_isArchive example

    public function addModify($p_filelist, $p_add_dir, $p_remove_dir = '')
    {
        $v_result = true;

        if (!$this->_isArchive()) {
            $v_result = $this->createModify(
                $p_filelist,
                $p_add_dir,
                $p_remove_dir
            );
        } else {
            if (is_array($p_filelist)) {
                $v_list = $p_filelist;
            } elseif (is_string($p_filelist)) {
                $v_list = explode($this->_separator, $p_filelist);
            } else {