RhodeCode

  }

  /// \ingroup lemon_io

  ///  

  /// \brief LGF reader for directed graphs

  ///

  /// This utility reads an \ref lgf-format "LGF" file.

  ///

  /// The reading method does a batch processing. The user creates a

  /// reader object, then various reading rules can be added to the

  /// reader, and eventually the reading is executed with the \c run()

  /// member function. A map reading rule can be added to the reader

  /// with the \c nodeMap() or \c arcMap() members. An optional

  /// converter parameter can also be added as a standard functor

  /// converting from std::string to the value type of the map. If it

  /// is set, it will determine how the tokens in the file should be

  /// is converted to the map's value type. If the functor is not set,

  /// then a default conversion will be used. One map can be read into

  /// multiple map objects at the same time. The \c attribute(), \c

  /// node() and \c arc() functions are used to add attribute reading

  /// rules.

  ///

  ///\code

  ///     DigraphReader<Digraph>(std::cin, digraph).

  ///       nodeMap("coordinates", coord_map).

  ///       arcMap("capacity", cap_map).

  ///       node("source", src).

  ///       node("target", trg).

  ///       attribute("caption", caption).

  ///       run();

  ///\endcode

  ///

  /// By default the reader uses the first section in the file of the

  /// proper type. If a section has an optional name, then it can be

  /// selected for reading by giving an optional name parameter to the

  /// \c nodes(), \c arcs() or \c attributes() functions. The readers

  /// also can load extra sections with the \c sectionLines() and

  /// sectionStream() functions.

  ///

  /// The \c useNodes() and \c useArcs() functions are used to tell the reader

  /// that the nodes or arcs should not be constructed (added to the

  /// graph) during the reading, but instead the label map of the items

  /// are given as a parameter of these functions. An

  /// application of these function is multipass reading, which is

  /// important if two \e \@arcs sections must be read from the

  /// file. In this example the first phase would read the node set and one

  /// of the arc sets, while the second phase would read the second arc

  /// set into an \e ArcSet class (\c SmartArcSet or \c ListArcSet).

  /// The previously read label node map should be passed to the \c

  /// useNodes() functions. Another application of multipass reading when

  /// paths are given as a node map or an arc map. It is impossible read this in

  /// a single pass, because the arcs are not constructed when the node

  /// maps are read.

  template <typename _Digraph>

  class DigraphReader {

  public:

    typedef _Digraph Digraph;

    TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);

  private:

    std::istream* _is;

    bool local_is;

    Digraph& _digraph;

    std::string _nodes_caption;

    std::string _arcs_caption;

    std::string _attributes_caption;

    typedef std::map<std::string, Node> NodeIndex;

    NodeIndex _node_index;

    typedef std::map<std::string, Arc> ArcIndex;

    ArcIndex _arc_index;

    typedef std::vector<std::pair<std::string, 

      _reader_bits::MapStorageBase<Node>*> > NodeMaps;    

    NodeMaps _node_maps; 

    typedef std::vector<std::pair<std::string,

      _reader_bits::MapStorageBase<Arc>*> >ArcMaps;

    ArcMaps _arc_maps;

    typedef std::multimap<std::string, _reader_bits::ValueStorageBase*> 

      Attributes;

    Attributes _attributes;

    typedef std::map<std::string, _reader_bits::Section*> Sections;

    Sections _sections;

    bool _use_nodes;

    bool _use_arcs;

    int line_num;

    std::istringstream line;

  public:

    /// \brief Constructor

    ///

    /// Construct a directed graph reader, which reads from the given

    /// input stream.

    DigraphReader(std::istream& is, Digraph& digraph) 

      : _is(&is), local_is(false), _digraph(digraph),

    /// \brief Constructor

    ///

    /// Construct a directed graph reader, which reads from the given

    /// file.

    DigraphReader(const std::string& fn, Digraph& digraph) 

      : _is(new std::ifstream(fn.c_str())), local_is(true), _digraph(digraph),

    /// \brief Constructor

    ///

    /// Construct a directed graph reader, which reads from the given

    /// file.

