github.com/mymmsc/gox@v1.3.33/util/uuid/uuid.go (about)

     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  }