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<div class="title">float_utils_google.hpp</div>  </div>
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<a href="a00242.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno">    1</span>&#160;<span class="preprocessor">#ifndef __STDAIR_BAS_FLOAT_UTILS_GOOGLE_HPP</span></div>
<div class="line"><a name="l00002"></a><span class="lineno">    2</span>&#160;<span class="preprocessor"></span><span class="preprocessor">#define __STDAIR_BAS_FLOAT_UTILS_GOOGLE_HPP</span></div>
<div class="line"><a name="l00003"></a><span class="lineno">    3</span>&#160;<span class="preprocessor"></span></div>
<div class="line"><a name="l00004"></a><span class="lineno">    4</span>&#160;<span class="comment">// Redistribution and use in source and binary forms, with or without</span></div>
<div class="line"><a name="l00005"></a><span class="lineno">    5</span>&#160;<span class="comment">// modification, are permitted provided that the following conditions are</span></div>
<div class="line"><a name="l00006"></a><span class="lineno">    6</span>&#160;<span class="comment">// met:</span></div>
<div class="line"><a name="l00007"></a><span class="lineno">    7</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00008"></a><span class="lineno">    8</span>&#160;<span class="comment">//     * Redistributions of source code must retain the above copyright</span></div>
<div class="line"><a name="l00009"></a><span class="lineno">    9</span>&#160;<span class="comment">// notice, this list of conditions and the following disclaimer.</span></div>
<div class="line"><a name="l00010"></a><span class="lineno">   10</span>&#160;<span class="comment">//     * Redistributions in binary form must reproduce the above</span></div>
<div class="line"><a name="l00011"></a><span class="lineno">   11</span>&#160;<span class="comment">// copyright notice, this list of conditions and the following disclaimer</span></div>
<div class="line"><a name="l00012"></a><span class="lineno">   12</span>&#160;<span class="comment">// in the documentation and/or other materials provided with the</span></div>
<div class="line"><a name="l00013"></a><span class="lineno">   13</span>&#160;<span class="comment">// distribution.</span></div>
<div class="line"><a name="l00014"></a><span class="lineno">   14</span>&#160;<span class="comment">//     * Neither the name of Google Inc. nor the names of its</span></div>
<div class="line"><a name="l00015"></a><span class="lineno">   15</span>&#160;<span class="comment">// contributors may be used to endorse or promote products derived from</span></div>
<div class="line"><a name="l00016"></a><span class="lineno">   16</span>&#160;<span class="comment">// this software without specific prior written permission.</span></div>
<div class="line"><a name="l00017"></a><span class="lineno">   17</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00018"></a><span class="lineno">   18</span>&#160;<span class="comment">// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS</span></div>
<div class="line"><a name="l00019"></a><span class="lineno">   19</span>&#160;<span class="comment">// &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT</span></div>
<div class="line"><a name="l00020"></a><span class="lineno">   20</span>&#160;<span class="comment">// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR</span></div>
<div class="line"><a name="l00021"></a><span class="lineno">   21</span>&#160;<span class="comment">// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT</span></div>
<div class="line"><a name="l00022"></a><span class="lineno">   22</span>&#160;<span class="comment">// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,</span></div>
<div class="line"><a name="l00023"></a><span class="lineno">   23</span>&#160;<span class="comment">// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT</span></div>
<div class="line"><a name="l00024"></a><span class="lineno">   24</span>&#160;<span class="comment">// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,</span></div>
<div class="line"><a name="l00025"></a><span class="lineno">   25</span>&#160;<span class="comment">// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY</span></div>
<div class="line"><a name="l00026"></a><span class="lineno">   26</span>&#160;<span class="comment">// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT</span></div>
<div class="line"><a name="l00027"></a><span class="lineno">   27</span>&#160;<span class="comment">// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE</span></div>
<div class="line"><a name="l00028"></a><span class="lineno">   28</span>&#160;<span class="comment">// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.</span></div>
<div class="line"><a name="l00029"></a><span class="lineno">   29</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00030"></a><span class="lineno">   30</span>&#160;<span class="comment">// Authors: wan@google.com (Zhanyong Wan), eefacm@gmail.com (Sean Mcafee)</span></div>
<div class="line"><a name="l00031"></a><span class="lineno">   31</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00032"></a><span class="lineno">   32</span>&#160;<span class="comment">// The Google C++ Testing Framework (Google Test)</span></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;</div>
<div class="line"><a name="l00035"></a><span class="lineno">   35</span>&#160;<span class="comment">// This template class serves as a compile-time function from size to</span></div>
