Added boost header

test/external/boost/graph/topological_sort.hpp

@@ -0,0 +1,77 @@
+//
+//=======================================================================
+// 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*/