first commit

.travis.yml

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+language: go
+sudo: false
+go:
+    - 1.6.x
+    - 1.7.x
+    - 1.8.x
+    - 1.9.x
+    - 1.10.x
+    - 1.11.x
+    - tip
+matrix:
+    allow_failures:
+        - go: tip
+    fast_finish: true
+before_install:
+    - go get github.com/mattn/goveralls
+    - go get golang.org/x/tools/cmd/cover
+script:
+    - $HOME/gopath/bin/goveralls -service=travis-ci
+notifications:
+    email: false

LICENSE

@@ -0,0 +1,20 @@
+Copyright (C) 2013-2018 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.

README.md

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+# UUID package for Go language
+
+[![Build Status](https://travis-ci.org/satori/go.uuid.svg?branch=master)](https://travis-ci.org/satori/go.uuid)
+[![Coverage Status](https://coveralls.io/repos/github/satori/go.uuid/badge.svg?branch=master)](https://coveralls.io/github/satori/go.uuid)
+[![GoDoc](http://godoc.org/github.com/satori/go.uuid?status.svg)](http://godoc.org/github.com/satori/go.uuid)
+
+This package provides pure Go implementation of Universally Unique Identifier (UUID). Supported both creation and parsing of UUIDs.
+
+With 100% test coverage and benchmarks out of box.
+
+Supported versions:
+* Version 1, based on timestamp and MAC address (RFC 4122)
+* Version 2, based on timestamp, MAC address and POSIX UID/GID (DCE 1.1)
+* Version 3, based on MD5 hashing (RFC 4122)
+* Version 4, based on random numbers (RFC 4122)
+* Version 5, based on SHA-1 hashing (RFC 4122)
+
+## Installation
+
+Use the `go` command:
+
+	$ go get github.com/satori/go.uuid
+
+## Requirements
+
+UUID package tested against Go >= 1.6.
+
+## Example
+
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/satori/go.uuid"
+)
+
+func main() {
+	// Creating UUID Version 4
+	// panic on error
+	u1 := uuid.Must(uuid.NewV4())
+	fmt.Printf("UUIDv4: %s\n", u1)
+
+	// or error handling
+	u2, err := uuid.NewV4()
+	if err != nil {
+		fmt.Printf("Something went wrong: %s", err)
+		return
+	}
+	fmt.Printf("UUIDv4: %s\n", u2)
+
+	// Parsing UUID from string input
+	u2, err := uuid.FromString("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+	if err != nil {
+		fmt.Printf("Something went wrong: %s", err)
+		return
+	}
+	fmt.Printf("Successfully parsed: %s", u2)
+}
+```
+
+## Documentation
+
+[Documentation](http://godoc.org/github.com/satori/go.uuid) is hosted at GoDoc project.
+
+## Links
+* [RFC 4122](http://tools.ietf.org/html/rfc4122)
+* [DCE 1.1: Authentication and Security Services](http://pubs.opengroup.org/onlinepubs/9696989899/chap5.htm#tagcjh_08_02_01_01)
+
+## Copyright
+
+Copyright (C) 2013-2018 by Maxim Bublis <b@codemonkey.ru>.
+
+UUID package released under MIT License.
+See [LICENSE](https://github.com/satori/go.uuid/blob/master/LICENSE) for details.

