `Mon` | `Tue` | `Wed` | `Thu` | `Fri` | `Sat` | `Sun`
+    /// --------------------------- | ----- | ----- | ----- | ----- | ----- | ----- | -----
+    /// `w.num_days_from_sunday()`: | 1     | 2     | 3     | 4     | 5     | 6     | 0
+    #[inline]
+    pub const fn num_days_from_sunday(&self) -> u32 {
+        self.days_since(Weekday::Sun)
+    }
+
+    /// The number of days since the given day.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use chrono::Weekday::*;
+    /// assert_eq!(Mon.days_since(Mon), 0);
+    /// assert_eq!(Sun.days_since(Tue), 5);
+    /// assert_eq!(Wed.days_since(Sun), 3);
+    /// ```
+    pub const fn days_since(&self, other: Weekday) -> u32 {
+        let lhs = *self as u32;
+        let rhs = other as u32;
+        if lhs < rhs { 7 + lhs - rhs } else { lhs - rhs }
+    }
+}
+
+impl fmt::Display for Weekday {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.pad(match *self {
+            Weekday::Mon => "Mon",
+            Weekday::Tue => "Tue",
+            Weekday::Wed => "Wed",
+            Weekday::Thu => "Thu",
+            Weekday::Fri => "Fri",
+            Weekday::Sat => "Sat",
+            Weekday::Sun => "Sun",
+        })
+    }
+}
+
+/// Any weekday can be represented as an integer from 0 to 6, which equals to
+/// [`Weekday::num_days_from_monday`](#method.num_days_from_monday) in this implementation.
+/// Do not heavily depend on this though; use explicit methods whenever possible.
+impl TryFrom<u8> for Weekday {
+    type Error = OutOfRange;
+
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
+        match value {
+            0 => Ok(Weekday::Mon),
+            1 => Ok(Weekday::Tue),
+            2 => Ok(Weekday::Wed),
+            3 => Ok(Weekday::Thu),
+            4 => Ok(Weekday::Fri),
+            5 => Ok(Weekday::Sat),
+            6 => Ok(Weekday::Sun),
+            _ => Err(OutOfRange::new()),
+        }
+    }
+}
+
+/// Any weekday can be represented as an integer from 0 to 6, which equals to
+/// [`Weekday::num_days_from_monday`](#method.num_days_from_monday) in this implementation.
+/// Do not heavily depend on this though; use explicit methods whenever possible.
+impl num_traits::FromPrimitive for Weekday {
+    #[inline]
+    fn from_i64(n: i64) -> Option<Weekday> {
+        match n {
+            0 => Some(Weekday::Mon),
+            1 => Some(Weekday::Tue),
+            2 => Some(Weekday::Wed),
+            3 => Some(Weekday::Thu),
+            4 => Some(Weekday::Fri),
+            5 => Some(Weekday::Sat),
+            6 => Some(Weekday::Sun),
+            _ => None,
+        }
+    }
+
+    #[inline]
+    fn from_u64(n: u64) -> Option<Weekday> {
+        match n {
+            0 => Some(Weekday::Mon),
+            1 => Some(Weekday::Tue),
+            2 => Some(Weekday::Wed),
+            3 => Some(Weekday::Thu),
+            4 => Some(Weekday::Fri),
+            5 => Some(Weekday::Sat),
+            6 => Some(Weekday::Sun),
+            _ => None,
+        }
+    }
+}
+
+/// An error resulting from reading `Weekday` value with `FromStr`.
