| protected checksum_s25 ( $code ) : integer | ||
| $code | (string) code to process. | |
| return | integer | checksum. |
protected function checksum_s25($code)
{
$len = strlen($code);
$sum = 0;
for ($i = 0; $i < $len; $i += 2) {
$sum += $code[$i];
}
$sum *= 3;
for ($i = 1; $i < $len; $i += 2) {
$sum += $code[$i];
}
$r = $sum % 10;
if ($r > 0) {
$r = 10 - $r;
}
return $r;
}