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// Copyright 2013 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.
package utils
import (
"crypto/rand"
"encoding/hex"
"fmt"
"io"
"regexp"
"strings"
)
// UUID represent a universal identifier with 16 octets.
type UUID [16]byte
var validUUID = regexp.MustCompile("[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[8,9,a,b][0-9a-f]{3}-[0-9a-f]{12}")
func UUIDFromString(s string) (UUID, error) {
if !IsValidUUIDString(s) {
return UUID{}, fmt.Errorf("invalid UUID: %q", s)
}
s = strings.Replace(s, "-", "", 4)
raw, err := hex.DecodeString(s)
if err != nil {
return UUID{}, err
}
var uuid UUID
copy(uuid[:], raw)
return uuid, nil
}
// IsValidUUIDString returns true, if the given string matches a valid UUID (version 4, variant 2).
func IsValidUUIDString(s string) bool {
return validUUID.MatchString(s)
}
// NewUUID generates a new version 4 UUID relying only on random numbers.
func NewUUID() (UUID, error) {
uuid := UUID{}
if _, err := io.ReadFull(rand.Reader, []byte(uuid[0:16])); err != nil {
return UUID{}, err
}
// Set version (4) and variant (2) according to RfC 4122.
var version byte = 4 << 4
var variant byte = 8 << 4
uuid[6] = version | (uuid[6] & 15)
uuid[8] = variant | (uuid[8] & 15)
return uuid, nil
}
// Copy returns a copy of the UUID.
func (uuid UUID) Copy() UUID {
uuidCopy := uuid
return uuidCopy
}
// Raw returns a copy of the UUID bytes.
func (uuid UUID) Raw() [16]byte {
return [16]byte(uuid)
}
// String returns a hexadecimal string representation with
// standardized separators.
func (uuid UUID) String() string {
return fmt.Sprintf("%x-%x-%x-%x-%x", uuid[0:4], uuid[4:6], uuid[6:8], uuid[8:10], uuid[10:16])
}
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