LuhnValidator.php in Plug 7

Namespace

Symfony\Component\Validator\Constraints

File

lib/Symfony/validator/Symfony/Component/Validator/Constraints/LuhnValidator.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <[e-mail]>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Symfony\Component\Validator\Constraints;

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;
use Symfony\Component\Validator\Exception\UnexpectedTypeException;

/**
 * Validates a PAN using the LUHN Algorithm.
 *
 * For a list of example card numbers that are used to test this
 * class, please see the LuhnValidatorTest class.
 *
 * @see    http://en.wikipedia.org/wiki/Luhn_algorithm
 *
 * @author Tim Nagel <[e-mail]>
 * @author Greg Knapp http://gregk.me/2011/php-implementation-of-bank-card-luhn-algorithm/
 * @author Bernhard Schussek <[e-mail]>
 */
class LuhnValidator extends ConstraintValidator {

  /**
   * Validates a credit card number with the Luhn algorithm.
   *
   * @param mixed      $value
   * @param Constraint $constraint
   *
   * @throws UnexpectedTypeException when the given credit card number is no string
   */
  public function validate($value, Constraint $constraint) {
    if (!$constraint instanceof Luhn) {
      throw new UnexpectedTypeException($constraint, __NAMESPACE__ . '\\Luhn');
    }
    if (null === $value || '' === $value) {
      return;
    }

    // Work with strings only, because long numbers are represented as floats
    // internally and don't work with strlen()
    if (!is_string($value) && !(is_object($value) && method_exists($value, '__toString'))) {
      throw new UnexpectedTypeException($value, 'string');
    }
    $value = (string) $value;
    if (!ctype_digit($value)) {
      $this
        ->buildViolation($constraint->message)
        ->setParameter('{{ value }}', $this
        ->formatValue($value))
        ->setCode(Luhn::INVALID_CHARACTERS_ERROR)
        ->addViolation();
      return;
    }
    $checkSum = 0;
    $length = strlen($value);

    // Starting with the last digit and walking left, add every second
    // digit to the check sum
    // e.g. 7  9  9  2  7  3  9  8  7  1  3
    //      ^     ^     ^     ^     ^     ^
    //    = 7  +  9  +  7  +  9  +  7  +  3
    for ($i = $length - 1; $i >= 0; $i -= 2) {
      $checkSum += $value[$i];
    }

    // Starting with the second last digit and walking left, double every
    // second digit and add it to the check sum
    // For doubles greater than 9, sum the individual digits
    // e.g. 7  9  9  2  7  3  9  8  7  1  3
    //         ^     ^     ^     ^     ^
    //    =    1+8 + 4  +  6  +  1+6 + 2
    for ($i = $length - 2; $i >= 0; $i -= 2) {
      $checkSum += array_sum(str_split($value[$i] * 2));
    }
    if (0 === $checkSum || 0 !== $checkSum % 10) {
      $this
        ->buildViolation($constraint->message)
        ->setParameter('{{ value }}', $this
        ->formatValue($value))
        ->setCode(Luhn::CHECKSUM_FAILED_ERROR)
        ->addViolation();
    }
  }

}

Classes

Name	Description
LuhnValidator	Validates a PAN using the LUHN Algorithm.