--- /dev/null
+// Copyright 2011 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 (
+ "bytes"
+ "crypto/rand"
+ "encoding/hex"
+ "fmt"
+ "io"
+ "strings"
+)
+
+// Array is a pass-by-value UUID that can be used as an effecient key in a map.
+type Array [16]byte
+
+// UUID converts uuid into a slice.
+func (uuid Array) UUID() UUID {
+ return uuid[:]
+}
+
+// String returns the string representation of uuid,
+// xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
+func (uuid Array) String() string {
+ return uuid.UUID().String()
+}
+
+// A UUID is a 128 bit (16 byte) Universal Unique IDentifier as defined in RFC
+// 4122.
+type UUID []byte
+
+// A Version represents a UUIDs version.
+type Version byte
+
+// A Variant represents a UUIDs variant.
+type Variant byte
+
+// Constants returned by Variant.
+const (
+ Invalid = Variant(iota) // Invalid UUID
+ RFC4122 // The variant specified in RFC4122
+ Reserved // Reserved, NCS backward compatibility.
+ Microsoft // Reserved, Microsoft Corporation backward compatibility.
+ Future // Reserved for future definition.
+)
+
+var rander = rand.Reader // random function
+
+// New returns a new random (version 4) UUID as a string. It is a convenience
+// function for NewRandom().String().
+func New() string {
+ return NewRandom().String()
+}
+
+// Parse decodes s into a UUID or returns nil. Both the UUID form of
+// xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx and
+// urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx are decoded.
+func Parse(s string) UUID {
+ if len(s) == 36+9 {
+ if strings.ToLower(s[:9]) != "urn:uuid:" {
+ return nil
+ }
+ s = s[9:]
+ } else if len(s) != 36 {
+ return nil
+ }
+ if s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-' {
+ return nil
+ }
+ var uuid [16]byte
+ for i, x := range [16]int{
+ 0, 2, 4, 6,
+ 9, 11,
+ 14, 16,
+ 19, 21,
+ 24, 26, 28, 30, 32, 34} {
+ if v, ok := xtob(s[x:]); !ok {
+ return nil
+ } else {
+ uuid[i] = v
+ }
+ }
+ return uuid[:]
+}
+
+// Equal returns true if uuid1 and uuid2 are equal.
+func Equal(uuid1, uuid2 UUID) bool {
+ return bytes.Equal(uuid1, uuid2)
+}
+
+// Array returns an array representation of uuid that can be used as a map key.
+// Array panics if uuid is not valid.
+func (uuid UUID) Array() Array {
+ if len(uuid) != 16 {
+ panic("invalid uuid")
+ }
+ var a Array
+ copy(a[:], uuid)
+ return a
+}
+
+// String returns the string form of uuid, xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+// , or "" if uuid is invalid.
+func (uuid UUID) String() string {
+ if len(uuid) != 16 {
+ return ""
+ }
+ var buf [36]byte
+ encodeHex(buf[:], uuid)
+ return string(buf[:])
+}
+
+// URN returns the RFC 2141 URN form of uuid,
+// urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, or "" if uuid is invalid.
+func (uuid UUID) URN() string {
+ if len(uuid) != 16 {
+ return ""
+ }
+ var buf [36 + 9]byte
+ copy(buf[:], "urn:uuid:")
+ encodeHex(buf[9:], uuid)
+ return string(buf[:])
+}
+
+func encodeHex(dst []byte, uuid UUID) {
+ hex.Encode(dst[:], uuid[:4])
+ dst[8] = '-'
+ hex.Encode(dst[9:13], uuid[4:6])
+ dst[13] = '-'
+ hex.Encode(dst[14:18], uuid[6:8])
+ dst[18] = '-'
+ hex.Encode(dst[19:23], uuid[8:10])
+ dst[23] = '-'
+ hex.Encode(dst[24:], uuid[10:])
+}
+
+// Variant returns the variant encoded in uuid. It returns Invalid if
+// uuid is invalid.
+func (uuid UUID) Variant() Variant {
+ if len(uuid) != 16 {
+ return Invalid
+ }
+ switch {
+ case (uuid[8] & 0xc0) == 0x80:
+ return RFC4122
+ case (uuid[8] & 0xe0) == 0xc0:
+ return Microsoft
+ case (uuid[8] & 0xe0) == 0xe0:
+ return Future
+ default:
+ return Reserved
+ }
+}
+
+// Version returns the version of uuid. It returns false if uuid is not
+// valid.
+func (uuid UUID) Version() (Version, bool) {
+ if len(uuid) != 16 {
+ return 0, false
+ }
+ return Version(uuid[6] >> 4), true
+}
+
+func (v Version) String() string {
+ if v > 15 {
+ return fmt.Sprintf("BAD_VERSION_%d", v)
+ }
+ return fmt.Sprintf("VERSION_%d", v)
+}
+
+func (v Variant) String() string {
+ switch v {
+ case RFC4122:
+ return "RFC4122"
+ case Reserved:
+ return "Reserved"
+ case Microsoft:
+ return "Microsoft"
+ case Future:
+ return "Future"
+ case Invalid:
+ return "Invalid"
+ }
+ return fmt.Sprintf("BadVariant%d", int(v))
+}
+
+// SetRand sets the random number generator to r, which implements io.Reader.
+// If r.Read returns an error when the package requests random data then
+// a panic will be issued.
+//
+// Calling SetRand with nil sets the random number generator to the default
+// generator.
+func SetRand(r io.Reader) {
+ if r == nil {
+ rander = rand.Reader
+ return
+ }
+ rander = r
+}
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