更新ID生成器

idGenerator/formater.go

@@ -0,0 +1,132 @@
+package idgenerator
+
+import (
+	"errors"
+	"math"
+	"strconv"
+	"time"
+)
+
+const (
+	YYYYMMDDHHmmss = "20060102150405"
+	YYYYMMDDHHmm   = "200601021504"
+	YYYYMMDDHH     = "2006010215"
+	YYYYMMDD       = "20060102"
+)
+
+type Layout int
+
+const (
+	Binary Layout = iota
+	Decimal
+)
+
+type formater interface {
+	MaxinalMachineCode() int64
+	MaximalSequence() int64
+	Format(machine, serial int64, reback bool) Id
+}
+
+type Id int64
+
+func (i Id) String() string {
+	if i == 0 {
+		return ""
+	}
+
+	return strconv.FormatInt(int64(i), 10)
+}
+
+func (i Id) Int64() int64 {
+	return int64(i)
+}
+
+// 标识生成器
+type generator struct {
+	maximalSequence    int64        // 序列段的最大值
+	maxinalMachineCode int64        // 机器码的最大值
+	sequenceLength     int64        // 序列段长度
+	machineCodeLength  int64        // 机器码长度
+	lastTimestamp      int64        // 最后回绕时间
+	getTimestampFunc   func() int64 // 获取时间段的方法
+}
+
+func (g generator) MaxinalMachineCode() int64 {
+	return g.maxinalMachineCode
+}
+
+func (g generator) MaximalSequence() int64 {
+	return g.maximalSequence
+}
+
+func (g *generator) getTimestamp(reback bool) int64 {
+	newTimestamp := g.getTimestampFunc()
+
+	for reback && g.lastTimestamp == newTimestamp {
+		time.Sleep(time.Microsecond * 10)
+		newTimestamp = g.getTimestampFunc()
+	}
+
+	g.lastTimestamp = newTimestamp
+	return newTimestamp
+}
+
+type binaryFormater struct {
+	generator
+}
+
+func newBinaryFormatter(start int64, sequenceLength, machineCodeLength int64) (*binaryFormater, error) {
+	return &binaryFormater{
+		generator: generator{
+			maximalSequence:    int64(-1 ^ (-1 << sequenceLength)),
+			maxinalMachineCode: int64(-1 ^ (-1 << machineCodeLength)),
+			sequenceLength:     sequenceLength,
+			machineCodeLength:  machineCodeLength,
+			getTimestampFunc:   func() int64 { return time.Now().Unix() - start },
+		},
+	}, nil
+}
+
+func (f *binaryFormater) Format(machine, serial int64, reback bool) Id {
+	timestamp := f.getTimestamp(reback)
+	return Id(timestamp<<(f.sequenceLength+f.machineCodeLength) | machine<<f.sequenceLength | serial)
+}
+
+type decimalFormater struct {
+	generator
+	supportReback bool
+}
+
+const (
+	decimalMaxLength = 19
+)
+
+func newDecimalFormater(format string, serialLength, machineLength int) (*decimalFormater, error) {
+	if len(format)+serialLength+machineLength > decimalMaxLength {
+		return nil, errors.New("the data length is out of limit")
+	}
+
+	serialShift := int64(math.Pow10(serialLength))
+	machineShift := int64(math.Pow10(machineLength))
+
+	return &decimalFormater{
+		generator: generator{
+			sequenceLength:     serialShift,
+			maximalSequence:    serialShift - 1,
+			machineCodeLength:  machineShift,
+			maxinalMachineCode: machineShift - 1,
+			getTimestampFunc: func() int64 {
+				now := time.Now()
+				v := now.Format(format)
+				r, _ := strconv.ParseInt(v, 10, 64)
+				return r
+			},
+		},
+		supportReback: len(format) == 14,
+	}, nil
+}
+
+func (f *decimalFormater) Format(machine, serial int64, reback bool) Id {
+	timestamp := f.getTimestamp(reback)
+	return Id(timestamp*f.sequenceLength*f.machineCodeLength + machine*f.sequenceLength + serial)
+}