refactor project structure

This commit is contained in:
hdt3213
2021-05-02 14:54:42 +08:00
parent bb9c140653
commit f29298cc68
78 changed files with 140 additions and 140 deletions

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package sortedset
import (
"errors"
"strconv"
)
/*
* ScoreBorder is a struct represents `min` `max` parameter of redis command `ZRANGEBYSCORE`
* can accept:
* int or float value, such as 2.718, 2, -2.718, -2 ...
* exclusive int or float value, such as (2.718, (2, (-2.718, (-2 ...
* infinity: +inf, -inf inf(same as +inf)
*/
const (
negativeInf int8 = -1
positiveInf int8 = 1
)
type ScoreBorder struct {
Inf int8
Value float64
Exclude bool
}
// if max.greater(score) then the score is within the upper border
// do not use min.greater()
func (border *ScoreBorder) greater(value float64) bool {
if border.Inf == negativeInf {
return false
} else if border.Inf == positiveInf {
return true
}
if border.Exclude {
return border.Value > value
} else {
return border.Value >= value
}
}
func (border *ScoreBorder) less(value float64) bool {
if border.Inf == negativeInf {
return true
} else if border.Inf == positiveInf {
return false
}
if border.Exclude {
return border.Value < value
} else {
return border.Value <= value
}
}
var positiveInfBorder = &ScoreBorder{
Inf: positiveInf,
}
var negativeInfBorder = &ScoreBorder{
Inf: negativeInf,
}
func ParseScoreBorder(s string) (*ScoreBorder, error) {
if s == "inf" || s == "+inf" {
return positiveInfBorder, nil
}
if s == "-inf" {
return negativeInfBorder, nil
}
if s[0] == '(' {
value, err := strconv.ParseFloat(s[1:], 64)
if err != nil {
return nil, errors.New("ERR min or max is not a float")
}
return &ScoreBorder{
Inf: 0,
Value: value,
Exclude: true,
}, nil
} else {
value, err := strconv.ParseFloat(s, 64)
if err != nil {
return nil, errors.New("ERR min or max is not a float")
}
return &ScoreBorder{
Inf: 0,
Value: value,
Exclude: false,
}, nil
}
}

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@@ -0,0 +1,344 @@
package sortedset
import "math/rand"
const (
maxLevel = 16
)
type Element struct {
Member string
Score float64
}
// level aspect of a Node
type Level struct {
forward *Node // forward node has greater score
span int64
}
type Node struct {
Element
backward *Node
level []*Level // level[0] is base level
}
type skiplist struct {
header *Node
tail *Node
length int64
level int16
}
func makeNode(level int16, score float64, member string) *Node {
n := &Node{
Element: Element{
Score: score,
Member: member,
},
level: make([]*Level, level),
}
for i := range n.level {
n.level[i] = new(Level)
}
return n
}
func makeSkiplist() *skiplist {
return &skiplist{
level: 1,
header: makeNode(maxLevel, 0, ""),
}
}
func randomLevel() int16 {
level := int16(1)
for float32(rand.Int31()&0xFFFF) < (0.25 * 0xFFFF) {
level++
}
if level < maxLevel {
return level
}
return maxLevel
}
func (skiplist *skiplist) insert(member string, score float64) *Node {
update := make([]*Node, maxLevel) // link new node with node in `update`
rank := make([]int64, maxLevel)
// find position to insert
node := skiplist.header
for i := skiplist.level - 1; i >= 0; i-- {
if i == skiplist.level-1 {
rank[i] = 0
} else {
rank[i] = rank[i+1] // store rank that is crossed to reach the insert position
}
if node.level[i] != nil {
// traverse the skip list
for node.level[i].forward != nil &&
(node.level[i].forward.Score < score ||
(node.level[i].forward.Score == score && node.level[i].forward.Member < member)) { // same score, different key
rank[i] += node.level[i].span
node = node.level[i].forward
}
}
update[i] = node
}
level := randomLevel()
// extend skiplist level
