vendor/github.com/satori/go.uuid/uuid.go

   1 // Copyright (C) 2013-2018 by Maxim Bublis <b@codemonkey.ru>
   2 //
   3 // Permission is hereby granted, free of charge, to any person obtaining
   4 // a copy of this software and associated documentation files (the
   5 // "Software"), to deal in the Software without restriction, including
   6 // without limitation the rights to use, copy, modify, merge, publish,
   7 // distribute, sublicense, and/or sell copies of the Software, and to
   8 // permit persons to whom the Software is furnished to do so, subject to
   9 // the following conditions:
  10 //
  11 // The above copyright notice and this permission notice shall be
  12 // included in all copies or substantial portions of the Software.
  13 //
  14 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  15 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  16 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  17 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  18 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  19 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  20 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  21
  22 // Package uuid provides implementation of Universally Unique Identifier (UUID).
  23 // Supported versions are 1, 3, 4 and 5 (as specified in RFC 4122) and
  24 // version 2 (as specified in DCE 1.1).
  25 package uuid
  26
  27 import (
  28         "bytes"
  29         "encoding/hex"
  30 )
  31
  32 // Size of a UUID in bytes.
  33 const Size = 16
  34
  35 // UUID representation compliant with specification
  36 // described in RFC 4122.
  37 type UUID [Size]byte
  38
  39 // UUID versions
  40 const (
  41         _ byte = iota
  42         V1
  43         V2
  44         V3
  45         V4
  46         V5
  47 )
  48
  49 // UUID layout variants.
  50 const (
  51         VariantNCS byte = iota
  52         VariantRFC4122
  53         VariantMicrosoft
  54         VariantFuture
  55 )
  56
  57 // UUID DCE domains.
  58 const (
  59         DomainPerson = iota
  60         DomainGroup
  61         DomainOrg
  62 )
  63
  64 // String parse helpers.
  65 var (
  66         urnPrefix  = []byte("urn:uuid:")
  67         byteGroups = []int{8, 4, 4, 4, 12}
  68 )
  69
  70 // Nil is special form of UUID that is specified to have all
  71 // 128 bits set to zero.
  72 var Nil = UUID{}
  73
  74 // Predefined namespace UUIDs.
  75 var (
  76         NamespaceDNS  = Must(FromString("6ba7b810-9dad-11d1-80b4-00c04fd430c8"))
  77         NamespaceURL  = Must(FromString("6ba7b811-9dad-11d1-80b4-00c04fd430c8"))
  78         NamespaceOID  = Must(FromString("6ba7b812-9dad-11d1-80b4-00c04fd430c8"))
  79         NamespaceX500 = Must(FromString("6ba7b814-9dad-11d1-80b4-00c04fd430c8"))
  80 )
  81
  82 // Equal returns true if u1 and u2 equals, otherwise returns false.
  83 func Equal(u1 UUID, u2 UUID) bool {
  84         return bytes.Equal(u1[:], u2[:])
  85 }
  86
  87 // Version returns algorithm version used to generate UUID.
  88 func (u UUID) Version() byte {
  89         return u[6] >> 4
  90 }
  91
  92 // Variant returns UUID layout variant.
  93 func (u UUID) Variant() byte {
  94         switch {
  95         case (u[8] >> 7) == 0x00:
  96                 return VariantNCS
  97         case (u[8] >> 6) == 0x02:
  98                 return VariantRFC4122
  99         case (u[8] >> 5) == 0x06:
 100                 return VariantMicrosoft
 101         case (u[8] >> 5) == 0x07:
 102                 fallthrough
 103         default:
 104                 return VariantFuture
 105         }
 106 }
 107
 108 // Bytes returns bytes slice representation of UUID.
 109 func (u UUID) Bytes() []byte {
 110         return u[:]
 111 }
 112
 113 // Returns canonical string representation of UUID:
 114 // xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
 115 func (u UUID) String() string {
 116         buf := make([]byte, 36)
 117
 118         hex.Encode(buf[0:8], u[0:4])
 119         buf[8] = '-'
 120         hex.Encode(buf[9:13], u[4:6])
 121         buf[13] = '-'
 122         hex.Encode(buf[14:18], u[6:8])
 123         buf[18] = '-'
 124         hex.Encode(buf[19:23], u[8:10])
 125         buf[23] = '-'
 126         hex.Encode(buf[24:], u[10:])
 127
 128         return string(buf)
 129 }
 130
 131 // SetVersion sets version bits.
 132 func (u *UUID) SetVersion(v byte) {
 133         u[6] = (u[6] & 0x0f) | (v << 4)
 134 }
 135
 136 // SetVariant sets variant bits.
 137 func (u *UUID) SetVariant(v byte) {
 138         switch v {
 139         case VariantNCS:
 140                 u[8] = (u[8]&(0xff>>1) | (0x00 << 7))
 141         case VariantRFC4122:
 142                 u[8] = (u[8]&(0xff>>2) | (0x02 << 6))
 143         case VariantMicrosoft:
 144                 u[8] = (u[8]&(0xff>>3) | (0x06 << 5))
 145         case VariantFuture:
 146                 fallthrough
 147         default:
 148                 u[8] = (u[8]&(0xff>>3) | (0x07 << 5))
 149         }
 150 }
 151
 152 // Must is a helper that wraps a call to a function returning (UUID, error)
 153 // and panics if the error is non-nil. It is intended for use in variable
 154 // initializations such as
 155 //      var packageUUID = uuid.Must(uuid.FromString("123e4567-e89b-12d3-a456-426655440000"));
 156 func Must(u UUID, err error) UUID {
 157         if err != nil {
 158                 panic(err)
 159         }
 160         return u
 161 }