/* -*- C++ -*-
 * lemon/graph_writer.h - Part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
 * (Egervary Research Group on Combinatorial Optimization, EGRES).
 *
 * Permission to use, modify and distribute this software is granted
 * provided that this copyright notice appears in all copies. For
 * precise terms see the accompanying LICENSE file.
 *
 * This software is provided "AS IS" with no warranty of any kind,
 * express or implied, and with no claim as to its suitability for any
 * purpose.
 *
 */

///\ingroup io_group
///\file
///\brief Lemon Graph Format writer.
///

#ifndef LEMON_GRAPH_WRITER_H
#define LEMON_GRAPH_WRITER_H

#include <iostream>

#include <lemon/error.h>
#include <lemon/lemon_writer.h>

namespace lemon {

  /// \addtogroup io_group
  /// @{

  /// \brief The graph writer class.
  ///
  /// The \c GraphWriter class provides the graph output. 
  /// Before you read this documentation it might be useful to read the general
  /// description of  \ref graph-io-page "Graph Input-Output".
  ///
  /// If you don't need very sophisticated
  /// behaviour then you can use the versions of the public function
  /// \ref writeGraph() to output a graph (or a max flow instance etc).
  ///
  /// To write a graph
  /// you should first give writing commands to the writer. You can declare
  /// write commands as \c NodeMap or \c EdgeMap writing and labeled Node and
  /// Edge writing.
  ///
  /// \code
  /// GraphWriter<ListGraph> writer(std::cout, graph);
  /// \endcode
  ///
  /// The \c writeNodeMap() function declares a \c NodeMap writing 
  /// command in the \c GraphWriter. You should give as parameter 
  /// the name of the map and the map object. The NodeMap writing 
  /// command with name "id" should write a unique map because it 
  /// is regarded as ID map (such a map is essential if the graph has edges).
  ///
  /// \code
  /// IdMap<ListGraph, Node> nodeIdMap;
  /// writer.writeNodeMap("id", nodeIdMap);
  ///
  /// writer.writeNodeMap("coords", coords);
  /// writer.writeNodeMap("color", colorMap);
  /// \endcode
  ///
  /// With the \c writeEdgeMap() member function you can give an edge map
  /// writing command similar to the NodeMaps.
  ///
  /// \code
  /// DescriptorMap<ListGraph, Edge, ListGraph::EdgeMap<int> > 
  ///   edgeDescMap(graph);
  /// writer.writeEdgeMap("descriptor", edgeDescMap);
  ///
  /// writer.writeEdgeMap("weight", weightMap);
  /// writer.writeEdgeMap("label", labelMap);
  /// \endcode
  ///
  /// With \c writeNode() and \c writeEdge() functions you can 
  /// point out Nodes and Edges in the graph. For example, you can 
  /// write out the source and target of a maximum flow instance.
  ///
  /// \code
  /// writer.writeNode("source", sourceNode);
  /// writer.writeNode("target", targetNode);
  ///
  /// writer.writeEdge("observed", edge);
  /// \endcode
  ///
  /// After you give all write commands you must call the \c run() member
  /// function, which executes all the writing commands.
  ///
  /// \code
  /// writer.run();
  /// \endcode
  ///
  /// \see DefaultWriterTraits
  /// \see QuotedStringWriter
  /// \see IdMap
  /// \see DescriptorMap
  /// \see \ref GraphReader
  /// \see \ref graph-io-page
  /// \author Balazs Dezso
  template <typename _Graph, typename _WriterTraits = DefaultWriterTraits> 
  class GraphWriter {
  public:
    
    typedef _Graph Graph;
    typedef typename Graph::Node Node;
    typedef typename Graph::Edge Edge;

    typedef _WriterTraits WriterTraits;

    /// \brief Construct a new GraphWriter.
    ///
    /// This function constructs a new GraphWriter to write the given graph
    /// to the given stream.
    GraphWriter(std::ostream& _os, const Graph& _graph) 
      : writer(new LemonWriter(_os)), own_writer(true), 
	nodeset_writer(*writer, _graph, std::string()),
	edgeset_writer(*writer, _graph, nodeset_writer, std::string()),
	node_writer(*writer, nodeset_writer, std::string()),
	edge_writer(*writer, edgeset_writer, std::string()),
	attribute_writer(*writer, std::string()) {}

