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  25 <a name="boost.sort.spreadsort.reverse_string_idp26192768"></a><div class="titlepage"></div>
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  27 <h2><span class="refentrytitle">Function template reverse_string_sort</span></h2>
  28 <p>boost::sort::spreadsort::reverse_string_sort &#8212; Reverse String sort algorithm using random access iterators. </p>
  29 </div>
  30 <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
  31 <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../../../header/boost/sort/spreadsort/string_sort_hpp.html" title="Header &lt;boost/sort/spreadsort/string_sort.hpp&gt;">boost/sort/spreadsort/string_sort.hpp</a>&gt;
  32
  33 </span>
  34 <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> RandomAccessIter<span class="special">,</span> <span class="keyword">typename</span> Get_char<span class="special">,</span> <span class="keyword">typename</span> Get_length<span class="special">,</span>
  35          <span class="keyword">typename</span> Compare<span class="special">&gt;</span>
  36   <span class="keyword">void</span> <span class="identifier">reverse_string_sort</span><span class="special">(</span><span class="identifier">RandomAccessIter</span> first<span class="special">,</span> <span class="identifier">RandomAccessIter</span> last<span class="special">,</span>
  37                            <span class="identifier">Get_char</span> getchar<span class="special">,</span> <span class="identifier">Get_length</span> length<span class="special">,</span> <span class="identifier">Compare</span> comp<span class="special">)</span><span class="special">;</span></pre></div>
  38 <div class="refsect1">
  39 <a name="idp103492624"></a><h2>Description</h2>
  40 <p>(All variants fall back to <code class="computeroutput">std::sort</code> if the data size is too small, &lt; <code class="computeroutput">detail::min_sort_size</code>).</p>
  41 <p><code class="computeroutput">integer_sort</code> is a fast templated in-place hybrid radix/comparison algorithm, which in testing tends to be roughly 50% to 2X faster than <code class="computeroutput">std::sort</code> for large tests (&gt;=100kB).<br>
  42 Worst-case performance is <span class="emphasis"><em> O(N * (lg(range)/s + s)) </em></span>, so <code class="computeroutput">integer_sort</code> is asymptotically faster than pure comparison-based algorithms. <code class="computeroutput">s</code> is <code class="computeroutput">max_splits</code>, which defaults to 11, so its worst-case with default settings for 32-bit integers is <span class="emphasis"><em> O(N * ((32/11) </em></span> slow radix-based iterations fast comparison-based iterations).<br>
  43 <br>
  44 Some performance plots of runtime vs. n and log(range) are provided:<br>
  45  <a href="../../../../../doc/graph/windows_integer_sort.htm" target="_top">windows_integer_sort</a> <br>
  46  <a href="../../../../../doc/graph/osx_integer_sort.htm" target="_top">osx_integer_sort</a></p>
  47 <p>
  48
  49
  50
  51
  52 </p>
  53 <div class="warning"><table border="0" summary="Warning">
  54 <tr>
  55 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../../../../doc/src/images/warning.png"></td>
  56 <th align="left">Warning</th>
  57 </tr>
  58 <tr><td align="left" valign="top">
  59 <p>Throwing an exception may cause data loss. This will also throw if a small vector resize throws, in which case there will be no data loss. </p>
  60 <p>Invalid arguments cause undefined behaviour. </p>
  61 </td></tr>
  62 </table></div>
  63 <p>
  64 </p>
  65 <div class="note"><table border="0" summary="Note">
  66 <tr>
  67 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../doc/src/images/note.png"></td>
  68 <th align="left">Note</th>
  69 </tr>
