zlibproxy/vendor/workerman/validation/library/Rules/Luhn.php
2023-01-02 19:56:44 +08:00

63 lines
1.4 KiB
PHP

<?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 file
* that was distributed with this source code.
*/
declare(strict_types=1);
namespace Respect\Validation\Rules;
use function array_map;
use function count;
use function str_split;
/**
* Validate whether a given input is a Luhn number.
*
* @see https://en.wikipedia.org/wiki/Luhn_algorithm
*
* @author Alexander Gorshkov <mazanax@yandex.ru>
* @author Danilo Correa <danilosilva87@gmail.com>
* @author Henrique Moody <henriquemoody@gmail.com>
*/
final class Luhn extends AbstractRule
{
/**
* {@inheritDoc}
*/
public function validate($input): bool
{
if (!(new Digit())->validate($input)) {
return false;
}
return $this->isValid((string) $input);
}
private function isValid(string $input): bool
{
$sum = 0;
$digits = array_map('intval', str_split($input));
$numDigits = count($digits);
$parity = $numDigits % 2;
for ($i = 0; $i < $numDigits; ++$i) {
$digit = $digits[$i];
if ($parity == ($i % 2)) {
$digit <<= 1;
if (9 < $digit) {
$digit = $digit - 9;
}
}
$sum += $digit;
}
return ($sum % 10) == 0;
}
}