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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 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
}
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