public function getHideFilesRegex()
    {
        static $fileRegex;

        if (!isset($fileRegex)) {
            if (is_array($this->_hideFiles) && $this->_hideFiles) {
                $fileRegex = join("|", $this->_hideFiles);
                $fileRegex = strtr($fileRegex, array("?" => "__QMK__", "*" => "__AST__", "|" => "__PIP__"));
                $fileRegex = preg_quote($fileRegex, "/");
                $fileRegex = strtr($fileRegex, array("__QMK__" => ".", "__AST__" => ".*", "__PIP__" => "|"));
                $fileRegex = "/^(?:" . $fileRegex . ")$/uim";
            }
            else {
                $fileRegex = "";
            }
        }

        return $fileRegex;
    }