* * 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 * @author Greg Knapp http://gregk.me/2011/php-implementation-of-bank-card-luhn-algorithm/ */ class LuhnValidator extends ConstraintValidator { /** * Validates a creditcard number with the Luhn algorithm. * * @param mixed $value * @param Constraint $constraint */ public function validate($value, Constraint $constraint) { if (null === $value || '' === $value) { return; } /** * need to work with strings only because long numbers are treated as floats and don't work with strlen */ if (!is_string($value)) { throw new UnexpectedTypeException($value, 'string'); } if (!is_numeric($value)) { $this->context->addViolation($constraint->message); return; } $length = strlen($value); $oddLength = $length % 2; for ($sum = 0, $i = $length - 1; $i >= 0; $i--) { $digit = (int) $value[$i]; $sum += (($i % 2) === $oddLength) ? array_sum(str_split($digit * 2)) : $digit; } if ($sum === 0 || ($sum % 10) !== 0) { $this->context->addViolation($constraint->message); } } }