+#[derive(Clone, PartialEq, Eq)]
+pub struct ParseWeekdayError {
+    pub(crate) _dummy: (),
+}
+
+#[cfg(feature = "std")]
+impl std::error::Error for ParseWeekdayError {}
+
+impl fmt::Display for ParseWeekdayError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_fmt(format_args!("{self:?}"))
+    }
+}
+
+impl fmt::Debug for ParseWeekdayError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "ParseWeekdayError {{ .. }}")
+    }
+}
+
+// the actual `FromStr` implementation is in the `format` module to leverage the existing code
+
+#[cfg(feature = "serde")]
+mod weekday_serde {
+    use super::Weekday;
+    use core::fmt;
+    use serde::{de, ser};
+
+    impl ser::Serialize for Weekday {
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: ser::Serializer,
+        {
+            serializer.collect_str(&self)
+        }
+    }
+
+    struct WeekdayVisitor;
+
+    impl de::Visitor<'_> for WeekdayVisitor {
+        type Value = Weekday;
+
+        fn expecting(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            f.write_str("Weekday")
+        }
+
+        fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+        where
+            E: de::Error,
+        {
+            value.parse().map_err(|_| E::custom("short or long weekday names expected"))
+        }
+    }
+
+    impl<'de> de::Deserialize<'de> for Weekday {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: de::Deserializer<'de>,
+        {
+            deserializer.deserialize_str(WeekdayVisitor)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Weekday;
+
+    #[test]
+    fn test_days_since() {
+        for i in 0..7 {
+            let base_day = Weekday::try_from(i).unwrap();
+
+            assert_eq!(base_day.num_days_from_monday(), base_day.days_since(Weekday::Mon));
+            assert_eq!(base_day.num_days_from_sunday(), base_day.days_since(Weekday::Sun));
+
+            assert_eq!(base_day.days_since(base_day), 0);
+
+            assert_eq!(base_day.days_since(base_day.pred()), 1);
+            assert_eq!(base_day.days_since(base_day.pred().pred()), 2);
+            assert_eq!(base_day.days_since(base_day.pred().pred().pred()), 3);
+            assert_eq!(base_day.days_since(base_day.pred().pred().pred().pred()), 4);
+            assert_eq!(base_day.days_since(base_day.pred().pred().pred().pred().pred()), 5);
+            assert_eq!(base_day.days_since(base_day.pred().pred().pred().pred().pred().pred()), 6);
+
+            assert_eq!(base_day.days_since(base_day.succ()), 6);
+            assert_eq!(base_day.days_since(base_day.succ().succ()), 5);
+            assert_eq!(base_day.days_since(base_day.succ().succ().succ()), 4);
+            assert_eq!(base_day.days_since(base_day.succ().succ().succ().succ()), 3);
+            assert_eq!(base_day.days_since(base_day.succ().succ().succ().succ().succ()), 2);
+            assert_eq!(base_day.days_since(base_day.succ().succ().succ().succ().succ().succ()), 1);
+        }
+    }
+
+    #[test]
+    fn test_formatting_alignment() {
+        // No exhaustive testing here as we just delegate the
+        // implementation to Formatter::pad. Just some basic smoke
+        // testing to ensure that it's in fact being done.
+        assert_eq!(format!("{:x>7}", Weekday::Mon), "xxxxMon");
+        assert_eq!(format!("{:^7}", Weekday::Mon), "  Mon  ");
+        assert_eq!(format!("{:Z<7}", Weekday::Mon), "MonZZZZ");
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_serialize() {
+        use Weekday::*;
+        use serde_json::to_string;
+
+        let cases: Vec<(Weekday, &str)> = vec![
+            (Mon, "\"Mon\""),
+            (Tue, "\"Tue\""),
+            (Wed, "\"Wed\""),
+            (Thu, "\"Thu\""),
+            (Fri, "\"Fri\""),
+            (Sat, "\"Sat\""),
+            (Sun, "\"Sun\""),
+        ];
+
+        for (weekday, expected_str) in cases {
+            let string = to_string(&weekday).unwrap();
+            assert_eq!(string, expected_str);
+        }
+    }
+
+    #[test]
+    #[cfg(feature = "serde")]
+    fn test_serde_deserialize() {
+        use Weekday::*;
+        use serde_json::from_str;
+
+        let cases: Vec<(&str, Weekday)> = vec![
+            ("\"mon\"", Mon),
+            ("\"MONDAY\"", Mon),
+            ("\"MonDay\"", Mon),
+            ("\"mOn\"", Mon),
+            ("\"tue\"", Tue),
+            ("\"tuesday\"", Tue),
+            ("\"wed\"", Wed),
+            ("\"wednesday\"", Wed),
+            ("\"thu\"", Thu),
+            ("\"thursday\"", Thu),
+            ("\"fri\"", Fri),
+            ("\"friday\"", Fri),
+            ("\"sat\"", Sat),
+            ("\"saturday\"", Sat),
+            ("\"sun\"", Sun),
+            ("\"sunday\"", Sun),
+        ];
+
+        for (str, expected_weekday) in cases {
+            let weekday = from_str::<Weekday>(str).unwrap();
+            assert_eq!(weekday, expected_weekday);
+        }
+
+        let errors: Vec<&str> =
+            vec!["\"not a weekday\"", "\"monDAYs\"", "\"mond\"", "mon", "\"thur\"", "\"thurs\""];
+
+        for str in errors {
+            from_str::<Weekday>(str).unwrap_err();
+        }
+    }
+
+    #[test]
+    #[cfg(feature = "rkyv-validation")]
+    fn test_rkyv_validation() {
+        let mon = Weekday::Mon;
+        let bytes = rkyv::to_bytes::<_, 1>(&mon).unwrap();
+
+        assert_eq!(rkyv::from_bytes::<Weekday>(&bytes).unwrap(), mon);
+    }
+}

patch/chrono-0.4.41/src/weekday_set.rs

@@ -0,0 +1,483 @@
+use core::{
+    fmt::{self, Debug},
+    iter::FusedIterator,
+};
+
+use crate::Weekday;
+
+/// A collection of [`Weekday`]s stored as a single byte.
