Weryfikacja numeru Dowodu Osobistego

dowod_osobisty.php

<?php
function check_do_number ($number)
{
	$t = 0;
	$n = array();
	$w = array(7, 3, 1);
	if (!preg_match('/^([A-Z]+)(\d{1})(\d+)$/', strtoupper($number), $n)) return false;
	foreach (str_split($n[1] . $n[3]) as $i => $l)
		$t += $w[$i % 3] * (is_numeric($l) ? $l : (ord($l) - 55));
	return ($t % 10) == (int)$n[2] ? true : false;
}