if level > skiplist.level {
for i := skiplist.level; i < level; i++ {
rank[i] = 0
update[i] = skiplist.header
update[i].level[i].span = skiplist.length
}
skiplist.level = level
}
// make node and link into skiplist
node = makeNode(level, score, member)
for i := int16(0); i < level; i++ {
node.level[i].forward = update[i].level[i].forward
update[i].level[i].forward = node
// update span covered by update[i] as node is inserted here
node.level[i].span = update[i].level[i].span - (rank[0] - rank[i])
update[i].level[i].span = (rank[0] - rank[i]) + 1
}
// increment span for untouched levels
for i := level; i < skiplist.level; i++ {
update[i].level[i].span++
}
// set backward node
if update[0] == skiplist.header {
node.backward = nil
} else {
node.backward = update[0]
}
if node.level[0].forward != nil {
node.level[0].forward.backward = node
} else {
skiplist.tail = node
}
skiplist.length++
return node
}
/*
* param node: node to delete
* param update: backward node (of target)
*/
func (skiplist *skiplist) removeNode(node *Node, update []*Node) {
for i := int16(0); i < skiplist.level; i++ {
if update[i].level[i].forward == node {
update[i].level[i].span += node.level[i].span - 1
update[i].level[i].forward = node.level[i].forward
} else {
update[i].level[i].span--
}
}
if node.level[0].forward != nil {
node.level[0].forward.backward = node.backward
} else {
skiplist.tail = node.backward
}
for skiplist.level > 1 && skiplist.header.level[skiplist.level-1].forward == nil {
skiplist.level--
}
skiplist.length--
}
/*
* return: has found and removed node
*/
func (skiplist *skiplist) remove(member string, score float64) bool {
/*
* find backward node (of target) or last node of each level
* their forward need to be updated
*/
update := make([]*Node, maxLevel)
node := skiplist.header
for i := skiplist.level - 1; i >= 0; i-- {
for node.level[i].forward != nil &&
(node.level[i].forward.Score < score ||
(node.level[i].forward.Score == score &&
node.level[i].forward.Member < member)) {
node = node.level[i].forward
}
update[i] = node
}
node = node.level[0].forward
if node != nil && score == node.Score && node.Member == member {
skiplist.removeNode(node, update)
// free x
return true
}
return false
}
/*
* return: 1 based rank, 0 means member not found
*/
func (skiplist *skiplist) getRank(member string, score float64) int64 {
var rank int64 = 0
x := skiplist.header
for i := skiplist.level - 1; i >= 0; i-- {
for x.level[i].forward != nil &&
(x.level[i].forward.Score < score ||
(x.level[i].forward.Score == score &&
x.level[i].forward.Member <= member)) {
rank += x.level[i].span
x = x.level[i].forward
}
/* x might be equal to zsl->header, so test if obj is non-NULL */
if x.Member == member {
return rank
}
}
return 0
}
/*
* 1-based rank
*/
func (skiplist *skiplist) getByRank(rank int64) *Node {
var i int64 = 0
n := skiplist.header
// scan from top level
for level := skiplist.level - 1; level >= 0; level-- {
for n.level[level].forward != nil && (i+n.level[level].span) <= rank {
i += n.level[level].span
n = n.level[level].forward
}
if i == rank {
return n
}
}
return nil
}
func (skiplist *skiplist) hasInRange(min *ScoreBorder, max *ScoreBorder) bool {
// min & max = empty
if min.Value > max.Value || (min.Value == max.Value && (min.Exclude || max.Exclude)) {
return false
}
// min > tail
n := skiplist.tail
if n == nil || !min.less(n.Score) {
return false
}
// max < head
n = skiplist.header.level[0].forward
if n == nil || !max.greater(n.Score) {
return false
}
return true
}
func (skiplist *skiplist) getFirstInScoreRange(min *ScoreBorder, max *ScoreBorder) *Node {
if !skiplist.hasInRange(min, max) {
return nil
}
n := skiplist.header
