public function read($length)
    {
        if (!$this->isConnected()) {
            throw new Rediska_Connection_Exception("Can't read without connection to Redis server. Do connect or write first.");
        }

        if ($length > 0) {
            $data = $this->_readAndThrowException($length);
        } else {
            $data = null;
        }

        if ($length !== -1) {
            $this->_readAndThrowException(2);
        }

        return $data;
    }