note 94959 added to function.uniqid
| From: | AndrewMoore at osu1 dot php dot net | Date: | Fri, 04 Dec 2009 16:45:11 +0000 |
| Subject: | note 94959 added to function.uniqid | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-163585@lists.php.net to get a copy of this message | ||
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;
// Get hexadecimal components of namespace
$nhex = str_replace(array('-','{','}'), '', $namespace);
// Binary Value
$nstr = '';
// Convert Namespace UUID to bits
for($i = 0; $i < strlen($nhex); $i+=2) {
$nstr .= chr(hexdec($nhex[$i].$nhex[$i+1]));
}
// Calculate hash value
$hash = md5($nstr . $name);
return sprintf('%08s-%04s-%04x-%04x-%12s',
// 32 bits for "time_low"
substr($hash, 0, 8),
// 16 bits for "time_mid"
substr($hash, 8, 4),
// 16 bits for "time_hi_and_version",
// four most significant bits holds version number 3
(hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x3000,
// 16 bits, 8 bits for "clk_seq_hi_res",
// 8 bits for "clk_seq_low",
// two most significant bits holds zero and one for variant DCE1.1
(hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,
// 48 bits for "node"
substr($hash, 20, 12)
);
}
public static function v4() {
return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
// 32 bits for "time_low"
mt_rand(0, 0xffff), mt_rand(0, 0xffff),
// 16 bits for "time_mid"
mt_rand(0, 0xffff),
// 16 bits for "time_hi_and_version",
// four most significant bits holds version number 4
mt_rand(0, 0x0fff) | 0x4000,
// 16 bits, 8 bits for "clk_seq_hi_res",
// 8 bits for "clk_seq_low",
// two most significant bits holds zero and one for variant DCE1.1
mt_rand(0, 0x3fff) | 0x8000,
// 48 bits for "node"
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;
// Get hexadecimal components of namespace
$nhex = str_replace(array('-','{','}'), '', $namespace);
// Binary Value
$nstr = '';
// Convert Namespace UUID to bits
for($i = 0; $i < strlen($nhex); $i+=2) {
$nstr .= chr(hexdec($nhex[$i].$nhex[$i+1]));
}
// Calculate hash value
$hash = sha1($nstr . $name);
return sprintf('%08s-%04s-%04x-%04x-%12s',
// 32 bits for "time_low"
substr($hash, 0, 8),
// 16 bits for "time_mid"
substr($hash, 8, 4),
// 16 bits for "time_hi_and_version",
// four most significant bits holds version number 5
(hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x5000,
// 16 bits, 8 bits for "clk_seq_hi_res",
// 8 bits for "clk_seq_low",
// two most significant bits holds zero and one for variant DCE1.1
(hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,
// 48 bits for "node"
substr($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;
}
}
// Usage
// Named-based UUID.
$v3uuid = UUID::v3('1546058f-5a25-4334-85ae-e68f2a44bbaf', 'SomeRandomString');
$v5uuid = UUID::v5('1546058f-5a25-4334-85ae-e68f2a44bbaf', 'SomeRandomString');
// Pseudo-random UUID
$v4uuid = UUID::v4();
?>
----
Server IP: 216.235.13.26
Probable Submitter: 216.162.77.44
----
Manual Page -- http://www.php.net/manual/en/function.uniqid.php
Edit -- https://master.php.net/note/edit/94959
Del: integrated -- https://master.php.net/note/delete/94959/integrated
Del: useless -- https://master.php.net/note/delete/94959/useless
Del: bad code -- https://master.php.net/note/delete/94959/bad+code
Del: spam -- https://master.php.net/note/delete/94959/spam
Del: non-english -- https://master.php.net/note/delete/94959/non-english
Del: in docs -- https://master.php.net/note/delete/94959/in+docs
Del: other reasons-- https://master.php.net/note/delete/94959
Reject -- https://master.php.net/note/reject/94959
Search -- https://master.php.net/manage/user-notes.php