1 files changed, 353 insertions, 0 deletions
diff --git a/modules/uuid/uuid.go b/modules/uuid/uuid.go
new file mode 100644
index 00000000..5c5566f0
--- /dev/null
+++ b/modules/uuid/uuid.go
@@ -0,0 +1,353 @@
+// Copyright (C) 2013 by Maxim Bublis <b@codemonkey.ru>
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+// Package uuid provides implementation of Universally Unique Identifier (UUID).
+// Supported versions are 1, 3, 4 and 5 (as specified in RFC 4122) and
+// version 2 (as specified in DCE 1.1).
+package uuid
+
+import (
+	"bytes"
+	"crypto/md5"
+	"crypto/rand"
+	"crypto/sha1"
+	"encoding/binary"
+	"encoding/hex"
+	"fmt"
+	"hash"
+	"net"
+	"os"
+	"strings"
+	"sync"
+	"time"
+)
+
+// UUID layout variants.
+const (
+	VariantNCS = iota
+	VariantRFC4122
+	VariantMicrosoft
+	VariantFuture
+)
+
+// UUID DCE domains.
+const (
+	DomainPerson = iota
+	DomainGroup
+	DomainOrg
+)
+
+// Difference in 100-nanosecond intervals between
+// UUID epoch (October 15, 1582) and Unix epoch (January 1, 1970).
+const epochStart = 122192928000000000
+
+// UUID v1/v2 storage.
+var (
+	storageMutex  sync.Mutex
+	clockSequence uint16
+	lastTime      uint64
+	hardwareAddr  [6]byte
+	posixUID      = uint32(os.Getuid())
+	posixGID      = uint32(os.Getgid())
+)
+
+// Epoch calculation function
+var epochFunc func() uint64
+
+// Initialize storage
+func init() {
+	buf := make([]byte, 2)
+	rand.Read(buf)
+	clockSequence = binary.BigEndian.Uint16(buf)
+
+	// Initialize hardwareAddr randomly in case
+	// of real network interfaces absence
+	rand.Read(hardwareAddr[:])
+
+	// Set multicast bit as recommended in RFC 4122
+	hardwareAddr[0] |= 0x01
+
+	interfaces, err := net.Interfaces()
+	if err == nil {
+		for _, iface := range interfaces {
+			if len(iface.HardwareAddr) >= 6 {
+				copy(hardwareAddr[:], iface.HardwareAddr)
+				break
+			}
+		}
+	}
+	epochFunc = unixTimeFunc
+}
+
+// Returns difference in 100-nanosecond intervals between
+// UUID epoch (October 15, 1582) and current time.
+// This is default epoch calculation function.
+func unixTimeFunc() uint64 {
+	return epochStart + uint64(time.Now().UnixNano()/100)
+}
+
+// UUID representation compliant with specification
+// described in RFC 4122.
+type UUID [16]byte
+
+// Predefined namespace UUIDs.
+var (
+	NamespaceDNS, _  = FromString("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+	NamespaceURL, _  = FromString("6ba7b811-9dad-11d1-80b4-00c04fd430c8")
+	NamespaceOID, _  = FromString("6ba7b812-9dad-11d1-80b4-00c04fd430c8")
+	NamespaceX500, _ = FromString("6ba7b814-9dad-11d1-80b4-00c04fd430c8")
+)
+
+// And returns result of binary AND of two UUIDs.
+func And(u1 UUID, u2 UUID) UUID {
+	u := UUID{}
+	for i := 0; i < 16; i++ {
+		u[i] = u1[i] & u2[i]
+	}
+	return u
+}
+
+// Or returns result of binary OR of two UUIDs.
+func Or(u1 UUID, u2 UUID) UUID {
+	u := UUID{}
+	for i := 0; i < 16; i++ {
+		u[i] = u1[i] | u2[i]
+	}
+	return u
+}
+
+// Equal returns true if u1 and u2 equals, otherwise returns false.
+func Equal(u1 UUID, u2 UUID) bool {
+	return bytes.Equal(u1[:], u2[:])
+}
+
+// Version returns algorithm version used to generate UUID.
+func (u UUID) Version() uint {
+	return uint(u[6] >> 4)
+}
+
+// Variant returns UUID layout variant.
+func (u UUID) Variant() uint {
+	switch {
+	case (u[8] & 0x80) == 0x00:
+		return VariantNCS
+	case (u[8]&0xc0)|0x80 == 0x80:
+		return VariantRFC4122
+	case (u[8]&0xe0)|0xc0 == 0xc0:
+		return VariantMicrosoft
+	}
+	return VariantFuture
+}
+
+// Bytes returns bytes slice representation of UUID.
+func (u UUID) Bytes() []byte {
+	return u[:]
+}
+
+// Returns canonical string representation of UUID:
+// xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
+func (u UUID) String() string {
+	return fmt.Sprintf("%x-%x-%x-%x-%x",
+		u[:4], u[4:6], u[6:8], u[8:10], u[10:])
+}
+
+// SetVersion sets version bits.
+func (u *UUID) SetVersion(v byte) {
+	u[6] = (u[6] & 0x0f) | (v << 4)
+}
+
+// SetVariant sets variant bits as described in RFC 4122.
