public function IssnValidator::validate

Checks if the passed value is valid.

@api

Parameters

mixed $value The value that should be validated:

Constraint $constraint The constraint for the validation:

Overrides ConstraintValidatorInterface::validate

File

drupal/core/vendor/symfony/validator/Symfony/Component/Validator/Constraints/IssnValidator.php, line 30

Class

IssnValidator

Validates whether the value is a valid ISSN.

Namespace

Code

public function validate($value, Constraint $constraint) {
  if (null === $value || '' === $value) {
    return;
  }
  if (!is_scalar($value) && !(is_object($value) && method_exists($value, '__toString'))) {
    throw new UnexpectedTypeException($value, 'string');
  }

  // Compose regex pattern
  $digitsPattern = $constraint->requireHyphen ? '\\d{4}-\\d{3}' : '\\d{4}-?\\d{3}';
  $checksumPattern = $constraint->caseSensitive ? '[\\d|X]' : '[\\d|X|x]';
  $pattern = "/^" . $digitsPattern . $checksumPattern . "\$/";
  if (!preg_match($pattern, $value)) {
    $this->context
      ->addViolation($constraint->message);
  }
  else {
    $digits = str_split(strtoupper(str_replace('-', '', $value)));
    $sum = 0;
    for ($i = 8; $i > 1; $i--) {
      $sum += $i * (int) array_shift($digits);
    }
    $checksum = 'X' == reset($digits) ? 10 : (int) reset($digits);
    if (0 != ($sum + $checksum) % 11) {
      $this->context
        ->addViolation($constraint->message);
    }
  }
}