1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> 4<title>Checked Arithmetic</title> 5<link rel="stylesheet" href="boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="index.html" title="Safe Numerics"> 8<link rel="up" href="library_implementation.html" title="Library Implementation"> 9<link rel="prev" href="checked_result.html" title="checked_result<R>"> 10<link rel="next" href="interval.html" title="interval<R>"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img href="index.html" height="164px" src="pre-boost.jpg" alt="Library Documentation Index"></td> 15<td><h2>Safe Numerics</h2></td> 16</tr></table> 17<div class="spirit-nav"> 18<a accesskey="p" href="checked_result.html"><img src="images/prev.png" alt="Prev"></a><a accesskey="u" href="library_implementation.html"><img src="images/up.png" alt="Up"></a><a accesskey="h" href="index.html"><img src="images/home.png" alt="Home"></a><a accesskey="n" href="interval.html"><img src="images/next.png" alt="Next"></a> 19</div> 20<div class="section"> 21<div class="titlepage"><div><div><h3 class="title"> 22<a name="safe_numerics.checked_arithmetic"></a>Checked Arithmetic</h3></div></div></div> 23<div class="toc"><dl class="toc"> 24<dt><span class="section"><a href="checked_arithmetic.html#idm130202409440">Description</a></span></dt> 25<dt><span class="section"><a href="checked_arithmetic.html#idm130202408112">Type requirements</a></span></dt> 26<dt><span class="section"><a href="checked_arithmetic.html#idm130202406112">Complexity</a></span></dt> 27<dt><span class="section"><a href="checked_arithmetic.html#idm130202404960">Example of use</a></span></dt> 28<dt><span class="section"><a href="checked_arithmetic.html#idm130202387696">Notes</a></span></dt> 29<dt><span class="section"><a href="checked_arithmetic.html#idm130202386128">Synopsis</a></span></dt> 30<dt><span class="section"><a href="checked_arithmetic.html#idm130202157712">See Also</a></span></dt> 31<dt><span class="section"><a href="checked_arithmetic.html#idm130202155984">Header</a></span></dt> 32</dl></div> 33<div class="section"> 34<div class="titlepage"><div><div><h4 class="title"> 35<a name="idm130202409440"></a>Description</h4></div></div></div> 36<p>Perform binary operations on arithmetic types. Return either a valid 37 result or an error code. Under no circumstances should an incorrect result 38 be returned.</p> 39</div> 40<div class="section"> 41<div class="titlepage"><div><div><h4 class="title"> 42<a name="idm130202408112"></a>Type requirements</h4></div></div></div> 43<p>All template parameters of the functions must model <a class="link" href="integer.html" title="Integer<T>">Numeric</a> type requirements.</p> 44</div> 45<div class="section"> 46<div class="titlepage"><div><div><h4 class="title"> 47<a name="idm130202406112"></a>Complexity</h4></div></div></div> 48<p>Each function performs one and only one arithmetic operation.</p> 49</div> 50<div class="section"> 51<div class="titlepage"><div><div><h4 class="title"> 52<a name="idm130202404960"></a>Example of use</h4></div></div></div> 53<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">numeric</span><span class="special">/</span><span class="identifier">safe_numerics</span><span class="special">/</span><span class="identifier">checked_default</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 54 55<span class="identifier">checked_result</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">r</span> <span class="special">=</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">multiply</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span><span class="special">(</span><span class="number">24</span><span class="special">,</span> <span class="number">42</span><span class="special">)</span><span class="special">;</span> 56</pre> 57</div> 58<div class="section"> 59<div class="titlepage"><div><div><h4 class="title"> 60<a name="idm130202387696"></a>Notes</h4></div></div></div> 61<p>Some compilers have command line switches (e.g. -ftrapv) which 62 enable special behavior such that erroneous integer operations are 63 detected at run time. The library has been implemented in such a way that 64 these facilities are not used. It's possible they might be helpful in 65 particular environment. These could be be exploited by re-implementing 66 some functions in this library.</p> 67</div> 68<div class="section"> 69<div class="titlepage"><div><div><h4 class="title"> 70<a name="idm130202386128"></a>Synopsis</h4></div></div></div> 71<pre class="programlisting"><span class="comment">// safe casting on primitive types</span> 72<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> 73<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">cast</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">T</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">)</span><span class="special">;</span> 74 75<span class="comment">// safe addition on primitive types</span> 76<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 77<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">add</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 78 79<span class="comment">// safe subtraction on primitive types</span> 80<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 81<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">subtract</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 82 83<span class="comment">// safe multiplication on primitive types</span> 