  70 <tr><td align="left" valign="top"><p><code class="computeroutput">spreadsort</code> function provides a wrapper that calls the fastest sorting algorithm available for a data type, enabling faster generic-programming.</p></td></tr>
  71 </table></div>
  72 <p>
  73 </p>
  74 <p>The lesser of <span class="emphasis"><em> O(N*log(N)) </em></span> comparisons and <span class="emphasis"><em> O(N*log(K/S + S)) </em></span>operations worst-case, where: </p>
  75 <p>* N is <code class="computeroutput">last</code> - <code class="computeroutput">first</code>, </p>
  76 <p>* K is the log of the range in bits (32 for 32-bit integers using their full range), </p>
  77 <p>* S is a constant called max_splits, defaulting to 11 (except for strings where it is the log of the character size). </p>
  78 <p>
  79 </p>
  80 <div class="variablelist"><table border="0" class="variablelist compact">
  81 <colgroup>
  82 <col align="left" valign="top">
  83 <col>
  84 </colgroup>
  85 <tbody>
  86 <tr>
  87 <td><p><span class="term">Parameters:</span></p></td>
  88 <td><div class="variablelist"><table border="0" class="variablelist compact">
  89 <colgroup>
  90 <col align="left" valign="top">
  91 <col>
  92 </colgroup>
  93 <tbody>
  94 <tr>
  95 <td><p><span class="term"><code class="computeroutput">comp</code></span></p></td>
  96 <td><p>A binary functor that returns whether the first element passed to it should go before the second in order.</p></td>
  97 </tr>
  98 <tr>
  99 <td><p><span class="term"><code class="computeroutput">first</code></span></p></td>
 100 <td><p>Iterator pointer to first element. </p></td>
 101 </tr>
 102 <tr>
 103 <td><p><span class="term"><code class="computeroutput">getchar</code></span></p></td>
 104 <td><p>Bracket functor equivalent to <code class="computeroutput">operator</code>[], taking a number corresponding to the character offset. </p></td>
 105 </tr>
 106 <tr>
 107 <td><p><span class="term"><code class="computeroutput">last</code></span></p></td>
 108 <td><p>Iterator pointing to one beyond the end of data. </p></td>
 109 </tr>
 110 <tr>
 111 <td><p><span class="term"><code class="computeroutput">length</code></span></p></td>
 112 <td><p>Functor to get the length of the string in characters. </p></td>
 113 </tr>
 114 </tbody>
 115 </table></div></td>
 116 </tr>
 117 <tr>
 118 <td><p><span class="term">Requires:</span></p></td>
 119 <td>
 120 <p>[<code class="computeroutput">first</code>, <code class="computeroutput">last</code>) is a valid range. </p>
 121 <p><code class="computeroutput">RandomAccessIter</code> <code class="computeroutput">value_type</code> is mutable. </p>
 122 <p><code class="computeroutput">RandomAccessIter</code> <code class="computeroutput">value_type</code> is <a href="http://en.cppreference.com/w/cpp/concept/LessThanComparable" target="_top">LessThanComparable</a> </p>
 123 </td>
 124 </tr>
 125 <tr>
 126 <td><p><span class="term">Postconditions:</span></p></td>
 127 <td><p>The elements in the range [<code class="computeroutput">first</code>, <code class="computeroutput">last</code>) are sorted in ascending order.</p></td>
 128 </tr>
 129 <tr>
 130 <td><p><span class="term">Returns:</span></p></td>
 131 <td><p><code class="computeroutput">void</code>.</p></td>
 132 </tr>
 133 <tr>
 134 <td><p><span class="term">Throws:</span></p></td>
 135 <td>std::exception Propagates exceptions if any of the element comparisons, the element swaps (or moves), the right shift, subtraction of right-shifted elements, functors, or any operations on iterators throw.</td>
 136 </tr>
 137 </tbody>
 138 </table></div>
 139 </div>
 140 </div>
 141 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 142 <td align="left"></td>
 143 <td align="right"><div class="copyright-footer">Copyright &#169; 2014 Steven Ross<p>
 144         Distributed under the <a href="http://boost.org/LICENSE_1_0.txt" target="_top">Boost
 145         Software License, Version 1.0</a>.
 146       </p>
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