<div class="line"><a name="l00036"></a><span class="lineno">   36</span>&#160;<span class="comment">// type.  It maps a size in bytes to a primitive type with that</span></div>
<div class="line"><a name="l00037"></a><span class="lineno">   37</span>&#160;<span class="comment">// size. e.g.</span></div>
<div class="line"><a name="l00038"></a><span class="lineno">   38</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00039"></a><span class="lineno">   39</span>&#160;<span class="comment">//   TypeWithSize&lt;4&gt;::UInt</span></div>
<div class="line"><a name="l00040"></a><span class="lineno">   40</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00041"></a><span class="lineno">   41</span>&#160;<span class="comment">// is typedef-ed to be unsigned int (unsigned integer made up of 4</span></div>
<div class="line"><a name="l00042"></a><span class="lineno">   42</span>&#160;<span class="comment">// bytes).</span></div>
<div class="line"><a name="l00043"></a><span class="lineno">   43</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00044"></a><span class="lineno">   44</span>&#160;<span class="comment">// Such functionality should belong to STL, but I cannot find it</span></div>
<div class="line"><a name="l00045"></a><span class="lineno">   45</span>&#160;<span class="comment">// there.</span></div>
<div class="line"><a name="l00046"></a><span class="lineno">   46</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00047"></a><span class="lineno">   47</span>&#160;<span class="comment">// Google Test uses this class in the implementation of floating-point</span></div>
<div class="line"><a name="l00048"></a><span class="lineno">   48</span>&#160;<span class="comment">// comparison.</span></div>
<div class="line"><a name="l00049"></a><span class="lineno">   49</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00050"></a><span class="lineno">   50</span>&#160;<span class="comment">// For now it only handles UInt (unsigned int) as that&#39;s all Google Test</span></div>
<div class="line"><a name="l00051"></a><span class="lineno">   51</span>&#160;<span class="comment">// needs.  Other types can be easily added in the future if need</span></div>
<div class="line"><a name="l00052"></a><span class="lineno">   52</span>&#160;<span class="comment">// arises.</span></div>
<div class="line"><a name="l00053"></a><span class="lineno">   53</span>&#160;<span class="keyword">template</span> &lt;<span class="keywordtype">size_t</span> size&gt;</div>
<div class="line"><a name="l00054"></a><span class="lineno"><a class="code" href="a00186.html">   54</a></span>&#160;<span class="keyword">class </span><a class="code" href="a00186.html">TypeWithSize</a> {</div>
<div class="line"><a name="l00055"></a><span class="lineno">   55</span>&#160; <span class="keyword">public</span>:</div>
<div class="line"><a name="l00056"></a><span class="lineno">   56</span>&#160;  <span class="comment">// This prevents the user from using TypeWithSize&lt;N&gt; with incorrect</span></div>
<div class="line"><a name="l00057"></a><span class="lineno">   57</span>&#160;  <span class="comment">// values of N.</span></div>
<div class="line"><a name="l00058"></a><span class="lineno"><a class="code" href="a00186.html#a133efc1585facfe51a535c4a7b233684">   58</a></span>&#160;  <span class="keyword">typedef</span> <span class="keywordtype">void</span> <a class="code" href="a00186.html#a133efc1585facfe51a535c4a7b233684">UInt</a>;</div>
<div class="line"><a name="l00059"></a><span class="lineno">   59</span>&#160;};</div>
<div class="line"><a name="l00060"></a><span class="lineno">   60</span>&#160;</div>
<div class="line"><a name="l00061"></a><span class="lineno">   61</span>&#160;<span class="comment">// The specialization for size 4.</span></div>
<div class="line"><a name="l00062"></a><span class="lineno">   62</span>&#160;<span class="keyword">template</span> &lt;&gt;</div>
<div class="line"><a name="l00063"></a><span class="lineno"><a class="code" href="a00187.html">   63</a></span>&#160;<span class="keyword">class </span><a class="code" href="a00186.html">TypeWithSize</a>&lt;4&gt; {</div>
<div class="line"><a name="l00064"></a><span class="lineno">   64</span>&#160; <span class="keyword">public</span>:</div>
<div class="line"><a name="l00065"></a><span class="lineno">   65</span>&#160;  <span class="comment">// unsigned int has size 4 in both gcc and MSVC.</span></div>
<div class="line"><a name="l00066"></a><span class="lineno">   66</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00067"></a><span class="lineno">   67</span>&#160;  <span class="comment">// As base/basictypes.h doesn&#39;t compile on Windows, we cannot use</span></div>
<div class="line"><a name="l00068"></a><span class="lineno">   68</span>&#160;  <span class="comment">// uint32, uint64, and etc here.</span></div>
<div class="line"><a name="l00069"></a><span class="lineno"><a class="code" href="a00187.html#af29a19528b5da0137818cc208ec05fe0">   69</a></span>&#160;  <span class="keyword">typedef</span> <span class="keywordtype">int</span> <a class="code" href="a00187.html#af29a19528b5da0137818cc208ec05fe0">Int</a>;</div>
<div class="line"><a name="l00070"></a><span class="lineno"><a class="code" href="a00187.html#aedd1425478450102b1c637d2db6a7d26">   70</a></span>&#160;  <span class="keyword">typedef</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> <a class="code" href="a00187.html#aedd1425478450102b1c637d2db6a7d26">UInt</a>;</div>
<div class="line"><a name="l00071"></a><span class="lineno">   71</span>&#160;};</div>