codec.go

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+// Copyright (C) 2013-2018 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
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+)
+
+// 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) {
+	err = u.UnmarshalBinary(input)
+	return
+}
+
+// FromBytesOrNil returns UUID converted from raw byte slice input.
+// Same behavior as FromBytes, but returns a Nil UUID on error.
+func FromBytesOrNil(input []byte) UUID {
+	uuid, err := FromBytes(input)
+	if err != nil {
+		return Nil
+	}
+	return uuid
+}
+
+// FromString returns UUID parsed from string input.
+// Input is expected in a form accepted by UnmarshalText.
+func FromString(input string) (u UUID, err error) {
+	err = u.UnmarshalText([]byte(input))
+	return
+}
+
+// FromStringOrNil returns UUID parsed from string input.
+// Same behavior as FromString, but returns a Nil UUID on error.
+func FromStringOrNil(input string) UUID {
+	uuid, err := FromString(input)
+	if err != nil {
+		return Nil
+	}
+	return uuid
+}
+
+// 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.
+// Following formats are supported:
+//   "6ba7b810-9dad-11d1-80b4-00c04fd430c8",
+//   "{6ba7b810-9dad-11d1-80b4-00c04fd430c8}",
+//   "urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8"
+//   "6ba7b8109dad11d180b400c04fd430c8"
+// ABNF for supported UUID text representation follows:
+//   uuid := canonical | hashlike | braced | urn
+//   plain := canonical | hashlike
+//   canonical := 4hexoct '-' 2hexoct '-' 2hexoct '-' 6hexoct
+//   hashlike := 12hexoct
+//   braced := '{' plain '}'
+//   urn := URN ':' UUID-NID ':' plain
+//   URN := 'urn'
+//   UUID-NID := 'uuid'
+//   12hexoct := 6hexoct 6hexoct
+//   6hexoct := 4hexoct 2hexoct
+//   4hexoct := 2hexoct 2hexoct
+//   2hexoct := hexoct hexoct
+//   hexoct := hexdig hexdig
+//   hexdig := '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' |
+//             'a' | 'b' | 'c' | 'd' | 'e' | 'f' |
+//             'A' | 'B' | 'C' | 'D' | 'E' | 'F'
+func (u *UUID) UnmarshalText(text []byte) (err error) {
+	switch len(text) {
+	case 32:
+		return u.decodeHashLike(text)
+	case 36:
+		return u.decodeCanonical(text)
+	case 38:
+		return u.decodeBraced(text)
+	case 41:
+		fallthrough
+	case 45:
+		return u.decodeURN(text)
+	default:
+		return fmt.Errorf("uuid: incorrect UUID length: %s", text)
+	}
+}
+
+// decodeCanonical decodes UUID string in format
+// "6ba7b810-9dad-11d1-80b4-00c04fd430c8".
+func (u *UUID) decodeCanonical(t []byte) (err error) {
+	if t[8] != '-' || t[13] != '-' || t[18] != '-' || t[23] != '-' {
+		return fmt.Errorf("uuid: incorrect UUID format %s", t)
+	}
+
+	src := t[:]
+	dst := u[:]
+
+	for i, byteGroup := range byteGroups {
+		if i > 0 {
+			src = src[1:] // skip dash
+		}
+		_, err = hex.Decode(dst[:byteGroup/2], src[:byteGroup])
+		if err != nil {
+			return
+		}
+		src = src[byteGroup:]
+		dst = dst[byteGroup/2:]
+	}
+
+	return
+}
+
+// decodeHashLike decodes UUID string in format
+// "6ba7b8109dad11d180b400c04fd430c8".
+func (u *UUID) decodeHashLike(t []byte) (err error) {
+	src := t[:]
+	dst := u[:]
+
+	if _, err = hex.Decode(dst, src); err != nil {
+		return err
+	}
+	return
+}
+
+// decodeBraced decodes UUID string in format
+// "{6ba7b810-9dad-11d1-80b4-00c04fd430c8}" or in format
+// "{6ba7b8109dad11d180b400c04fd430c8}".
+func (u *UUID) decodeBraced(t []byte) (err error) {
+	l := len(t)
+
+	if t[0] != '{' || t[l-1] != '}' {
+		return fmt.Errorf("uuid: incorrect UUID format %s", t)
+	}
+
+	return u.decodePlain(t[1 : l-1])
+}
+
+// decodeURN decodes UUID string in format
+// "urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8" or in format
+// "urn:uuid:6ba7b8109dad11d180b400c04fd430c8".
+func (u *UUID) decodeURN(t []byte) (err error) {
+	total := len(t)
+
+	urn_uuid_prefix := t[:9]
+
+	if !bytes.Equal(urn_uuid_prefix, urnPrefix) {
+		return fmt.Errorf("uuid: incorrect UUID format: %s", t)
+	}
+
+	return u.decodePlain(t[9:total])
+}
+
+// decodePlain decodes UUID string in canonical format
+// "6ba7b810-9dad-11d1-80b4-00c04fd430c8" or in hash-like format
+// "6ba7b8109dad11d180b400c04fd430c8".
+func (u *UUID) decodePlain(t []byte) (err error) {
+	switch len(t) {
+	case 32:
+		return u.decodeHashLike(t)
+	case 36:
+		return u.decodeCanonical(t)
+	default:
+		return fmt.Errorf("uuid: incorrrect UUID length: %s", t)
+	}
+}
+
+// MarshalBinary implements the encoding.BinaryMarshaler interface.
+func (u UUID) MarshalBinary() (data []byte, err error) {
+	data = u.Bytes()
+	return
+}
+
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+// It will return error if the slice isn't 16 bytes long.
+func (u *UUID) UnmarshalBinary(data []byte) (err error) {
+	if len(data) != Size {
+		err = fmt.Errorf("uuid: UUID must be exactly 16 bytes long, got %d bytes", len(data))
+		return
+	}
+	copy(u[:], data)
+
+	return
+}

