| // 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 ( |
| "encoding/binary" |
| ) |
| |
| // 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) { |
| 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) |
| |
| nodeMu.Lock() |
| if nodeID == zeroID { |
| setNodeInterface("") |
| } |
| copy(uuid[10:], nodeID[:]) |
| nodeMu.Unlock() |
| |
| return uuid, nil |
| } |