]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | <html> |
2 | <head> | |
3 | <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> | |
4 | <title>Compile time min/max calculation</title> | |
5 | <link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> | |
6 | <meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> | |
7 | <link rel="home" href="../index.html" title="Boost.Integer"> | |
8 | <link rel="up" href="../index.html" title="Boost.Integer"> | |
9 | <link rel="prev" href="log2.html" title="Compile Time log2 Calculation"> | |
10 | <link rel="next" href="history.html" title="History"> | |
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 alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> | |
15 | <td align="center"><a href="../../../../../index.html">Home</a></td> | |
16 | <td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> | |
17 | <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> | |
18 | <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> | |
19 | <td align="center"><a href="../../../../../more/index.htm">More</a></td> | |
20 | </tr></table> | |
21 | <hr> | |
22 | <div class="spirit-nav"> | |
23 | <a accesskey="p" href="log2.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="history.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> | |
24 | </div> | |
25 | <div class="section"> | |
26 | <div class="titlepage"><div><div><h2 class="title" style="clear: both"> | |
27 | <a name="boost_integer.minmax"></a><a class="link" href="minmax.html" title="Compile time min/max calculation">Compile time min/max calculation</a> | |
28 | </h2></div></div></div> | |
29 | <div class="toc"><dl class="toc"> | |
30 | <dt><span class="section"><a href="minmax.html#boost_integer.minmax.synopsis">Synopsis</a></span></dt> | |
31 | <dt><span class="section"><a href="minmax.html#boost_integer.minmax.usage">Usage</a></span></dt> | |
32 | <dt><span class="section"><a href="minmax.html#boost_integer.minmax.example">Example</a></span></dt> | |
33 | <dt><span class="section"><a href="minmax.html#boost_integer.minmax.demonstration_program">Demonstration | |
34 | Program</a></span></dt> | |
35 | <dt><span class="section"><a href="minmax.html#boost_integer.minmax.rationale">Rationale</a></span></dt> | |
36 | <dt><span class="section"><a href="minmax.html#boost_integer.minmax.credits">Credits</a></span></dt> | |
37 | </dl></div> | |
38 | <p> | |
39 | The class templates in <a href="../../../../../boost/integer/static_min_max.hpp" target="_top"><boost/integer/static_min_max.hpp></a> | |
40 | provide a compile-time evaluation of the minimum or maximum of two integers. | |
41 | These facilities are useful for generic programming problems. | |
42 | </p> | |
43 | <div class="section"> | |
44 | <div class="titlepage"><div><div><h3 class="title"> | |
45 | <a name="boost_integer.minmax.synopsis"></a><a class="link" href="minmax.html#boost_integer.minmax.synopsis" title="Synopsis">Synopsis</a> | |
46 | </h3></div></div></div> | |
47 | <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> | |
48 | <span class="special">{</span> | |
49 | ||
50 | <span class="keyword">typedef</span> <span class="emphasis"><em>implementation-defined</em></span> <span class="identifier">static_min_max_signed_type</span><span class="special">;</span> | |
51 | <span class="keyword">typedef</span> <span class="emphasis"><em>implementation-defined</em></span> <span class="identifier">static_min_max_unsigned_type</span><span class="special">;</span> | |
52 | ||
53 | <span class="keyword">template</span> <span class="special"><</span><span class="identifier">static_min_max_signed_type</span> <span class="identifier">Value1</span><span class="special">,</span> <span class="identifier">static_min_max_signed_type</span> <span class="identifier">Value2</span> <span class="special">></span> | |
54 | <span class="keyword">struct</span> <span class="identifier">static_signed_min</span><span class="special">;</span> | |
55 | ||
56 | <span class="keyword">template</span> <span class="special"><</span><span class="identifier">static_min_max_signed_type</span> <span class="identifier">Value1</span><span class="special">,</span> <span class="identifier">static_min_max_signed_type</span> <span class="identifier">Value2</span><span class="special">></span> | |
57 | <span class="keyword">struct</span> <span class="identifier">static_signed_max</span><span class="special">;</span> | |
58 | ||
59 | <span class="keyword">template</span> <span class="special"><</span><span class="identifier">static_min_max_unsigned_type</span> <span class="identifier">Value1</span><span class="special">,</span> <span class="identifier">static_min_max_unsigned_type</span> <span class="identifier">Value2</span><span class="special">></span> | |