codec_test.go

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+// Copyright (C) 2013-2018 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
+
+import (
+	"bytes"
+
+	. "gopkg.in/check.v1"
+)
+
+type codecTestSuite struct{}
+
+var _ = Suite(&codecTestSuite{})
+
+func (s *codecTestSuite) TestFromBytes(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	b1 := []byte{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+
+	u1, err := FromBytes(b1)
+	c.Assert(err, IsNil)
+	c.Assert(u1, Equals, u)
+
+	b2 := []byte{}
+	_, err = FromBytes(b2)
+	c.Assert(err, NotNil)
+}
+
+func (s *codecTestSuite) BenchmarkFromBytes(c *C) {
+	bytes := []byte{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	for i := 0; i < c.N; i++ {
+		FromBytes(bytes)
+	}
+}
+
+func (s *codecTestSuite) TestMarshalBinary(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	b1 := []byte{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+
+	b2, err := u.MarshalBinary()
+	c.Assert(err, IsNil)
+	c.Assert(bytes.Equal(b1, b2), Equals, true)
+}
+
+func (s *codecTestSuite) BenchmarkMarshalBinary(c *C) {
+	u, err := NewV4()
+	c.Assert(err, IsNil)
+	for i := 0; i < c.N; i++ {
+		u.MarshalBinary()
+	}
+}
+
+func (s *codecTestSuite) TestUnmarshalBinary(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	b1 := []byte{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+
+	u1 := UUID{}
+	err := u1.UnmarshalBinary(b1)
+	c.Assert(err, IsNil)
+	c.Assert(u1, Equals, u)
+
+	b2 := []byte{}
+	u2 := UUID{}
+	err = u2.UnmarshalBinary(b2)
+	c.Assert(err, NotNil)
+}
+
+func (s *codecTestSuite) TestFromString(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+
+	s1 := "6ba7b810-9dad-11d1-80b4-00c04fd430c8"
+	s2 := "{6ba7b810-9dad-11d1-80b4-00c04fd430c8}"
+	s3 := "urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8"
+	s4 := "6ba7b8109dad11d180b400c04fd430c8"
+	s5 := "urn:uuid:6ba7b8109dad11d180b400c04fd430c8"
+
+	_, err := FromString("")
+	c.Assert(err, NotNil)
+
+	u1, err := FromString(s1)
+	c.Assert(err, IsNil)
+	c.Assert(u1, Equals, u)
+
+	u2, err := FromString(s2)
+	c.Assert(err, IsNil)
+	c.Assert(u2, Equals, u)
+
+	u3, err := FromString(s3)
+	c.Assert(err, IsNil)
+	c.Assert(u3, Equals, u)
+
+	u4, err := FromString(s4)
+	c.Assert(err, IsNil)
+	c.Assert(u4, Equals, u)
+
+	u5, err := FromString(s5)
+	c.Assert(err, IsNil)
+	c.Assert(u5, Equals, u)
+}
+
+func (s *codecTestSuite) BenchmarkFromString(c *C) {
+	str := "6ba7b810-9dad-11d1-80b4-00c04fd430c8"
+	for i := 0; i < c.N; i++ {
+		FromString(str)
+	}
+}
+
+func (s *codecTestSuite) BenchmarkFromStringUrn(c *C) {
+	str := "urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8"
+	for i := 0; i < c.N; i++ {
+		FromString(str)
+	}
+}
+
+func (s *codecTestSuite) BenchmarkFromStringWithBrackets(c *C) {
+	str := "{6ba7b810-9dad-11d1-80b4-00c04fd430c8}"
+	for i := 0; i < c.N; i++ {
+		FromString(str)
+	}
+}
+
+func (s *codecTestSuite) TestFromStringShort(c *C) {
+	// Invalid 35-character UUID string
+	s1 := "6ba7b810-9dad-11d1-80b4-00c04fd430c"
+
+	for i := len(s1); i >= 0; i-- {
+		_, err := FromString(s1[:i])
+		c.Assert(err, NotNil)
+	}
+}
+
+func (s *codecTestSuite) TestFromStringLong(c *C) {
+	// Invalid 37+ character UUID string
+	strings := []string{
+		"6ba7b810-9dad-11d1-80b4-00c04fd430c8=",
+		"6ba7b810-9dad-11d1-80b4-00c04fd430c8}",
+		"{6ba7b810-9dad-11d1-80b4-00c04fd430c8}f",
+		"6ba7b810-9dad-11d1-80b4-00c04fd430c800c04fd430c8",
+	}
+
+	for _, str := range strings {
+		_, err := FromString(str)
+		c.Assert(err, NotNil)
+	}
+}
+
+func (s *codecTestSuite) TestFromStringInvalid(c *C) {
+	// Invalid UUID string formats
+	strings := []string{
+		"6ba7b8109dad11d180b400c04fd430c86ba7b8109dad11d180b400c04fd430c8",
+		"urn:uuid:{6ba7b810-9dad-11d1-80b4-00c04fd430c8}",
+		"uuid:urn:6ba7b810-9dad-11d1-80b4-00c04fd430c8",
+		"uuid:urn:6ba7b8109dad11d180b400c04fd430c8",
+		"6ba7b8109-dad-11d1-80b4-00c04fd430c8",
+		"6ba7b810-9dad1-1d1-80b4-00c04fd430c8",
+		"6ba7b810-9dad-11d18-0b4-00c04fd430c8",
+		"6ba7b810-9dad-11d1-80b40-0c04fd430c8",
+		"6ba7b810+9dad+11d1+80b4+00c04fd430c8",
+		"(6ba7b810-9dad-11d1-80b4-00c04fd430c8}",
+		"{6ba7b810-9dad-11d1-80b4-00c04fd430c8>",
+		"zba7b810-9dad-11d1-80b4-00c04fd430c8",
+		"6ba7b810-9dad11d180b400c04fd430c8",
+		"6ba7b8109dad-11d180b400c04fd430c8",
+		"6ba7b8109dad11d1-80b400c04fd430c8",
+		"6ba7b8109dad11d180b4-00c04fd430c8",
+	}
+
+	for _, str := range strings {
+		_, err := FromString(str)
+		c.Assert(err, NotNil)
+	}
+}
+
+func (s *codecTestSuite) TestFromStringOrNil(c *C) {
+	u := FromStringOrNil("")
+	c.Assert(u, Equals, Nil)
+}
+
+func (s *codecTestSuite) TestFromBytesOrNil(c *C) {
+	b := []byte{}
+	u := FromBytesOrNil(b)
+	c.Assert(u, Equals, Nil)
+}
+
+func (s *codecTestSuite) TestMarshalText(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	b1 := []byte("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+
+	b2, err := u.MarshalText()
+	c.Assert(err, IsNil)
+	c.Assert(bytes.Equal(b1, b2), Equals, true)
+}
+
+func (s *codecTestSuite) BenchmarkMarshalText(c *C) {
+	u, err := NewV4()
+	c.Assert(err, IsNil)
+	for i := 0; i < c.N; i++ {
+		u.MarshalText()
+	}
+}
+
+func (s *codecTestSuite) TestUnmarshalText(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	b1 := []byte("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+
+	u1 := UUID{}
+	err := u1.UnmarshalText(b1)
+	c.Assert(err, IsNil)
+	c.Assert(u1, Equals, u)
+
+	b2 := []byte("")
+	u2 := UUID{}
+	err = u2.UnmarshalText(b2)
+	c.Assert(err, NotNil)
+}
+
+func (s *codecTestSuite) BenchmarkUnmarshalText(c *C) {
+	bytes := []byte("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+	u := UUID{}
+	for i := 0; i < c.N; i++ {
+		u.UnmarshalText(bytes)
+	}
+}
+
+var sink string
+
+func (s *codecTestSuite) BenchmarkMarshalToString(c *C) {
+	u, err := NewV4()
+	c.Assert(err, IsNil)
+	for i := 0; i < c.N; i++ {
+		sink = u.String()
+	}
+}

