note 88400 added to function.uniqid
| From: | MariusKarthaus at osu1 dot php dot net | Date: | Thu, 22 Jan 2009 13:39:55 +0000 |
| Subject: | note 88400 added to function.uniqid | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-149651@lists.php.net to get a copy of this message | ||
I've created a class from the function below. With it, creating a lot of uuids beomes about 100
times faster because you do not need to fopen() for each uuid.
uuid::get() still works as a static function if you just need a single uuid.
<?php
class uuid {
protected $urand;
public function __construct() {
$this->urand = @fopen ( '/dev/urandom', 'rb' );
}
/**
* @brief Generates a Universally Unique IDentifier, version 4.
*
* This function generates a truly random UUID. The built in CakePHP String::uuid() function
* is not cryptographically secure. You should uses this function instead.
*
* @see http://tools.ietf.org/html/rfc4122#section-4.4
* @see http://en.wikipedia.org/wiki/UUID
* @return string A UUID, made up of 32 hex digits and 4 hyphens.
*/
function get() {
$pr_bits = false;
if (is_a ( $this, 'uuid' )) {
if (is_resource ( $this->urand )) {
$pr_bits .= @fread ( $this->urand, 16 );
}
}
if (! $pr_bits) {
$fp = @fopen ( '/dev/urandom', 'rb' );
if ($fp !== false) {
$pr_bits .= @fread ( $fp, 16 );
@fclose ( $fp );
} else {
// If /dev/urandom isn't available (eg: in non-unix systems), use mt_rand().
$pr_bits = "";
for($cnt = 0; $cnt < 16; $cnt ++) {
$pr_bits .= chr ( mt_rand ( 0, 255 ) );
}
}
}
$time_low = bin2hex ( substr ( $pr_bits, 0, 4 ) );
$time_mid = bin2hex ( substr ( $pr_bits, 4, 2 ) );
$time_hi_and_version = bin2hex ( substr ( $pr_bits, 6, 2 ) );
$clock_seq_hi_and_reserved = bin2hex ( substr ( $pr_bits, 8, 2 ) );
$node = bin2hex ( substr ( $pr_bits, 10, 6 ) );
/**
* Set the four most significant bits (bits 12 through 15) of the
* time_hi_and_version field to the 4-bit version number from
* Section 4.1.3.
* @see http://tools.ietf.org/html/rfc4122#section-4.1.3
*/
$time_hi_and_version = hexdec ( $time_hi_and_version );
$time_hi_and_version = $time_hi_and_version >> 4;
$time_hi_and_version = $time_hi_and_version | 0x4000;
/**
* Set the two most significant bits (bits 6 and 7) of the
* clock_seq_hi_and_reserved to zero and one, respectively.
*/
$clock_seq_hi_and_reserved = hexdec ( $clock_seq_hi_and_reserved );
$clock_seq_hi_and_reserved = $clock_seq_hi_and_reserved >> 2;
$clock_seq_hi_and_reserved = $clock_seq_hi_and_reserved | 0x8000;
return sprintf ( '%08s-%04s-%04x-%04x-%012s', $time_low, $time_mid,
$time_hi_and_version, $clock_seq_hi_and_reserved, $node );
}
}
----
Server IP: 89.248.170.61
Probable Submitter: 85.147.192.41
----
Manual Page -- http://www.php.net/manual/en/function.uniqid.php
Edit -- https://master.php.net/note/edit/88400
Del: integrated -- https://master.php.net/note/delete/88400/integrated
Del: useless -- https://master.php.net/note/delete/88400/useless
Del: bad code -- https://master.php.net/note/delete/88400/bad+code
Del: spam -- https://master.php.net/note/delete/88400/spam
Del: non-english -- https://master.php.net/note/delete/88400/non-english
Del: in docs -- https://master.php.net/note/delete/88400/in+docs
Del: other reasons-- https://master.php.net/note/delete/88400
Reject -- https://master.php.net/note/reject/88400
Search -- https://master.php.net/manage/user-notes.php