//======================================================================= // Copyright 2009 Trustees of Indiana University // Author: Jeremiah Willcock // // Distributed under the Boost Software License, Version 1.0. (See // accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) //======================================================================= #ifndef BOOST_GRAPH_LOOKUP_EDGE_HPP #define BOOST_GRAPH_LOOKUP_EDGE_HPP #include <utility> #include <boost/config.hpp> #include <boost/utility/enable_if.hpp> #include <boost/graph/graph_traits.hpp> // lookup_edge: a function that acts like edge() but falls back to out_edges() // and a search when edge() is not provided. namespace boost { template <typename Graph> std::pair<typename boost::graph_traits<Graph>::edge_descriptor, bool> lookup_edge(typename boost::graph_traits<Graph>::vertex_descriptor src, typename boost::graph_traits<Graph>::vertex_descriptor tgt, const Graph& g, typename boost::enable_if<is_adjacency_matrix<Graph>, int>::type = 0) { return edge(src, tgt, g); } template <typename Graph> std::pair<typename boost::graph_traits<Graph>::edge_descriptor, bool> lookup_edge(typename boost::graph_traits<Graph>::vertex_descriptor src, typename boost::graph_traits<Graph>::vertex_descriptor tgt, const Graph& g, typename boost::disable_if<is_adjacency_matrix<Graph>, int>::type = 0) { typedef typename boost::graph_traits<Graph>::out_edge_iterator it; typedef typename boost::graph_traits<Graph>::edge_descriptor edesc; std::pair<it, it> oe = out_edges(src, g); for (; oe.first != oe.second; ++oe.first) { edesc e = *oe.first; if (target(e, g) == tgt) return std::make_pair(e, true); } return std::make_pair(edesc(), false); } } #endif // BOOST_GRAPH_LOOKUP_EDGE_HPP