PageRenderTime 7ms CodeModel.GetById 1ms app.highlight 3ms RepoModel.GetById 1ms app.codeStats 0ms

/Src/Dependencies/Boost/libs/property_map/doc/vector_property_map.html

http://hadesmem.googlecode.com/
HTML | 221 lines | 164 code | 50 blank | 7 comment | 0 complexity | 82b80b6dff2103f943397a8c510ad81d MD5 | raw file
  1<HTML>
  2<!--
  3     Copyright (c) Jeremy Siek, Lie-Quan Lee, and Andrew Lumsdaine 2000
  4    
  5     Distributed under the Boost Software License, Version 1.0.
  6     (See accompanying file LICENSE_1_0.txt or copy at
  7     http://www.boost.org/LICENSE_1_0.txt)
  8  -->
  9<Head>
 10<Title>Vector Property Map</Title>
 11<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" 
 12	ALINK="#ff0000"> 
 13<IMG SRC="../../../boost.png" 
 14     ALT="C++ Boost" width="277" height="86"> 
 15
 16<BR Clear>
 17
 18
 19<H2><A NAME="sec:vector-property-map"></A>
 20</h2>
 21<PRE>
 22template&lt;typename T, typename IndexMap = identity_property_map&gt;
 23class vector_property_map;
 24</PRE>
 25
 26<P>
 27This property map is used to efficiently store properties for a variable 
 28number of elements. It's somewhere between <a
 29href="associative_property_map.html">associative_property_map</a> and 
 30<a href="iterator_property_map.html">iterator_property_map</a>. The latter
 31is very fast, but requires that the number of stored elements is known
 32when creating property map. The former does not have this requirement, but
 33is slower, and requires stored elements to be comparable.
 34
 35<p>
 36The <tt>vector_property_map</tt> uses mapping from key to indices,
 37and allows to add new elements. It accoplishes this by storing values
 38in a vector, which is resized on demand. 
 39
 40<p>
 41Note that <tt>vector_property_map</tt> does not provide reference/pointer 
 42stability for stored values.
 43
 44<h3>Example</h3>
 45
 46<a href="../example/example3.cpp">example3.cpp</a>:
 47
 48<p>
 49<pre>
 50#include &lt;boost/property_map/vector_property_map.hpp&gt;
 51#include &lt;string&gt;
 52#include &lt;iostream&gt;
 53
 54int main()
 55{
 56    boost::vector_property_map&lt;std::string&gt; m;
 57    
 58    // Assign string to '4'. 
 59    m[4] = &quot;e&quot;;
 60    std::cout &lt;&lt; &quot;'&quot; &lt;&lt; m[4] &lt;&lt; &quot;'\n&quot;;
 61    
 62    // Grab string from '10'. Since none is associated,
 63    // &quot;&quot; will be returned.
 64    std::cout &lt;&lt; &quot;'&quot; &lt;&lt; m[10] &lt;&lt; &quot;'\n&quot;;
 65}
 66</pre>
 67
 68<H3>Where Defined</H3>
 69
 70<P>
 71<a href="../../../boost/property_map/vector_property_map.hpp"><TT>boost/property_map/vector_property_map.hpp</TT></a>
 72
 73<p>
 74<H3>Model Of</H3>
 75
 76<a href="./LvaluePropertyMap.html">Lvalue Property Map</a>
 77
 78<P>
 79
 80<H3>Template Parameters</H3>
 81
 82<P>
 83
 84<TABLE border>
 85<TR>
 86<th>Parameter</th><th>Description</th><th>Default</th>
 87</tr>
 88
 89
 90<TR>
 91<TD><TT>T</TT></TD> 
 92<TD>The type of property value. Must be both <a
 93href="http://www.sgi.com/tech/stl/Assignable.html">Assignable</a>
 94and <a
 95href="http://www.sgi.com/tech/stl/DefaultConstructible.html">DefaultConstructible</a>.
