graph/example/loops_dfs.cpp

//=======================================================================
// Copyright 2001 Jeremy G. Siek, Andrew Lumsdaine, Lie-Quan Lee, 
//
// This file is part of the Boost Graph Library
//
// You should have received a copy of the License Agreement for the
// Boost Graph Library along with the software; see the file LICENSE.
// If not, contact Office of Research, Indiana University,
// Bloomington, IN 47405.
//
// Permission to modify the code and to distribute the code is
// granted, provided the text of this NOTICE is retained, a notice if
// the code was modified is included with the above COPYRIGHT NOTICE
// and with the COPYRIGHT NOTICE in the LICENSE file, and that the
// LICENSE file is distributed with the modified code.
//
// LICENSOR MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED.
// By way of example, but not limitation, Licensor MAKES NO
// REPRESENTATIONS OR WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY
// PARTICULAR PURPOSE OR THAT THE USE OF THE LICENSED SOFTWARE COMPONENTS
// OR DOCUMENTATION WILL NOT INFRINGE ANY PATENTS, COPYRIGHTS, TRADEMARKS
// OR OTHER RIGHTS.
//=======================================================================
#include <boost/config.hpp>
#include <iostream>
#include <fstream>
#include <stack>
#include <map>
#include <boost/lexical_cast.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/depth_first_search.hpp>
#include <boost/graph/graphviz.hpp>
#include <boost/graph/copy.hpp>
#include <boost/graph/reverse_graph.hpp>

using namespace boost;

template < typename OutputIterator > class back_edge_recorder:public default_dfs_visitor
{
public:
back_edge_recorder(OutputIterator out):m_out(out) {
  }
  template < typename Edge, typename Graph >
    void back_edge(Edge e, const Graph &)
  {
    *m_out++ = e;
  }
private:
  OutputIterator m_out;
};

// object generator function
template < typename OutputIterator >
  back_edge_recorder < OutputIterator >
make_back_edge_recorder(OutputIterator out)
{
  return back_edge_recorder < OutputIterator > (out);
}

template < typename Graph, typename Loops > void
find_loops(typename graph_traits < Graph >::vertex_descriptor entry, const Graph & g, Loops & loops)    // A container of sets of vertices
{
  function_requires < BidirectionalGraphConcept < Graph > >();
  typedef typename graph_traits < Graph >::edge_descriptor Edge;
  typedef typename graph_traits < Graph >::vertex_descriptor Vertex;
  std::vector < Edge > back_edges;
  std::vector < default_color_type > color_map(num_vertices(g));
  depth_first_visit(g, entry,
                    make_back_edge_recorder(std::back_inserter(back_edges)),
                    make_iterator_property_map(color_map.begin(),
                                               get(vertex_index, g)));

  for (std::vector < Edge >::size_type i = 0; i < back_edges.size(); ++i) {
    loops.push_back(typename Loops::value_type());
    compute_loop_extent(back_edges[i], g, loops.back());
  }

}

template < typename Graph, typename Set > void
compute_loop_extent(typename graph_traits <
                    Graph >::edge_descriptor back_edge, const Graph & g,
                    Set & loop_set)
{
  function_requires < BidirectionalGraphConcept < Graph > >();
  typedef typename graph_traits < Graph >::vertex_descriptor Vertex;
  typedef color_traits < default_color_type > Color;

  Vertex loop_head, loop_tail, u, v;
  loop_tail = source(back_edge, g);
  loop_head = target(back_edge, g);

  std::vector < default_color_type >
    reachable_from_head(num_vertices(g), Color::white());
  depth_first_visit(g, loop_head, default_dfs_visitor(),
                    make_iterator_property_map(reachable_from_head.begin(),
                                               get(vertex_index, g)));

  std::vector < default_color_type > reachable_to_tail(num_vertices(g));
  reverse_graph < Graph > reverse_g(g);
  depth_first_visit(reverse_g, loop_tail, default_dfs_visitor(),
                    make_iterator_property_map(reachable_to_tail.begin(),
                                               get(vertex_index, g)));

  typename graph_traits < Graph >::vertex_iterator vi, vi_end;
  for (tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi)
    if (reachable_from_head[*vi] != Color::white()
        && reachable_to_tail[*vi] != Color::white())
      loop_set.insert(*vi);

}


int
main(int argc, char *argv[])
{
  if (argc < 3) {
    std::cerr << "usage: loops_dfs <in-file> <out-file>" << std::endl;
    return -1;
  }
  GraphvizDigraph g_in;
  read_graphviz(argv[1], g_in);

  typedef adjacency_list < vecS, vecS, bidirectionalS,
    GraphvizVertexProperty,
    GraphvizEdgeProperty, GraphvizGraphProperty > Graph;
  typedef graph_traits < Graph >::vertex_descriptor Vertex;

  Graph g;
  get_property(g, graph_name) = "loops";
  copy_graph(g_in, g);

  typedef std::set < Vertex > set_t;
  typedef std::list < set_t > list_of_sets_t;
  list_of_sets_t loops;

  Vertex entry = *vertices(g).first;

  find_loops(entry, g, loops);

  for (list_of_sets_t::iterator i = loops.begin(); i != loops.end(); ++i) {
    std::vector < bool > in_loop(num_vertices(g), false);
    for (set_t::iterator j = (*i).begin(); j != (*i).end(); ++j) {
      get(vertex_attribute, g)[*j]["color"] = "gray";
      in_loop[*j] = true;
    }
    graph_traits < Graph >::edge_iterator ei, ei_end;
    for (tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
      if (in_loop[source(*ei, g)] && in_loop[target(*ei, g)])
        get(edge_attribute, g)[*ei]["color"] = "gray";
  }

  get_property(g, graph_graph_attribute)["size"] = "3,3";
  get_property(g, graph_graph_attribute)["ratio"] = "fill";
  get_property(g, graph_vertex_attribute)["shape"] = "box";

  std::ofstream loops_out(argv[2]);
  write_graphviz(loops_out, g,
                 make_vertex_attributes_writer(g),
                 make_edge_attributes_writer(g),
                 make_graph_attributes_writer(g));


  return 0;
}