    /// \brief Construct a new GraphWriter.
    ///
    /// This function constructs a new GraphWriter to write the given graph
    /// to the given file.
    GraphWriter(const std::string& _filename, const Graph& _graph) 
      : writer(new LemonWriter(_filename)), own_writer(true), 
	nodeset_writer(*writer, _graph, std::string()),
	edgeset_writer(*writer, _graph, nodeset_writer, std::string()),
	node_writer(*writer, nodeset_writer, std::string()),
	edge_writer(*writer, edgeset_writer, std::string()),
	attribute_writer(*writer, std::string()) {}

    /// \brief Construct a new GraphWriter.
    ///
    /// This function constructs a new GraphWriter to write the given graph
    /// to the given LemonReader.
    GraphWriter(LemonWriter& _writer, const Graph& _graph)
      : writer(_writer), own_writer(false), 
	nodeset_writer(*writer, _graph, std::string()),
	edgeset_writer(*writer, _graph, nodeset_writer, std::string()),
	node_writer(*writer, nodeset_writer, std::string()),
	edge_writer(*writer, edgeset_writer, std::string()),
	attribute_writer(*writer, std::string()) {}

    /// \brief Destruct the graph writer.
    ///
    /// This function destructs the graph writer.
    ~GraphWriter() {
      if (own_writer) 
	delete writer;
    }

    /// \brief Issue a new node map writing command for the writer.
    ///
   /// This function issues a new <i> node map writing command</i> to the writer.
    template <typename Map>
    GraphWriter& writeNodeMap(std::string name, const Map& map) {
      nodeset_writer.writeNodeMap(name, map);
      return *this;
    }


    /// \brief Issue a new node map writing command for the writer.
    ///
   /// This function issues a new <i> node map writing command</i> to the writer.
    template <typename Writer, typename Map>
    GraphWriter& writeNodeMap(std::string name, const Map& map, 
			      const Writer& writer = Writer()) {
      nodeset_writer.writeNodeMap(name, map, writer);
      return *this;
    }


    /// \brief Issue a new edge map writing command for the writer.
    ///
   /// This function issues a new <i> edge map writing command</i> to the writer.
    template <typename Map>
    GraphWriter& writeEdgeMap(std::string name, const Map& map) { 
      edgeset_writer.writeEdgeMap(name, map);
      return *this;
    }


    /// \brief Issue a new edge map writing command for the writer.
    ///
   /// This function issues a new <i> edge map writing command</i> to the writer.
    template <typename Writer, typename Map>
    GraphWriter& writeEdgeMap(std::string name, const Map& map,
			      const Writer& writer = Writer()) {
      edgeset_writer.writeEdgeMap(name, map, writer);
      return *this;
    }

    /// \brief Issue a new labeled node writing command to the writer.
    ///
    /// This function issues a new <i> labeled node writing command</i> 
    /// to the writer.
    GraphWriter& writeNode(std::string name, const Node& node) {
      node_writer.writeNode(name, node);
      return *this;
    }

    /// \brief Issue a new labeled edge writing command to the writer.
    ///
    /// This function issues a new <i> labeled edge writing command</i> 
    /// to the writer.
    GraphWriter& writeEdge(std::string name, const Edge& edge) {
      edge_writer.writeEdge(name, edge);
    }

    /// \brief Issue a new attribute writing command.
    ///
    /// This function issues a new <i> attribute writing command</i> 
    /// to the writer.
    template <typename Value>
    GraphWriter& writeAttribute(std::string name, const Value& value) {
      attribute_writer.writeAttribute(name, value);
      return *this;
    }
    
    /// \brief Issue a new attribute writing command.
    ///
    /// This function issues a new <i> attribute writing command</i> 
    /// to the writer.
    template <typename Writer, typename Value>
    GraphWriter& writeAttribute(std::string name, const Value& value, 
			       const Writer& writer) {
      attribute_writer.writeAttribute<Writer>(name, value, writer);
      return *this;
    }

    /// \brief Conversion operator to LemonWriter.
    ///
    /// Conversion operator to LemonWriter. It makes possible
    /// to access the encapsulated \e LemonWriter, this way
    /// you can attach to this writer new instances of 
    /// \e LemonWriter::SectionWriter. For more details see
    /// the \ref rwbackground "Background of Reading and Writing".
    operator LemonWriter&() {
      return *writer;
    }

