><span class="identifier">data_type</span></code>
          to the number of unused bits in the last byte taken from <code class="computeroutput"><span class="identifier">zs</span><span class="special">.</span><span class="identifier">next_in</span></code>,
          plus 64 if <code class="computeroutput"><span class="identifier">write</span></code> is currently
          decoding the last block in the deflate stream, plus 128 if <code class="computeroutput"><span class="identifier">write</span></code> ret