<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <meta http-equiv="X-UA-Compatible" content="IE=9"/> <meta name="generator" content="Doxygen 1.8.13"/> <meta name="viewport" content="width=device-width, initial-scale=1"/> <title>libstdc++: functional_hash.h Source File</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript" src="dynsections.js"></script> <link href="navtree.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="resize.js"></script> <script type="text/javascript" src="navtreedata.js"></script> <script type="text/javascript" src="navtree.js"></script> <script type="text/javascript"> $(document).ready(initResizable); </script> <link href="doxygen.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="top"><!-- do not remove this div, it is closed by doxygen! --> <div id="titlearea"> <table cellspacing="0" cellpadding="0"> <tbody> <tr style="height: 56px;"> <td id="projectalign" style="padding-left: 0.5em;"> <div id="projectname">libstdc++ </div> </td> </tr> </tbody> </table> </div> <!-- end header part --> <!-- Generated by Doxygen 1.8.13 --> </div><!-- top --> <div id="side-nav" class="ui-resizable side-nav-resizable"> <div id="nav-tree"> <div id="nav-tree-contents"> <div id="nav-sync" class="sync"></div> </div> </div> <div id="splitbar" style="-moz-user-select:none;" class="ui-resizable-handle"> </div> </div> <script type="text/javascript"> $(document).ready(function(){initNavTree('a00335_source.html','');}); </script> <div id="doc-content"> <div class="header"> <div class="headertitle"> <div class="title">functional_hash.h</div> </div> </div><!--header--> <div class="contents"> <a href="a00335.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">// functional_hash.h header -*- C++ -*-</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> </div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment">// Copyright (C) 2007-2015 Free Software Foundation, Inc.</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment">//</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment">// This file is part of the GNU ISO C++ Library. This library is free</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment">// software; you can redistribute it and/or modify it under the</span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment">// terms of the GNU General Public License as published by the</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="comment">// Free Software Foundation; either version 3, or (at your option)</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> <span class="comment">// any later version.</span></div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> </div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="comment">// This library is distributed in the hope that it will be useful,</span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> <span class="comment">// but WITHOUT ANY WARRANTY; without even the implied warranty of</span></div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span> <span class="comment">// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</span></div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="comment">// GNU General Public License for more details.</span></div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> </div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="comment">// Under Section 7 of GPL version 3, you are granted additional</span></div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="comment">// permissions described in the GCC Runtime Library Exception, version</span></div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="comment">// 3.1, as published by the Free Software Foundation.</span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> </div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="comment">// You should have received a copy of the GNU General Public License and</span></div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="comment">// a copy of the GCC Runtime Library Exception along with this program;</span></div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> <span class="comment">// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see</span></div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> <span class="comment">// <http://www.gnu.org/licenses/>.</span></div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> <span class="comment"></span></div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> <span class="comment">/** @file bits/functional_hash.h</span></div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> <span class="comment"> * This is an internal header file, included by other library headers.</span></div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span> <span class="comment"> * Do not attempt to use it directly. @headername{functional}</span></div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> <span class="comment"> */</span></div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> </div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span> <span class="preprocessor">#ifndef _FUNCTIONAL_HASH_H</span></div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span> <span class="preprocessor">#define _FUNCTIONAL_HASH_H 1</span></div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span> </div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span> <span class="preprocessor">#pragma GCC system_header</span></div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> </div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span> <span class="preprocessor">#include <<a class="code" href="a00344.html">bits/hash_bytes.h</a>></span></div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span> </div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span> <span class="keyword">namespace </span><a class="code" href="a01487.html">std</a> _GLIBCXX_VISIBILITY(default)</div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span> {</div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span> _GLIBCXX_BEGIN_NAMESPACE_VERSION</div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span> <span class="comment"></span></div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span> <span class="comment"> /** @defgroup hashes Hashes</span></div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span> <span class="comment"> * @ingroup functors</span></div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span> <span class="comment"> *</span></div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span> <span class="comment"> * Hashing functors taking a variable type and returning a @c std::size_t.