    /// \brief Executes the writing commands.
    ///
    /// Executes the writing commands.
    void run() {
      writer->run();
    }

    /// \brief Write the id of the given node.
    ///
    /// It writes the id of the given node. If there was written an "id"
    /// named node map then it will write the map value belonging to the node.
    void writeId(std::ostream& os, const Node& item) const {
      nodeset_writer.writeId(os, item);
    } 

    /// \brief Write the id of the given edge.
    ///
    /// It writes the id of the given edge. If there was written an "id"
    /// named edge map then it will write the map value belonging to the edge.
    void writeId(std::ostream& os, const Edge& item) const {
      edgeset_writer.writeId(os, item);
    } 

  private:

    LemonWriter* writer;
    bool own_writer;

    NodeSetWriter<Graph, WriterTraits> nodeset_writer;
    EdgeSetWriter<Graph, WriterTraits> edgeset_writer;

    NodeWriter<Graph> node_writer;
    EdgeWriter<Graph> edge_writer;
    
    AttributeWriter<WriterTraits> attribute_writer;
  };


  ///\anchor writeGraph()
  ///
  /// \brief Write a graph to the output.
  ///
  /// Write a graph to the output.
  /// \param os The output stream.
  /// \param g The graph.
  template<typename Graph>
  void writeGraph(std::ostream& os, const Graph &g) {
    GraphWriter<Graph> writer(os, g);
    IdMap<Graph, typename Graph::Node> nodeIdMap(g);
    writer.writeNodeMap("id", nodeIdMap);
    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);
    writer.writeEdgeMap("id", edgeIdMap);
    writer.run();
  }

  /// \brief Write a capacitated graph instance to the output.
  /// 
  /// Write a capacitated graph (graph+capacity on the
  /// edges) to the output.
  /// \param os The output stream.
  /// \param g The graph.
  /// \param capacity The capacity map.
  template<typename Graph, typename CapacityMap>
  void writeGraph(std::ostream& os, const Graph &g, 
		  const CapacityMap& capacity) {
    GraphWriter<Graph> writer(os, g);
    IdMap<Graph, typename Graph::Node> nodeIdMap(g);
    writer.writeNodeMap("id", nodeIdMap);
    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);
    writer.writeEdgeMap("id", edgeIdMap);
    writer.writeEdgeMap("capacity", capacity);
    writer.run();
  }

  /// \brief Write a shortest path instance to the output.
  /// 
  /// Write a shortest path instance (graph+capacity on the
  /// edges+designated source) to the output.
  /// \param os The output stream.
  /// \param g The graph.
  /// \param capacity The capacity map.
  /// \param s The source node.
  template<typename Graph, typename CapacityMap>
  void writeGraph(std::ostream& os, const Graph &g, 
		  const CapacityMap& capacity, const typename Graph::Node &s) {
    GraphWriter<Graph> writer(os, g);
    IdMap<Graph, typename Graph::Node> nodeIdMap(g);
    writer.writeNodeMap("id", nodeIdMap);
    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);
    writer.writeEdgeMap("id", edgeIdMap);
    writer.writeEdgeMap("capacity", capacity);
    writer.writeNode("source", s);
    writer.run();
  }


  /// \brief Write a max flow instance to the output.
  ///
  /// Write a max flow instance (graph+capacity on the
  /// edges+designated source and target) to the output.
  ///
  /// \param os The output stream.
  /// \param g The graph.
  /// \param capacity The capacity map.
  /// \param s The source node.
  /// \param t The target node.
  template<typename Graph, typename CapacityMap>
  void writeGraph(std::ostream& os, const Graph &g, 
		  const CapacityMap& capacity, const typename Graph::Node &s,
		  const typename Graph::Node &t) {
    GraphWriter<Graph> writer(os, g);
    IdMap<Graph, typename Graph::Node> nodeIdMap(g);
    writer.writeNodeMap("id", nodeIdMap);
    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);
    writer.writeEdgeMap("id", edgeIdMap);
    writer.writeEdgeMap("capacity", capacity);
    writer.writeNode("source", s);
    writer.writeNode("target", t);
    writer.run();
  }