<div class="line"><a name="l00072"></a><span class="lineno">   72</span>&#160;</div>
<div class="line"><a name="l00073"></a><span class="lineno">   73</span>&#160;<span class="comment">// The specialization for size 8.</span></div>
<div class="line"><a name="l00074"></a><span class="lineno">   74</span>&#160;<span class="keyword">template</span> &lt;&gt;</div>
<div class="line"><a name="l00075"></a><span class="lineno"><a class="code" href="a00188.html">   75</a></span>&#160;<span class="keyword">class </span><a class="code" href="a00186.html">TypeWithSize</a>&lt;8&gt; {</div>
<div class="line"><a name="l00076"></a><span class="lineno">   76</span>&#160; <span class="keyword">public</span>:</div>
<div class="line"><a name="l00077"></a><span class="lineno">   77</span>&#160;<span class="preprocessor">#if GTEST_OS_WINDOWS</span></div>
<div class="line"><a name="l00078"></a><span class="lineno">   78</span>&#160;<span class="preprocessor"></span>  <span class="keyword">typedef</span> __int64 <a class="code" href="a00188.html#af02c7e5d997bd247bdb252ce9537a295">Int</a>;</div>
<div class="line"><a name="l00079"></a><span class="lineno">   79</span>&#160;  <span class="keyword">typedef</span> <span class="keywordtype">unsigned</span> __int64 <a class="code" href="a00186.html#a133efc1585facfe51a535c4a7b233684">UInt</a>;</div>
<div class="line"><a name="l00080"></a><span class="lineno">   80</span>&#160;<span class="preprocessor">#else</span></div>
<div class="line"><a name="l00081"></a><span class="lineno"><a class="code" href="a00188.html#af02c7e5d997bd247bdb252ce9537a295">   81</a></span>&#160;<span class="preprocessor"></span>  <span class="keyword">typedef</span> <span class="keywordtype">long</span> <span class="keywordtype">long</span> <a class="code" href="a00188.html#af02c7e5d997bd247bdb252ce9537a295">Int</a>;  <span class="comment">// NOLINT</span></div>
<div class="line"><a name="l00082"></a><span class="lineno"><a class="code" href="a00188.html#aad4d80a31c855d3f6feb970627dce6e9">   82</a></span>&#160;  <span class="keyword">typedef</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">long</span> <span class="keywordtype">long</span> <a class="code" href="a00188.html#aad4d80a31c855d3f6feb970627dce6e9">UInt</a>;  <span class="comment">// NOLINT</span></div>
<div class="line"><a name="l00083"></a><span class="lineno">   83</span>&#160;<span class="preprocessor">#endif  // GTEST_OS_WINDOWS</span></div>
<div class="line"><a name="l00084"></a><span class="lineno">   84</span>&#160;<span class="preprocessor"></span>};</div>
<div class="line"><a name="l00085"></a><span class="lineno">   85</span>&#160;</div>
<div class="line"><a name="l00086"></a><span class="lineno">   86</span>&#160;</div>
<div class="line"><a name="l00087"></a><span class="lineno">   87</span>&#160;<span class="comment">// This template class represents an IEEE floating-point number</span></div>
<div class="line"><a name="l00088"></a><span class="lineno">   88</span>&#160;<span class="comment">// (either single-precision or double-precision, depending on the</span></div>
<div class="line"><a name="l00089"></a><span class="lineno">   89</span>&#160;<span class="comment">// template parameters).</span></div>
<div class="line"><a name="l00090"></a><span class="lineno">   90</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00091"></a><span class="lineno">   91</span>&#160;<span class="comment">// The purpose of this class is to do more sophisticated number</span></div>
<div class="line"><a name="l00092"></a><span class="lineno">   92</span>&#160;<span class="comment">// comparison.  (Due to round-off error, etc, it&#39;s very unlikely that</span></div>
<div class="line"><a name="l00093"></a><span class="lineno">   93</span>&#160;<span class="comment">// two floating-points will be equal exactly.  Hence a naive</span></div>
<div class="line"><a name="l00094"></a><span class="lineno">   94</span>&#160;<span class="comment">// comparison by the == operation often doesn&#39;t work.)</span></div>
<div class="line"><a name="l00095"></a><span class="lineno">   95</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00096"></a><span class="lineno">   96</span>&#160;<span class="comment">// Format of IEEE floating-point:</span></div>
<div class="line"><a name="l00097"></a><span class="lineno">   97</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00098"></a><span class="lineno">   98</span>&#160;<span class="comment">//   The most-significant bit being the leftmost, an IEEE</span></div>
<div class="line"><a name="l00099"></a><span class="lineno">   99</span>&#160;<span class="comment">//   floating-point looks like</span></div>
<div class="line"><a name="l00100"></a><span class="lineno">  100</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00101"></a><span class="lineno">  101</span>&#160;<span class="comment">//     sign_bit exponent_bits fraction_bits</span></div>
<div class="line"><a name="l00102"></a><span class="lineno">  102</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00103"></a><span class="lineno">  103</span>&#160;<span class="comment">//   Here, sign_bit is a single bit that designates the sign of the</span></div>
<div class="line"><a name="l00104"></a><span class="lineno">  104</span>&#160;<span class="comment">//   number.</span></div>
<div class="line"><a name="l00105"></a><span class="lineno">  105</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00106"></a><span class="lineno">  106</span>&#160;<span class="comment">//   For float, there are 8 exponent bits and 23 fraction bits.</span></div>
