Chris@0: <?php
Chris@0: 
Chris@0: /*
Chris@0:  * This file is part of the Symfony package.
Chris@0:  *
Chris@0:  * (c) Fabien Potencier <fabien@symfony.com>
Chris@0:  *
Chris@0:  * For the full copyright and license information, please view the LICENSE
Chris@0:  * file that was distributed with this source code.
Chris@0:  */
Chris@0: 
Chris@0: namespace Symfony\Component\Validator\Constraints;
Chris@0: 
Chris@0: use Symfony\Component\Validator\Constraint;
Chris@0: use Symfony\Component\Validator\ConstraintValidator;
Chris@0: use Symfony\Component\Validator\Exception\UnexpectedTypeException;
Chris@0: 
Chris@0: /**
Chris@0:  * Validates a PAN using the LUHN Algorithm.
Chris@0:  *
Chris@0:  * For a list of example card numbers that are used to test this
Chris@0:  * class, please see the LuhnValidatorTest class.
Chris@0:  *
Chris@0:  * @see    http://en.wikipedia.org/wiki/Luhn_algorithm
Chris@0:  *
Chris@0:  * @author Tim Nagel <t.nagel@infinite.net.au>
Chris@0:  * @author Greg Knapp http://gregk.me/2011/php-implementation-of-bank-card-luhn-algorithm/
Chris@0:  * @author Bernhard Schussek <bschussek@gmail.com>
Chris@0:  */
Chris@0: class LuhnValidator extends ConstraintValidator
Chris@0: {
Chris@0:     /**
Chris@0:      * Validates a credit card number with the Luhn algorithm.
Chris@0:      *
Chris@0:      * @param mixed      $value
Chris@0:      * @param Constraint $constraint
Chris@0:      *
Chris@0:      * @throws UnexpectedTypeException when the given credit card number is no string
Chris@0:      */
Chris@0:     public function validate($value, Constraint $constraint)
Chris@0:     {
Chris@0:         if (!$constraint instanceof Luhn) {
Chris@0:             throw new UnexpectedTypeException($constraint, __NAMESPACE__.'\Luhn');
Chris@0:         }
Chris@0: 
Chris@0:         if (null === $value || '' === $value) {
Chris@0:             return;
Chris@0:         }
Chris@0: 
Chris@0:         // Work with strings only, because long numbers are represented as floats
Chris@0:         // internally and don't work with strlen()
Chris@17:         if (!\is_string($value) && !(\is_object($value) && method_exists($value, '__toString'))) {
Chris@0:             throw new UnexpectedTypeException($value, 'string');
Chris@0:         }
Chris@0: 
Chris@0:         $value = (string) $value;
Chris@0: 
Chris@0:         if (!ctype_digit($value)) {
Chris@0:             $this->context->buildViolation($constraint->message)
Chris@0:                 ->setParameter('{{ value }}', $this->formatValue($value))
Chris@0:                 ->setCode(Luhn::INVALID_CHARACTERS_ERROR)
Chris@0:                 ->addViolation();
Chris@0: 
Chris@0:             return;
Chris@0:         }
Chris@0: 
Chris@0:         $checkSum = 0;
Chris@17:         $length = \strlen($value);
Chris@0: 
Chris@0:         // Starting with the last digit and walking left, add every second
Chris@0:         // digit to the check sum
Chris@0:         // e.g. 7  9  9  2  7  3  9  8  7  1  3
Chris@0:         //      ^     ^     ^     ^     ^     ^
Chris@0:         //    = 7  +  9  +  7  +  9  +  7  +  3
Chris@0:         for ($i = $length - 1; $i >= 0; $i -= 2) {
Chris@0:             $checkSum += $value[$i];
Chris@0:         }
Chris@0: 
Chris@0:         // Starting with the second last digit and walking left, double every
Chris@0:         // second digit and add it to the check sum
Chris@0:         // For doubles greater than 9, sum the individual digits
Chris@0:         // e.g. 7  9  9  2  7  3  9  8  7  1  3
Chris@0:         //         ^     ^     ^     ^     ^
Chris@0:         //    =    1+8 + 4  +  6  +  1+6 + 2
Chris@0:         for ($i = $length - 2; $i >= 0; $i -= 2) {
Chris@0:             $checkSum += array_sum(str_split($value[$i] * 2));
Chris@0:         }
Chris@0: 
Chris@0:         if (0 === $checkSum || 0 !== $checkSum % 10) {
Chris@0:             $this->context->buildViolation($constraint->message)
Chris@0:                 ->setParameter('{{ value }}', $this->formatValue($value))
Chris@0:                 ->setCode(Luhn::CHECKSUM_FAILED_ERROR)
Chris@0:                 ->addViolation();
Chris@0:         }
Chris@0:     }
Chris@0: }