  /// \brief Write a min cost flow instance to the output.
  ///
  /// Write a min cost flow instance (graph+capacity on the edges+cost
  /// function on the edges+designated source and target) to the output.
  ///
  /// \param os The output stream.
  /// \param g The graph.
  /// \param capacity The capacity map.
  /// \param s The source node.
  /// \param t The target node.
  /// \param cost The cost map.
  template<typename Graph, typename CapacityMap, typename CostMap>
  void writeGraph(std::ostream& os, const Graph &g, 
		  const CapacityMap& capacity, const typename Graph::Node &s,
		  const typename Graph::Node &t, const CostMap& cost) {
    GraphWriter<Graph> writer(os, g);
    IdMap<Graph, typename Graph::Node> nodeIdMap(g);
    writer.writeNodeMap("id", nodeIdMap);
    IdMap<Graph, typename Graph::Edge> edgeIdMap(g);
    writer.writeEdgeMap("id", edgeIdMap);
    writer.writeEdgeMap("capacity", capacity);
    writer.writeEdgeMap("cost", cost);
    writer.writeNode("source", s);
    writer.writeNode("target", t);
    writer.run();
  }

  /// \brief The undirected graph writer class.
  ///
  /// The \c UndirGraphWriter class provides the undir graph output. To write 
  /// a graph you should first give writing commands to the writer. You can 
  /// declare write command as \c NodeMap, \c EdgeMap or \c UndirEdgeMap 
  /// writing and labeled Node, Edge or UndirEdge writing.
  ///
  /// \code
  /// UndirGraphWriter<UndirListGraph> writer(std::cout, graph);
  /// \endcode
  ///
  /// The \c writeNodeMap() function declares a \c NodeMap writing 
  /// command in the \c UndirGraphWriter. You should give as parameter 
  /// the name of the map and the map object. The NodeMap writing 
  /// command with name "id" should write a unique map because it 
  /// is regarded as ID map.
  ///
  /// \code
  /// IdMap<UndirListGraph, Node> nodeIdMap;
  /// writer.writeNodeMap("id", nodeIdMap);
  ///
  /// writer.writeNodeMap("coords", coords);
  /// writer.writeNodeMap("color", colorMap);
  /// \endcode
  ///
  /// With the \c writeUndirEdgeMap() member function you can give an 
  /// undirected edge map writing command similar to the NodeMaps.
  ///
  /// \code
  /// DescriptorMap<ListGraph, Edge, ListGraph::EdgeMap<int> > 
  ///   edgeDescMap(graph);
  /// writer.writeUndirEdgeMap("descriptor", edgeDescMap);
  ///
  /// writer.writeUndirEdgeMap("weight", weightMap);
  /// writer.writeUndirEdgeMap("label", labelMap);
  /// \endcode
  /// 
  /// The EdgeMap handling is just a syntactical sugar. It writes
  /// two undirected edge map with '+' and '-' prefix in the name.
  ///
  /// \code
  /// writer.writeEdgeMap("capacity", capacityMap);
  /// \endcode
  ///
  ///
  /// With \c writeNode() and \c writeUndirEdge() functions you can 
  /// designate nodes and undirected edges in the graph. For example, you can 
  /// write out the source and target of the graph.
  ///
  /// \code
  /// writer.writeNode("source", sourceNode);
  /// writer.writeNode("target", targetNode);
  ///
  /// writer.writeUndirEdge("observed", undirEdge);
  /// \endcode
  ///
  /// After you give all write commands you must call the \c run() member
  /// function, which executes all the writing commands.
  ///
  /// \code
  /// writer.run();
  /// \endcode
  ///
  /// \see DefaultWriterTraits
  /// \see QuotedStringWriter
  /// \see IdMap
  /// \see DescriptorMap
  /// \see \ref GraphWriter
  /// \see \ref graph-io-page
  /// \author Balazs Dezso
  template <typename _Graph, typename _WriterTraits = DefaultWriterTraits> 
  class UndirGraphWriter {
  public:
    
    typedef _Graph Graph;
    typedef typename Graph::Node Node;
    typedef typename Graph::Edge Edge;
    typedef typename Graph::UndirEdge UndirEdge;

    typedef _WriterTraits WriterTraits;

