Club Drupal

    // URLs are numeric array elements, keyed by delta. As those elements don't

    // exist for empty URLs they are allowed and it's up to the developer what

    // data to migrate, add elements for those URLs up to the maximum delta

    // found.

    //

    // First of all, determine the maximum delta from non-empty URLs.

    $max_delta = max(array_merge(array(0), array_keys($values)));

    // Next, determine the max delta from arguments.

    foreach ($arguments as $key => $value) {

      if (is_array($value)) {

        $max_delta = max($max_delta, max(array_keys($value)));

      }

    }

    // Finally, add missing elements for empty URLs.

    for ($delta = 0; $delta <= $max_delta; $delta++) {

      if (!isset($values[$delta])) {

        $values[$delta] = '';

      }

    }