projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | <html> |
| 2 | <head> | |
| 3 | <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> | |
| 4 | <title>Party</title> | |
| 5 | <link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> | |
| 6 | <meta name="generator" content="DocBook XSL Stylesheets V1.74.0"> | |
| 7 | <link rel="home" href="../../index.html" title="Chapter 1. Boost.Icl"> | |
| 8 | <link rel="up" href="../examples.html" title="Examples"> | |
| 9 | <link rel="prev" href="../examples.html" title="Examples"> | |
| 10 | <link rel="next" href="interval.html" title="Interval"> | |
| 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="../../../../../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="../examples.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../examples.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="interval.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> | |
| 24 | </div> | |
| 25 | <div class="section boost_icl_examples_party" lang="en"> | |
| 26 | <div class="titlepage"><div><div><h3 class="title"> | |
| 27 | <a name="boost_icl.examples.party"></a><a class="link" href="party.html" title="Party">Party</a> | |
| 28 | </h3></div></div></div> | |
| 29 | <p> | |
| 30 | Example <span class="bold"><strong>party</strong></span> demonstrates the possibilities | |
| 31 | of an interval map (<code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code> | |
| 32 | or <code class="computeroutput"><a class="link" href="../../boost/icl/split_interval_map.html" title="Class template split_interval_map">split_interval_map</a></code>). | |
| 33 | An <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code> maps | |
| 34 | intervals to a given content. In this case the content is a set of party | |
| 35 | guests represented by their name strings. | |
| 36 | </p> | |
| 37 | <p> | |
| 38 | As time goes by, groups of people join the party and leave later in the evening. | |
| 39 | So we add a time interval and a name set to the <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code> | |
| 40 | for the attendance of each group of people, that come together and leave | |
| 41 | together. On every overlap of intervals, the corresponding name sets are | |
| 42 | accumulated. At the points of overlap the intervals are split. The accumulation | |
| 43 | of content is done via an operator += that has to be implemented for the | |
| 44 | content parameter of the <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_map</a></code>. | |
| 45 | Finally the interval_map contains the history of attendance and all points | |
| 46 | in time, where the group of party guests changed. | |
| 47 | </p> | |
| 48 | <p> | |
| 49 | Party demonstrates a principle that we call <span class="emphasis"><em><span class="bold"><strong>aggregate | |
| 50 | on overlap</strong></span></em></span>: On insertion a value associated to the | |
| 51 | interval is aggregated with those values in the interval_map that overlap | |
| 52 | with the inserted value. There are two behavioral aspects to <span class="emphasis"><em><span class="bold"><strong>aggregate on overlap</strong></span></em></span>: a <span class="emphasis"><em><span class="bold"><strong>decompositional behavior</strong></span></em></span> and an <span class="emphasis"><em><span class="bold"><strong>accumulative behavior</strong></span></em></span>. | |
| 53 | </p> | |
| 54 | <div class="itemizedlist"><ul type="disc"> | |
| 55 | <li> | |
| 56 | The <span class="emphasis"><em><span class="bold"><strong>decompositional behavior</strong></span></em></span> | |
| 57 | splits up intervals on the <span class="emphasis"><em>time</em></span><span class="emphasis"><em>dimension</em></span> | |
| 58 | of the interval_map so that the intervals are split whenever associated | |
| 59 | values change. | |
| 60 | </li> | |
| 61 | <li> | |
| 62 | The <span class="emphasis"><em><span class="bold"><strong>accumulative behavior</strong></span></em></span> | |
| 63 | accumulates associated values on every overlap of an insertion for the | |
| 64 | associated values. | |
| 65 | </li> | |
| 66 | </ul></div> | |
| 67 | <p> | |
| 68 | The aggregation function is += by default. Different aggregations can be | |
| 69 | used, if desired. | |
| 70 | </p> | |
| 71 | <p> | |
| 72 | </p> | |
| 73 | <p> | |
| 74 | ||
| 75 | </p> | |
| 76 | <pre class="programlisting"><span class="comment">// The next line includes <boost/date_time/posix_time/posix_time.hpp> | |
| 77 | </span><span class="comment">// and a few lines of adapter code. | |
| 78 | </span><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">icl</span><span class="special">/</span><span class="identifier">ptime</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> | |
| 79 | <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> | |
| 80 | <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">icl</span><span class="special">/</span><span class="identifier">interval_map</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> | |
| 81 | ||
| 82 | <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">std</span><span class="special">;</span> | |
| 83 | <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">posix_time</span><span class="special">;</span> | |
| 84 | <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">icl</span><span class="special">;</span> | |
