DragonBe\Vies\Validator\ValidatorAbstract::crossSum PHP Method

    protected function crossSum($val)
    {
        $val = (string) $val;
        $sum = 0;
        $count = strlen($val);
        for ($i = 0; $i < $count; $i++) {
            $sum += (int) $val[$i];
        }
        return $sum;
    }