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- //
- //=======================================================================
- // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
- // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
- //
- // 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_TOPOLOGICAL_SORT_HPP
- #define BOOST_GRAPH_TOPOLOGICAL_SORT_HPP
- #include <boost/config.hpp>
- #include <boost/property_map/property_map.hpp>
- #include <boost/graph/depth_first_search.hpp>
- #include <boost/graph/visitors.hpp>
- #include <boost/graph/exception.hpp>
- #include <boost/throw_exception.hpp>
- namespace boost {
- // Topological sort visitor
- //
- // This visitor merely writes the linear ordering into an
- // OutputIterator. The OutputIterator could be something like an
- // ostream_iterator, or it could be a back/front_insert_iterator.
- // Note that if it is a back_insert_iterator, the recorded order is
- // the reverse topological order. On the other hand, if it is a
- // front_insert_iterator, the recorded order is the topological
- // order.
- //
- template <typename OutputIterator>
- struct topo_sort_visitor : public dfs_visitor<>
- {
- topo_sort_visitor(OutputIterator _iter)
- : m_iter(_iter) { }
-
- template <typename Edge, typename Graph>
- void back_edge(const Edge&, Graph&) { BOOST_THROW_EXCEPTION(not_a_dag()); }
-
- template <typename Vertex, typename Graph>
- void finish_vertex(const Vertex& u, Graph&) { *m_iter++ = u; }
-
- OutputIterator m_iter;
- };
- // Topological Sort
- //
- // The topological sort algorithm creates a linear ordering
- // of the vertices such that if edge (u,v) appears in the graph,
- // then u comes before v in the ordering. The graph must
- // be a directed acyclic graph (DAG). The implementation
- // consists mainly of a call to depth-first search.
- //
- template <typename VertexListGraph, typename OutputIterator,
- typename P, typename T, typename R>
- void topological_sort(VertexListGraph& g, OutputIterator result,
- const bgl_named_params<P, T, R>& params)
- {
- typedef topo_sort_visitor<OutputIterator> TopoVisitor;
- depth_first_search(g, params.visitor(TopoVisitor(result)));
- }
- template <typename VertexListGraph, typename OutputIterator>
- void topological_sort(VertexListGraph& g, OutputIterator result)
- {
- topological_sort(g, result,
- bgl_named_params<int, buffer_param_t>(0)); // bogus
- }
- } // namespace boost
- #endif /*BOOST_GRAPH_TOPOLOGICAL_SORT_H*/
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