</span></div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span> <span class="comment"> *</span></div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span> <span class="comment"> * @{</span></div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span> <span class="comment"> */</span></div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span> </div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _Result, <span class="keyword">typename</span> _Arg></div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span>  <span class="keyword">struct </span>__hash_base</div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span>  {</div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span>  <span class="keyword">typedef</span> _Result result_type;</div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span>  <span class="keyword">typedef</span> _Arg argument_type;</div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span>  };</div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span> <span class="comment"></span></div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span> <span class="comment"> /// Primary class template hash.</span></div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span> <span class="comment"></span> <span class="keyword">template</span><<span class="keyword">typename</span> _Tp></div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span>  <span class="keyword">struct </span>hash;</div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span> <span class="comment"></span></div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span> <span class="comment"> /// Partial specializations for pointer types.</span></div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span> <span class="comment"></span> <span class="keyword">template</span><<span class="keyword">typename</span> _Tp></div><div class="line"><a name="l00062"></a><span class="lineno"><a class="line" href="a04897.html"> 62</a></span>  <span class="keyword">struct </span><a class="code" href="a03257.html">hash</a><_Tp*> : <span class="keyword">public</span> __hash_base<size_t, _Tp*></div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span>  {</div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span>  <span class="keywordtype">size_t</span></div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span>  operator()(_Tp* __p) <span class="keyword">const</span> noexcept</div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span>  { <span class="keywordflow">return</span> <span class="keyword">reinterpret_cast<</span><span class="keywordtype">size_t</span><span class="keyword">></span>(__p); }</div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span>  };</div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span> </div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span>  <span class="comment">// Explicit specializations for integer types.</span></div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span> <span class="preprocessor">#define _Cxx_hashtable_define_trivial_hash(_Tp) \</span></div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span> <span class="preprocessor"> template<> \</span></div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span> <span class="preprocessor"> struct hash<_Tp> : public __hash_base<size_t, _Tp> \</span></div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span> <span class="preprocessor"> { \</span></div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span> <span class="preprocessor"> size_t \</span></div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span> <span class="preprocessor"> operator()(_Tp __val) const noexcept \</span></div><div class="line"><a name="l00076"></a><span class="lineno"> 76</span> <span class="preprocessor"> { return static_cast<size_t>(__val); } \</span></div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span> <span class="preprocessor"> };</span></div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span> <span class="comment"></span></div><div class="line"><a name="l00079"></a><span class="lineno"> 79</span> <span class="comment"> /// Explicit specialization for bool.</span></div><div class="line"><a name="l00080"></a><span class="lineno"><a class="line" href="a04901.html"> 80</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">bool</span>)</div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span> </div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span>  <span class="comment">/// Explicit specialization for char.</span></div><div class="line"><a name="l00083"></a><span class="lineno"><a class="line" href="a04905.html"> 83</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">char</span>)</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span> <span class="comment"></span></div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span> <span class="comment"> /// Explicit specialization for signed char.</span></div><div class="line"><a name="l00086"></a><span class="lineno"><a class="line" href="a04909.html"> 86</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">signed</span> <span class="keywordtype">char</span>)</div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span> <span class="comment"></span></div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span> <span class="comment"> /// Explicit specialization for unsigned char.