Validation::date PHP Method

    public static function date($value)
    {
        $regex = '%^(?:(?:31(/|-|\\.)(?:0?[13578]|1[02]))\\1|(?:(?:29|30)(/|-|\\.)(?:0?[1,3-9]|1[0-2])\\2))(?:(?:1[6-9]|[2-9]\\d)?\\d{2})$|^(?:29(/|-|\\.)0?2\\3(?:(?:(?:1[6-9]|[2-9]\\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:0?[1-9]|1\\d|2[0-8])(/|-|\\.)(?:(?:0?[1-9])|(?:1[0-2]))\\4(?:(?:1[6-9]|[2-9]\\d)?\\d{2})$%';
        return (bool) preg_match($regex, $value);
    }

 /**
  * Compares whether or not a date is some number of days | months | years after a date
  * This is a magic method and can be called via daysInFuture, monthsInFuture and yearsInFuture
  * 
  * @param object $model
  * @param string $method the name of hte magic method
  * @param array  $check the data of the field to be checked 
  * @param integer $value of days | months | years that $check should be in the future
  * @param array $params [optional]
  * 						- 'fields'	array of fields that should be matched against (default: array())
  * 						- 'timezone' string timezone identifier (default: 'UTC')
  * @return boolean if $check is at least $value days | months | years in the future
  * @access public
  * @author Jose Diaz-Gonzales
  * @author Thomas Ploch
  * @link http://snipplr.com/view/2223/get-number-of-days-between-two-dates/
  */
 function inFuture(&$model, $method, $check, $value, $params = array())
 {
     $valid = false;
     // If $check is not a valid date
     if (!Validation::date(reset($check), 'Y-m-d')) {
         return $valid;
     }
     // Get the $mode from method name
     $mode = str_replace('infuture', '', $method);
     /* PHP5
      * $mode = str_replace(low(__METHOD__), '', $method);
      */
     // Default config
     $defaultConfig = array('fields' => array(), 'timezone' => 'UTC');
     // Get options
     extract(am($defaultConfig, $params));
     if (empty($fields)) {
         return $valid;
     }
     // Setting the timezone if possible
     if (function_exists('date_default_timezone_set')) {
         date_default_timezone_set($timezone);
     }
     /*
      * TODO: add cases for months and years to switch
      * FIXME: refactor cases into helper functions
      */
     switch ($mode) {
         case 'days':
             foreach ($fields as $field) {
                 // First we need to break these dates into their constituent parts:
                 $gd_a = getdate(strtotime($model->data[$model->alias][$field]));
                 $gd_b = getdate(strtotime(reset($check)));
                 // Now recreate these timestamps, based upon noon on each day
                 // The specific time doesn't matter but it must be the same each day
                 $a_new = mktime(12, 0, 0, $gd_a['mon'], $gd_a['mday'], $gd_a['year']);
                 $b_new = mktime(12, 0, 0, $gd_b['mon'], $gd_b['mday'], $gd_b['year']);
                 // Subtract these two numbers and divide by the number of seconds in a
                 //  day. Round the result since crossing over a daylight savings time
                 //  barrier will cause this time to be off by an hour or two.
                 $valid = round(abs($a_new - $b_new) / 86400) >= $params['days'];
                 if (!$valid) {
                     return $valid;
                 }
             }
             return $valid;
         default:
             return $valid;
     }
 }