mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-15 08:23:34 +01:00
124 lines
3.4 KiB
Go
124 lines
3.4 KiB
Go
// Copyright 2016 Google Inc. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package uuid
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"sync"
|
|
"time"
|
|
)
|
|
|
|
// A Time represents a time as the number of 100's of nanoseconds since 15 Oct
|
|
// 1582.
|
|
type Time int64
|
|
|
|
const (
|
|
lillian = 2299160 // Julian day of 15 Oct 1582
|
|
unix = 2440587 // Julian day of 1 Jan 1970
|
|
epoch = unix - lillian // Days between epochs
|
|
g1582 = epoch * 86400 // seconds between epochs
|
|
g1582ns100 = g1582 * 10000000 // 100s of a nanoseconds between epochs
|
|
)
|
|
|
|
var (
|
|
timeMu sync.Mutex
|
|
lasttime uint64 // last time we returned
|
|
clockSeq uint16 // clock sequence for this run
|
|
|
|
timeNow = time.Now // for testing
|
|
)
|
|
|
|
// UnixTime converts t the number of seconds and nanoseconds using the Unix
|
|
// epoch of 1 Jan 1970.
|
|
func (t Time) UnixTime() (sec, nsec int64) {
|
|
sec = int64(t - g1582ns100)
|
|
nsec = (sec % 10000000) * 100
|
|
sec /= 10000000
|
|
return sec, nsec
|
|
}
|
|
|
|
// GetTime returns the current Time (100s of nanoseconds since 15 Oct 1582) and
|
|
// clock sequence as well as adjusting the clock sequence as needed. An error
|
|
// is returned if the current time cannot be determined.
|
|
func GetTime() (Time, uint16, error) {
|
|
defer timeMu.Unlock()
|
|
timeMu.Lock()
|
|
return getTime()
|
|
}
|
|
|
|
func getTime() (Time, uint16, error) {
|
|
t := timeNow()
|
|
|
|
// If we don't have a clock sequence already, set one.
|
|
if clockSeq == 0 {
|
|
setClockSequence(-1)
|
|
}
|
|
now := uint64(t.UnixNano()/100) + g1582ns100
|
|
|
|
// If time has gone backwards with this clock sequence then we
|
|
// increment the clock sequence
|
|
if now <= lasttime {
|
|
clockSeq = ((clockSeq + 1) & 0x3fff) | 0x8000
|
|
}
|
|
lasttime = now
|
|
return Time(now), clockSeq, nil
|
|
}
|
|
|
|
// ClockSequence returns the current clock sequence, generating one if not
|
|
// already set. The clock sequence is only used for Version 1 UUIDs.
|
|
//
|
|
// The uuid package does not use global static storage for the clock sequence or
|
|
// the last time a UUID was generated. Unless SetClockSequence is used, a new
|
|
// random clock sequence is generated the first time a clock sequence is
|
|
// requested by ClockSequence, GetTime, or NewUUID. (section 4.2.1.1)
|
|
func ClockSequence() int {
|
|
defer timeMu.Unlock()
|
|
timeMu.Lock()
|
|
return clockSequence()
|
|
}
|
|
|
|
func clockSequence() int {
|
|
if clockSeq == 0 {
|
|
setClockSequence(-1)
|
|
}
|
|
return int(clockSeq & 0x3fff)
|
|
}
|
|
|
|
// SetClockSequence sets the clock sequence to the lower 14 bits of seq. Setting to
|
|
// -1 causes a new sequence to be generated.
|
|
func SetClockSequence(seq int) {
|
|
defer timeMu.Unlock()
|
|
timeMu.Lock()
|
|
setClockSequence(seq)
|
|
}
|
|
|
|
func setClockSequence(seq int) {
|
|
if seq == -1 {
|
|
var b [2]byte
|
|
randomBits(b[:]) // clock sequence
|
|
seq = int(b[0])<<8 | int(b[1])
|
|
}
|
|
oldSeq := clockSeq
|
|
clockSeq = uint16(seq&0x3fff) | 0x8000 // Set our variant
|
|
if oldSeq != clockSeq {
|
|
lasttime = 0
|
|
}
|
|
}
|
|
|
|
// Time returns the time in 100s of nanoseconds since 15 Oct 1582 encoded in
|
|
// uuid. The time is only defined for version 1 and 2 UUIDs.
|
|
func (uuid UUID) Time() Time {
|
|
time := int64(binary.BigEndian.Uint32(uuid[0:4]))
|
|
time |= int64(binary.BigEndian.Uint16(uuid[4:6])) << 32
|
|
time |= int64(binary.BigEndian.Uint16(uuid[6:8])&0xfff) << 48
|
|
return Time(time)
|
|
}
|
|
|
|
// ClockSequence returns the clock sequence encoded in uuid.
|
|
// The clock sequence is only well defined for version 1 and 2 UUIDs.
|
|
func (uuid UUID) ClockSequence() int {
|
|
return int(binary.BigEndian.Uint16(uuid[8:10])) & 0x3fff
|
|
}
|