</span></div><div class="line"><a name="l00089"></a><span class="lineno"><a class="line" href="a04913.html"> 89</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span>)</div><div class="line"><a name="l00090"></a><span class="lineno"> 90</span> <span class="comment"></span></div><div class="line"><a name="l00091"></a><span class="lineno"> 91</span> <span class="comment"> /// Explicit specialization for wchar_t.</span></div><div class="line"><a name="l00092"></a><span class="lineno"><a class="line" href="a04917.html"> 92</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">wchar_t</span>)</div><div class="line"><a name="l00093"></a><span class="lineno"> 93</span> <span class="comment"></span></div><div class="line"><a name="l00094"></a><span class="lineno"> 94</span> <span class="comment"> /// Explicit specialization for char16_t.</span></div><div class="line"><a name="l00095"></a><span class="lineno"><a class="line" href="a04921.html"> 95</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(char16_t)</div><div class="line"><a name="l00096"></a><span class="lineno"> 96</span> <span class="comment"></span></div><div class="line"><a name="l00097"></a><span class="lineno"> 97</span> <span class="comment"> /// Explicit specialization for char32_t.</span></div><div class="line"><a name="l00098"></a><span class="lineno"><a class="line" href="a04925.html"> 98</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(char32_t)</div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span> <span class="comment"></span></div><div class="line"><a name="l00100"></a><span class="lineno"> 100</span> <span class="comment"> /// Explicit specialization for short.</span></div><div class="line"><a name="l00101"></a><span class="lineno"><a class="line" href="a04929.html"> 101</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">short</span>)</div><div class="line"><a name="l00102"></a><span class="lineno"> 102</span> <span class="comment"></span></div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span> <span class="comment"> /// Explicit specialization for int.</span></div><div class="line"><a name="l00104"></a><span class="lineno"><a class="line" href="a04933.html"> 104</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">int</span>)</div><div class="line"><a name="l00105"></a><span class="lineno"> 105</span> <span class="comment"></span></div><div class="line"><a name="l00106"></a><span class="lineno"> 106</span> <span class="comment"> /// Explicit specialization for long.</span></div><div class="line"><a name="l00107"></a><span class="lineno"><a class="line" href="a04937.html"> 107</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">long</span>)</div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span> <span class="comment"></span></div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span> <span class="comment"> /// Explicit specialization for long long.</span></div><div class="line"><a name="l00110"></a><span class="lineno"><a class="line" href="a04941.html"> 110</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">long</span> <span class="keywordtype">long</span>)</div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span> <span class="comment"></span></div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span> <span class="comment"> /// Explicit specialization for unsigned short.</span></div><div class="line"><a name="l00113"></a><span class="lineno"><a class="line" href="a04945.html"> 113</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">unsigned</span> <span class="keywordtype">short</span>)</div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span> <span class="comment"></span></div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span> <span class="comment"> /// Explicit specialization for unsigned int.</span></div><div class="line"><a name="l00116"></a><span class="lineno"><a class="line" href="a04949.html"> 116</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>)</div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span> <span class="comment"></span></div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span> <span class="comment"> /// Explicit specialization for unsigned long.</span></div><div class="line"><a name="l00119"></a><span class="lineno"><a class="line" href="a04953.html"> 119</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span>)</div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span> <span class="comment"></span></div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span> <span class="comment"> /// Explicit specialization for unsigned long long.</span></div><div class="line"><a name="l00122"></a><span class="lineno"><a class="line" href="a04957.html"> 122</a></span> <span class="comment"></span> _Cxx_hashtable_define_trivial_hash(<span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> <span class="keywordtype">long</span>)</div><div class="line"><a name="l00123"></a><span class="lineno"> 123</span> </div><div class="line"><a name="l00124"></a><span class="lineno"> 124</span> <span class="preprocessor">#undef _Cxx_hashtable_define_trivial_hash</span></div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span> </div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span>  <span class="keyword">struct </span>_Hash_impl</div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span>  {</div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span>  <span class="keyword">static</span> <span class="keywordtype">size_t</span></div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span>  <a class="code" href="a03257.html">hash</a>(<span class="keyword">const</span> <span class="keywordtype">void</span>* __ptr, <span class="keywordtype">size_t</span> __clength,</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span>  <span