generator.go

@@ -0,0 +1,265 @@
+// Copyright (C) 2013-2018 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
+
+import (
+	"crypto/md5"
+	"crypto/rand"
+	"crypto/sha1"
+	"encoding/binary"
+	"fmt"
+	"hash"
+	"io"
+	"net"
+	"os"
+	"sync"
+	"time"
+)
+
+// Difference in 100-nanosecond intervals between
+// UUID epoch (October 15, 1582) and Unix epoch (January 1, 1970).
+const epochStart = 122192928000000000
+
+type epochFunc func() time.Time
+type hwAddrFunc func() (net.HardwareAddr, error)
+
+var (
+	global = newRFC4122Generator()
+
+	posixUID = uint32(os.Getuid())
+	posixGID = uint32(os.Getgid())
+)
+
+// NewV1 returns UUID based on current timestamp and MAC address.
+func NewV1() (UUID, error) {
+	return global.NewV1()
+}
+
+// NewV2 returns DCE Security UUID based on POSIX UID/GID.
+func NewV2(domain byte) (UUID, error) {
+	return global.NewV2(domain)
+}
+
+// NewV3 returns UUID based on MD5 hash of namespace UUID and name.
+func NewV3(ns UUID, name string) UUID {
+	return global.NewV3(ns, name)
+}
+
+// NewV4 returns random generated UUID.
+func NewV4() (UUID, error) {
+	return global.NewV4()
+}
+
+// NewV5 returns UUID based on SHA-1 hash of namespace UUID and name.
+func NewV5(ns UUID, name string) UUID {
+	return global.NewV5(ns, name)
+}
+
+// Generator provides interface for generating UUIDs.
+type Generator interface {
+	NewV1() (UUID, error)
+	NewV2(domain byte) (UUID, error)
+	NewV3(ns UUID, name string) UUID
+	NewV4() (UUID, error)
+	NewV5(ns UUID, name string) UUID
+}
+
+// Default generator implementation.
+type rfc4122Generator struct {
+	clockSequenceOnce sync.Once
+	hardwareAddrOnce  sync.Once
+	storageMutex      sync.Mutex
+
+	rand io.Reader
+
+	epochFunc     epochFunc
+	hwAddrFunc    hwAddrFunc
+	lastTime      uint64
+	clockSequence uint16
+	hardwareAddr  [6]byte
+}
+
+func newRFC4122Generator() Generator {
+	return &rfc4122Generator{
+		epochFunc:  time.Now,
+		hwAddrFunc: defaultHWAddrFunc,
+		rand:       rand.Reader,
+	}
+}
+
+// NewV1 returns UUID based on current timestamp and MAC address.
+func (g *rfc4122Generator) NewV1() (UUID, error) {
+	u := UUID{}
+
+	timeNow, clockSeq, err := g.getClockSequence()
+	if err != nil {
+		return Nil, err
+	}
+	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)
+
+	hardwareAddr, err := g.getHardwareAddr()
+	if err != nil {
+		return Nil, err
+	}
+	copy(u[10:], hardwareAddr)
+
+	u.SetVersion(V1)
+	u.SetVariant(VariantRFC4122)
+
+	return u, nil
+}
+
+// NewV2 returns DCE Security UUID based on POSIX UID/GID.
+func (g *rfc4122Generator) NewV2(domain byte) (UUID, error) {
+	u, err := g.NewV1()
+	if err != nil {
+		return Nil, err
+	}
+
+	switch domain {
+	case DomainPerson:
+		binary.BigEndian.PutUint32(u[:], posixUID)
+	case DomainGroup:
+		binary.BigEndian.PutUint32(u[:], posixGID)
+	}
+
+	u[9] = domain
+
+	u.SetVersion(V2)
+	u.SetVariant(VariantRFC4122)
+
+	return u, nil
+}
+
+// NewV3 returns UUID based on MD5 hash of namespace UUID and name.
+func (g *rfc4122Generator) NewV3(ns UUID, name string) UUID {
+	u := newFromHash(md5.New(), ns, name)
+	u.SetVersion(V3)
+	u.SetVariant(VariantRFC4122)
+
+	return u
+}
+
+// NewV4 returns random generated UUID.
+func (g *rfc4122Generator) NewV4() (UUID, error) {
+	u := UUID{}
+	if _, err := io.ReadFull(g.rand, u[:]); err != nil {
+		return Nil, err
+	}
+	u.SetVersion(V4)
+	u.SetVariant(VariantRFC4122)
+
+	return u, nil
+}
+
+// NewV5 returns UUID based on SHA-1 hash of namespace UUID and name.
+func (g *rfc4122Generator) NewV5(ns UUID, name string) UUID {
+	u := newFromHash(sha1.New(), ns, name)
+	u.SetVersion(V5)
+	u.SetVariant(VariantRFC4122)
+
+	return u
+}
+
+// Returns epoch and clock sequence.
+func (g *rfc4122Generator) getClockSequence() (uint64, uint16, error) {
+	var err error
+	g.clockSequenceOnce.Do(func() {
+		buf := make([]byte, 2)
+		if _, err = io.ReadFull(g.rand, buf); err != nil {
+			return
+		}
+		g.clockSequence = binary.BigEndian.Uint16(buf)
+	})
+	if err != nil {
+		return 0, 0, err
+	}
+
+	g.storageMutex.Lock()
+	defer g.storageMutex.Unlock()
+
+	timeNow := g.getEpoch()
+	// Clock didn't change since last UUID generation.
+	// Should increase clock sequence.
+	if timeNow <= g.lastTime {
+		g.clockSequence++
+	}
+	g.lastTime = timeNow
+
+	return timeNow, g.clockSequence, nil
+}
+
+// Returns hardware address.
+func (g *rfc4122Generator) getHardwareAddr() ([]byte, error) {
+	var err error
+	g.hardwareAddrOnce.Do(func() {
+		if hwAddr, err := g.hwAddrFunc(); err == nil {
+			copy(g.hardwareAddr[:], hwAddr)
+			return
+		}
+
+		// Initialize hardwareAddr randomly in case
+		// of real network interfaces absence.
+		if _, err = io.ReadFull(g.rand, g.hardwareAddr[:]); err != nil {
+			return
+		}
+		// Set multicast bit as recommended by RFC 4122
+		g.hardwareAddr[0] |= 0x01
+	})
+	if err != nil {
+		return []byte{}, err
+	}
+	return g.hardwareAddr[:], nil
+}
+
+// Returns difference in 100-nanosecond intervals between
+// UUID epoch (October 15, 1582) and current time.
+func (g *rfc4122Generator) getEpoch() uint64 {
+	return epochStart + uint64(g.epochFunc().UnixNano()/100)
+}
+
+// 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
+}
+
+// Returns hardware address.
+func defaultHWAddrFunc() (net.HardwareAddr, error) {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return []byte{}, err
+	}
+	for _, iface := range ifaces {
+		if len(iface.HardwareAddr) >= 6 {
+			return iface.HardwareAddr, nil
+		}
+	}
+	return []byte{}, fmt.Errorf("uuid: no HW address found")
+}