    /// \brief Construct a new UndirGraphWriter.
    ///
    /// Construct a new UndirGraphWriter. It writes the given graph
    /// to the given stream.
    UndirGraphWriter(std::ostream& _os, const Graph& _graph) 
      : writer(new LemonWriter(_os)), own_writer(true), 
	nodeset_writer(*writer, _graph, std::string()),
	undir_edgeset_writer(*writer, _graph, nodeset_writer, std::string()),
	node_writer(*writer, nodeset_writer, std::string()),
	undir_edge_writer(*writer, undir_edgeset_writer, std::string()),
	attribute_writer(*writer, std::string()) {}

    /// \brief Construct a new UndirGraphWriter.
    ///
    /// Construct a new UndirGraphWriter. It writes the given graph
    /// to the given file.
    UndirGraphWriter(const std::string& _filename, const Graph& _graph) 
      : writer(new LemonWriter(_filename)), own_writer(true), 
	nodeset_writer(*writer, _graph, std::string()),
	undir_edgeset_writer(*writer, _graph, nodeset_writer, std::string()),
	node_writer(*writer, nodeset_writer, std::string()),
	undir_edge_writer(*writer, undir_edgeset_writer, std::string()),
	attribute_writer(*writer, std::string()) {}

    /// \brief Construct a new UndirGraphWriter.
    ///
    /// Construct a new UndirGraphWriter. It writes the given graph
    /// to given LemonReader.
    UndirGraphWriter(LemonWriter& _writer, const Graph& _graph)
      : writer(_writer), own_writer(false), 
	nodeset_writer(*writer, _graph, std::string()),
	undir_edgeset_writer(*writer, _graph, nodeset_writer, std::string()),
	node_writer(*writer, nodeset_writer, std::string()),
	undir_edge_writer(*writer, undir_edgeset_writer, std::string()),
	attribute_writer(*writer, std::string()) {}

    /// \brief Destruct the graph writer.
    ///
    /// Destruct the graph writer.
    ~UndirGraphWriter() {
      if (own_writer) 
	delete writer;
    }

    /// \brief Issue a new node map writing command to the writer.
    ///
   /// This function issues a new <i> node map writing command</i> to the writer.
    template <typename Map>
    UndirGraphWriter& writeNodeMap(std::string name, const Map& map) {
      nodeset_writer.writeNodeMap(name, map);
      return *this;
    }

    /// \brief Issue a new node map writing command to the writer.
    ///
   /// This function issues a new <i> node map writing command</i> to the writer.
    template <typename Writer, typename Map>
    UndirGraphWriter& writeNodeMap(std::string name, const Map& map, 
			      const Writer& writer = Writer()) {
      nodeset_writer.writeNodeMap(name, map, writer);
      return *this;
    }

    /// \brief Issue a new edge map writing command to the writer.
    ///
   /// This function issues a new <i> edge map writing command</i> to the writer.
    template <typename Map>
    UndirGraphWriter& writeEdgeMap(std::string name, const Map& map) { 
      undir_edgeset_writer.writeEdgeMap(name, map);
      return *this;
    }

    /// \brief Issue a new edge map writing command to the writer.
    ///
   /// This function issues a new <i> edge map writing command</i> to the writer.
    template <typename Writer, typename Map>
    UndirGraphWriter& writeEdgeMap(std::string name, const Map& map,
				   const Writer& writer = Writer()) {
      undir_edgeset_writer.writeEdgeMap(name, map, writer);
      return *this;
    }

    /// \brief Issue a new undirected edge map writing command to the writer.
    ///
    /// This function issues a new <i> undirected edge map writing
    /// command</i> to the writer.
    template <typename Map>
    UndirGraphWriter& writeUndirEdgeMap(std::string name, const Map& map) { 
      undir_edgeset_writer.writeUndirEdgeMap(name, map);
      return *this;
    }

    /// \brief Issue a new undirected edge map writing command to the writer.
    ///
    /// This function issues a new <i> undirected edge map writing
    /// command</i> to the writer.
   template <typename Writer, typename Map>
    UndirGraphWriter& writeUndirEdgeMap(std::string name, const Map& map,
					const Writer& writer = Writer()) {
      undir_edgeset_writer.writeUndirEdgeMap(name, map, writer);
      return *this;
    }

