blob: 199a1ac65403edc1438d27c9aa71c698e6efeda4 [file] [log] [blame]
// 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 (
// NewUUID returns a Version 1 UUID based on the current NodeID and clock
// sequence, and the current time. If the NodeID has not been set by SetNodeID
// or SetNodeInterface then it will be set automatically. If the NodeID cannot
// be set NewUUID returns nil. If clock sequence has not been set by
// SetClockSequence then it will be set automatically. If GetTime fails to
// return the current NewUUID returns nil and an error.
// In most cases, New should be used.
func NewUUID() (UUID, error) {
if nodeID == zeroID {
var uuid UUID
now, seq, err := GetTime()
if err != nil {
return uuid, err
timeLow := uint32(now & 0xffffffff)
timeMid := uint16((now >> 32) & 0xffff)
timeHi := uint16((now >> 48) & 0x0fff)
timeHi |= 0x1000 // Version 1
binary.BigEndian.PutUint32(uuid[0:], timeLow)
binary.BigEndian.PutUint16(uuid[4:], timeMid)
binary.BigEndian.PutUint16(uuid[6:], timeHi)
binary.BigEndian.PutUint16(uuid[8:], seq)
copy(uuid[10:], nodeID[:])
return uuid, nil