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2d3c2a9cc5
* Add NewV6WithTime * Refactor generateV6 * fix NewV6WithTime doc comment * fix: remove fmt.Println from test --------- Co-authored-by: nicumicle <20170987+nicumicleI@users.noreply.github.com>
84 lines
3.0 KiB
Go
84 lines
3.0 KiB
Go
// Copyright 2023 Google Inc. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package uuid
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import (
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"encoding/binary"
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"time"
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)
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// UUID version 6 is a field-compatible version of UUIDv1, reordered for improved DB locality.
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// It is expected that UUIDv6 will primarily be used in contexts where there are existing v1 UUIDs.
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// Systems that do not involve legacy UUIDv1 SHOULD consider using UUIDv7 instead.
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//
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// see https://datatracker.ietf.org/doc/html/rfc9562#uuidv6
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//
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// NewV6 returns a Version 6 UUID based on the current NodeID and clock
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// sequence, and the current time. If the NodeID has not been set by SetNodeID
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// or SetNodeInterface then it will be set automatically. If the NodeID cannot
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// be set NewV6 set NodeID is random bits automatically . If clock sequence has not been set by
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// SetClockSequence then it will be set automatically. If GetTime fails to
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// return the current NewV6 returns Nil and an error.
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func NewV6() (UUID, error) {
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now, seq, err := GetTime()
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if err != nil {
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return Nil, err
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}
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return generateV6(now, seq), nil
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}
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// NewV6WithTime returns a Version 6 UUID based on the current NodeID, clock
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// sequence, and a specified time. It is similar to the NewV6 function, but allows
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// you to specify the time. If time is passed as nil, then the current time is used.
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//
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// There is a limit on how many UUIDs can be generated for the same time, so if you
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// are generating multiple UUIDs, it is recommended to increment the time.
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// If getTime fails to return the current NewV6WithTime returns Nil and an error.
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func NewV6WithTime(customTime *time.Time) (UUID, error) {
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now, seq, err := getTime(customTime)
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if err != nil {
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return Nil, err
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}
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return generateV6(now, seq), nil
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}
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func generateV6(now Time, seq uint16) UUID {
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var uuid UUID
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/*
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0 1 2 3
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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
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| time_high |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| time_mid | time_low_and_version |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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|clk_seq_hi_res | clk_seq_low | node (0-1) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| node (2-5) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*/
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timeHigh := uint32((now >> 28) & 0xffffffff)
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timeMid := uint16((now >> 12) & 0xffff)
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timeLow := uint16(now & 0x0fff)
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timeLow |= 0x6000 // Version 6
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binary.BigEndian.PutUint32(uuid[0:], timeHigh)
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binary.BigEndian.PutUint16(uuid[4:], timeMid)
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binary.BigEndian.PutUint16(uuid[6:], timeLow)
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binary.BigEndian.PutUint16(uuid[8:], seq)
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nodeMu.Lock()
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if nodeID == zeroID {
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setNodeInterface("")
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}
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copy(uuid[10:], nodeID[:])
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nodeMu.Unlock()
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return uuid
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}
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