    DigraphReader(const char* fn, Digraph& digraph) 

      : _is(new std::ifstream(fn)), local_is(true), _digraph(digraph),

    /// \brief Copy constructor

    ///

    /// The copy constructor transfers all data from the other reader,

    /// therefore the copied reader will not be usable more. 

    DigraphReader(DigraphReader& other) 

      : _is(other._is), local_is(other.local_is), _digraph(other._digraph),

      other._is = 0;

      other.local_is = false;

      _node_index.swap(other._node_index);

      _arc_index.swap(other._arc_index);

      _node_maps.swap(other._node_maps);

      _arc_maps.swap(other._arc_maps);

      _attributes.swap(other._attributes);

      _nodes_caption = other._nodes_caption;

      _arcs_caption = other._arcs_caption;

      _attributes_caption = other._attributes_caption;

      _sections.swap(other._sections);

    }

    /// \brief Destructor

    ~DigraphReader() {

      for (typename NodeMaps::iterator it = _node_maps.begin(); 

	   it != _node_maps.end(); ++it) {

	delete it->second;

      }

      for (typename ArcMaps::iterator it = _arc_maps.begin(); 

	   it != _arc_maps.end(); ++it) {

	delete it->second;

      }

      for (typename Attributes::iterator it = _attributes.begin(); 

	   it != _attributes.end(); ++it) {

	delete it->second;

      }

      for (typename Sections::iterator it = _sections.begin(); 

	   it != _sections.end(); ++it) {

	delete it->second;

      }

      if (local_is) {

	delete _is;

      }

    }

  private:

    DigraphReader& operator=(const DigraphReader&);

  public:

    /// \name Reading rules

    /// @{

    /// \brief Node map reading rule

    ///

    /// Add a node map reading rule to the reader.

    template <typename Map>

    DigraphReader& nodeMap(const std::string& caption, Map& map) {

      checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();

      _reader_bits::MapStorageBase<Node>* storage = 

	new _reader_bits::MapStorage<Node, Map>(map);

      _node_maps.push_back(std::make_pair(caption, storage));

      return *this;

    }

    /// \brief Node map reading rule

    ///

    /// Add a node map reading rule with specialized converter to the

    /// reader.

    template <typename Map, typename Converter>

    DigraphReader& nodeMap(const std::string& caption, Map& map, 

			   const Converter& converter = Converter()) {

      checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();

      _reader_bits::MapStorageBase<Node>* storage = 

	new _reader_bits::MapStorage<Node, Map, Converter>(map, converter);

      _node_maps.push_back(std::make_pair(caption, storage));

      return *this;

    }

    /// \brief Arc map reading rule

    ///

    /// Add an arc map reading rule to the reader.

    template <typename Map>

    DigraphReader& arcMap(const std::string& caption, Map& map) {

      checkConcept<concepts::WriteMap<Arc, typename Map::Value>, Map>();

      _reader_bits::MapStorageBase<Arc>* storage = 

	new _reader_bits::MapStorage<Arc, Map>(map);

      _arc_maps.push_back(std::make_pair(caption, storage));

      return *this;

    }

    /// \brief Arc map reading rule

    ///

    /// Add an arc map reading rule with specialized converter to the

    template <typename Functor>

    DigraphReader& sectionLines(const std::string& type, Functor functor) {

      LEMON_ASSERT(!type.empty(), "Type is not empty.");

      LEMON_ASSERT(_sections.find(type) == _sections.end(), 

		   "Multiple reading of section.");

      LEMON_ASSERT(type != "nodes" && type != "arcs" && type != "edges" &&

		   type != "attributes", "Multiple reading of section.");

      _sections.insert(std::make_pair(type, 

        new _reader_bits::LineSection<Functor>(functor)));

      return *this;

    }

    /// \brief Add a section processor with stream oriented reading

    ///

    /// In the \e LGF file extra sections can be placed, which contain

    /// any data in arbitrary format. These sections can be read

    /// directly with this function. The first parameter is the type

    /// of the section, the second is a functor, which takes an \c

    /// std::istream& and an int& parameter, the latter regard to the

    /// line number of stream. The functor can read the input while

    /// the section go on, and the line number should be modified

    /// accordingly.