<div class="line"><a name="l00107"></a><span class="lineno">  107</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00108"></a><span class="lineno">  108</span>&#160;<span class="comment">//   For double, there are 11 exponent bits and 52 fraction bits.</span></div>
<div class="line"><a name="l00109"></a><span class="lineno">  109</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00110"></a><span class="lineno">  110</span>&#160;<span class="comment">//   More details can be found at</span></div>
<div class="line"><a name="l00111"></a><span class="lineno">  111</span>&#160;<span class="comment">//   http://en.wikipedia.org/wiki/IEEE_floating-point_standard.</span></div>
<div class="line"><a name="l00112"></a><span class="lineno">  112</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00113"></a><span class="lineno">  113</span>&#160;<span class="comment">// Template parameter:</span></div>
<div class="line"><a name="l00114"></a><span class="lineno">  114</span>&#160;<span class="comment">//</span></div>
<div class="line"><a name="l00115"></a><span class="lineno">  115</span>&#160;<span class="comment">//   RawType: the raw floating-point type (either float or double)</span></div>
<div class="line"><a name="l00116"></a><span class="lineno">  116</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> RawType&gt;</div>
<div class="line"><a name="l00117"></a><span class="lineno"><a class="code" href="a00107.html">  117</a></span>&#160;<span class="keyword">class </span><a class="code" href="a00107.html">FloatingPoint</a> {</div>
<div class="line"><a name="l00118"></a><span class="lineno">  118</span>&#160; <span class="keyword">public</span>:</div>
<div class="line"><a name="l00119"></a><span class="lineno">  119</span>&#160;  <span class="comment">// Defines the unsigned integer type that has the same size as the</span></div>
<div class="line"><a name="l00120"></a><span class="lineno">  120</span>&#160;  <span class="comment">// floating point number.</span></div>
<div class="line"><a name="l00121"></a><span class="lineno"><a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">  121</a></span>&#160;  <span class="keyword">typedef</span> <span class="keyword">typename</span> <a class="code" href="a00186.html">TypeWithSize&lt;sizeof(RawType)&gt;::UInt</a> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a>;</div>
<div class="line"><a name="l00122"></a><span class="lineno">  122</span>&#160;</div>
<div class="line"><a name="l00123"></a><span class="lineno">  123</span>&#160;  <span class="comment">// Constants.</span></div>
<div class="line"><a name="l00124"></a><span class="lineno">  124</span>&#160;</div>
<div class="line"><a name="l00125"></a><span class="lineno">  125</span>&#160;  <span class="comment">// # of bits in a number.</span></div>
<div class="line"><a name="l00126"></a><span class="lineno"><a class="code" href="a00107.html#af2429a12aef6052e91b2d50df5800df9">  126</a></span>&#160;  <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">size_t</span> <a class="code" href="a00107.html#af2429a12aef6052e91b2d50df5800df9">kBitCount</a> = 8*<span class="keyword">sizeof</span>(RawType);</div>
<div class="line"><a name="l00127"></a><span class="lineno">  127</span>&#160;</div>
<div class="line"><a name="l00128"></a><span class="lineno">  128</span>&#160;  <span class="comment">// # of fraction bits in a number.</span></div>
<div class="line"><a name="l00129"></a><span class="lineno"><a class="code" href="a00107.html#af29024bbbb5abcbaf8aabfc465f3bd33">  129</a></span>&#160;  <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">size_t</span> <a class="code" href="a00107.html#af29024bbbb5abcbaf8aabfc465f3bd33">kFractionBitCount</a> =</div>
<div class="line"><a name="l00130"></a><span class="lineno">  130</span>&#160;    std::numeric_limits&lt;RawType&gt;::digits - 1;</div>
<div class="line"><a name="l00131"></a><span class="lineno">  131</span>&#160;</div>
<div class="line"><a name="l00132"></a><span class="lineno">  132</span>&#160;  <span class="comment">// # of exponent bits in a number.</span></div>
<div class="line"><a name="l00133"></a><span class="lineno"><a class="code" href="a00107.html#a00f3d689988b1c00f3d8a98d3bc9c685">  133</a></span>&#160;  <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">size_t</span> <a class="code" href="a00107.html#a00f3d689988b1c00f3d8a98d3bc9c685">kExponentBitCount</a> = <a class="code" href="a00107.html#af2429a12aef6052e91b2d50df5800df9">kBitCount</a> - 1 - <a class="code" href="a00107.html#af29024bbbb5abcbaf8aabfc465f3bd33">kFractionBitCount</a>;</div>
<div class="line"><a name="l00134"></a><span class="lineno">  134</span>&#160;</div>
<div class="line"><a name="l00135"></a><span class="lineno">  135</span>&#160;  <span class="comment">// The mask for the sign bit.</span></div>
<div class="line"><a name="l00136"></a><span class="lineno"><a class="code" href="a00107.html#a026944d92c195ce2c755dde816cd6b0c">  136</a></span>&#160;  <span class="keyword">static</span> <span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> <a class="code" href="a00107.html#a026944d92c195ce2c755dde816cd6b0c">kSignBitMask</a> = <span class="keyword">static_cast&lt;</span><a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a><span class="keyword">&gt;</span>(1) &lt;&lt; (<a class="code" href="a00107.html#af2429a12aef6052e91b2d50df5800df9">kBitCount</a> - 1);</div>
<div class="line"><a name="l00137"></a><span class="lineno">  137</span>&#160;</div>