60 | <span class="keyword">struct</span> <span class="identifier">static_unsigned_min</span><span class="special">;</span> | |
61 | ||
62 | <span class="keyword">template</span> <span class="special"><</span><span class="identifier">static_min_max_unsigned_type</span> <span class="identifier">Value1</span><span class="special">,</span> <span class="identifier">static_min_max_unsigned_type</span> <span class="identifier">Value2</span><span class="special">></span> | |
63 | <span class="keyword">struct</span> <span class="identifier">static_unsigned_max</span><span class="special">;</span> | |
64 | ||
65 | <span class="special">}</span> | |
66 | </pre> | |
67 | </div> | |
68 | <div class="section"> | |
69 | <div class="titlepage"><div><div><h3 class="title"> | |
70 | <a name="boost_integer.minmax.usage"></a><a class="link" href="minmax.html#boost_integer.minmax.usage" title="Usage">Usage</a> | |
71 | </h3></div></div></div> | |
72 | <p> | |
73 | The four class templates provide the combinations for finding the minimum | |
74 | or maximum of two <code class="literal">signed</code> or <code class="literal">unsigned</code> | |
75 | (<code class="literal">long</code>) parameters, <span class="emphasis"><em>Value1</em></span> and <span class="emphasis"><em>Value2</em></span>, | |
76 | at compile-time. Each template has a single static data member, <code class="literal">value</code>, | |
77 | which is set to the respective minimum or maximum of the template's parameters. | |
78 | </p> | |
79 | </div> | |
80 | <div class="section"> | |
81 | <div class="titlepage"><div><div><h3 class="title"> | |
82 | <a name="boost_integer.minmax.example"></a><a class="link" href="minmax.html#boost_integer.minmax.example" title="Example">Example</a> | |
83 | </h3></div></div></div> | |
84 | <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">integer</span><span class="special">/</span><span class="identifier">static_min_max</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> | |
85 | ||
86 | <span class="keyword">template</span> <span class="special"><</span> <span class="keyword">unsigned</span> <span class="keyword">long</span> <span class="identifier">AddendSize1</span><span class="special">,</span> <span class="keyword">unsigned</span> <span class="keyword">long</span> <span class="identifier">AddendSize2</span> <span class="special">></span> | |
87 | <span class="keyword">class</span> <span class="identifier">adder</span> | |
88 | <span class="special">{</span> | |
89 | <span class="keyword">public</span><span class="special">:</span> | |
90 | <span class="keyword">static</span> <span class="keyword">unsigned</span> <span class="keyword">long</span> <span class="keyword">const</span> <span class="identifier">addend1_size</span> <span class="special">=</span> <span class="identifier">AddendSize1</span><span class="special">;</span> | |
91 | <span class="keyword">static</span> <span class="keyword">unsigned</span> <span class="keyword">long</span> <span class="keyword">const</span> <span class="identifier">addend2_size</span> <span class="special">=</span> <span class="identifier">AddendSize2</span><span class="special">;</span> | |
92 | <span class="keyword">static</span> <span class="keyword">unsigned</span> <span class="keyword">long</span> <span class="keyword">const</span> <span class="identifier">sum_size</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">static_unsigned_max</span><span class="special"><</span><span class="identifier">AddendSize1</span><span class="special">,</span> <span class="identifier">AddendSize2</span><span class="special">>::</span><span class="identifier">value</span> <span class="special">+</span> <span class="number">1</span><span class="special">;</span> | |
93 | ||
94 | <span class="keyword">typedef</span> <span class="keyword">int</span> <span class="identifier">addend1_type</span><span class="special">[</span> <span class="identifier">addend1_size</span> <span class="special">];</span> | |
95 | <span class="keyword">typedef</span> <span class="keyword">int</span> <span class="identifier">addend2_type</span><span class="special">[</span> <span class="identifier">addend2_size</span> <span class="special">];</span> | |
96 | <span class="keyword">typedef</span> <span class="keyword">int</span> <span class="identifier">sum_type</span><span class="special">[</span> <span class="identifier">sum_size</span> <span class="special">];</span> | |
97 | ||