+func (u *UUID) SetVariant() {
+	u[8] = (u[8] & 0xbf) | 0x80
+}
+
+// MarshalText implements the encoding.TextMarshaler interface.
+// The encoding is the same as returned by String.
+func (u UUID) MarshalText() (text []byte, err error) {
+	text = []byte(u.String())
+	return
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+// UUID is expected in a form accepted by FromString.
+func (u *UUID) UnmarshalText(text []byte) error {
+	s := string(text)
+	u2, err := FromString(s)
+	if err != nil {
+		return err
+	}
+	*u = u2
+	return nil
+}
+
+// MarshalBinary implements the encoding.BinaryMarshaler interface.
+func (u UUID) MarshalBinary() (data []byte, err error) {
+	data = u.Bytes()
+	return
+}
+
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+func (u *UUID) UnmarshalBinary(data []byte) error {
+	u2, err := FromBytes(data)
+	if err != nil {
+		return err
+	}
+	*u = u2
+	return nil
+}
+
+// FromBytes returns UUID converted from raw byte slice input.
+// It will return error if the slice isn't 16 bytes long.
+func FromBytes(input []byte) (u UUID, err error) {
+	if len(input) != 16 {
+		err = fmt.Errorf("uuid: UUID must be exactly 16 bytes long, got %d bytes", len(input))
+		return
+	}
+
+	copy(u[:], input)
+
+	return
+}
+
+// FromString returns UUID parsed from string input.
+// Following formats are supported:
+// "6ba7b810-9dad-11d1-80b4-00c04fd430c8",
+// "{6ba7b810-9dad-11d1-80b4-00c04fd430c8}",
+// "urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8"
+func FromString(input string) (u UUID, err error) {
+	s := strings.Replace(input, "-", "", -1)
+
+	if len(s) == 41 && s[:9] == "urn:uuid:" {
+		s = s[9:]
+	} else if len(s) == 34 && s[0] == '{' && s[33] == '}' {
+		s = s[1:33]
+	}
+
+	if len(s) != 32 {
+		err = fmt.Errorf("uuid: invalid UUID string: %s", input)
+		return
+	}
+
+	b := []byte(s)
+	_, err = hex.Decode(u[:], b)
+
+	return
+}
+
+// Returns UUID v1/v2 storage state.
+// Returns epoch timestamp and clock sequence.
+func getStorage() (uint64, uint16) {
+	storageMutex.Lock()
+	defer storageMutex.Unlock()
+
+	timeNow := epochFunc()
+	// Clock changed backwards since last UUID generation.
+	// Should increase clock sequence.
+	if timeNow <= lastTime {
+		clockSequence++
+	}
+	lastTime = timeNow
+
+	return timeNow, clockSequence
+}
+
+// NewV1 returns UUID based on current timestamp and MAC address.
+func NewV1() UUID {
+	u := UUID{}
+
+	timeNow, clockSeq := getStorage()
+
+	binary.BigEndian.PutUint32(u[0:], uint32(timeNow))
+	binary.BigEndian.PutUint16(u[4:], uint16(timeNow>>32))
+	binary.BigEndian.PutUint16(u[6:], uint16(timeNow>>48))
+	binary.BigEndian.PutUint16(u[8:], clockSeq)
+
+	copy(u[10:], hardwareAddr[:])
+
+	u.SetVersion(1)
+	u.SetVariant()
+
+	return u
+}
+
+// NewV2 returns DCE Security UUID based on POSIX UID/GID.
+func NewV2(domain byte) UUID {
+	u := UUID{}
+
+	switch domain {
+	case DomainPerson:
+		binary.BigEndian.PutUint32(u[0:], posixUID)
+	case DomainGroup:
+		binary.BigEndian.PutUint32(u[0:], posixGID)
+	}
+
+	timeNow, clockSeq := getStorage()
+
+	binary.BigEndian.PutUint16(u[4:], uint16(timeNow>>32))
+	binary.BigEndian.PutUint16(u[6:], uint16(timeNow>>48))
+	binary.BigEndian.PutUint16(u[8:], clockSeq)
+	u[9] = domain
+
+	copy(u[10:], hardwareAddr[:])
+
+	u.SetVersion(2)
+	u.SetVariant()
+
+	return u
+}
+
+// NewV3 returns UUID based on MD5 hash of namespace UUID and name.
+func NewV3(ns UUID, name string) UUID {
+	u := newFromHash(md5.New(), ns, name)
+	u.SetVersion(3)
+	u.SetVariant()
+
+	return u
+}
+
+// NewV4 returns random generated UUID.
+func NewV4() UUID {
+	u := UUID{}
+	rand.Read(u[:])
+	u.SetVersion(4)
+	u.SetVariant()
+
+	return u
+}
+
+// NewV5 returns UUID based on SHA-1 hash of namespace UUID and name.
+func NewV5(ns UUID, name string) UUID {
+	u := newFromHash(sha1.New(), ns, name)
+	u.SetVersion(5)
+	u.SetVariant()
+
+	return u
+}
+
+// Returns UUID based on hashing of namespace UUID and name.
+func newFromHash(h hash.Hash, ns UUID, name string) UUID {
+	u := UUID{}
+	h.Write(ns[:])
+	h.Write([]byte(name))
+	copy(u[:], h.Sum(nil))
+
+	return u
+}