<div class="line"><a name="l00138"></a><span class="lineno">  138</span>&#160;  <span class="comment">// The mask for the fraction bits.</span></div>
<div class="line"><a name="l00139"></a><span class="lineno"><a class="code" href="a00107.html#a4909a899f6cc1a1bdb7835cec3629a0f">  139</a></span>&#160;  <span class="keyword">static</span> <span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> <a class="code" href="a00107.html#a4909a899f6cc1a1bdb7835cec3629a0f">kFractionBitMask</a> =</div>
<div class="line"><a name="l00140"></a><span class="lineno">  140</span>&#160;    ~static_cast&lt;<a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a>&gt;(0) &gt;&gt; (<a class="code" href="a00107.html#a00f3d689988b1c00f3d8a98d3bc9c685">kExponentBitCount</a> + 1);</div>
<div class="line"><a name="l00141"></a><span class="lineno">  141</span>&#160;</div>
<div class="line"><a name="l00142"></a><span class="lineno">  142</span>&#160;  <span class="comment">// The mask for the exponent bits.</span></div>
<div class="line"><a name="l00143"></a><span class="lineno"><a class="code" href="a00107.html#a590938e82e2f449c0557744a6c5619ad">  143</a></span>&#160;  <span class="keyword">static</span> <span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> <a class="code" href="a00107.html#a590938e82e2f449c0557744a6c5619ad">kExponentBitMask</a> = ~(<a class="code" href="a00107.html#a026944d92c195ce2c755dde816cd6b0c">kSignBitMask</a> | <a class="code" href="a00107.html#a4909a899f6cc1a1bdb7835cec3629a0f">kFractionBitMask</a>);</div>
<div class="line"><a name="l00144"></a><span class="lineno">  144</span>&#160;</div>
<div class="line"><a name="l00145"></a><span class="lineno">  145</span>&#160;  <span class="comment">// How many ULP&#39;s (Units in the Last Place) we want to tolerate when</span></div>
<div class="line"><a name="l00146"></a><span class="lineno">  146</span>&#160;  <span class="comment">// comparing two numbers.  The larger the value, the more error we</span></div>
<div class="line"><a name="l00147"></a><span class="lineno">  147</span>&#160;  <span class="comment">// allow.  A 0 value means that two numbers must be exactly the same</span></div>
<div class="line"><a name="l00148"></a><span class="lineno">  148</span>&#160;  <span class="comment">// to be considered equal.</span></div>
<div class="line"><a name="l00149"></a><span class="lineno">  149</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00150"></a><span class="lineno">  150</span>&#160;  <span class="comment">// The maximum error of a single floating-point operation is 0.5</span></div>
<div class="line"><a name="l00151"></a><span class="lineno">  151</span>&#160;  <span class="comment">// units in the last place.  On Intel CPU&#39;s, all floating-point</span></div>
<div class="line"><a name="l00152"></a><span class="lineno">  152</span>&#160;  <span class="comment">// calculations are done with 80-bit precision, while double has 64</span></div>
<div class="line"><a name="l00153"></a><span class="lineno">  153</span>&#160;  <span class="comment">// bits.  Therefore, 4 should be enough for ordinary use.</span></div>
<div class="line"><a name="l00154"></a><span class="lineno">  154</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00155"></a><span class="lineno">  155</span>&#160;  <span class="comment">// See the following article for more details on ULP:</span></div>
<div class="line"><a name="l00156"></a><span class="lineno">  156</span>&#160;  <span class="comment">// http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm.</span></div>
<div class="line"><a name="l00157"></a><span class="lineno"><a class="code" href="a00107.html#ad52b8184e122a8fe484f0d9633e960e1">  157</a></span>&#160;  <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">size_t</span> <a class="code" href="a00107.html#ad52b8184e122a8fe484f0d9633e960e1">kMaxUlps</a> = 4;</div>
<div class="line"><a name="l00158"></a><span class="lineno">  158</span>&#160;</div>
<div class="line"><a name="l00159"></a><span class="lineno">  159</span>&#160;  <span class="comment">// Constructs a FloatingPoint from a raw floating-point number.</span></div>
<div class="line"><a name="l00160"></a><span class="lineno">  160</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00161"></a><span class="lineno">  161</span>&#160;  <span class="comment">// On an Intel CPU, passing a non-normalized NAN (Not a Number)</span></div>
<div class="line"><a name="l00162"></a><span class="lineno">  162</span>&#160;  <span class="comment">// around may change its bits, although the new value is guaranteed</span></div>
<div class="line"><a name="l00163"></a><span class="lineno">  163</span>&#160;  <span class="comment">// to be also a NAN.  Therefore, don&#39;t expect this constructor to</span></div>
<div class="line"><a name="l00164"></a><span class="lineno">  164</span>&#160;  <span class="comment">// preserve the bits in x when x is a NAN.</span></div>
<div class="line"><a name="l00165"></a><span class="lineno"><a class="code" href="a00107.html#a223158362fd04a1c21fd514699bc480d">  165</a></span>&#160;  <span class="keyword">explicit</span> <a class="code" href="a00107.html#a223158362fd04a1c21fd514699bc480d">FloatingPoint</a>(<span class="keyword">const</span> RawType&amp; x) { u_.value_ = x; }</div>
<div class="line"><a name="l00166"></a><span class="lineno">  166</span>&#160;</div>
<div class="line"><a name="l00167"></a><span class="lineno">  167</span>&#160;  <span class="comment">// Static methods</span></div>
