hash.go

Documentation: github.com/pborman/uuid

     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.
     4  
     5  package uuid
     6  
     7  import (
     8  	"crypto/md5"
     9  	"crypto/sha1"
    10  	"hash"
    11  )
    12  
    13  // Well known Name Space IDs and UUIDs
    14  var (
    15  	NameSpace_DNS  = Parse("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
    16  	NameSpace_URL  = Parse("6ba7b811-9dad-11d1-80b4-00c04fd430c8")
    17  	NameSpace_OID  = Parse("6ba7b812-9dad-11d1-80b4-00c04fd430c8")
    18  	NameSpace_X500 = Parse("6ba7b814-9dad-11d1-80b4-00c04fd430c8")
    19  	NIL            = Parse("00000000-0000-0000-0000-000000000000")
    20  )
    21  
    22  // NewHash returns a new UUID derived from the hash of space concatenated with
    23  // data generated by h.  The hash should be at least 16 byte in length.  The
    24  // first 16 bytes of the hash are used to form the UUID.  The version of the
    25  // UUID will be the lower 4 bits of version.  NewHash is used to implement
    26  // NewMD5 and NewSHA1.
    27  func NewHash(h hash.Hash, space UUID, data []byte, version int) UUID {
    28  	h.Reset()
    29  	h.Write(space)
    30  	h.Write([]byte(data))
    31  	s := h.Sum(nil)
    32  	uuid := make([]byte, 16)
    33  	copy(uuid, s)
    34  	uuid[6] = (uuid[6] & 0x0f) | uint8((version&0xf)<<4)
    35  	uuid[8] = (uuid[8] & 0x3f) | 0x80 // RFC 4122 variant
    36  	return uuid
    37  }
    38  
    39  // NewMD5 returns a new MD5 (Version 3) UUID based on the
    40  // supplied name space and data.
    41  //
    42  //  NewHash(md5.New(), space, data, 3)
    43  func NewMD5(space UUID, data []byte) UUID {
    44  	return NewHash(md5.New(), space, data, 3)
    45  }
    46  
    47  // NewSHA1 returns a new SHA1 (Version 5) UUID based on the
    48  // supplied name space and data.
    49  //
    50  //  NewHash(sha1.New(), space, data, 5)
    51  func NewSHA1(space UUID, data []byte) UUID {
    52  	return NewHash(sha1.New(), space, data, 5)
    53  }
    54
View as plain text