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  26 <a name="boost.sort.spreadsort.string_s_idm46709764719456"></a><div class="titlepage"></div>
  27 <div class="refnamediv">
  28 <h2><span class="refentrytitle">Function template string_sort</span></h2>
  29 <p>boost::sort::spreadsort::string_sort &#8212; String sort algorithm using random access iterators, wraps using default of <code class="computeroutput">unsigned</code> char. </p>
  30 </div>
  31 <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
  32 <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;
  33
  34 </span>
  35 <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">&gt;</span>
  36   <span class="keyword">void</span> <span class="identifier">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> get_character<span class="special">,</span> <span class="identifier">Get_length</span> length<span class="special">)</span><span class="special">;</span></pre></div>
  38 <div class="refsect1">
  39 <a name="idm45993902362992"></a><h2>Description</h2>
  40 <p>(All variants fall back to <code class="computeroutput">boost::sort::pdqsort</code> if the data size is too small, &lt; <code class="computeroutput">detail::min_sort_size</code>).</p>
  41 <p><code class="computeroutput">string_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 </p>
  43 <p><b>&#160;</b>Worst-case performance is <span class="emphasis"><em> O(N * (lg(range)/s + s)) </em></span>, so <code class="computeroutput">string_sort</code> is asymptotically faster than pure comparison-based algorithms. <br>
  44 <br>
  45 Some performance plots of runtime vs. n and log(range) are provided:<br>
  46 <a href="../../../../../doc/graph/windows_string_sort.htm" target="_top">windows_string_sort</a><br>
  47 <a href="../../../../../doc/graph/osx_string_sort.htm" target="_top">osx_string_sort</a></p>
  48 <p>
  49
  50
  51
  52
  53
  54
  55
  56
  57 </p>
  58 <div class="warning"><table border="0" summary="Warning">
  59 <tr>
  60 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../../../../doc/src/images/warning.png"></td>
  61 <th align="left">Warning</th>
  62 </tr>
  63 <tr><td align="left" valign="top"><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></td></tr>
  64 </table></div>
  65 <p>
  66 </p>
  67 <div class="warning"><table border="0" summary="Warning">
  68 <tr>
  69 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../../../../doc/src/images/warning.png"></td>
  70 <th align="left">Warning</th>
  71 </tr>
  72 <tr><td align="left" valign="top"><p>Invalid arguments cause undefined behaviour. </p></td></tr>
  73 </table></div>
  74 <p>
  75 </p>
  76 <div class="note"><table border="0" summary="Note">
  77 <tr>
  78 <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../doc/src/images/note.png"></td>
  79 <th align="left">Note</th>
  80 </tr>
  81 <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>
  82 </table></div>
  83 <p>
  84 </p>
  85 <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>
  86 <p>
  87
  88 </p>
  89 <p>* N is <code class="computeroutput">last</code> - <code class="computeroutput">first</code>, </p>
  90 <p>
  91
  92 </p>
  93 <p>* K is the log of the range in bits (32 for 32-bit integers using their full range), </p>
  94 <p>
  95
  96 </p>
  97 <p>* S is a constant called max_splits, defaulting to 11 (except for strings where it is the log of the character size). </p>
  98 <p>
  99
 100 </p>
 101 <div class="variablelist"><table border="0" class="variablelist compact">
 102 <colgroup>
 103 <col align="left" valign="top">
 104 <col>
 105 </colgroup>
 106 <tbody>
 107 <tr>
 108 <td><p><span class="term">Parameters:</span></p></td>
 109 <td><div class="variablelist"><table border="0" class="variablelist compact">
 110 <colgroup>
 111 <col align="left" valign="top">
 112 <col>
 113 </colgroup>
 114 <tbody>
 115 <tr>
 116 <td><p><span class="term"><code class="computeroutput">first</code></span></p></td>
 117 <td><p>Iterator pointer to first element. </p></td>
 118 </tr>
 119 <tr>
 120 <td><p><span class="term"><code class="computeroutput">get_character</code></span></p></td>
 121 <td><p>Bracket functor equivalent to <code class="computeroutput">operator</code>[], taking a number corresponding to the character offset. </p></td>
 122 </tr>
 123 <tr>
 124 <td><p><span class="term"><code class="computeroutput">last</code></span></p></td>
 125 <td><p>Iterator pointing to one beyond the end of data. </p></td>
 126 </tr>
 127 <tr>
 128 <td><p><span class="term"><code class="computeroutput">length</code></span></p></td>
 129 <td><p>Functor to get the length of the string in characters.</p></td>
 130 </tr>
 131 </tbody>
 132 </table></div></td>
 133 </tr>
 134 <tr>
 135 <td><p><span class="term">Requires:</span></p></td>
 136 <td><p>[<code class="computeroutput">first</code>, <code class="computeroutput">last</code>) is a valid range. </p></td>
 137 </tr>
 138 <tr>
 139 <td><p><span class="term">Requires:</span></p></td>
 140 <td><p><code class="computeroutput">RandomAccessIter</code> <code class="computeroutput">value_type</code> is mutable. </p></td>
 141 </tr>
 142 <tr>
 143 <td><p><span class="term">Requires:</span></p></td>
 144 <td><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></td>
 145 </tr>
 146 <tr>
 147 <td><p><span class="term">Requires:</span></p></td>
 148 <td><p><code class="computeroutput">RandomAccessIter</code> <code class="computeroutput">value_type</code> supports the <code class="computeroutput">operator&gt;&gt;</code>, which returns an integer-type right-shifted a specified number of bits. </p></td>
 149 </tr>
 150 <tr>
 151 <td><p><span class="term">Postconditions:</span></p></td>
 152 <td><p>The elements in the range [<code class="computeroutput">first</code>, <code class="computeroutput">last</code>) are sorted in ascending order.</p></td>
 153 </tr>
 154 <tr>
 155 <td><p><span class="term">Returns:</span></p></td>
 156 <td><p><code class="computeroutput">void</code>.</p></td>
 157 </tr>
 158 <tr>
 159 <td><p><span class="term">Throws:</span></p></td>
 160 <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>
 161 </tr>
 162 </tbody>
 163 </table></div>
 164 </div>
 165 </div>
 166 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 167 <td align="left"></td>
 168 <td align="right"><div class="copyright-footer">Copyright &#169; 2014-2017 Steven
 169       Ross, Francisco Tapia, Orson Peters<p>
 170         Distributed under the <a href="http://boost.org/LICENSE_1_0.txt" target="_top">Boost
 171         Software License, Version 1.0</a>.
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