e"><a name="l00031"></a><span class="lineno">   31</span>&#160;    <span class="keyword">using</span> buffer_t = std::vector&lt;element_t&gt;;</div><div class="line"><a name="l00032"></a><span class="lineno">   32</span>&#160;    <span class="keyword">using</span> iterator_t = <span class="keyword">typename</span> buffer_t::iterator;</div><div class="line"><a name="l00033"></a><span class="lineno">   33</span>&#160;</div><div class="line"><a name="l00034"></a><span class="lineno">   34</span>&#160;    row_b