public function addSearchDirs($dirs)
    {
        // just force to array
        settype($dirs, 'array');

        // loop through the path directories
        foreach ($dirs as $dir) {
            // no surrounding spaces allowed!
            $dir = $this->_unifyPath(trim($dir));

            // remove trailing slash
            if (substr($dir, -1) == DS) {
                $dir = substr_replace($dir, '', -1);
            }

            // add to the top of the search dirs
            array_unshift($this->_dirs, $dir);
        }

        return $this;
    }