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>Iterator Property Map Adaptor</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:iterator-property-map"></A> 20</h2> 21<PRE> 22iterator_property_map<<a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">RandomAccessIterator</a>, OffsetMap, T, R> 23</PRE> 24 25<P> 26This property map is an adaptor that converts any random access 27iterator into a <a 28href="./LvaluePropertyMap.html">Lvalue Property Map</a>. 29The <tt>OffsetMap</tt> type is responsible for converting 30key objects to integers that can be used as offsets with the 31random access iterator. 32 33<P> 34 35<h3>Example</h3> 36 37<pre> 38// print out the capacity and flow for all the edges in the graph 39template <class Graph, class CapacityPMap, class FlowPMap> 40void print_network(Graph& G, CapacityPMap capacity, FlowPMap flow) 41{ 42 typedef typename boost::graph_traits<Graph>::vertex_iterator Viter; 43 typedef typename boost::graph_traits<Graph>::out_edge_iterator OutEdgeIter; 44 typedef typename boost::graph_traits<Graph>::in_edge_iterator InEdgeIter; 45 46 Viter ui, uiend; 47 for (boost::tie(ui, uiend) = vertices(G); ui != uiend; ++ui) { 48 OutEdgeIter out, out_end; 49 std::cout << *ui << "\t"; 50 51 for(boost::tie(out, out_end) = out_edges(*ui, G); out != out_end; ++out) 52 std::cout << "--(" << get(capacity, *out) << ", " 53 << get(flow, *out) << ")--> " << target(*out,G) << "\t"; 54 std::cout << std::endl << "\t"; 55 56 InEdgeIter in, in_end; 57 for(boost::tie(in, in_end) = in_edges(*ui, G); in != in_end; ++in) 58 std::cout << "<--(" << get(capacity, *in) << "," << get(flow, *in) << ")-- " 59 << source(*in,G) << "\t"; 60 std::cout << std::endl; 61 } 62} 63 64int main(int, char*[]) 65{ 66 typedef boost::adjacency_list<boost::vecS, boost::vecS, 67 boost::bidirectionalS, boost::no_plugin, 68 boost::plugin<boost::id_tag, std::size_t> > Graph; 69 70 const int num_vertices = 9; 71 Graph G(num_vertices); 72 73 int capacity[] = { 10, 20, 20, 20, 40, 40, 20, 20, 20, 10 }; 74 int flow[] = { 8, 12, 12, 12, 12, 12, 16, 16, 16, 8 }; 75 76 // add edges to the graph, and assign each edge an ID number 77 // to index into the property arrays 78 add_edge(G, 0, 1, 0); 79 // ... 80 81 typedef boost::graph_traits<Graph>::edge_descriptor Edge; 82 typedef boost::property_map<Graph, boost::id_tag>::type EdgeID_PMap; 83 EdgeID_PMap edge_id = get(boost::edge_index(), G); 84 85 boost::iterator_property_map<int*, EdgeID_PMap, int, int&> 86 capacity_pa(capacity, edge_id), 87 flow_pa(flow, edge_id); 88 89 print_network(G, capacity_pa, flow_pa); 90 91 return 0; 92} 93</pre> 94 95<H3>Where Defined</H3> 96 97<P> 98<a href="../../../boost/property_map/property_map.hpp"><TT>boost/property_map/property_map.hpp</TT></a> 99 100<p> 101<H3>Model Of</H3> 102 103<a href="./LvaluePropertyMap.html">Lvalue Property Map</a> 104 105<P> 106 107<H3>Template Parameters</H3> 108 109<P> 110 111<TABLE border> 112<TR> 113<th>Parameter</th><th>Description</th><th>Default</th> 114</tr> 115 116 117<TR> 118<TD><TT>Iterator</TT></TD> 119<TD>Must be a model of <a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access Iterator</a>.</TD> 120<TD> </td> 121</tr> 122 123<TR> 124<TD><TT>OffsetMap</TT></TD> <TD>Must be a model of <a 125href="./ReadablePropertyMap.html">Readable Property Map</a> 126and the value type must be convertible to the difference type of the 127iterator.</TD> <TD> </TD> 128</TR> 129 130<TR> 131<TD><TT>T</TT></TD> 132<TD>The value type of the iterator.</TD> 133<TD><TT>std::iterator_traits<RandomAccessIterator>::value_type</TT></TD> 134</TR> 135 136 137<TR> 138<TD><TT>R</TT></TD> 139<TD>The reference type of the iterator.</TD> 140<TD><TT>std::iterator_traits<RandomAccessIterator>::reference</TT></TD> 141</TR> 142 143</TABLE> 144<P> 145 146<H3>Members</H3> 147 148<P> 149In addition to the methods and functions required by <a 150href="./LvaluePropertyMap.html">Lvalue Property Map</a>, this 151class has the following members. 152 153<hr> 154 155<pre> 156property_traits<iterator_property_map>::value_type 157</pre> 158This is the same type as 159<TT>std::iterator_traits<Iterator>::value_type</TT>. 160 161<hr> 162 163<pre> 164iterator_property_map(Iterator i) 165</pre> 166Constructor. The OffsetMap is default constructed. 167 168<hr> 169 170<pre> 171iterator_property_map(Iterator i, OffsetMap m) 172</pre> 173Constructor. 174 175<hr> 176 177<pre> 178reference operator[](const key_type& v) const 179</pre> 180The operator bracket for property access. The <TT>reference</TT> is from 181<TT>std::iterator_traits<Iterator></TT> and the <tt>key_type</tt> is from <tt>boost::property_traits<OffsetMap></tt>. 182<hr> 183 184<h3>Non-Member functions</h3> 185 186<hr> 187 188<pre> 189 template <class RAIter, class OffsetMap> 190 iterator_property_map<RAIter, OffsetMap, 191 typename std::iterator_traits<RAIter>::value_type, 192 typename std::iterator_traits<RAIter>::reference 193 > 194 make_iterator_property_map(RAIter iter, OffsetMap omap) 195</pre> 196A function for conveniently creating an iterator map. 197 198 199<hr> 200 201<pre> 202 template <class RAIter, class OffsetMap, class ValueType> 203 iterator_property_map<RAIter, OffsetMap, 204 typename std::iterator_traits<RAIter>::value_type, 205 typename std::iterator_traits<RAIter>::reference 206 > 207 make_iterator_property_map(RAIter iter, OffsetMap omap, ValueType dummy_arg) 208</pre> 209Use this function instead of the 2-argument version if 210your compiler does not support partial specialization 211(like Visual C++). 212 213 214<hr> 215 216 217<br> 218<HR> 219<TABLE> 220<TR valign=top> 221<TD nowrap>Copyright © 2000-2002</TD><TD> 222<a HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</a>, 223Univ.of Notre Dame (<A 224HREF="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</A>)<br> 225<A HREF="http://www.boost.org/people/liequan_lee.htm">Lie-Quan Lee</A>, Univ.of Notre Dame (<A HREF="mailto:llee1@osl.iu.edu">llee1@osl.iu.edu</A>)<br> 226<A HREF="http://www.osl.iu.edu/~lums">Andrew Lumsdaine</A>, 227Univ.of Notre Dame (<A 228HREF="mailto:lums@osl.iu.edu">lums@osl.iu.edu</A>) 229</TD></TR></TABLE> 230 231</BODY> 232</HTML> 233