class="keywordtype">size_t</span> __seed = static_cast<size_t>(0xc70f6907UL))</div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  { <span class="keywordflow">return</span> _Hash_bytes(__ptr, __clength, __seed); }</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span> </div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _Tp></div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  <span class="keyword">static</span> <span class="keywordtype">size_t</span></div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span>  <a class="code" href="a03257.html">hash</a>(<span class="keyword">const</span> _Tp& __val)</div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span>  { <span class="keywordflow">return</span> <a class="code" href="a03257.html">hash</a>(&__val, <span class="keyword">sizeof</span>(__val)); }</div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span> </div><div class="line"><a name="l00138"></a><span class="lineno"> 138</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _Tp></div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span>  <span class="keyword">static</span> <span class="keywordtype">size_t</span></div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span>  __hash_combine(<span class="keyword">const</span> _Tp& __val, <span class="keywordtype">size_t</span> __hash)</div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span>  { <span class="keywordflow">return</span> <a class="code" href="a03257.html">hash</a>(&__val, <span class="keyword">sizeof</span>(__val), __hash); }</div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span>  };</div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span> </div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span>  <span class="keyword">struct </span>_Fnv_hash_impl</div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span>  {</div><div class="line"><a name="l00146"></a><span class="lineno"> 146</span>  <span class="keyword">static</span> <span class="keywordtype">size_t</span></div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span>  <a class="code" href="a03257.html">hash</a>(<span class="keyword">const</span> <span class="keywordtype">void</span>* __ptr, <span class="keywordtype">size_t</span> __clength,</div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span>  <span class="keywordtype">size_t</span> __seed = static_cast<size_t>(2166136261UL))</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span>  { <span class="keywordflow">return</span> _Fnv_hash_bytes(__ptr, __clength, __seed); }</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span> </div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _Tp></div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span>  <span class="keyword">static</span> <span class="keywordtype">size_t</span></div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span>  <a class="code" href="a03257.html">hash</a>(<span class="keyword">const</span> _Tp& __val)</div><div class="line"><a name="l00154"></a><span class="lineno"> 154</span>  { <span class="keywordflow">return</span> <a class="code" href="a03257.html">hash</a>(&__val, <span class="keyword">sizeof</span>(__val)); }</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span> </div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _Tp></div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span>  <span class="keyword">static</span> <span class="keywordtype">size_t</span></div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span>  __hash_combine(<span class="keyword">const</span> _Tp& __val, <span class="keywordtype">size_t</span> __hash)</div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span>  { <span class="keywordflow">return</span> <a class="code" href="a03257.html">hash</a>(&__val, <span class="keyword">sizeof</span>(__val), __hash); }</div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span>  };</div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span> <span class="comment"></span></div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span> <span class="comment"> /// Specialization for float.</span></div><div class="line"><a name="l00163"></a><span class="lineno"> 163</span> <span class="comment"></span> <span class="keyword">template</span><></div><div class="line"><a name="l00164"></a><span class="lineno"><a class="line" href="a04969.html"> 164</a></span>  <span class="keyword">struct </span><a class="code" href="a03257.html">hash</a><float> : <span class="keyword">public</span> __hash_base<size_t, float></div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span>  {</div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span>  <span class="keywordtype">size_t</span></div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span>  operator()(<span class="keywordtype">float</span> __val) <span class="keyword">const</span> noexcept</div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span>  {</div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span>  <span class="comment">// 0 and -0 both hash to zero.</span></div><div class="line"><a name="l00170"></a><span class="lineno"> 170</span>  <span class="keywordflow">return</span> __val != 0.0f ? std::_Hash_impl::hash(__val) : 0;</div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span>  }</div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span>  };</div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span> <span class="comment"></span></div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span> <span class="comment"> /// Specialization for double.