| 85 | ||
| 86 | <span class="comment">// Type set<string> collects the names of party guests. Since std::set is | |
| 87 | </span><span class="comment">// a model of the itl's set concept, the concept provides an operator += | |
| 88 | </span><span class="comment">// that performs a set union on overlap of intervals. | |
| 89 | </span><span class="keyword">typedef</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span><span class="special"><</span><span class="identifier">string</span><span class="special">></span> <span class="identifier">GuestSetT</span><span class="special">;</span> | |
| 90 | ||
| 91 | <span class="keyword">void</span> <span class="identifier">boost_party</span><span class="special">()</span> | |
| 92 | <span class="special">{</span> | |
| 93 | <span class="identifier">GuestSetT</span> <span class="identifier">mary_harry</span><span class="special">;</span> | |
| 94 | <span class="identifier">mary_harry</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Mary"</span><span class="special">);</span> | |
| 95 | <span class="identifier">mary_harry</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Harry"</span><span class="special">);</span> | |
| 96 | ||
| 97 | <span class="identifier">GuestSetT</span> <span class="identifier">diana_susan</span><span class="special">;</span> | |
| 98 | <span class="identifier">diana_susan</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Diana"</span><span class="special">);</span> | |
| 99 | <span class="identifier">diana_susan</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Susan"</span><span class="special">);</span> | |
| 100 | ||
| 101 | <span class="identifier">GuestSetT</span> <span class="identifier">peter</span><span class="special">;</span> | |
| 102 | <span class="identifier">peter</span><span class="special">.</span><span class="identifier">insert</span><span class="special">(</span><span class="string">"Peter"</span><span class="special">);</span> | |
| 103 | ||
| 104 | <span class="comment">// A party is an interval map that maps time intervals to sets of guests | |
| 105 | </span> <span class="identifier">interval_map</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">,</span> <span class="identifier">GuestSetT</span><span class="special">></span> <span class="identifier">party</span><span class="special">;</span> | |
| 106 | ||
| 107 | <span class="identifier">party</span><span class="special">.</span><span class="identifier">add</span><span class="special">(</span> <span class="comment">// add and element | |
| 108 | </span> <span class="identifier">make_pair</span><span class="special">(</span> | |
| 109 | <span class="identifier">interval</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">>::</span><span class="identifier">right_open</span><span class="special">(</span> | |
| 110 | <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-20 19:30"</span><span class="special">),</span> | |
| 111 | <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-20 23:00"</span><span class="special">)),</span> | |
| 112 | <span class="identifier">mary_harry</span><span class="special">));</span> | |
| 113 | ||
| 114 | <span class="identifier">party</span> <span class="special">+=</span> <span class="comment">// element addition can also be done via operator += | |
| 115 | </span> <span class="identifier">make_pair</span><span class="special">(</span> | |
| 116 | <span class="identifier">interval</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">>::</span><span class="identifier">right_open</span><span class="special">(</span> | |
| 117 | <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-20 20:10"</span><span class="special">),</span> | |
| 118 | <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-21 00:00"</span><span class="special">)),</span> | |
| 119 | <span class="identifier">diana_susan</span><span class="special">);</span> | |
| 120 | ||
| 121 | <span class="identifier">party</span> <span class="special">+=</span> | |
| 122 | <span class="identifier">make_pair</span><span class="special">(</span> | |
| 123 | <span class="identifier">interval</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">>::</span><span class="identifier">right_open</span><span class="special">(</span> | |
| 124 | <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-20 22:15"</span><span class="special">),</span> | |
| 125 | <span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2008-05-21 00:30"</span><span class="special">)),</span> | |
| 126 | <span class="identifier">peter</span><span class="special">);</span> | |
| 127 | ||
| 128 | ||
| 129 | <span class="identifier">interval_map</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">,</span> <span class="identifier">GuestSetT</span><span class="special">>::</span><span class="identifier">iterator</span> <span class="identifier">it</span> <span class="special">=</span> <span class="identifier">party</span><span class="special">.</span><span class="identifier">begin</span><span class="special">();</span> | |
| 130 | <span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"----- History of party guests -------------------------\n"</span><span class="special">;</span> | |