+///
+/// This type is `Copy` and provides efficient set-like and slice-like operations.
+/// Many operations are `const` as well.
+///
+/// Implemented as a bitmask where bits 1-7 correspond to Monday-Sunday.
+#[derive(Clone, Copy, Default, Hash, PartialEq, Eq, PartialOrd, Ord)]
+pub struct WeekdaySet(u8); // Invariant: the 8-th bit is always 0.
+
+impl WeekdaySet {
+    /// Create a `WeekdaySet` from an array of [`Weekday`]s.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::EMPTY, WeekdaySet::from_array([]));
+    /// assert_eq!(WeekdaySet::single(Mon), WeekdaySet::from_array([Mon]));
+    /// assert_eq!(WeekdaySet::ALL, WeekdaySet::from_array([Mon, Tue, Wed, Thu, Fri, Sat, Sun]));
+    /// ```
+    pub const fn from_array<const C: usize>(days: [Weekday; C]) -> Self {
+        let mut acc = Self::EMPTY;
+        let mut idx = 0;
+        while idx < days.len() {
+            acc.0 |= Self::single(days[idx]).0;
+            idx += 1;
+        }
+        acc
+    }
+
+    /// Create a `WeekdaySet` from a single [`Weekday`].
+    pub const fn single(weekday: Weekday) -> Self {
+        match weekday {
+            Weekday::Mon => Self(0b000_0001),
+            Weekday::Tue => Self(0b000_0010),
+            Weekday::Wed => Self(0b000_0100),
+            Weekday::Thu => Self(0b000_1000),
+            Weekday::Fri => Self(0b001_0000),
+            Weekday::Sat => Self(0b010_0000),
+            Weekday::Sun => Self(0b100_0000),
+        }
+    }
+
+    /// Returns `Some(day)` if this collection contains exactly one day.
+    ///
+    /// Returns `None` otherwise.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::single(Mon).single_day(), Some(Mon));
+    /// assert_eq!(WeekdaySet::from_array([Mon, Tue]).single_day(), None);
+    /// assert_eq!(WeekdaySet::EMPTY.single_day(), None);
+    /// assert_eq!(WeekdaySet::ALL.single_day(), None);
+    /// ```
+    pub const fn single_day(self) -> Option<Weekday> {
+        match self {
+            Self(0b000_0001) => Some(Weekday::Mon),
+            Self(0b000_0010) => Some(Weekday::Tue),
+            Self(0b000_0100) => Some(Weekday::Wed),
+            Self(0b000_1000) => Some(Weekday::Thu),
+            Self(0b001_0000) => Some(Weekday::Fri),
+            Self(0b010_0000) => Some(Weekday::Sat),
+            Self(0b100_0000) => Some(Weekday::Sun),
+            _ => None,
+        }
+    }
+
+    /// Adds a day to the collection.
+    ///
+    /// Returns `true` if the day was new to the collection.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// let mut weekdays = WeekdaySet::single(Mon);
+    /// assert!(weekdays.insert(Tue));
+    /// assert!(!weekdays.insert(Tue));
+    /// ```
+    pub fn insert(&mut self, day: Weekday) -> bool {
+        if self.contains(day) {
+            return false;
+        }
+
+        self.0 |= Self::single(day).0;
+        true
+    }
+
+    /// Removes a day from the collection.