    template <typename Functor>

    DigraphReader& sectionStream(const std::string& type, Functor functor) {

      LEMON_ASSERT(!type.empty(), "Type is not empty.");

      LEMON_ASSERT(_sections.find(type) == _sections.end(), 

		   "Multiple reading of section.");

      LEMON_ASSERT(type != "nodes" && type != "arcs" && type != "edges" &&

		   type != "attributes", "Multiple reading of section.");

      _sections.insert(std::make_pair(type, 

	 new _reader_bits::StreamSection<Functor>(functor)));

      return *this;

    }    

    /// @}

    /// \name Using previously constructed node or arc set

    /// @{

    /// \brief Use previously constructed node set

    ///

    /// Use previously constructed node set, and specify the node

    /// label map.

    template <typename Map>

    DigraphReader& useNodes(const Map& map) {

      checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();

      LEMON_ASSERT(!_use_nodes, "Multiple usage of useNodes() member"); 

      _use_nodes = true;

      _writer_bits::DefaultConverter<typename Map::Value> converter;

      for (NodeIt n(_digraph); n != INVALID; ++n) {

	_node_index.insert(std::make_pair(converter(map[n]), n));

      }

      return *this;

    }

    /// \brief Use previously constructed node set

    ///

    /// Use previously constructed node set, and specify the node

    /// label map and a functor which converts the label map values to

    /// std::string.

    template <typename Map, typename Converter>

    DigraphReader& useNodes(const Map& map, 

			    const Converter& converter = Converter()) {

      checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();

      LEMON_ASSERT(!_use_nodes, "Multiple usage of useNodes() member"); 

      _use_nodes = true;

      for (NodeIt n(_digraph); n != INVALID; ++n) {

	_node_index.insert(std::make_pair(converter(map[n]), n));

      }

      return *this;

    }

    /// \brief Use previously constructed arc set

    ///

    /// Use previously constructed arc set, and specify the arc

    /// label map.

    template <typename Map>

    DigraphReader& useArcs(const Map& map) {

      checkConcept<concepts::ReadMap<Arc, typename Map::Value>, Map>();

      LEMON_ASSERT(!_use_arcs, "Multiple usage of useArcs() member");

      _use_arcs = true;

      _writer_bits::DefaultConverter<typename Map::Value> converter;

      for (ArcIt a(_digraph); a != INVALID; ++a) {

	_arc_index.insert(std::make_pair(converter(map[a]), a));

      }

      return *this;

    }

    /// \brief Use previously constructed arc set

    ///

    /// Use previously constructed arc set, and specify the arc

    /// label map and a functor which converts the label map values to

    /// std::string.

    template <typename Map, typename Converter>

    DigraphReader& useArcs(const Map& map, 

      checkConcept<concepts::ReadMap<Arc, typename Map::Value>, Map>();

      LEMON_ASSERT(!_use_arcs, "Multiple usage of useArcs() member"); 

      _use_arcs = true;

      for (ArcIt a(_digraph); a != INVALID; ++a) {

	_arc_index.insert(std::make_pair(converter(map[a]), a));

      }

      return *this;

    }

    /// @}

  private:

    bool readLine() {

      std::string str;

      while(++line_num, std::getline(*_is, str)) {

	line.clear(); line.str(str);

	char c;

	if (line >> std::ws >> c && c != '#') {

	  line.putback(c);

	  return true;

	}

      }

      return false;

    }

    bool readSuccess() {

      return static_cast<bool>(*_is);

    }

    void skipSection() {

      char c;

      while (readSuccess() && line >> c && c != '@') {

	readLine();

      }

      line.putback(c);

    }

    void readNodes() {

      std::vector<int> map_index(_node_maps.size());

      int map_num, label_index;

      char c;

      if (!readLine() || !(line >> c) || c == '@') {

	if (readSuccess() && line) line.putback(c);

	if (!_node_maps.empty()) 

	  throw DataFormatError("Cannot find map names");

	return;

      }

      line.putback(c);

