1 //=======================================================================
2 // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
3 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
4 //
5 // Distributed under the Boost Software License, Version 1.0. (See
6 // accompanying file LICENSE_1_0.txt or copy at
7 // http://www.boost.org/LICENSE_1_0.txt)
8 //=======================================================================
9
10 /*
11 Sample data (edge_iterator_constructor.dat):
12 5
13 10
14 0 1
15 1 2
16 1 3
17 2 4
18 3 4
19 1 0
20 2 1
21 3 1
22 4 2
23 4 3
24
25 Sample output:
26
27 0 --> 1
28 1 --> 2 3 0
29 2 --> 4 1
30 3 --> 4 1
31 4 --> 2 3
32
33 */
34
35 #include <boost/config.hpp>
36 #include <utility>
37 #include <iostream>
38 #include <fstream>
39
40 #include <iterator>
41 #include <boost/graph/graph_utility.hpp>
42 #include <boost/graph/adjacency_list.hpp>
43
44 class edge_stream_iterator {
45 public:
46 typedef std::input_iterator_tag iterator_category;
47 typedef std::pair<int,int> value_type;
48 typedef std::ptrdiff_t difference_type;
49 typedef const value_type* pointer;
50 typedef const value_type& reference;
51
edge_stream_iterator()52 edge_stream_iterator() : m_stream(0), m_end_marker(false) {}
edge_stream_iterator(std::istream & s)53 edge_stream_iterator(std::istream& s) : m_stream(&s) { m_read(); }
operator *() const54 reference operator*() const { return m_edge; }
operator ++()55 edge_stream_iterator& operator++() {
56 m_read();
57 return *this;
58 }
operator ++(int)59 edge_stream_iterator operator++(int) {
60 edge_stream_iterator tmp = *this;
61 m_read();
62 return tmp;
63 }
64 protected:
65 std::istream* m_stream;
66 value_type m_edge;
67 bool m_end_marker;
m_read()68 void m_read() {
69 m_end_marker = (*m_stream) ? true : false;
70 if (m_end_marker) {
71 *m_stream >> m_edge.first >> m_edge.second;
72 }
73 m_end_marker = (*m_stream) ? true : false;
74 }
75 friend bool operator==(const edge_stream_iterator& x,
76 const edge_stream_iterator& y);
77
78 };
operator ==(const edge_stream_iterator & x,const edge_stream_iterator & y)79 bool operator==(const edge_stream_iterator& x,
80 const edge_stream_iterator& y)
81 {
82 return (x.m_stream == y.m_stream && x.m_end_marker == y.m_end_marker)
83 || (x.m_end_marker == false && y.m_end_marker == false);
84 }
operator !=(const edge_stream_iterator & x,const edge_stream_iterator & y)85 bool operator!=(const edge_stream_iterator& x,
86 const edge_stream_iterator& y)
87 {
88 return !(x == y);
89 }
90
91
92
93 int
main(int argc,const char ** argv)94 main(int argc, const char** argv)
95 {
96 typedef boost::adjacency_list<> IteratorConstructibleGraph;
97 typedef boost::graph_traits<IteratorConstructibleGraph> Traits;
98 Traits::vertices_size_type size_V;
99 Traits::edges_size_type size_E;
100
101 std::ifstream f(argc >= 2 ? argv[1] : "edge_iterator_constructor.dat");
102 f >> size_V >> size_E;
103
104 edge_stream_iterator edge_iter(f), end;
105 #if defined(BOOST_MSVC) && BOOST_MSVC <= 1300
106 // VC++ can't handle the iterator constructor
107 IteratorConstructibleGraph G(size_V);
108 while (edge_iter != end) {
109 int i, j;
110 boost::tie(i, j) = *edge_iter++;
111 boost::add_edge(i, j, G);
112 }
113 #else
114 IteratorConstructibleGraph G(edge_iter, end, size_V);
115 #endif
116 boost::print_graph(G);
117
118 return 0;
119 }
120