<div class="line"><a name="l00168"></a><span class="lineno">  168</span>&#160;</div>
<div class="line"><a name="l00169"></a><span class="lineno">  169</span>&#160;  <span class="comment">// Reinterprets a bit pattern as a floating-point number.</span></div>
<div class="line"><a name="l00170"></a><span class="lineno">  170</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00171"></a><span class="lineno">  171</span>&#160;  <span class="comment">// This function is needed to test the AlmostEquals() method.</span></div>
<div class="line"><a name="l00172"></a><span class="lineno"><a class="code" href="a00107.html#a80c340111da59015517dde85bcc8966b">  172</a></span>&#160;  <span class="keyword">static</span> RawType <a class="code" href="a00107.html#a80c340111da59015517dde85bcc8966b">ReinterpretBits</a>(<span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> <a class="code" href="a00107.html#a6b240b584668f5590c1e47108afdec33">bits</a>) {</div>
<div class="line"><a name="l00173"></a><span class="lineno">  173</span>&#160;    <a class="code" href="a00107.html">FloatingPoint</a> fp(0);</div>
<div class="line"><a name="l00174"></a><span class="lineno">  174</span>&#160;    fp.u_.bits_ = <a class="code" href="a00107.html#a6b240b584668f5590c1e47108afdec33">bits</a>;</div>
<div class="line"><a name="l00175"></a><span class="lineno">  175</span>&#160;    <span class="keywordflow">return</span> fp.u_.value_;</div>
<div class="line"><a name="l00176"></a><span class="lineno">  176</span>&#160;  }</div>
<div class="line"><a name="l00177"></a><span class="lineno">  177</span>&#160;</div>
<div class="line"><a name="l00178"></a><span class="lineno">  178</span>&#160;  <span class="comment">// Returns the floating-point number that represent positive infinity.</span></div>
<div class="line"><a name="l00179"></a><span class="lineno"><a class="code" href="a00107.html#aa0cdd12e8007eea844d83757b531241a">  179</a></span>&#160;  <span class="keyword">static</span> RawType <a class="code" href="a00107.html#aa0cdd12e8007eea844d83757b531241a">Infinity</a>() {</div>
<div class="line"><a name="l00180"></a><span class="lineno">  180</span>&#160;    <span class="keywordflow">return</span> <a class="code" href="a00107.html#a80c340111da59015517dde85bcc8966b">ReinterpretBits</a>(<a class="code" href="a00107.html#a590938e82e2f449c0557744a6c5619ad">kExponentBitMask</a>);</div>
<div class="line"><a name="l00181"></a><span class="lineno">  181</span>&#160;  }</div>
<div class="line"><a name="l00182"></a><span class="lineno">  182</span>&#160;</div>
<div class="line"><a name="l00183"></a><span class="lineno">  183</span>&#160;  <span class="comment">// Non-static methods</span></div>
<div class="line"><a name="l00184"></a><span class="lineno">  184</span>&#160;</div>
<div class="line"><a name="l00185"></a><span class="lineno">  185</span>&#160;  <span class="comment">// Returns the bits that represents this number.</span></div>
<div class="line"><a name="l00186"></a><span class="lineno"><a class="code" href="a00107.html#a6b240b584668f5590c1e47108afdec33">  186</a></span>&#160;  <span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> &amp;<a class="code" href="a00107.html#a6b240b584668f5590c1e47108afdec33">bits</a>()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> u_.bits_; }</div>
<div class="line"><a name="l00187"></a><span class="lineno">  187</span>&#160;</div>
<div class="line"><a name="l00188"></a><span class="lineno">  188</span>&#160;  <span class="comment">// Returns the exponent bits of this number.</span></div>
<div class="line"><a name="l00189"></a><span class="lineno"><a class="code" href="a00107.html#ae44ba56b6c843e9384d58d24b283308f">  189</a></span>&#160;  <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> <a class="code" href="a00107.html#ae44ba56b6c843e9384d58d24b283308f">exponent_bits</a>()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> <a class="code" href="a00107.html#a590938e82e2f449c0557744a6c5619ad">kExponentBitMask</a> &amp; u_.bits_; }</div>
<div class="line"><a name="l00190"></a><span class="lineno">  190</span>&#160;</div>
<div class="line"><a name="l00191"></a><span class="lineno">  191</span>&#160;  <span class="comment">// Returns the fraction bits of this number.</span></div>
<div class="line"><a name="l00192"></a><span class="lineno"><a class="code" href="a00107.html#af2f11a2b43c1647b8b6bdd4a4389bc66">  192</a></span>&#160;  <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> <a class="code" href="a00107.html#af2f11a2b43c1647b8b6bdd4a4389bc66">fraction_bits</a>()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> <a class="code" href="a00107.html#a4909a899f6cc1a1bdb7835cec3629a0f">kFractionBitMask</a> &amp; u_.bits_; }</div>
<div class="line"><a name="l00193"></a><span class="lineno">  193</span>&#160;</div>
<div class="line"><a name="l00194"></a><span class="lineno">  194</span>&#160;  <span class="comment">// Returns the sign bit of this number.</span></div>
<div class="line"><a name="l00195"></a><span class="lineno"><a class="code" href="a00107.html#a1007ce80d456d1e8262749bdd83ee7e7">  195</a></span>&#160;  <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> <a class="code" href="a00107.html#a1007ce80d456d1e8262749bdd83ee7e7">sign_bit</a>()<span class="keyword"> const </span>{ <span class="keywordflow">return</span> <a class="code" href="a00107.html#a026944d92c195ce2c755dde816cd6b0c">kSignBitMask</a> &amp; u_.bits_; }</div>
<div class="line"><a name="l00196"></a><span class="lineno">  196</span>&#160;</div>
