bump(code.google.com/p/go-uuid/uuid): 3da0bf12e76e1048469b95fb20e29f1bc9799ae1

third_party/src/code.google.com/p/go-uuid/uuid/uuid.go

@@ -0,0 +1,163 @@
+// 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"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// 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
+	}
+	uuid := make([]byte, 16)
+	for i, x := range []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)
+}
+
+// String returns the string form of uuid, xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+// , or "" if uuid is invalid.
+func (uuid UUID) String() string {
+	if uuid == nil || len(uuid) != 16 {
+		return ""
+	}
+	b := []byte(uuid)
+	return fmt.Sprintf("%08x-%04x-%04x-%04x-%012x",
+		b[:4], b[4:6], b[6:8], b[8:10], b[10:])
+}
+
+// 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 uuid == nil || len(uuid) != 16 {
+		return ""
+	}
+	b := []byte(uuid)
+	return fmt.Sprintf("urn:uuid:%08x-%04x-%04x-%04x-%012x",
+		b[:4], b[4:6], b[6:8], b[8:10], b[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
+	}
+	panic("unreachable")
+}
+
+// Version returns the verison 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 implents 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
+}