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// Copyright 2016 Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package uuid
import (
"crypto/md5"
"crypto/sha1"
"hash"
)
// Well known namespace IDs and UUIDs
var (
NameSpaceDNS = Must(Parse("6ba7b810-9dad-11d1-80b4-00c04fd430c8"))
NameSpaceURL = Must(Parse("6ba7b811-9dad-11d1-80b4-00c04fd430c8"))
NameSpaceOID = Must(Parse("6ba7b812-9dad-11d1-80b4-00c04fd430c8"))
NameSpaceX500 = Must(Parse("6ba7b814-9dad-11d1-80b4-00c04fd430c8"))
Nil UUID // empty UUID, all zeros
)
// NewHash returns a new UUID derived from the hash of space concatenated with
// data generated by h. The hash should be at least 16 byte in length. The
// first 16 bytes of the hash are used to form the UUID. The version of the
// UUID will be the lower 4 bits of version. NewHash is used to implement
// NewMD5 and NewSHA1.
func NewHash(h hash.Hash, space UUID, data []byte, version int) UUID {
h.Reset()
h.Write(space[:])
h.Write(data)
s := h.Sum(nil)
var uuid UUID
copy(uuid[:], s)
uuid[6] = (uuid[6] & 0x0f) | uint8((version&0xf)<<4)
uuid[8] = (uuid[8] & 0x3f) | 0x80 // RFC 4122 variant
return uuid
}
// NewMD5 returns a new MD5 (Version 3) UUID based on the
// supplied name space and data. It is the same as calling:
//
// NewHash(md5.New(), space, data, 3)
func NewMD5(space UUID, data []byte) UUID {
return NewHash(md5.New(), space, data, 3)
}
// NewSHA1 returns a new SHA1 (Version 5) UUID based on the
// supplied name space and data. It is the same as calling:
//
// NewHash(sha1.New(), space, data, 5)
func NewSHA1(space UUID, data []byte) UUID {
return NewHash(sha1.New(), space, data, 5)
}
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