gtsocial-umbx

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version1.go (1257B)

      1 // Copyright 2016 Google Inc.  All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 package uuid
      6 
      7 import (
      8 	"encoding/binary"
      9 )
     10 
     11 // NewUUID returns a Version 1 UUID based on the current NodeID and clock
     12 // sequence, and the current time.  If the NodeID has not been set by SetNodeID
     13 // or SetNodeInterface then it will be set automatically.  If the NodeID cannot
     14 // be set NewUUID returns nil.  If clock sequence has not been set by
     15 // SetClockSequence then it will be set automatically.  If GetTime fails to
     16 // return the current NewUUID returns nil and an error.
     17 //
     18 // In most cases, New should be used.
     19 func NewUUID() (UUID, error) {
     20 	var uuid UUID
     21 	now, seq, err := GetTime()
     22 	if err != nil {
     23 		return uuid, err
     24 	}
     25 
     26 	timeLow := uint32(now & 0xffffffff)
     27 	timeMid := uint16((now >> 32) & 0xffff)
     28 	timeHi := uint16((now >> 48) & 0x0fff)
     29 	timeHi |= 0x1000 // Version 1
     30 
     31 	binary.BigEndian.PutUint32(uuid[0:], timeLow)
     32 	binary.BigEndian.PutUint16(uuid[4:], timeMid)
     33 	binary.BigEndian.PutUint16(uuid[6:], timeHi)
     34 	binary.BigEndian.PutUint16(uuid[8:], seq)
     35 
     36 	nodeMu.Lock()
     37 	if nodeID == zeroID {
     38 		setNodeInterface("")
     39 	}
     40 	copy(uuid[10:], nodeID[:])
     41 	nodeMu.Unlock()
     42 
     43 	return uuid, nil
     44 }