 96</TD>
 97<TD>&nbsp;</td>
 98</tr>
 99
100<TR>
101<TD><TT>IndexMap</TT></TD> <TD>Must be a model of <a
102href="./ReadablePropertyMap.html">Readable Property Map</a>
103and the value type must be convertible to
104<tt>std::vector&lt;T&gt;::size_type</tt>.</TD> 
105<TD><a href="identity_property_map.html">identity_property_map</a></TD>
106</TR>
107
108</TABLE>
109<P>
110
111<H3>Members</H3>
112
113<P>
114In addition to the methods and functions required by <a
115href="./LvaluePropertyMap.html">Lvalue Property Map</a>, this
116class has the following members.
117
118<hr>
119
120<pre>
121vector_property_map(const IndexMap& index = IndexMap())
122</pre>
123Constructor which takes an index map.
124
125<hr>
126
127<pre>
128vector_property_map(unsigned initial_size, const IndexMap& index = IndexMap())
129</pre>
130This constructor version allows to specify maximum index of element
131that will be stored. Correct number will improve performance, but semantic
132is always the same.
133
134<hr>
135
136<pre>
137vector_property_map(const vector_property_map&amp;)
138</pre>
139Copy constructor. The copy will share the same data and changes
140made to it will affect original property map.
141
142<hr>
143
144<pre>
145vector_property_map&amp; operator=(const vector_property_map&amp;)
146</pre>
147Assignment operator. The semantic is the same as for copy constructor.
148
149<hr>
150
151<pre>
152reference operator[](const key_type&amp; v) const
153</pre>
154The operator bracket for property access.
155
156<hr>
157
158<pre>
159std::vector&lt;T&gt;::iterator storage_begin()
160std::vector&lt;T&gt;::iterator storage_end()
161std::vector&lt;T&gt;::const_iterator storage_begin()
162std::vector&lt;T&gt;::const_iterator storage_end()
163</pre>
164
165<p>This group of methods gives access to begin and end iterators of the
166underlying vector.</p>
167
168<p><b>Rationale:</b> The methods are handy, for example, when it's needed to
169specify a single value for all elements in a freshly created property map. The
170methods are not called simply &quot;begin&quot; and &quot;end&quot; since
171conceptually, <tt>vector_property_map</tt> is unbounded map, and has no end
172iterator. The direct access to the underlying method is not provided, since
173it would decrease encapsulation and make future performance tuning dangerous.
174
175<p><b>Acknolegements:</b> Matthias Troyer suggested adding those functions.
176
177<hr>
178
179<pre>
180void reserve(unsigned size)
181</pre>
182Reserve the space for storing elements with maximum index of 'size'. Unless
183element with greater index is accesses, all accesses will be take O(1) time.
184
185
186<hr>
187
188<h3>Non-Member functions</h3>
189
190<hr>
191
192<pre>
193template<typename T, typename IndexMap>
194vector_property_map<T, IndexMap>
195make_vector_property_map(IndexMap index)
196{
197  return vector_property_map<T, IndexMap>(index);
198} 
199</pre>
200A function for conveniently creating a vector property map.
201
202<br>
203<HR>
204<TABLE>
205<TR valign=top>
206<TD nowrap>Copyright &copy 2002</TD><TD>
207<a HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</a>,
208Indiana University (<A
209HREF="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</A>)<br>
210<A HREF="http://www.boost.org/people/liequan_lee.htm">Lie-Quan Lee</A>, Indiana University (<A HREF="mailto:llee1@osl.iu.edu">llee1@osl.iu.edu</A>)<br>
211<A HREF="http://www.osl.iu.edu/~lums">Andrew Lumsdaine</A>,
212Indiana University (<A
213HREF="mailto:lums@osl.iu.edu">lums@osl.iu.edu</A>)
214</TD></TR>
215<tr>
216<td nowrap>Copyright &copy; 2003</td><td>Vladimir Prus</td>
217</tr>
218</TABLE>
219
220</BODY>
221</HTML>