generator_test.go

@@ -0,0 +1,240 @@
+// Copyright (C) 2013-2018 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
+
+import (
+	"bytes"
+	"crypto/rand"
+	"fmt"
+	"net"
+	"testing/iotest"
+	"time"
+
+	. "gopkg.in/check.v1"
+)
+
+type faultyReader struct {
+	callsNum   int
+	readToFail int // Read call number to fail
+}
+
+func (r *faultyReader) Read(dest []byte) (int, error) {
+	r.callsNum++
+	if (r.callsNum - 1) == r.readToFail {
+		return 0, fmt.Errorf("io: reader is faulty")
+	}
+	return rand.Read(dest)
+}
+
+type genTestSuite struct{}
+
+var _ = Suite(&genTestSuite{})
+
+func (s *genTestSuite) TestNewV1(c *C) {
+	u1, err := NewV1()
+	c.Assert(err, IsNil)
+	c.Assert(u1.Version(), Equals, V1)
+	c.Assert(u1.Variant(), Equals, VariantRFC4122)
+
+	u2, err := NewV1()
+	c.Assert(err, IsNil)
+	c.Assert(u1, Not(Equals), u2)
+}
+
+func (s *genTestSuite) TestNewV1EpochStale(c *C) {
+	g := &rfc4122Generator{
+		epochFunc: func() time.Time {
+			return time.Unix(0, 0)
+		},
+		hwAddrFunc: defaultHWAddrFunc,
+		rand:       rand.Reader,
+	}
+	u1, err := g.NewV1()
+	c.Assert(err, IsNil)
+	u2, err := g.NewV1()
+	c.Assert(err, IsNil)
+	c.Assert(u1, Not(Equals), u2)
+}
+
+func (s *genTestSuite) TestNewV1FaultyRand(c *C) {
+	g := &rfc4122Generator{
+		epochFunc:  time.Now,
+		hwAddrFunc: defaultHWAddrFunc,
+		rand:       &faultyReader{},
+	}
+	u1, err := g.NewV1()
+	c.Assert(err, NotNil)
+	c.Assert(u1, Equals, Nil)
+}
+
+func (s *genTestSuite) TestNewV1MissingNetworkInterfaces(c *C) {
+	g := &rfc4122Generator{
+		epochFunc: time.Now,
+		hwAddrFunc: func() (net.HardwareAddr, error) {
+			return []byte{}, fmt.Errorf("uuid: no hw address found")
+		},
+		rand: rand.Reader,
+	}
+	_, err := g.NewV1()
+	c.Assert(err, IsNil)
+}
+
+func (s *genTestSuite) TestNewV1MissingNetInterfacesAndFaultyRand(c *C) {
+	g := &rfc4122Generator{
+		epochFunc: time.Now,
+		hwAddrFunc: func() (net.HardwareAddr, error) {
+			return []byte{}, fmt.Errorf("uuid: no hw address found")
+		},
+		rand: &faultyReader{
+			readToFail: 1,
+		},
+	}
+	u1, err := g.NewV1()
+	c.Assert(err, NotNil)
+	c.Assert(u1, Equals, Nil)
+}
+
+func (s *genTestSuite) BenchmarkNewV1(c *C) {
+	for i := 0; i < c.N; i++ {
+		NewV1()
+	}
+}
+
+func (s *genTestSuite) TestNewV2(c *C) {
+	u1, err := NewV2(DomainPerson)
+	c.Assert(err, IsNil)
+	c.Assert(u1.Version(), Equals, V2)
+	c.Assert(u1.Variant(), Equals, VariantRFC4122)
+
+	u2, err := NewV2(DomainGroup)
+	c.Assert(err, IsNil)
+	c.Assert(u2.Version(), Equals, V2)
+	c.Assert(u2.Variant(), Equals, VariantRFC4122)
+
+	u3, err := NewV2(DomainOrg)
+	c.Assert(err, IsNil)
+	c.Assert(u3.Version(), Equals, V2)
