/**
  * check client side cache
  *
  * @param \Smarty_Template_Cached  $cached
  * @param \Smarty_Internal_Template $_template
  * @param  string                  $content
  */
 public function cacheModifiedCheck(Smarty_Template_Cached $cached, Smarty_Internal_Template $_template, $content)
 {
     $_isCached = $_template->isCached() && !$_template->compiled->has_nocache_code;
     $_last_modified_date = @substr($_SERVER['HTTP_IF_MODIFIED_SINCE'], 0, strpos($_SERVER['HTTP_IF_MODIFIED_SINCE'], 'GMT') + 3);
     if ($_isCached && $cached->timestamp <= strtotime($_last_modified_date)) {
         switch (PHP_SAPI) {
             case 'cgi':
                 // php-cgi < 5.3
             // php-cgi < 5.3
             case 'cgi-fcgi':
                 // php-cgi >= 5.3
             // php-cgi >= 5.3
             case 'fpm-fcgi':
                 // php-fpm >= 5.3.3
                 header('Status: 304 Not Modified');
                 break;
             case 'cli':
                 if (!empty($_SERVER['SMARTY_PHPUNIT_DISABLE_HEADERS'])) {
                     $_SERVER['SMARTY_PHPUNIT_HEADERS'][] = '304 Not Modified';
                 }
                 break;
             default:
                 if (!empty($_SERVER['SMARTY_PHPUNIT_DISABLE_HEADERS'])) {
                     $_SERVER['SMARTY_PHPUNIT_HEADERS'][] = '304 Not Modified';
                 } else {
                     header($_SERVER['SERVER_PROTOCOL'] . ' 304 Not Modified');
                 }
                 break;
         }
     } else {
         switch (PHP_SAPI) {
             case 'cli':
                 if (!empty($_SERVER['SMARTY_PHPUNIT_DISABLE_HEADERS'])) {
                     $_SERVER['SMARTY_PHPUNIT_HEADERS'][] = 'Last-Modified: ' . gmdate('D, d M Y H:i:s', $cached->timestamp) . ' GMT';
                 }
                 break;
             default:
                 header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $cached->timestamp) . ' GMT');
                 break;
         }
         echo $content;
     }
 }