public function LuhnValidator::validate in Plug 7

Validates a credit card number with the Luhn algorithm.

Parameters

mixed $value:

Constraint $constraint:

Throws

UnexpectedTypeException when the given credit card number is no string

Overrides ConstraintValidatorInterface::validate

File

lib/Symfony/validator/Symfony/Component/Validator/Constraints/LuhnValidator.php, line 40

Class

LuhnValidator

Validates a PAN using the LUHN Algorithm.

Namespace

Symfony\Component\Validator\Constraints

Code

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();
  }
}