xzopen example

    public function _openWrite()
    {
        if ($this->_compress_type == 'gz' && function_exists('gzopen')) {
            $this->_file = @gzopen($this->_tarname, "wb9");
        } else {
            if ($this->_compress_type == 'bz2' && function_exists('bzopen')) {
                $this->_file = @bzopen($this->_tarname, "w");
            } else {
                if ($this->_compress_type == 'lzma2' && function_exists('xzopen')) {
                    $this->_file = @xzopen($this->_tarname, 'w');
                } else {
                    if ($this->_compress_type == 'none') {
                        $this->_file = @fopen($this->_tarname, "wb");
                    } else {
                        $this->_error(
                            'Unknown or missing compression type ('
                            . $this->_compress_type . ')'
                        );
                        return false;
                    }
                }
            }