+    ///
+    /// Returns `true` if the collection did contain the day.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// let mut weekdays = WeekdaySet::single(Mon);
+    /// assert!(weekdays.remove(Mon));
+    /// assert!(!weekdays.remove(Mon));
+    /// ```
+    pub fn remove(&mut self, day: Weekday) -> bool {
+        if self.contains(day) {
+            self.0 &= !Self::single(day).0;
+            return true;
+        }
+
+        false
+    }
+
+    /// Returns `true` if `other` contains all days in `self`.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert!(WeekdaySet::single(Mon).is_subset(WeekdaySet::ALL));
+    /// assert!(!WeekdaySet::single(Mon).is_subset(WeekdaySet::EMPTY));
+    /// assert!(WeekdaySet::EMPTY.is_subset(WeekdaySet::single(Mon)));
+    /// ```
+    pub const fn is_subset(self, other: Self) -> bool {
+        self.intersection(other).0 == self.0
+    }
+
+    /// Returns days that are in both `self` and `other`.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::single(Mon).intersection(WeekdaySet::single(Mon)), WeekdaySet::single(Mon));
+    /// assert_eq!(WeekdaySet::single(Mon).intersection(WeekdaySet::single(Tue)), WeekdaySet::EMPTY);
+    /// assert_eq!(WeekdaySet::ALL.intersection(WeekdaySet::single(Mon)), WeekdaySet::single(Mon));
+    /// assert_eq!(WeekdaySet::ALL.intersection(WeekdaySet::EMPTY), WeekdaySet::EMPTY);
+    /// ```
+    pub const fn intersection(self, other: Self) -> Self {
+        Self(self.0 & other.0)
+    }
+
+    /// Returns days that are in either `self` or `other`.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::single(Mon).union(WeekdaySet::single(Mon)), WeekdaySet::single(Mon));
+    /// assert_eq!(WeekdaySet::single(Mon).union(WeekdaySet::single(Tue)), WeekdaySet::from_array([Mon, Tue]));
+    /// assert_eq!(WeekdaySet::ALL.union(WeekdaySet::single(Mon)), WeekdaySet::ALL);
+    /// assert_eq!(WeekdaySet::ALL.union(WeekdaySet::EMPTY), WeekdaySet::ALL);
+    /// ```
+    pub const fn union(self, other: Self) -> Self {
+        Self(self.0 | other.0)
+    }
+
+    /// Returns days that are in `self` or `other` but not in both.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::single(Mon).symmetric_difference(WeekdaySet::single(Mon)), WeekdaySet::EMPTY);
+    /// assert_eq!(WeekdaySet::single(Mon).symmetric_difference(WeekdaySet::single(Tue)), WeekdaySet::from_array([Mon, Tue]));
+    /// assert_eq!(
+    ///     WeekdaySet::ALL.symmetric_difference(WeekdaySet::single(Mon)),
+    ///     WeekdaySet::from_array([Tue, Wed, Thu, Fri, Sat, Sun]),
+    /// );
+    /// assert_eq!(WeekdaySet::ALL.symmetric_difference(WeekdaySet::EMPTY), WeekdaySet::ALL);
+    /// ```
+    pub const fn symmetric_difference(self, other: Self) -> Self {
+        Self(self.0 ^ other.0)
+    }
+
+    /// Returns days that are in `self` but not in `other`.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::single(Mon).difference(WeekdaySet::single(Mon)), WeekdaySet::EMPTY);
+    /// assert_eq!(WeekdaySet::single(Mon).difference(WeekdaySet::single(Tue)), WeekdaySet::single(Mon));
+    /// assert_eq!(WeekdaySet::EMPTY.difference(WeekdaySet::single(Mon)), WeekdaySet::EMPTY);
+    /// ```
+    pub const fn difference(self, other: Self) -> Self {
+        Self(self.0 & !other.0)
+    }
+
+    /// Get the first day in the collection, starting from Monday.
+    ///
+    /// Returns `None` if the collection is empty.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::single(Mon).first(), Some(Mon));
+    /// assert_eq!(WeekdaySet::single(Tue).first(), Some(Tue));
+    /// assert_eq!(WeekdaySet::ALL.first(), Some(Mon));
+    /// assert_eq!(WeekdaySet::EMPTY.first(), None);
+    /// ```
+    pub const fn first(self) -> Option<Weekday> {
+        if self.is_empty() {
+            return None;
+        }
+
+        // Find the first non-zero bit.
+        let bit = 1 << self.0.trailing_zeros();
+
+        Self(bit).single_day()
+    }
+
+    /// Get the last day in the collection, starting from Sunday.
+    ///
+    /// Returns `None` if the collection is empty.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::single(Mon).last(), Some(Mon));
+    /// assert_eq!(WeekdaySet::single(Sun).last(), Some(Sun));
+    /// assert_eq!(WeekdaySet::from_array([Mon, Tue]).last(), Some(Tue));
+    /// assert_eq!(WeekdaySet::EMPTY.last(), None);
+    /// ```
+    pub fn last(self) -> Option<Weekday> {
+        if self.is_empty() {
+            return None;
+        }
+
+        // Find the last non-zero bit.
