Respect\Validation\Rules\Luhn

Complexity

Total Complexity

5

Size/Duplication

Total Lines	28
Duplicated Lines	0 %

Coupling/Cohesion

Components	0
Dependencies	2

Importance

Changes	1
Bugs	0	Features	0

1 Method

Rating	Name	Duplication	Size	Complexity
B	validate()	0	22	5

<?php

/*
 * This file is part of Respect/Validation.
 *
 * (c) Alexandre Gomes Gaigalas <alexandre@gaigalas.net>
 *
 * For the full copyright and license information, please view the "LICENSE.md"
 * file that was distributed with this source code.
 */

namespace Respect\Validation\Rules;

/**
 * @link https://en.wikipedia.org/wiki/Luhn_algorithm
 */
class Luhn extends AbstractRule
{
    /**
     * {@inheritdoc}
     */
    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));
    }
}