The following class generates VALID RFC 4211 COMPLIANT Universally Unique IDentifiers (UUID) version 3, 4 and 5.
Version 3 and 5 UUIDs are named based. They require a namespace (another valid UUID) and a value (the name). Given the same namespace and name, the output is always the same.
Version 4 UUIDs are pseudo-random.
UUIDs generated below validates using OSSP UUID Tool, and output for named-based UUIDs are exactly the same. This is a pure PHP implementation.
<?php
class UUID {
public static function v3($namespace, $name) {
if(!self::is_valid($namespace)) return false;
$nhex = str_replace(array('-','{','}'), '', $namespace);
$nstr = '';
for($i = 0; $i < strlen($nhex); $i+=2) {
$nstr .= chr(hexdec($nhex[$i].$nhex[$i+1]));
}
$hash = md5($nstr . $name);
return sprintf('%08s-%04s-%04x-%04x-%12s',
substr($hash, 0, 8),
substr($hash, 8, 4),
(hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x3000,
(hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,
substr($hash, 20, 12)
);
}
public static function v4() {
return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
mt_rand(0, 0xffff), mt_rand(0, 0xffff),
mt_rand(0, 0xffff),
mt_rand(0, 0x0fff) | 0x4000,
mt_rand(0, 0x3fff) | 0x8000,
mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
);
}
public static function v5($namespace, $name) {
if(!self::is_valid($namespace)) return false;
$nhex = str_replace(array('-','{','}'), '', $namespace);
$nstr = '';
for($i = 0; $i < strlen($nhex); $i+=2) {
$nstr .= chr(hexdec($nhex[$i].$nhex[$i+1]));
}
$hash = sha1($nstr . $name);
return sprintf('%08s-%04s-%04x-%04x-%12s',
substr($hash, 0, 8),
substr($hash, 8, 4),
(hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x5000,
(hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,
substr($hash, 20, 12)
);
}
public static function is_valid($uuid) {
return preg_match('/^\{?[0-9a-f]{8}\-?[0-9a-f]{4}\-?[0-9a-f]{4}\-?'.
'[0-9a-f]{4}\-?[0-9a-f]{12}\}?$/i', $uuid) === 1;
}
}
$v3uuid = UUID::v3('1546058f-5a25-4334-85ae-e68f2a44bbaf', 'SomeRandomString');
$v5uuid = UUID::v5('1546058f-5a25-4334-85ae-e68f2a44bbaf', 'SomeRandomString');
$v4uuid = UUID::v4();
?>