</span></div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span> <span class="comment"></span> <span class="keyword">template</span><></div><div class="line"><a name="l00176"></a><span class="lineno"><a class="line" href="a04973.html"> 176</a></span>  <span class="keyword">struct </span><a class="code" href="a03257.html">hash</a><double> : <span class="keyword">public</span> __hash_base<size_t, double></div><div class="line"><a name="l00177"></a><span class="lineno"> 177</span>  {</div><div class="line"><a name="l00178"></a><span class="lineno"> 178</span>  <span class="keywordtype">size_t</span></div><div class="line"><a name="l00179"></a><span class="lineno"> 179</span>  operator()(<span class="keywordtype">double</span> __val) <span class="keyword">const</span> noexcept</div><div class="line"><a name="l00180"></a><span class="lineno"> 180</span>  {</div><div class="line"><a name="l00181"></a><span class="lineno"> 181</span>  <span class="comment">// 0 and -0 both hash to zero.</span></div><div class="line"><a name="l00182"></a><span class="lineno"> 182</span>  <span class="keywordflow">return</span> __val != 0.0 ? std::_Hash_impl::hash(__val) : 0;</div><div class="line"><a name="l00183"></a><span class="lineno"> 183</span>  }</div><div class="line"><a name="l00184"></a><span class="lineno"> 184</span>  };</div><div class="line"><a name="l00185"></a><span class="lineno"> 185</span> <span class="comment"></span></div><div class="line"><a name="l00186"></a><span class="lineno"> 186</span> <span class="comment"> /// Specialization for long double.</span></div><div class="line"><a name="l00187"></a><span class="lineno"> 187</span> <span class="comment"></span> <span class="keyword">template</span><></div><div class="line"><a name="l00188"></a><span class="lineno"><a class="line" href="a04977.html"> 188</a></span>  <span class="keyword">struct </span><a class="code" href="a03257.html">hash</a><long double></div><div class="line"><a name="l00189"></a><span class="lineno"> 189</span>  : <span class="keyword">public</span> __hash_base<size_t, long double></div><div class="line"><a name="l00190"></a><span class="lineno"> 190</span>  {</div><div class="line"><a name="l00191"></a><span class="lineno"> 191</span>  _GLIBCXX_PURE <span class="keywordtype">size_t</span></div><div class="line"><a name="l00192"></a><span class="lineno"> 192</span>  operator()(<span class="keywordtype">long</span> <span class="keywordtype">double</span> __val) <span class="keyword">const</span> noexcept;</div><div class="line"><a name="l00193"></a><span class="lineno"> 193</span>  };</div><div class="line"><a name="l00194"></a><span class="lineno"> 194</span> </div><div class="line"><a name="l00195"></a><span class="lineno"> 195</span>  <span class="comment">// @} group hashes</span></div><div class="line"><a name="l00196"></a><span class="lineno"> 196</span> </div><div class="line"><a name="l00197"></a><span class="lineno"> 197</span>  <span class="comment">// Hint about performance of hash functor. If not fast the hash based</span></div><div class="line"><a name="l00198"></a><span class="lineno"> 198</span>  <span class="comment">// containers will cache the hash code.</span></div><div class="line"><a name="l00199"></a><span class="lineno"> 199</span>  <span class="comment">// Default behavior is to consider that hasher are fast unless specified</span></div><div class="line"><a name="l00200"></a><span class="lineno"> 200</span>  <span class="comment">// otherwise.</span></div><div class="line"><a name="l00201"></a><span class="lineno"> 201</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _Hash></div><div class="line"><a name="l00202"></a><span class="lineno"> 202</span>  <span class="keyword">struct </span>__is_fast_hash : <span class="keyword">public</span> <a class="code" href="a03485.html">std::true_type</a></div><div class="line"><a name="l00203"></a><span class="lineno"> 203</span>  { };</div><div class="line"><a name="l00204"></a><span class="lineno"> 204</span> </div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span>  <span class="keyword">template</span><></div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span>  <span class="keyword">struct </span>__is_fast_hash<hash<long double>> : <span class="keyword">public</span> <a class="code" href="a03485.html">std::false_type</a></div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span>  { };</div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span> </div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span> _GLIBCXX_END_NAMESPACE_VERSION</div><div class="line"><a name="l00210"></a><span class="lineno"> 210</span> } <span class="comment">// namespace</span></div><div class="line"><a name="l00211"></a><span class="lineno"> 211</span> </div><div class="line"><a name="l00212"></a><span class="lineno"> 212</span> <span class="preprocessor">#endif // _FUNCTIONAL_HASH_H</span></div><div class="ttc" id="a03485_html"><div class="ttname"><a href="a03485.html">std::integral_constant</a></div><div class="ttdoc">integral_constant </div><div class="ttdef"><b>Definition:</b> <a href="a00161_source.html#l00069">type_traits:69</a></div></div> <div class="ttc" id="a00344_html"><div class="ttname"><a href="a00344.html">hash_bytes.h</a></div></div> <div class="ttc" id="a01487_html"><div class="ttname"><a href="a01487.html">std</a></div><div class="ttdoc">ISO C++ entities toplevel namespace is std. </div></div> <div class="ttc" id="a03257_html"><div class="ttname"><a href="a03257.html">std::hash</a></div><div class="ttdoc">Primary class template hash. </div><div class="ttdef"><b>Definition:</b> <a href="a00149_source.html#l00134">system_error:134</a></div></div> </div><!-- fragment --></div><!-- contents --> </div><!-- doc-content --> <!-- start footer part --> <div id="nav-path" class="navpath"><!-- id is needed for treeview function! --> <ul> <li class="navelem"><a class="el" href="dir_3a83f109ff04170a1f8448445d1bdcba.html">include</a></li><li class="navelem"><a class="el" href="dir_599c955538774c0249d4ddd97c0a9ae8.html">bits</a></li><li class="navelem"><a class="el" href="a00335.html">functional_hash.h</a></li> <li class="footer">Generated by <a href="http://www.doxygen.org/index.html"> <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.8.13 </li> </ul> </div> </body> </html>