Respect\Validation\Rules\Luhn::validate()

Complexity

Conditions	5
Paths	5

Size

Total Lines	22
Code Lines	14

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

<?php
    public function validate($input)
    {
        if (!(new Digit())->validate($input)) {
            return false;
        }

        $sum = 0;
        $numDigits = strlen($input);
        $parity = $numDigits % 2;
        for ($i = 0; $i < $numDigits; $i++) {
            $digit = substr($input, $i, 1);
            if ($parity == ($i % 2)) {
                $digit <<= 1;
                if (9 < $digit) {
                    $digit = $digit - 9;
                }
            }
            $sum += $digit;
        }

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