mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-26 20:30:10 +01:00
76 lines
2.5 KiB
Go
76 lines
2.5 KiB
Go
// Copyright 2023 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 (
|
|
"io"
|
|
)
|
|
|
|
// UUID version 7 features a time-ordered value field derived from the widely
|
|
// implemented and well known Unix Epoch timestamp source,
|
|
// the number of milliseconds seconds since midnight 1 Jan 1970 UTC, leap seconds excluded.
|
|
// As well as improved entropy characteristics over versions 1 or 6.
|
|
//
|
|
// see https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format-03#name-uuid-version-7
|
|
//
|
|
// Implementations SHOULD utilize UUID version 7 over UUID version 1 and 6 if possible.
|
|
//
|
|
// NewV7 returns a Version 7 UUID based on the current time(Unix Epoch).
|
|
// Uses the randomness pool if it was enabled with EnableRandPool.
|
|
// On error, NewV7 returns Nil and an error
|
|
func NewV7() (UUID, error) {
|
|
uuid, err := NewRandom()
|
|
if err != nil {
|
|
return uuid, err
|
|
}
|
|
makeV7(uuid[:])
|
|
return uuid, nil
|
|
}
|
|
|
|
// NewV7FromReader returns a Version 7 UUID based on the current time(Unix Epoch).
|
|
// it use NewRandomFromReader fill random bits.
|
|
// On error, NewV7FromReader returns Nil and an error.
|
|
func NewV7FromReader(r io.Reader) (UUID, error) {
|
|
uuid, err := NewRandomFromReader(r)
|
|
if err != nil {
|
|
return uuid, err
|
|
}
|
|
|
|
makeV7(uuid[:])
|
|
return uuid, nil
|
|
}
|
|
|
|
// makeV7 fill 48 bits time (uuid[0] - uuid[5]), set version b0111 (uuid[6])
|
|
// uuid[8] already has the right version number (Variant is 10)
|
|
// see function NewV7 and NewV7FromReader
|
|
func makeV7(uuid []byte) {
|
|
/*
|
|
0 1 2 3
|
|
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| unix_ts_ms |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| unix_ts_ms | ver | rand_a |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
|var| rand_b |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
| rand_b |
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*/
|
|
_ = uuid[15] // bounds check
|
|
|
|
t := timeNow().UnixMilli()
|
|
|
|
uuid[0] = byte(t >> 40)
|
|
uuid[1] = byte(t >> 32)
|
|
uuid[2] = byte(t >> 24)
|
|
uuid[3] = byte(t >> 16)
|
|
uuid[4] = byte(t >> 8)
|
|
uuid[5] = byte(t)
|
|
|
|
uuid[6] = 0x70 | (uuid[6] & 0x0F)
|
|
// uuid[8] has already has right version
|
|
}
|