<div class="line"><a name="l00197"></a><span class="lineno">  197</span>&#160;  <span class="comment">// Returns true iff this is NAN (not a number).</span></div>
<div class="line"><a name="l00198"></a><span class="lineno"><a class="code" href="a00107.html#a44265079d31ee49d60d05b5f662a7a10">  198</a></span>&#160;  <span class="keywordtype">bool</span> <a class="code" href="a00107.html#a44265079d31ee49d60d05b5f662a7a10">is_nan</a>()<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00199"></a><span class="lineno">  199</span>&#160;    <span class="comment">// It&#39;s a NAN if the exponent bits are all ones and the fraction</span></div>
<div class="line"><a name="l00200"></a><span class="lineno">  200</span>&#160;    <span class="comment">// bits are not entirely zeros.</span></div>
<div class="line"><a name="l00201"></a><span class="lineno">  201</span>&#160;    <span class="keywordflow">return</span> (<a class="code" href="a00107.html#ae44ba56b6c843e9384d58d24b283308f">exponent_bits</a>() == <a class="code" href="a00107.html#a590938e82e2f449c0557744a6c5619ad">kExponentBitMask</a>) &amp;&amp; (<a class="code" href="a00107.html#af2f11a2b43c1647b8b6bdd4a4389bc66">fraction_bits</a>() != 0);</div>
<div class="line"><a name="l00202"></a><span class="lineno">  202</span>&#160;  }</div>
<div class="line"><a name="l00203"></a><span class="lineno">  203</span>&#160;</div>
<div class="line"><a name="l00204"></a><span class="lineno">  204</span>&#160;  <span class="comment">// Returns true iff this number is at most kMaxUlps ULP&#39;s away from</span></div>
<div class="line"><a name="l00205"></a><span class="lineno">  205</span>&#160;  <span class="comment">// rhs.  In particular, this function:</span></div>
<div class="line"><a name="l00206"></a><span class="lineno">  206</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00207"></a><span class="lineno">  207</span>&#160;  <span class="comment">//   - returns false if either number is (or both are) NAN.</span></div>
<div class="line"><a name="l00208"></a><span class="lineno">  208</span>&#160;  <span class="comment">//   - treats really large numbers as almost equal to infinity.</span></div>
<div class="line"><a name="l00209"></a><span class="lineno">  209</span>&#160;  <span class="comment">//   - thinks +0.0 and -0.0 are 0 DLP&#39;s apart.</span></div>
<div class="line"><a name="l00210"></a><span class="lineno"><a class="code" href="a00107.html#af6aab835c96f51ac4549e0e8a38f6767">  210</a></span>&#160;  <span class="keywordtype">bool</span> <a class="code" href="a00107.html#af6aab835c96f51ac4549e0e8a38f6767">AlmostEquals</a>(<span class="keyword">const</span> <a class="code" href="a00107.html">FloatingPoint</a>&amp; rhs)<span class="keyword"> const </span>{</div>
<div class="line"><a name="l00211"></a><span class="lineno">  211</span>&#160;    <span class="comment">// The IEEE standard says that any comparison operation involving</span></div>
<div class="line"><a name="l00212"></a><span class="lineno">  212</span>&#160;    <span class="comment">// a NAN must return false.</span></div>
<div class="line"><a name="l00213"></a><span class="lineno">  213</span>&#160;    <span class="keywordflow">if</span> (<a class="code" href="a00107.html#a44265079d31ee49d60d05b5f662a7a10">is_nan</a>() || rhs.<a class="code" href="a00107.html#a44265079d31ee49d60d05b5f662a7a10">is_nan</a>()) <span class="keywordflow">return</span> <span class="keyword">false</span>;</div>
<div class="line"><a name="l00214"></a><span class="lineno">  214</span>&#160;</div>
<div class="line"><a name="l00215"></a><span class="lineno">  215</span>&#160;    <span class="keywordflow">return</span> DistanceBetweenSignAndMagnitudeNumbers(u_.bits_, rhs.u_.bits_)</div>
<div class="line"><a name="l00216"></a><span class="lineno">  216</span>&#160;        &lt;= <a class="code" href="a00107.html#ad52b8184e122a8fe484f0d9633e960e1">kMaxUlps</a>;</div>
<div class="line"><a name="l00217"></a><span class="lineno">  217</span>&#160;  }</div>
<div class="line"><a name="l00218"></a><span class="lineno">  218</span>&#160;</div>
<div class="line"><a name="l00219"></a><span class="lineno">  219</span>&#160; <span class="keyword">private</span>:</div>
<div class="line"><a name="l00220"></a><span class="lineno">  220</span>&#160;  <span class="comment">// The data type used to store the actual floating-point number.</span></div>
<div class="line"><a name="l00221"></a><span class="lineno">  221</span>&#160;  <span class="keyword">union </span>FloatingPointUnion {</div>
<div class="line"><a name="l00222"></a><span class="lineno">  222</span>&#160;    RawType value_;  <span class="comment">// The raw floating-point number.</span></div>
<div class="line"><a name="l00223"></a><span class="lineno">  223</span>&#160;    <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> bits_;      <span class="comment">// The bits that represent the number.</span></div>
<div class="line"><a name="l00224"></a><span class="lineno">  224</span>&#160;  };</div>
<div class="line"><a name="l00225"></a><span class="lineno">  225</span>&#160;</div>
<div class="line"><a name="l00226"></a><span class="lineno">  226</span>&#160;  <span class="comment">// Converts an integer from the sign-and-magnitude representation to</span></div>
<div class="line"><a name="l00227"></a><span class="lineno">  227</span>&#160;  <span class="comment">// the biased representation.  More precisely, let N be 2 to the</span></div>
<div class="line"><a name="l00228"></a><span class="lineno">  228</span>&#160;  <span class="comment">// power of (kBitCount - 1), an integer x is represented by the</span></div>
