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 "crypto/md5"
9 "crypto/sha1"
10 "hash"
11 )
12 13 // Well known namespace IDs and UUIDs
14 var (
15 NameSpaceDNS = Must(Parse("6ba7b810-9dad-11d1-80b4-00c04fd430c8"))
16 NameSpaceURL = Must(Parse("6ba7b811-9dad-11d1-80b4-00c04fd430c8"))
17 NameSpaceOID = Must(Parse("6ba7b812-9dad-11d1-80b4-00c04fd430c8"))
18 NameSpaceX500 = Must(Parse("6ba7b814-9dad-11d1-80b4-00c04fd430c8"))
19 Nil UUID // empty UUID, all zeros
20 21 // The Max UUID is special form of UUID that is specified to have all 128 bits set to 1.
22 Max = UUID{
23 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
24 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
25 }
26 )
27 28 // NewHash returns a new UUID derived from the hash of space concatenated with
29 // data generated by h. The hash should be at least 16 byte in length. The
30 // first 16 bytes of the hash are used to form the UUID. The version of the
31 // UUID will be the lower 4 bits of version. NewHash is used to implement
32 // NewMD5 and NewSHA1.
33 func NewHash(h hash.Hash, space UUID, data []byte, version int) UUID {
34 h.Reset()
35 h.Write(space[:]) //nolint:errcheck
36 h.Write(data) //nolint:errcheck
37 s := h.Sum(nil)
38 var uuid UUID
39 copy(uuid[:], s)
40 uuid[6] = (uuid[6] & 0x0f) | uint8((version&0xf)<<4)
41 uuid[8] = (uuid[8] & 0x3f) | 0x80 // RFC 4122 variant
42 return uuid
43 }
44 45 // NewMD5 returns a new MD5 (Version 3) UUID based on the
46 // supplied name space and data. It is the same as calling:
47 //
48 // NewHash(md5.New(), space, data, 3)
49 func NewMD5(space UUID, data []byte) UUID {
50 return NewHash(md5.New(), space, data, 3)
51 }
52 53 // NewSHA1 returns a new SHA1 (Version 5) UUID based on the
54 // supplied name space and data. It is the same as calling:
55 //
56 // NewHash(sha1.New(), space, data, 5)
57 func NewSHA1(space UUID, data []byte) UUID {
58 return NewHash(sha1.New(), space, data, 5)
59 }
60