refactor project structure

datastruct/sortedset/border.go

@@ -0,0 +1,91 @@
+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
+	}
+}