+	c.Assert(u3.Variant(), Equals, VariantRFC4122)
+}
+
+func (s *genTestSuite) TestNewV2FaultyRand(c *C) {
+	g := &rfc4122Generator{
+		epochFunc:  time.Now,
+		hwAddrFunc: defaultHWAddrFunc,
+		rand:       &faultyReader{},
+	}
+	u1, err := g.NewV2(DomainPerson)
+	c.Assert(err, NotNil)
+	c.Assert(u1, Equals, Nil)
+}
+
+func (s *genTestSuite) BenchmarkNewV2(c *C) {
+	for i := 0; i < c.N; i++ {
+		NewV2(DomainPerson)
+	}
+}
+
+func (s *genTestSuite) TestNewV3(c *C) {
+	u1 := NewV3(NamespaceDNS, "www.example.com")
+	c.Assert(u1.Version(), Equals, V3)
+	c.Assert(u1.Variant(), Equals, VariantRFC4122)
+	c.Assert(u1.String(), Equals, "5df41881-3aed-3515-88a7-2f4a814cf09e")
+
+	u2 := NewV3(NamespaceDNS, "example.com")
+	c.Assert(u2, Not(Equals), u1)
+
+	u3 := NewV3(NamespaceDNS, "example.com")
+	c.Assert(u3, Equals, u2)
+
+	u4 := NewV3(NamespaceURL, "example.com")
+	c.Assert(u4, Not(Equals), u3)
+}
+
+func (s *genTestSuite) BenchmarkNewV3(c *C) {
+	for i := 0; i < c.N; i++ {
+		NewV3(NamespaceDNS, "www.example.com")
+	}
+}
+
+func (s *genTestSuite) TestNewV4(c *C) {
+	u1, err := NewV4()
+	c.Assert(err, IsNil)
+	c.Assert(u1.Version(), Equals, V4)
+	c.Assert(u1.Variant(), Equals, VariantRFC4122)
+
+	u2, err := NewV4()
+	c.Assert(err, IsNil)
+	c.Assert(u1, Not(Equals), u2)
+}
+
+func (s *genTestSuite) TestNewV4FaultyRand(c *C) {
+	g := &rfc4122Generator{
+		epochFunc:  time.Now,
+		hwAddrFunc: defaultHWAddrFunc,
+		rand:       &faultyReader{},
+	}
+	u1, err := g.NewV4()
+	c.Assert(err, NotNil)
+	c.Assert(u1, Equals, Nil)
+}
+
+func (s *genTestSuite) TestNewV4PartialRead(c *C) {
+	g := &rfc4122Generator{
+		epochFunc:  time.Now,
+		hwAddrFunc: defaultHWAddrFunc,
+		rand:       iotest.OneByteReader(rand.Reader),
+	}
+	u1, err := g.NewV4()
+	zeros := bytes.Count(u1.Bytes(), []byte{0})
+	mostlyZeros := zeros >= 10
+
+	c.Assert(err, IsNil)
+	c.Assert(mostlyZeros, Equals, false)
+}
+
+func (s *genTestSuite) BenchmarkNewV4(c *C) {
+	for i := 0; i < c.N; i++ {
+		NewV4()
+	}
+}
+
+func (s *genTestSuite) TestNewV5(c *C) {
+	u1 := NewV5(NamespaceDNS, "www.example.com")
+	c.Assert(u1.Version(), Equals, V5)
+	c.Assert(u1.Variant(), Equals, VariantRFC4122)
+	c.Assert(u1.String(), Equals, "2ed6657d-e927-568b-95e1-2665a8aea6a2")
+
+	u2 := NewV5(NamespaceDNS, "example.com")
+	c.Assert(u2, Not(Equals), u1)
+
+	u3 := NewV5(NamespaceDNS, "example.com")
+	c.Assert(u3, Equals, u2)
+
+	u4 := NewV5(NamespaceURL, "example.com")
+	c.Assert(u4, Not(Equals), u3)
+}
+
+func (s *genTestSuite) BenchmarkNewV5(c *C) {
+	for i := 0; i < c.N; i++ {
+		NewV5(NamespaceDNS, "www.example.com")
+	}
+}

