42 lines
1.1 KiB
Go
42 lines
1.1 KiB
Go
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// Copyright 2011 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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)
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// NewUUID returns a Version 1 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 NewUUID returns nil. 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 NewUUID returns nil.
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func NewUUID() UUID {
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if nodeID == nil {
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SetNodeInterface("")
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}
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now, err := GetTime()
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if err != nil {
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return nil
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}
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uuid := make([]byte, 16)
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time_low := uint32(now & 0xffffffff)
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time_mid := uint16((now >> 32) & 0xffff)
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time_hi := uint16((now >> 48) & 0x0fff)
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time_hi |= 0x1000 // Version 1
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binary.BigEndian.PutUint32(uuid[0:], time_low)
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binary.BigEndian.PutUint16(uuid[4:], time_mid)
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binary.BigEndian.PutUint16(uuid[6:], time_hi)
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binary.BigEndian.PutUint16(uuid[8:], clock_seq)
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copy(uuid[10:], nodeID)
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return uuid
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}
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