<?php
declare(strict_types=1);
namespace ParagonIE\Ionizer\Filter\Special;
use ParagonIE\ConstantTime\Binary;
use ParagonIE\Ionizer\Filter\StringFilter;
use ParagonIE\Ionizer\InvalidDataException;
/**
* Class CreditCardNumberFilter
* @package ParagonIE\Ionizer\Filter\Special
*/
class CreditCardNumberFilter extends StringFilter
{
public function __construct()
{
$this->addCallback([__CLASS__, 'validateCreditCardNumber']);
}
/**
* Validate a credit card number, based on input length and Luhn's Algorithm
*
* @param string $input
*
* @return string
* @throws InvalidDataException
*/
public static function validateCreditCardNumber(string $input): string
{
// Strip all non-decimal characters
$stripped = \preg_replace('/[^0-9]/', '', $input);
/** @var int $length */
$length = Binary::safeStrlen($stripped);
if ($length < 13 || $length > 19) {
throw new InvalidDataException('Invalid credit card number (invalid length)');
}
/** @var array<int, string> $split */
$split = \str_split($stripped, 1);
/** @var int $calc */
$calc = 0;
/** @var int $l */
$l = \count($split);
for ($i = 0; $i < $l; ++$i) {
/** @var int $n */
$n = (int) ($split[$l - $i - 1]) << ($i & 1);
if ($n > 9) {
$n = ((int) ($n / 10)) + ($n % 10);
}
$calc += $n;
}
if ($calc % 10 !== 0) {
throw new InvalidDataException('Invalid credit card number (Luhn)');
}
return $stripped;
}
}
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