sql.go

@@ -0,0 +1,78 @@
+// Copyright (C) 2013-2018 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
+
+import (
+	"database/sql/driver"
+	"fmt"
+)
+
+// Value implements the driver.Valuer interface.
+func (u UUID) Value() (driver.Value, error) {
+	return u.String(), nil
+}
+
+// Scan implements the sql.Scanner interface.
+// A 16-byte slice is handled by UnmarshalBinary, while
+// a longer byte slice or a string is handled by UnmarshalText.
+func (u *UUID) Scan(src interface{}) error {
+	switch src := src.(type) {
+	case []byte:
+		if len(src) == Size {
+			return u.UnmarshalBinary(src)
+		}
+		return u.UnmarshalText(src)
+
+	case string:
+		return u.UnmarshalText([]byte(src))
+	}
+
+	return fmt.Errorf("uuid: cannot convert %T to UUID", src)
+}
+
+// NullUUID can be used with the standard sql package to represent a
+// UUID value that can be NULL in the database
+type NullUUID struct {
+	UUID  UUID
+	Valid bool
+}
+
+// Value implements the driver.Valuer interface.
+func (u NullUUID) Value() (driver.Value, error) {
+	if !u.Valid {
+		return nil, nil
+	}
+	// Delegate to UUID Value function
+	return u.UUID.Value()
+}
+
+// Scan implements the sql.Scanner interface.
+func (u *NullUUID) Scan(src interface{}) error {
+	if src == nil {
+		u.UUID, u.Valid = Nil, false
+		return nil
+	}
+
+	// Delegate to UUID Scan function
+	u.Valid = true
+	return u.UUID.Scan(src)
+}

sql_test.go

@@ -0,0 +1,136 @@
+// Copyright (C) 2013-2018 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
+
+import (
+	. "gopkg.in/check.v1"
+)
+
+type sqlTestSuite struct{}
+
+var _ = Suite(&sqlTestSuite{})
+
+func (s *sqlTestSuite) TestValue(c *C) {
+	u, err := FromString("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+	c.Assert(err, IsNil)
+
+	val, err := u.Value()
+	c.Assert(err, IsNil)
+	c.Assert(val, Equals, u.String())
+}
+
+func (s *sqlTestSuite) TestValueNil(c *C) {
+	u := UUID{}
+
+	val, err := u.Value()
+	c.Assert(err, IsNil)
+	c.Assert(val, Equals, Nil.String())
+}
+
+func (s *sqlTestSuite) TestNullUUIDValueNil(c *C) {
+	u := NullUUID{}
+
+	val, err := u.Value()
+	c.Assert(err, IsNil)
+	c.Assert(val, IsNil)
+}
+
+func (s *sqlTestSuite) TestScanBinary(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	b1 := []byte{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+
+	u1 := UUID{}
+	err := u1.Scan(b1)
+	c.Assert(err, IsNil)
+	c.Assert(u, Equals, u1)
+
+	b2 := []byte{}
+	u2 := UUID{}
+
+	err = u2.Scan(b2)
+	c.Assert(err, NotNil)
+}
+
+func (s *sqlTestSuite) TestScanString(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	s1 := "6ba7b810-9dad-11d1-80b4-00c04fd430c8"
+
+	u1 := UUID{}
+	err := u1.Scan(s1)
+	c.Assert(err, IsNil)
+	c.Assert(u, Equals, u1)
+
+	s2 := ""
+	u2 := UUID{}
+
+	err = u2.Scan(s2)
+	c.Assert(err, NotNil)
+}
+
+func (s *sqlTestSuite) TestScanText(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	b1 := []byte("6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+
+	u1 := UUID{}
+	err := u1.Scan(b1)
+	c.Assert(err, IsNil)
+	c.Assert(u, Equals, u1)
+
+	b2 := []byte("")
+	u2 := UUID{}
+	err = u2.Scan(b2)
+	c.Assert(err, NotNil)
+}
+
+func (s *sqlTestSuite) TestScanUnsupported(c *C) {
+	u := UUID{}
+
+	err := u.Scan(true)
+	c.Assert(err, NotNil)
+}
+
+func (s *sqlTestSuite) TestScanNil(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+
+	err := u.Scan(nil)
+	c.Assert(err, NotNil)
+}
+
+func (s *sqlTestSuite) TestNullUUIDScanValid(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+	s1 := "6ba7b810-9dad-11d1-80b4-00c04fd430c8"
+
+	u1 := NullUUID{}
+	err := u1.Scan(s1)
+	c.Assert(err, IsNil)
+	c.Assert(u1.Valid, Equals, true)
+	c.Assert(u1.UUID, Equals, u)
+}
+
+func (s *sqlTestSuite) TestNullUUIDScanNil(c *C) {
+	u := NullUUID{UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}, true}
+
+	err := u.Scan(nil)
+	c.Assert(err, IsNil)
+	c.Assert(u.Valid, Equals, false)
+	c.Assert(u.UUID, Equals, Nil)
+}

