GUMP::validate_iban PHP Метод

    protected function validate_iban($field, $input, $param = null)
    {
        if (!isset($input[$field]) || empty($input[$field])) {
            return;
        }
        static $character = array('A' => 10, 'C' => 12, 'D' => 13, 'E' => 14, 'F' => 15, 'G' => 16, 'H' => 17, 'I' => 18, 'J' => 19, 'K' => 20, 'L' => 21, 'M' => 22, 'N' => 23, 'O' => 24, 'P' => 25, 'Q' => 26, 'R' => 27, 'S' => 28, 'T' => 29, 'U' => 30, 'V' => 31, 'W' => 32, 'X' => 33, 'Y' => 34, 'Z' => 35, 'B' => 11);
        if (!preg_match("/\\A[A-Z]{2}\\d{2} ?[A-Z\\d]{4}( ?\\d{4}){1,} ?\\d{1,4}\\z/", $input[$field])) {
            return array('field' => $field, 'value' => $input[$field], 'rule' => __FUNCTION__, 'param' => $param);
        }
        $iban = str_replace(' ', '', $input[$field]);
        $iban = substr($iban, 4) . substr($iban, 0, 4);
        $iban = strtr($iban, $character);
        if (bcmod($iban, 97) != 1) {
            return array('field' => $field, 'value' => $input[$field], 'rule' => __FUNCTION__, 'param' => $param);
        }
    }