    /// \brief Issue a new labeled node writer to the writer.
    ///
    /// This function issues a new <i> labeled node writing
    /// command</i> to the writer.
    UndirGraphWriter& writeNode(std::string name, const Node& node) {
      node_writer.writeNode(name, node);
      return *this;
    }

    /// \brief Issue a new labeled edge writer to the writer.
    ///
    /// This function issues a new <i> labeled edge writing
    /// command</i> to the writer.
    UndirGraphWriter& writeEdge(std::string name, const Edge& edge) {
      undir_edge_writer.writeEdge(name, edge);
    }

    /// \brief Issue a new labeled undirected edge writing command to
    /// the writer.
    ///
    /// Issue a new <i>labeled undirected edge writing command</i> to
    /// the writer.
    UndirGraphWriter& writeUndirEdge(std::string name, const UndirEdge& edge) {
      undir_edge_writer.writeUndirEdge(name, edge);
    }

    /// \brief Issue a new attribute writing command.
    ///
    /// This function issues a new <i> attribute writing
    /// command</i> to the writer.
    template <typename Value>
    UndirGraphWriter& writeAttribute(std::string name, const Value& value) {
      attribute_writer.writeAttribute(name, value);
      return *this;
    }
    
    /// \brief Issue a new attribute writing command.
    ///
    /// This function issues a new <i> attribute writing
    /// command</i> to the writer.
    template <typename Writer, typename Value>
    UndirGraphWriter& writeAttribute(std::string name, const Value& value, 
			       const Writer& writer) {
      attribute_writer.writeAttribute<Writer>(name, value, writer);
      return *this;
    }

    /// \brief Conversion operator to LemonWriter.
    ///
    /// Conversion operator to LemonWriter. It makes possible
    /// to access the encapsulated \e LemonWriter, this way
    /// you can attach to this writer new instances of 
    /// \e LemonWriter::SectionWriter.
    operator LemonWriter&() {
      return *writer;
    }

    /// \brief Executes the writing commands.
    ///
    /// Executes the writing commands.
    void run() {
      writer->run();
    }

    /// \brief Write the id of the given node.
    ///
    /// It writes the id of the given node. If there was written an "id"
    /// named node map then it will write the map value belonging to the node.
    void writeId(std::ostream& os, const Node& item) const {
      nodeset_writer.writeId(os, item);
    } 

    /// \brief Write the id of the given edge.
    ///
    /// It writes the id of the given edge. If there was written an "id"
    /// named edge map then it will write the map value belonging to the edge.
    void writeId(std::ostream& os, const Edge& item) const {
      undir_edgeset_writer.writeId(os, item);
    } 

    /// \brief Write the id of the given undirected edge.
    ///
    /// It writes the id of the given undirected edge. If there was written 
    /// an "id" named edge map then it will write the map value belonging to 
    /// the edge.
    void writeId(std::ostream& os, const UndirEdge& item) const {
      undir_edgeset_writer.writeId(os, item);
    } 


  private:

    LemonWriter* writer;
    bool own_writer;

    NodeSetWriter<Graph, WriterTraits> nodeset_writer;
    UndirEdgeSetWriter<Graph, WriterTraits> undir_edgeset_writer;

    NodeWriter<Graph> node_writer;
    UndirEdgeWriter<Graph> undir_edge_writer;
    
    AttributeWriter<WriterTraits> attribute_writer;
  };

  /// \brief Write an undirected graph to the output.
  ///
  /// Write an undirected graph to the output.
  /// \param os The output stream.
  /// \param g The graph.
  template<typename Graph>
  void writeUndirGraph(std::ostream& os, const Graph &g) {
    UndirGraphWriter<Graph> writer(os, g);
    writer.run();
  }

  /// \brief Write an undirected multigraph (undirected graph + capacity
  /// map on the edges) to the output.
  ///
  /// Write an undirected multigraph (undirected graph + capacity
  /// map on the edges) to the output.
  /// \param os The output stream.
  /// \param g The graph.
  /// \param capacity The capacity undirected map.
  template<typename Graph, typename CapacityMap>
  void writeUndirGraph(std::ostream& os, const Graph &g, 
		       const CapacityMap& capacity) {
    UndirGraphWriter<Graph> writer(os, g);
    writer.writeUndirEdgeMap("capacity", capacity);
    writer.run();
  }


  /// @}

}

#endif