uuid.go

@@ -0,0 +1,161 @@
+// Copyright (C) 2013-2018 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"
+	"encoding/hex"
+)
+
+// Size of a UUID in bytes.
+const Size = 16
+
+// UUID representation compliant with specification
+// described in RFC 4122.
+type UUID [Size]byte
+
+// UUID versions
+const (
+	_ byte = iota
+	V1
+	V2
+	V3
+	V4
+	V5
+)
+
+// UUID layout variants.
+const (
+	VariantNCS byte = iota
+	VariantRFC4122
+	VariantMicrosoft
+	VariantFuture
+)
+
+// UUID DCE domains.
+const (
+	DomainPerson = iota
+	DomainGroup
+	DomainOrg
+)
+
+// String parse helpers.
+var (
+	urnPrefix  = []byte("urn:uuid:")
+	byteGroups = []int{8, 4, 4, 4, 12}
+)
+
+// Nil is special form of UUID that is specified to have all
+// 128 bits set to zero.
+var Nil = UUID{}
+
+// Predefined namespace UUIDs.
+var (
+	NamespaceDNS  = Must(FromString("6ba7b810-9dad-11d1-80b4-00c04fd430c8"))
+	NamespaceURL  = Must(FromString("6ba7b811-9dad-11d1-80b4-00c04fd430c8"))
+	NamespaceOID  = Must(FromString("6ba7b812-9dad-11d1-80b4-00c04fd430c8"))
+	NamespaceX500 = Must(FromString("6ba7b814-9dad-11d1-80b4-00c04fd430c8"))
+)
+
+// 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() byte {
+	return u[6] >> 4
+}
+
+// Variant returns UUID layout variant.
+func (u UUID) Variant() byte {
+	switch {
+	case (u[8] >> 7) == 0x00:
+		return VariantNCS
+	case (u[8] >> 6) == 0x02:
+		return VariantRFC4122
+	case (u[8] >> 5) == 0x06:
+		return VariantMicrosoft
+	case (u[8] >> 5) == 0x07:
+		fallthrough
+	default:
+		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 {
+	buf := make([]byte, 36)
+
+	hex.Encode(buf[0:8], u[0:4])
+	buf[8] = '-'
+	hex.Encode(buf[9:13], u[4:6])
+	buf[13] = '-'
+	hex.Encode(buf[14:18], u[6:8])
+	buf[18] = '-'
+	hex.Encode(buf[19:23], u[8:10])
+	buf[23] = '-'
+	hex.Encode(buf[24:], u[10:])
+
+	return string(buf)
+}
+
+// SetVersion sets version bits.
+func (u *UUID) SetVersion(v byte) {
+	u[6] = (u[6] & 0x0f) | (v << 4)
+}
+
+// SetVariant sets variant bits.
+func (u *UUID) SetVariant(v byte) {
+	switch v {
+	case VariantNCS:
+		u[8] = (u[8]&(0xff>>1) | (0x00 << 7))
+	case VariantRFC4122:
+		u[8] = (u[8]&(0xff>>2) | (0x02 << 6))
+	case VariantMicrosoft:
+		u[8] = (u[8]&(0xff>>3) | (0x06 << 5))
+	case VariantFuture:
+		fallthrough
+	default:
+		u[8] = (u[8]&(0xff>>3) | (0x07 << 5))
+	}
+}
+
+// Must is a helper that wraps a call to a function returning (UUID, error)
+// and panics if the error is non-nil. It is intended for use in variable
+// initializations such as
+//	var packageUUID = uuid.Must(uuid.FromString("123e4567-e89b-12d3-a456-426655440000"));
+func Must(u UUID, err error) UUID {
+	if err != nil {
+		panic(err)
+	}
+	return u
+}

uuid_test.go

@@ -0,0 +1,100 @@
+// Copyright (C) 2013-2018 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
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	. "gopkg.in/check.v1"
+)
+
+// Hook up gocheck into the "go test" runner.
+func TestUUID(t *testing.T) { TestingT(t) }
+
+type testSuite struct{}
+
+var _ = Suite(&testSuite{})
+
+func (s *testSuite) TestBytes(c *C) {
+	u := UUID{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+
+	bytes1 := []byte{0x6b, 0xa7, 0xb8, 0x10, 0x9d, 0xad, 0x11, 0xd1, 0x80, 0xb4, 0x00, 0xc0, 0x4f, 0xd4, 0x30, 0xc8}
+
+	c.Assert(bytes.Equal(u.Bytes(), bytes1), Equals, true)
+}
+
+func (s *testSuite) TestString(c *C) {
+	c.Assert(NamespaceDNS.String(), Equals, "6ba7b810-9dad-11d1-80b4-00c04fd430c8")
+}
+
+func (s *testSuite) TestEqual(c *C) {
+	c.Assert(Equal(NamespaceDNS, NamespaceDNS), Equals, true)
+	c.Assert(Equal(NamespaceDNS, NamespaceURL), Equals, false)
+}
+
+func (s *testSuite) TestVersion(c *C) {
+	u := UUID{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
+	c.Assert(u.Version(), Equals, V1)
+}
+
+func (s *testSuite) TestSetVersion(c *C) {
+	u := UUID{}
+	u.SetVersion(4)
+	c.Assert(u.Version(), Equals, V4)
+}
+
+func (s *testSuite) TestVariant(c *C) {
+	u1 := UUID{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
+	c.Assert(u1.Variant(), Equals, VariantNCS)
+
+	u2 := UUID{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
+	c.Assert(u2.Variant(), Equals, VariantRFC4122)
+
+	u3 := UUID{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
+	c.Assert(u3.Variant(), Equals, VariantMicrosoft)
+
+	u4 := UUID{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xe0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
+	c.Assert(u4.Variant(), Equals, VariantFuture)
+}
+
+func (s *testSuite) TestSetVariant(c *C) {
+	u := UUID{}
+	u.SetVariant(VariantNCS)
+	c.Assert(u.Variant(), Equals, VariantNCS)
+	u.SetVariant(VariantRFC4122)
+	c.Assert(u.Variant(), Equals, VariantRFC4122)
+	u.SetVariant(VariantMicrosoft)
+	c.Assert(u.Variant(), Equals, VariantMicrosoft)
+	u.SetVariant(VariantFuture)
+	c.Assert(u.Variant(), Equals, VariantFuture)
+}
+
+func (s *testSuite) TestMust(c *C) {
+	defer func() {
+		c.Assert(recover(), NotNil)
+	}()
+	Must(func() (UUID, error) {
+		return Nil, fmt.Errorf("uuid: expected error")
+	}())
+}