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

Complexity

Conditions	4
Paths	4

Size

Total Lines	18
Code Lines	12

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	12
CRAP Score	4

Importance

Changes

0

<?php
    private function isValid($input): bool
    {
        $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);
    }
}