84<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 85<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">multiply</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 86 87<span class="comment">// safe division on primitive types</span> 88<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 89<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">divide</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 90 91<span class="comment">// safe modulus on primitive types</span> 92<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 93<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">modulus</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 94 95<span class="comment">// safe less than predicate on primitive types</span> 96<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 97<span class="keyword">bool</span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">less_than</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 98 99<span class="comment">// safe greater_than_equal predicate on primitive types</span> 100<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 101<span class="keyword">bool</span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">greater_than_equal</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 102 103<span class="comment">// safe greater_than predicate on primitive types</span> 104<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 105<span class="keyword">bool</span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">greater_than</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 106 107<span class="comment">// safe less_than_equal predicate on primitive types</span> 108<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 109<span class="keyword">bool</span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">less_than_equal</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 110 111<span class="comment">// safe equal predicate on primitive types</span> 112<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 113<span class="keyword">bool</span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">equal</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 114 115<span class="comment">// left shift</span> 116<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 117<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">left_shift</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 118 119<span class="comment">// right shift</span> 120<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 121<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">right_shift</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 122 123<span class="comment">// bitwise operations</span> 124<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 125<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">bitwise_or</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 126 127<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 128<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">bitwise_and</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 129 130<span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</span><span class="special">></span> 131<span class="identifier">checked_result</span><span class="special"><</span><span class="identifier">R</span><span class="special">></span> <span class="keyword">constexpr</span> <span class="identifier">checked</span><span class="special">::</span><span class="identifier">bitwise_xor</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">R</span> <span class="special">&</span> <span class="identifier">u</span><span class="special">)</span><span class="special">;</span> 132</pre> 133</div> 134<div class="section"> 135<div class="titlepage"><div><div><h4 class="title"> 136<a name="idm130202157712"></a>See Also</h4></div></div></div> 137<p><a class="link" href="checked_result.html" title="checked_result<R>">checked_result<R></a></p> 138</div> 139<div class="section"> 140<div class="titlepage"><div><div><h4 class="title"> 141<a name="idm130202155984"></a>Header</h4></div></div></div> 142<p><a href="../../include/checked.hpp" target="_top"><code class="computeroutput">#include 143 <boost/numeric/safe_numerics/checked_default.hpp> 144 </code></a></p> 145<p><a href="../../include/checked_integer.hpp" target="_top"><code class="computeroutput">#include 146 <boost/numeric/safe_numerics/checked_integer.hpp> 147 </code></a></p> 148<p><a href="../../include/checked.hpp" target="_top"><code class="computeroutput"></code></a><a href="../../include/checked_float.hpp" target="_top"><code class="computeroutput">#include 149 <boost/numeric/safe_numerics/checked_float.hpp> 150 </code></a></p> 151</div> 152</div> 153<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 154<td align="left"></td> 155<td align="right"><div class="copyright-footer">Copyright © 2012-2018 Robert Ramey<p><a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">Subject to Boost 156 Software License</a></p> 157</div></td> 158</tr></table> 159<hr> 160<div class="spirit-nav"> 161<a accesskey="p" href="checked_result.html"><img src="images/prev.png" alt="Prev"></a><a accesskey="u" href="library_implementation.html"><img src="images/up.png" alt="Up"></a><a accesskey="h" href="index.html"><img src="images/home.png" alt="Home"></a><a accesskey="n" href="interval.html"><img src="images/next.png" alt="Next"></a> 162</div> 163</body> 164</html> 165