+        let bit = 1 << (7 - self.0.leading_zeros());
+
+        Self(bit).single_day()
+    }
+
+    /// Split the collection in two at the given day.
+    ///
+    /// Returns a tuple `(before, after)`. `before` contains all days starting from Monday
+    /// up to but __not__ including `weekday`. `after` contains all days starting from `weekday`
+    /// up to and including Sunday.
+    const fn split_at(self, weekday: Weekday) -> (Self, Self) {
+        let days_after = 0b1000_0000 - Self::single(weekday).0;
+        let days_before = days_after ^ 0b0111_1111;
+        (Self(self.0 & days_before), Self(self.0 & days_after))
+    }
+
+    /// Iterate over the [`Weekday`]s in the collection starting from a given day.
+    ///
+    /// Wraps around from Sunday to Monday if necessary.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// let weekdays = WeekdaySet::from_array([Mon, Wed, Fri]);
+    /// let mut iter = weekdays.iter(Wed);
+    /// assert_eq!(iter.next(), Some(Wed));
+    /// assert_eq!(iter.next(), Some(Fri));
+    /// assert_eq!(iter.next(), Some(Mon));
+    /// assert_eq!(iter.next(), None);
+    /// ```
+    pub const fn iter(self, start: Weekday) -> WeekdaySetIter {
+        WeekdaySetIter { days: self, start }
+    }
+
+    /// Returns `true` if the collection contains the given day.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert!(WeekdaySet::single(Mon).contains(Mon));
+    /// assert!(WeekdaySet::from_array([Mon, Tue]).contains(Tue));
+    /// assert!(!WeekdaySet::single(Mon).contains(Tue));
+    /// ```
+    pub const fn contains(self, day: Weekday) -> bool {
+        self.0 & Self::single(day).0 != 0
+    }
+
+    /// Returns `true` if the collection is empty.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::{Weekday, WeekdaySet};
+    /// assert!(WeekdaySet::EMPTY.is_empty());
+    /// assert!(!WeekdaySet::single(Weekday::Mon).is_empty());
+    /// ```
+    pub const fn is_empty(self) -> bool {
+        self.len() == 0
+    }
+    /// Returns the number of days in the collection.
+    ///
+    /// # Example
+    /// ```
+    /// # use chrono::WeekdaySet;
+    /// use chrono::Weekday::*;
+    /// assert_eq!(WeekdaySet::single(Mon).len(), 1);
+    /// assert_eq!(WeekdaySet::from_array([Mon, Wed, Fri]).len(), 3);
+    /// assert_eq!(WeekdaySet::ALL.len(), 7);
+    /// ```
+    pub const fn len(self) -> u8 {
+        self.0.count_ones() as u8
+    }
+
+    /// An empty `WeekdaySet`.
+    pub const EMPTY: Self = Self(0b000_0000);
+    /// A `WeekdaySet` containing all seven `Weekday`s.
+    pub const ALL: Self = Self(0b111_1111);
+}
+
+/// Print the underlying bitmask, padded to 7 bits.
+///
+/// # Example
+/// ```
+/// # use chrono::WeekdaySet;
+/// use chrono::Weekday::*;
+/// assert_eq!(format!("{:?}", WeekdaySet::single(Mon)), "WeekdaySet(0000001)");
+/// assert_eq!(format!("{:?}", WeekdaySet::single(Tue)), "WeekdaySet(0000010)");
+/// assert_eq!(format!("{:?}", WeekdaySet::ALL), "WeekdaySet(1111111)");
+/// ```
+impl Debug for WeekdaySet {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "WeekdaySet({:0>7b})", self.0)
+    }
+}
+
+/// An iterator over a collection of weekdays, starting from a given day.
+///
+/// See [`WeekdaySet::iter()`].
+#[derive(Debug, Clone)]
+pub struct WeekdaySetIter {
+    days: WeekdaySet,
+    start: Weekday,
+}
+
+impl Iterator for WeekdaySetIter {
+    type Item = Weekday;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.days.is_empty() {
+            return None;
+        }
+
+        // Split the collection in two at `start`.
+        // Look for the first day among the days after `start` first, including `start` itself.
+        // If there are no days after `start`, look for the first day among the days before `start`.
