uuid.php
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<?php
namespace OCA\Contacts\Utils;
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.
* From http://php.net/manual/en/function.uniqid.php comments
*
* @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.
*/
public function get() {
$prBits = false;
if (is_a($this, 'uuid')) {
if (is_resource($this->urand)) {
$prBits .= @fread($this->urand, 16);
}
}
if (!$prBits) {
$fp = @fopen('/dev/urandom', 'rb');
if ($fp !== false) {
$prBits .= @fread($fp, 16);
@fclose ( $fp );
} else {
// If /dev/urandom isn't available (eg: in non-unix systems), use mt_rand().
$prBits = "";
for($cnt = 0; $cnt < 16; $cnt ++) {
$prBits .= chr(mt_rand(0, 255));
}
}
}
$timeLow = bin2hex(substr($prBits, 0, 4));
$timeMid = bin2hex(substr($prBits, 4, 2));
$timeHiAndVersion = bin2hex(substr($prBits, 6, 2));
$clockSeqHiAndReserved = bin2hex(substr($prBits, 8, 2));
$node = bin2hex(substr($prBits, 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
*/
$timeHiAndVersion = hexdec($timeHiAndVersion);
$timeHiAndVersion = $timeHiAndVersion >> 4;
$timeHiAndVersion = $timeHiAndVersion | 0x4000;
/**
* Set the two most significant bits (bits 6 and 7) of the
* clock_seq_hi_and_reserved to zero and one, respectively.
*/
$clockSeqHiAndReserved = hexdec($clockSeqHiAndReserved);
$clockSeqHiAndReserved = $clockSeqHiAndReserved >> 2;
$clockSeqHiAndReserved = $clockSeqHiAndReserved | 0x8000;
return sprintf('%08s-%04s-%04x-%04x-%012s', $timeLow, $timeMid, $timeHiAndVersion, $clockSeqHiAndReserved, $node);
}
}