xzread example

public function _readBlock()
    {
        $v_block = null;
        if (is_resource($this->_file)) {
            if ($this->_compress_type == 'gz') {
                $v_block = @gzread($this->_file, 512);
            } else {
                if ($this->_compress_type == 'bz2') {
                    $v_block = @bzread($this->_file, 512);
                } else {
                    if ($this->_compress_type == 'lzma2') {
                        $v_block = @xzread($this->_file, 512);
                    } else {
                        if ($this->_compress_type == 'none') {
                            $v_block = @fread($this->_file, 512);
                        } else {
                            $this->_error(
                                'Unknown or missing compression type ('
                                . $this->_compress_type . ')'
                            );
                        }
                    }
                }
            }