<div class="line"><a name="l00229"></a><span class="lineno">  229</span>&#160;  <span class="comment">// unsigned number x + N.</span></div>
<div class="line"><a name="l00230"></a><span class="lineno">  230</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00231"></a><span class="lineno">  231</span>&#160;  <span class="comment">// For instance,</span></div>
<div class="line"><a name="l00232"></a><span class="lineno">  232</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00233"></a><span class="lineno">  233</span>&#160;  <span class="comment">//   -N + 1 (the most negative number representable using</span></div>
<div class="line"><a name="l00234"></a><span class="lineno">  234</span>&#160;  <span class="comment">//          sign-and-magnitude) is represented by 1;</span></div>
<div class="line"><a name="l00235"></a><span class="lineno">  235</span>&#160;  <span class="comment">//   0      is represented by N; and</span></div>
<div class="line"><a name="l00236"></a><span class="lineno">  236</span>&#160;  <span class="comment">//   N - 1  (the biggest number representable using</span></div>
<div class="line"><a name="l00237"></a><span class="lineno">  237</span>&#160;  <span class="comment">//          sign-and-magnitude) is represented by 2N - 1.</span></div>
<div class="line"><a name="l00238"></a><span class="lineno">  238</span>&#160;  <span class="comment">//</span></div>
<div class="line"><a name="l00239"></a><span class="lineno">  239</span>&#160;  <span class="comment">// Read http://en.wikipedia.org/wiki/Signed_number_representations</span></div>
<div class="line"><a name="l00240"></a><span class="lineno">  240</span>&#160;  <span class="comment">// for more details on signed number representations.</span></div>
<div class="line"><a name="l00241"></a><span class="lineno">  241</span>&#160;  <span class="keyword">static</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> SignAndMagnitudeToBiased(<span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> &amp;sam) {</div>
<div class="line"><a name="l00242"></a><span class="lineno">  242</span>&#160;    <span class="keywordflow">if</span> (<a class="code" href="a00107.html#a026944d92c195ce2c755dde816cd6b0c">kSignBitMask</a> &amp; sam) {</div>
<div class="line"><a name="l00243"></a><span class="lineno">  243</span>&#160;      <span class="comment">// sam represents a negative number.</span></div>
<div class="line"><a name="l00244"></a><span class="lineno">  244</span>&#160;      <span class="keywordflow">return</span> ~sam + 1;</div>
<div class="line"><a name="l00245"></a><span class="lineno">  245</span>&#160;    } <span class="keywordflow">else</span> {</div>
<div class="line"><a name="l00246"></a><span class="lineno">  246</span>&#160;      <span class="comment">// sam represents a positive number.</span></div>
<div class="line"><a name="l00247"></a><span class="lineno">  247</span>&#160;      <span class="keywordflow">return</span> <a class="code" href="a00107.html#a026944d92c195ce2c755dde816cd6b0c">kSignBitMask</a> | sam;</div>
<div class="line"><a name="l00248"></a><span class="lineno">  248</span>&#160;    }</div>
<div class="line"><a name="l00249"></a><span class="lineno">  249</span>&#160;  }</div>
<div class="line"><a name="l00250"></a><span class="lineno">  250</span>&#160;</div>
<div class="line"><a name="l00251"></a><span class="lineno">  251</span>&#160;  <span class="comment">// Given two numbers in the sign-and-magnitude representation,</span></div>
<div class="line"><a name="l00252"></a><span class="lineno">  252</span>&#160;  <span class="comment">// returns the distance between them as an unsigned number.</span></div>
<div class="line"><a name="l00253"></a><span class="lineno">  253</span>&#160;  <span class="keyword">static</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> DistanceBetweenSignAndMagnitudeNumbers(<span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> &amp;sam1,</div>
<div class="line"><a name="l00254"></a><span class="lineno">  254</span>&#160;                                                     <span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> &amp;sam2) {</div>
<div class="line"><a name="l00255"></a><span class="lineno">  255</span>&#160;    <span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> biased1 = SignAndMagnitudeToBiased(sam1);</div>
<div class="line"><a name="l00256"></a><span class="lineno">  256</span>&#160;    <span class="keyword">const</span> <a class="code" href="a00107.html#aa0912a8f805308568ebd2609557680b4">Bits</a> biased2 = SignAndMagnitudeToBiased(sam2);</div>
<div class="line"><a name="l00257"></a><span class="lineno">  257</span>&#160;    <span class="keywordflow">return</span> (biased1 &gt;= biased2) ? (biased1 - biased2) : (biased2 - biased1);</div>
<div class="line"><a name="l00258"></a><span class="lineno">  258</span>&#160;  }</div>
<div class="line"><a name="l00259"></a><span class="lineno">  259</span>&#160;</div>
<div class="line"><a name="l00260"></a><span class="lineno">  260</span>&#160;  FloatingPointUnion u_;</div>
<div class="line"><a name="l00261"></a><span class="lineno">  261</span>&#160;};</div>
<div class="line"><a name="l00262"></a><span class="lineno">  262</span>&#160;</div>
<div class="line"><a name="l00263"></a><span class="lineno">  263</span>&#160;<span class="preprocessor">#endif // __STDAIR_BAS_FLOAT_UTILS_GOOGLE_HPP</span></div>
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