// scan from top level
for level := skiplist.level - 1; level >= 0; level-- {
// if forward is not in range than move forward
for n.level[level].forward != nil && !min.less(n.level[level].forward.Score) {
n = n.level[level].forward
}
}
/* This is an inner range, so the next node cannot be NULL. */
n = n.level[0].forward
if !max.greater(n.Score) {
return nil
}
return n
}
func (skiplist *skiplist) getLastInScoreRange(min *ScoreBorder, max *ScoreBorder) *Node {
if !skiplist.hasInRange(min, max) {
return nil
}
n := skiplist.header
// scan from top level
for level := skiplist.level - 1; level >= 0; level-- {
for n.level[level].forward != nil && max.greater(n.level[level].forward.Score) {
n = n.level[level].forward
}
}
if !min.less(n.Score) {
return nil
}
return n
}
/*
* return removed elements
*/
func (skiplist *skiplist) RemoveRangeByScore(min *ScoreBorder, max *ScoreBorder) (removed []*Element) {
update := make([]*Node, maxLevel)
removed = make([]*Element, 0)
// find backward nodes (of target range) or last node of each level
node := skiplist.header
for i := skiplist.level - 1; i >= 0; i-- {
for node.level[i].forward != nil {
if min.less(node.level[i].forward.Score) { // already in range
break
}
node = node.level[i].forward
}
update[i] = node
}
// node is the first one within range
node = node.level[0].forward
// remove nodes in range
for node != nil {
if !max.greater(node.Score) { // already out of range
break
}
next := node.level[0].forward
removedElement := node.Element
removed = append(removed, &removedElement)
skiplist.removeNode(node, update)
node = next
}
return removed
}
// 1-based rank, including start, exclude stop
func (skiplist *skiplist) RemoveRangeByRank(start int64, stop int64) (removed []*Element) {
var i int64 = 0 // rank of iterator
update := make([]*Node, maxLevel)
removed = make([]*Element, 0)
// scan from top level
node := skiplist.header
for level := skiplist.level - 1; level >= 0; level-- {
for node.level[level].forward != nil && (i+node.level[level].span) < start {
i += node.level[level].span
node = node.level[level].forward
}
update[level] = node
}
i++
node = node.level[0].forward // first node in range
// remove nodes in range
for node != nil && i < stop {
next := node.level[0].forward
removedElement := node.Element
removed = append(removed, &removedElement)
skiplist.removeNode(node, update)
node = next
i++
}
return removed
}

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@@ -0,0 +1,226 @@
package sortedset
import (
"strconv"
)
type SortedSet struct {
dict map[string]*Element
skiplist *skiplist
}
func Make() *SortedSet {
return &SortedSet{
dict: make(map[string]*Element),
skiplist: makeSkiplist(),
}
}
/*
* return: has inserted new node
*/
func (sortedSet *SortedSet) Add(member string, score float64) bool {
element, ok := sortedSet.dict[member]
sortedSet.dict[member] = &Element{
Member: member,
Score: score,
}
if ok {
if score != element.Score {
sortedSet.skiplist.remove(member, score)
sortedSet.skiplist.insert(member, score)
}
return false
} else {
sortedSet.skiplist.insert(member, score)
return true
}
}
func (sortedSet *SortedSet) Len() int64 {
return int64(len(sortedSet.dict))
}
func (sortedSet *SortedSet) Get(member string) (element *Element, ok bool) {
element, ok = sortedSet.dict[member]
if !ok {
return nil, false
}
return element, true
}
func (sortedSet *SortedSet) Remove(member string) bool {
v, ok := sortedSet.dict[member]
if ok {
sortedSet.skiplist.remove(member, v.Score)
delete(sortedSet.dict, member)
return true
}
return false
}
/**
* get 0-based rank
*/
func (sortedSet *SortedSet) GetRank(member string, desc bool) (rank int64) {