98 | <span class="keyword">void</span> <span class="keyword">operator</span> <span class="special">()(</span> <span class="identifier">addend1_type</span> <span class="keyword">const</span> <span class="special">&</span><span class="identifier">a1</span><span class="special">,</span> <span class="identifier">addend2_type</span> <span class="keyword">const</span> <span class="special">&</span><span class="identifier">a2</span><span class="special">,</span> <span class="identifier">sum_type</span> <span class="special">&</span><span class="identifier">s</span> <span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> | |
99 | <span class="special">};</span> | |
100 | ||
101 | <span class="comment">//...</span> | |
102 | ||
103 | <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> | |
104 | <span class="special">{</span> | |
105 | <span class="keyword">int</span> <span class="keyword">const</span> <span class="identifier">a1</span><span class="special">[]</span> <span class="special">=</span> <span class="special">{</span> <span class="number">0</span><span class="special">,</span> <span class="number">4</span><span class="special">,</span> <span class="number">3</span> <span class="special">};</span> <span class="comment">// 340</span> | |
106 | <span class="keyword">int</span> <span class="keyword">const</span> <span class="identifier">a2</span><span class="special">[]</span> <span class="special">=</span> <span class="special">{</span> <span class="number">9</span><span class="special">,</span> <span class="number">8</span> <span class="special">};</span> <span class="comment">// 89</span> | |
107 | <span class="keyword">int</span> <span class="identifier">s</span><span class="special">[</span> <span class="number">4</span> <span class="special">];</span> | |
108 | <span class="identifier">adder</span><span class="special"><</span><span class="number">3</span><span class="special">,</span><span class="number">2</span><span class="special">></span> <span class="identifier">obj</span><span class="special">;</span> | |
109 | ||
110 | <span class="identifier">obj</span><span class="special">(</span> <span class="identifier">a1</span><span class="special">,</span> <span class="identifier">a2</span><span class="special">,</span> <span class="identifier">s</span> <span class="special">);</span> <span class="comment">// 's' should be 429 or { 9, 2, 4, 0 }</span> | |
111 | <span class="comment">//...</span> | |
112 | <span class="special">}</span> | |
113 | </pre> | |
114 | </div> | |
115 | <div class="section"> | |
116 | <div class="titlepage"><div><div><h3 class="title"> | |
117 | <a name="boost_integer.minmax.demonstration_program"></a><a class="link" href="minmax.html#boost_integer.minmax.demonstration_program" title="Demonstration Program">Demonstration | |
118 | Program</a> | |
119 | </h3></div></div></div> | |
120 | <p> | |
121 | The program <a href="../../../test/static_min_max_test.cpp" target="_top">static_min_max_test.cpp</a> | |
122 | is a simplistic demonstration of various comparisons using the compile-time | |
123 | extrema class templates. | |
124 | </p> | |
125 | </div> | |
126 | <div class="section"> | |
127 | <div class="titlepage"><div><div><h3 class="title"> | |
128 | <a name="boost_integer.minmax.rationale"></a><a class="link" href="minmax.html#boost_integer.minmax.rationale" title="Rationale">Rationale</a> | |
129 | </h3></div></div></div> | |
130 | <p> | |
131 | Sometimes the minimum or maximum of several values needs to be found for | |
132 | later compile-time processing, <span class="emphasis"><em>e.g.</em></span> for a bound for | |
133 | another class template. | |
134 | </p> | |
135 | </div> | |
136 | <div class="section"> | |
137 | <div class="titlepage"><div><div><h3 class="title"> | |
138 | <a name="boost_integer.minmax.credits"></a><a class="link" href="minmax.html#boost_integer.minmax.credits" title="Credits">Credits</a> | |
139 | </h3></div></div></div> | |
140 | <p> | |
141 | The author of the Boost compile-time extrema class templates is <a href="http://www.boost.org/people/daryle_walker.html" target="_top">Daryle | |
142 | Walker</a>. | |
143 | </p> | |
144 | </div> | |
145 | </div> | |
146 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
147 | <td align="left"></td> | |
148 | <td align="right"><div class="copyright-footer">Copyright © 2001-2009 Beman | |
149 | Dawes, Daryle Walker, Gennaro Prota, John Maddock<p> | |
150 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
151 | file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) | |
152 | </p> | |
153 | </div></td> | |
154 | </tr></table> | |
155 | <hr> | |
156 | <div class="spirit-nav"> | |
157 | <a accesskey="p" href="log2.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="history.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> | |
158 | </div> | |
159 | </body> | |
160 | </html> |