+        let (before, after) = self.days.split_at(self.start);
+        let days = if after.is_empty() { before } else { after };
+
+        let next = days.first().expect("the collection is not empty");
+        self.days.remove(next);
+        Some(next)
+    }
+}
+
+impl DoubleEndedIterator for WeekdaySetIter {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        if self.days.is_empty() {
+            return None;
+        }
+
+        // Split the collection in two at `start`.
+        // Look for the last day among the days before `start` first, NOT including `start` itself.
+        // If there are no days before `start`, look for the last day among the days after `start`.
+        let (before, after) = self.days.split_at(self.start);
+        let days = if before.is_empty() { after } else { before };
+
+        let next_back = days.last().expect("the collection is not empty");
+        self.days.remove(next_back);
+        Some(next_back)
+    }
+}
+
+impl ExactSizeIterator for WeekdaySetIter {
+    fn len(&self) -> usize {
+        self.days.len().into()
+    }
+}
+
+impl FusedIterator for WeekdaySetIter {}
+
+/// Print the collection as a slice-like list of weekdays.
+///
+/// # Example
+/// ```
+/// # use chrono::WeekdaySet;
+/// use chrono::Weekday::*;
+/// assert_eq!("[]", WeekdaySet::EMPTY.to_string());
+/// assert_eq!("[Mon]", WeekdaySet::single(Mon).to_string());
+/// assert_eq!("[Mon, Fri, Sun]", WeekdaySet::from_array([Mon, Fri, Sun]).to_string());
+/// ```
+impl fmt::Display for WeekdaySet {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "[")?;
+        let mut iter = self.iter(Weekday::Mon);
+        if let Some(first) = iter.next() {
+            write!(f, "{first}")?;
+        }
+        for weekday in iter {
+            write!(f, ", {weekday}")?;
+        }
+        write!(f, "]")
+    }
+}
+
+impl FromIterator<Weekday> for WeekdaySet {
+    fn from_iter<T: IntoIterator<Item = Weekday>>(iter: T) -> Self {
+        iter.into_iter().map(Self::single).fold(Self::EMPTY, Self::union)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::Weekday;
+
+    use super::WeekdaySet;
+
+    impl WeekdaySet {
+        /// Iterate over all 128 possible sets, from `EMPTY` to `ALL`.
+        fn iter_all() -> impl Iterator<Item = Self> {
+            (0b0000_0000..0b1000_0000).map(Self)
+        }
+    }
+
+    /// Panics if the 8-th bit of `self` is not 0.
+    fn assert_8th_bit_invariant(days: WeekdaySet) {
+        assert!(days.0 & 0b1000_0000 == 0, "the 8-th bit of {days:?} is not 0");
+    }
+
+    #[test]
+    fn debug_prints_8th_bit_if_not_zero() {
+        assert_eq!(format!("{:?}", WeekdaySet(0b1000_0000)), "WeekdaySet(10000000)");
+    }
+
+    #[test]
+    fn bitwise_set_operations_preserve_8th_bit_invariant() {
+        for set1 in WeekdaySet::iter_all() {
+            for set2 in WeekdaySet::iter_all() {
+                assert_8th_bit_invariant(set1.union(set2));
+                assert_8th_bit_invariant(set1.intersection(set2));
+                assert_8th_bit_invariant(set1.symmetric_difference(set2));
+            }
+        }
+    }
+
+    /// Test `split_at` on all possible arguments.
+    #[test]
+    fn split_at_is_equivalent_to_iterating() {
+        use Weekday::*;
+
+        // `split_at()` is used in `iter()`, so we must not iterate
+        // over all days with `WeekdaySet::ALL.iter(Mon)`.
+        const WEEK: [Weekday; 7] = [Mon, Tue, Wed, Thu, Fri, Sat, Sun];
+
+        for weekdays in WeekdaySet::iter_all() {
+            for split_day in WEEK {
+                let expected_before: WeekdaySet = WEEK
+                    .into_iter()
+                    .take_while(|&day| day != split_day)
+                    .filter(|&day| weekdays.contains(day))
+                    .collect();
+                let expected_after: WeekdaySet = WEEK
+                    .into_iter()
+                    .skip_while(|&day| day != split_day)
+                    .filter(|&day| weekdays.contains(day))
+                    .collect();
+
+                assert_eq!(
+                    (expected_before, expected_after),
+                    weekdays.split_at(split_day),
+                    "split_at({split_day}) failed for {weekdays}",
+                );
+            }
+        }
+    }
+}