validate_SE_PNO.php

<?php

protected static function validatePNumber($pnumber) {
	/* Check valid form (existing month and day) */
	if (!preg_match("/^[0-9]{2}((0[1-9])|(1[0-2]))((0[1-9])|([1-2][0-9])|(3[0-1]))[0-9]{4}$/", $pnumber)) return false;

	/* Calculate check sum and check wether or not the control digit is correct */
	$sum = 0;
	$x = 0;
	for ($i = 0; $i < 10; $i++) {
		$x = (int) $pnumber[$i];
		if ($i % 2 == 0) {
			$x = 2 * $x;
		}
		$sum += floor($x / 10) + ($x % 10);
	}

	return ($sum % 10 == 0);
}

?>