| 131 | <span class="keyword">while</span><span class="special">(</span><span class="identifier">it</span> <span class="special">!=</span> <span class="identifier">party</span><span class="special">.</span><span class="identifier">end</span><span class="special">())</span> | |
| 132 | <span class="special">{</span> | |
| 133 | <span class="identifier">interval</span><span class="special"><</span><span class="identifier">ptime</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">when</span> <span class="special">=</span> <span class="identifier">it</span><span class="special">-></span><span class="identifier">first</span><span class="special">;</span> | |
| 134 | <span class="comment">// Who is at the party within the time interval 'when' ? | |
| 135 | </span> <span class="identifier">GuestSetT</span> <span class="identifier">who</span> <span class="special">=</span> <span class="special">(*</span><span class="identifier">it</span><span class="special">++).</span><span class="identifier">second</span><span class="special">;</span> | |
| 136 | <span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">when</span> <span class="special"><<</span> <span class="string">": "</span> <span class="special"><<</span> <span class="identifier">who</span> <span class="special"><<</span> <span class="identifier">endl</span><span class="special">;</span> | |
| 137 | <span class="special">}</span> | |
| 138 | ||
| 139 | <span class="special">}</span> | |
| 140 | ||
| 141 | ||
| 142 | <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> | |
| 143 | <span class="special">{</span> | |
| 144 | <span class="identifier">cout</span> <span class="special"><<</span> <span class="string">">>Interval Container Library: Sample boost_party.cpp <<\n"</span><span class="special">;</span> | |
| 145 | <span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"-------------------------------------------------------\n"</span><span class="special">;</span> | |
| 146 | <span class="identifier">boost_party</span><span class="special">();</span> | |
| 147 | <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> | |
| 148 | <span class="special">}</span> | |
| 149 | ||
| 150 | <span class="comment">// Program output: | |
| 151 | </span><span class="comment">/*----------------------------------------------------------------------------- | |
| 152 | >>Interval Container Library: Sample boost_party.cpp << | |
| 153 | ------------------------------------------------------- | |
| 154 | ----- History of party guests ------------------------- | |
| 155 | [2008-May-20 19:30:00, 2008-May-20 20:10:00): Harry Mary | |
| 156 | [2008-May-20 20:10:00, 2008-May-20 22:15:00): Diana Harry Mary Susan | |
| 157 | [2008-May-20 22:15:00, 2008-May-20 23:00:00): Diana Harry Mary Peter Susan | |
| 158 | [2008-May-20 23:00:00, 2008-May-21 00:00:00): Diana Peter Susan | |
| 159 | [2008-May-21 00:00:00, 2008-May-21 00:30:00): Peter | |
| 160 | -----------------------------------------------------------------------------*/</span> | |
| 161 | </pre> | |
| 162 | <p> | |
| 163 | </p> | |
| 164 | <p> | |
| 165 | </p> | |
| 166 | <div class="caution"><table border="0" summary="Caution"> | |
| 167 | <tr> | |
| 168 | <td rowspan="2" align="center" valign="top" width="25"><img alt="[Caution]" src="../../../../../../doc/src/images/caution.png"></td> | |
| 169 | <th align="left">Caution</th> | |
| 170 | </tr> | |
| 171 | <tr><td align="left" valign="top"> | |
| 172 | <p> | |
| 173 | </p> | |
| 174 | <p> | |
| 175 | We are introducing <code class="computeroutput"><a class="link" href="../../boost/icl/interval_map.html" title="Class template interval_map">interval_maps</a></code> | |
| 176 | using an <span class="emphasis"><em>interval map <span class="emphasis"><em><span class="bold"><strong>of sets | |
| 177 | of strings</strong></span></em></span></em></span>, because of it's didactic advantages. | |
| 178 | The party example is used to give an immediate access to the basic ideas | |
| 179 | of interval maps and <span class="emphasis"><em>aggregate on overlap</em></span>. For real | |
| 180 | world applications, an interval_map of sets is not necessarily recommended. | |
| 181 | It has the same efficiency problems as a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span></code> | |
| 182 | of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">sets</span></code>. There is a big realm though of | |
| 183 | using interval_maps with numerical and other efficient data types for the | |
| 184 | associated values. | |
| 185 | </p> | |
| 186 | </td></tr> | |
| 187 | </table></div> | |
| 188 | </div> | |
| 189 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
| 190 | <td align="left"></td> | |
| 191 | <td align="right"><div class="copyright-footer">Copyright © 2007 -2010 Joachim Faulhaber<br>Copyright © 1999 -2006 Cortex Software GmbH<p> | |
| 192 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| 193 | 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>) | |
| 194 | </p> | |
| 195 | </div></td> | |
| 196 | </tr></table> | |
| 197 | <hr> | |
| 198 | <div class="spirit-nav"> | |
| 199 | <a accesskey="p" href="../examples.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../examples.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="interval.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> | |
| 200 | </div> | |
| 201 | </body> | |
| 202 | </html> |