ducky/devices
2015-11-12
ducky/devices/vendor/code.google.com/p/go-uuid/uuid/uuid.go
Initial attempt. Create the basic types (Device, DeviceType, DeviceChange) that we'll be using in the service. Also, create our Storer interface, and the helper methods to store, retrieve, and update information in the datastore. Also, we're using Godep, so check in our Godeps folder and the vendor folder. Note that this only works on Go 1.5 and later, with the GO15VENDOREXPERIMENT environment variable set to 1.
1 // Copyright 2011 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.
5 package uuid
7 import (
8 "bytes"
9 "crypto/rand"
10 "fmt"
11 "io"
12 "strings"
13 )
15 // A UUID is a 128 bit (16 byte) Universal Unique IDentifier as defined in RFC
16 // 4122.
17 type UUID []byte
19 // A Version represents a UUIDs version.
20 type Version byte
22 // A Variant represents a UUIDs variant.
23 type Variant byte
25 // Constants returned by Variant.
26 const (
27 Invalid = Variant(iota) // Invalid UUID
28 RFC4122 // The variant specified in RFC4122
29 Reserved // Reserved, NCS backward compatibility.
30 Microsoft // Reserved, Microsoft Corporation backward compatibility.
31 Future // Reserved for future definition.
32 )
34 var rander = rand.Reader // random function
36 // New returns a new random (version 4) UUID as a string. It is a convenience
37 // function for NewRandom().String().
38 func New() string {
39 return NewRandom().String()
40 }
42 // Parse decodes s into a UUID or returns nil. Both the UUID form of
43 // xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx and
44 // urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx are decoded.
45 func Parse(s string) UUID {
46 if len(s) == 36+9 {
47 if strings.ToLower(s[:9]) != "urn:uuid:" {
48 return nil
49 }
50 s = s[9:]
51 } else if len(s) != 36 {
52 return nil
53 }
54 if s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-' {
55 return nil
56 }
57 uuid := make([]byte, 16)
58 for i, x := range []int{
59 0, 2, 4, 6,
60 9, 11,
61 14, 16,
62 19, 21,
63 24, 26, 28, 30, 32, 34} {
64 if v, ok := xtob(s[x:]); !ok {
65 return nil
66 } else {
67 uuid[i] = v
68 }
69 }
70 return uuid
71 }
73 // Equal returns true if uuid1 and uuid2 are equal.
74 func Equal(uuid1, uuid2 UUID) bool {
75 return bytes.Equal(uuid1, uuid2)
76 }
78 // String returns the string form of uuid, xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
79 // , or "" if uuid is invalid.
80 func (uuid UUID) String() string {
81 if uuid == nil || len(uuid) != 16 {
82 return ""
83 }
84 b := []byte(uuid)
85 return fmt.Sprintf("%08x-%04x-%04x-%04x-%012x",
86 b[:4], b[4:6], b[6:8], b[8:10], b[10:])
87 }
89 // URN returns the RFC 2141 URN form of uuid,
90 // urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, or "" if uuid is invalid.
91 func (uuid UUID) URN() string {
92 if uuid == nil || len(uuid) != 16 {
93 return ""
94 }
95 b := []byte(uuid)
96 return fmt.Sprintf("urn:uuid:%08x-%04x-%04x-%04x-%012x",
97 b[:4], b[4:6], b[6:8], b[8:10], b[10:])
98 }
100 // Variant returns the variant encoded in uuid. It returns Invalid if
101 // uuid is invalid.
102 func (uuid UUID) Variant() Variant {
103 if len(uuid) != 16 {
104 return Invalid
105 }
106 switch {
107 case (uuid[8] & 0xc0) == 0x80:
108 return RFC4122
109 case (uuid[8] & 0xe0) == 0xc0:
110 return Microsoft
111 case (uuid[8] & 0xe0) == 0xe0:
112 return Future
113 default:
114 return Reserved
115 }
116 panic("unreachable")
117 }
119 // Version returns the verison of uuid. It returns false if uuid is not
120 // valid.
121 func (uuid UUID) Version() (Version, bool) {
122 if len(uuid) != 16 {
123 return 0, false
124 }
125 return Version(uuid[6] >> 4), true
126 }
128 func (v Version) String() string {
129 if v > 15 {
130 return fmt.Sprintf("BAD_VERSION_%d", v)
131 }
132 return fmt.Sprintf("VERSION_%d", v)
133 }
135 func (v Variant) String() string {
136 switch v {
137 case RFC4122:
138 return "RFC4122"
139 case Reserved:
140 return "Reserved"
141 case Microsoft:
142 return "Microsoft"
143 case Future:
144 return "Future"
145 case Invalid:
146 return "Invalid"
147 }
148 return fmt.Sprintf("BadVariant%d", int(v))
149 }
151 // SetRand sets the random number generator to r, which implents io.Reader.
152 // If r.Read returns an error when the package requests random data then
153 // a panic will be issued.
154 //
155 // Calling SetRand with nil sets the random number generator to the default
156 // generator.
157 func SetRand(r io.Reader) {
158 if r == nil {
159 rander = rand.Reader
160 return
161 }
162 rander = r
163 }