element, ok := sortedSet.dict[member]
if !ok {
return -1
}
r := sortedSet.skiplist.getRank(member, element.Score)
if desc {
r = sortedSet.skiplist.length - r
} else {
r--
}
return r
}
/**
* traverse [start, stop), 0-based rank
*/
func (sortedSet *SortedSet) ForEach(start int64, stop int64, desc bool, consumer func(element *Element) bool) {
size := int64(sortedSet.Len())
if start < 0 || start >= size {
panic("illegal start " + strconv.FormatInt(start, 10))
}
if stop < start || stop > size {
panic("illegal end " + strconv.FormatInt(stop, 10))
}
// find start node
var node *Node
if desc {
node = sortedSet.skiplist.tail
if start > 0 {
node = sortedSet.skiplist.getByRank(int64(size - start))
}
} else {
node = sortedSet.skiplist.header.level[0].forward
if start > 0 {
node = sortedSet.skiplist.getByRank(int64(start + 1))
}
}
sliceSize := int(stop - start)
for i := 0; i < sliceSize; i++ {
if !consumer(&node.Element) {
break
}
if desc {
node = node.backward
} else {
node = node.level[0].forward
}
}
}
/**
* return [start, stop), 0-based rank
* assert start in [0, size), stop in [start, size]
*/
func (sortedSet *SortedSet) Range(start int64, stop int64, desc bool) []*Element {
sliceSize := int(stop - start)
slice := make([]*Element, sliceSize)
i := 0
sortedSet.ForEach(start, stop, desc, func(element *Element) bool {
slice[i] = element
i++
return true
})
return slice
}
func (sortedSet *SortedSet) Count(min *ScoreBorder, max *ScoreBorder) int64 {
var i int64 = 0
// ascending order
sortedSet.ForEach(0, sortedSet.Len(), false, func(element *Element) bool {
gtMin := min.less(element.Score) // greater than min
if !gtMin {
// has not into range, continue foreach
return true
}
ltMax := max.greater(element.Score) // less than max
if !ltMax {
// break through score border, break foreach
return false
}
// gtMin && ltMax
i++
return true
})
return i
}
func (sortedSet *SortedSet) ForEachByScore(min *ScoreBorder, max *ScoreBorder, offset int64, limit int64, desc bool, consumer func(element *Element) bool) {
// find start node
var node *Node
if desc {
node = sortedSet.skiplist.getLastInScoreRange(min, max)
} else {
node = sortedSet.skiplist.getFirstInScoreRange(min, max)
}
for node != nil && offset > 0 {
if desc {
node = node.backward
} else {
node = node.level[0].forward
}
offset--
}
// A negative limit returns all elements from the offset
for i := 0; (i < int(limit) || limit < 0) && node != nil; i++ {
if !consumer(&node.Element) {
break
}
if desc {
node = node.backward
} else {
node = node.level[0].forward
}
if node == nil {
break
}
gtMin := min.less(node.Element.Score) // greater than min
ltMax := max.greater(node.Element.Score)
if !gtMin || !ltMax {
break // break through score border
}
}
}
/*
* param limit: <0 means no limit
*/
func (sortedSet *SortedSet) RangeByScore(min *ScoreBorder, max *ScoreBorder, offset int64, limit int64, desc bool) []*Element {
if limit == 0 || offset < 0 {
return make([]*Element, 0)
}
slice := make([]*Element, 0)
sortedSet.ForEachByScore(min, max, offset, limit, desc, func(element *Element) bool {
slice = append(slice, element)
return true
})
return slice
}
func (sortedSet *SortedSet) RemoveByScore(min *ScoreBorder, max *ScoreBorder) int64 {
removed := sortedSet.skiplist.RemoveRangeByScore(min, max)
for _, element := range removed {
delete(sortedSet.dict, element.Member)
}
return int64(len(removed))
}
/*
* 0-based rank, [start, stop)
*/
func (sortedSet *SortedSet) RemoveByRank(start int64, stop int64) int64 {
removed := sortedSet.skiplist.RemoveRangeByRank(start+1, stop+1)
for _, element := range removed {
delete(sortedSet.dict, element.Member)
}
return int64(len(removed))
}