      {

	std::map<std::string, int> maps;

	std::string map;

	int index = 0;

	while (_reader_bits::readToken(line, map)) {

	  if (maps.find(map) != maps.end()) {

	    std::ostringstream msg;

	    msg << "Multiple occurence of node map: " << map;

	    throw DataFormatError(msg.str().c_str());

	  }

	  maps.insert(std::make_pair(map, index));

	  ++index;

	}

	for (int i = 0; i < static_cast<int>(_node_maps.size()); ++i) {

	  std::map<std::string, int>::iterator jt = 

	    maps.find(_node_maps[i].first);

	  if (jt == maps.end()) {

	    std::ostringstream msg;

	    msg << "Map not found in file: " << _node_maps[i].first;

	    throw DataFormatError(msg.str().c_str());

	  }

	  map_index[i] = jt->second;

	}

	{

	  std::map<std::string, int>::iterator jt = maps.find("label");

	  if (jt != maps.end()) {

	    label_index = jt->second;

	  } else {

	    label_index = -1;

	  }

	}

	map_num = maps.size();

      }

      while (readLine() && line >> c && c != '@') {

	line.putback(c);

	std::vector<std::string> tokens(map_num);

	for (int i = 0; i < map_num; ++i) {

	  if (!_reader_bits::readToken(line, tokens[i])) {

	    std::ostringstream msg;

	    msg << "Column not found (" << i + 1 << ")";

	    throw DataFormatError(msg.str().c_str());

	  }

	}

	if (line >> std::ws >> c)

	  throw DataFormatError("Extra character on the end of line");

	Node n;

	if (!_use_nodes) {

          it = _node_index.find(target_token);

          if (it == _node_index.end()) {       

            std::ostringstream msg;            

            msg << "Item not found: " << target_token;

            throw DataFormatError(msg.str().c_str());

          }                                          

          Node target = it->second;                            

	  a = _digraph.addArc(source, target);

	  if (label_index != -1) 

	    _arc_index.insert(std::make_pair(tokens[label_index], a));

	} else {

	  if (label_index == -1) 

	    throw DataFormatError("Label map not found in file");

	  typename std::map<std::string, Arc>::iterator it =

	    _arc_index.find(tokens[label_index]);

	  if (it == _arc_index.end()) {

	    std::ostringstream msg;

	    msg << "Arc with label not found: " << tokens[label_index];

	    throw DataFormatError(msg.str().c_str());	    

	  }

	  a = it->second;

	}

	for (int i = 0; i < static_cast<int>(_arc_maps.size()); ++i) {

	  _arc_maps[i].second->set(a, tokens[map_index[i]]);

	}

      }

      if (readSuccess()) {

	line.putback(c);

      }

    }

    void readAttributes() {

      std::set<std::string> read_attr;

      char c;

      while (readLine() && line >> c && c != '@') {

	line.putback(c);

	std::string attr, token;

	if (!_reader_bits::readToken(line, attr))

	  throw DataFormatError("Attribute name not found");

	if (!_reader_bits::readToken(line, token))

	  throw DataFormatError("Attribute value not found");

	if (line >> c)

	  throw DataFormatError("Extra character on the end of line");	  

	{

	  std::set<std::string>::iterator it = read_attr.find(attr);

	  if (it != read_attr.end()) {

	    std::ostringstream msg;

	    msg << "Multiple occurence of attribute " << attr;

	    throw DataFormatError(msg.str().c_str());

	  }

	  read_attr.insert(attr);

	}

	{

	  typename Attributes::iterator it = _attributes.lower_bound(attr);

	  while (it != _attributes.end() && it->first == attr) {

	    it->second->set(token);

	    ++it;

	  }

	}

      }

      if (readSuccess()) {

	line.putback(c);

      }

      for (typename Attributes::iterator it = _attributes.begin();

	   it != _attributes.end(); ++it) {

	if (read_attr.find(it->first) == read_attr.end()) {

	  std::ostringstream msg;

	  msg << "Attribute not found in file: " << it->first;

	  throw DataFormatError(msg.str().c_str());

	}	

      }

    }

  public:

    /// \name Execution of the reader    

    /// @{

    /// \brief Start the batch processing

    ///

    /// This function starts the batch processing

    void run() {

      LEMON_ASSERT(_is != 0, "This reader assigned to an other reader");

      if (!*_is) {

	throw DataFormatError("Cannot find file");

      }

      bool attributes_done = false;

      std::set<std::string> extra_sections;

      line_num = 0;      

      readLine();

      skipSection();

      while (readSuccess()) {

	try {

	  char c;

	  std::string section, caption;

	  line >> c;

	  _reader_bits::readToken(line, section);

	  _reader_bits::readToken(line, caption);

	  if (line >> c) 

	    throw DataFormatError("Extra character on the end of line");

	  if (section == "nodes" && !nodes_done) {

	    if (_nodes_caption.empty() || _nodes_caption == caption) {

	      readNodes();

	      nodes_done = true;

	    }

	  } else if ((section == "arcs" || section == "edges") && 

		     !arcs_done) {

	    if (_arcs_caption.empty() || _arcs_caption == caption) {

	      readArcs();

	      arcs_done = true;

	    }

	  } else if (section == "attributes" && !attributes_done) {

	    if (_attributes_caption.empty() || _attributes_caption == caption) {

	      readAttributes();

	      attributes_done = true;

	    }

	  } else {

	    if (extra_sections.find(section) != extra_sections.end()) {

	      std::ostringstream msg;

	      msg << "Multiple occurence of section " << section;

	      throw DataFormatError(msg.str().c_str());

	    }

	    Sections::iterator it = _sections.find(section);

	    if (it != _sections.end()) {

	      extra_sections.insert(section);

	      it->second->process(*_is, line_num);

	    }

	    readLine();

	    skipSection();

	  }

	} catch (DataFormatError& error) {

	  error.line(line_num);

	  throw;

	}	

      }

      if (!nodes_done) {

	throw DataFormatError("Section @nodes not found");

      }

      if (!arcs_done) {

	throw DataFormatError("Section @arcs not found");

      }

      if (!attributes_done && !_attributes.empty()) {

	throw DataFormatError("Section @attributes not found");

      }

    }

    /// @}

  };

  /// \relates DigraphReader

  template <typename Digraph>

  DigraphReader<Digraph> digraphReader(std::istream& is, Digraph& digraph) {

    DigraphReader<Digraph> tmp(is, digraph);

    return tmp;

  }

  /// \relates DigraphReader

  template <typename Digraph>

  DigraphReader<Digraph> digraphReader(const std::string& fn, 

				       Digraph& digraph) {

    DigraphReader<Digraph> tmp(fn, digraph);

    return tmp;

  }

  /// \relates DigraphReader

  template <typename Digraph>

  DigraphReader<Digraph> digraphReader(const char* fn, Digraph& digraph) {

    DigraphReader<Digraph> tmp(fn, digraph);

    return tmp;

  }

  /// \ingroup lemon_io

  ///  

  /// \brief LGF reader for undirected graphs

  ///

  /// This utility reads an \ref lgf-format "LGF" file.

  template <typename _Graph>

  class GraphReader {

  public:

    typedef _Graph Graph;

    TEMPLATE_GRAPH_TYPEDEFS(Graph);

  private:

    std::istream* _is;

    bool local_is;

    Graph& _graph;

    std::string _nodes_caption;

    std::string _edges_caption;

    std::string _attributes_caption;

    typedef std::map<std::string, Node> NodeIndex;

    NodeIndex _node_index;

    typedef std::map<std::string, Edge> EdgeIndex;

    EdgeIndex _edge_index;

    typedef std::vector<std::pair<std::string, 

      _reader_bits::MapStorageBase<Node>*> > NodeMaps;    

    NodeMaps _node_maps; 

    typedef std::vector<std::pair<std::string,

      _reader_bits::MapStorageBase<Edge>*> > EdgeMaps;

    EdgeMaps _edge_maps;

    typedef std::multimap<std::string, _reader_bits::ValueStorageBase*> 

      Attributes;

    Attributes _attributes;

    typedef std::map<std::string, _reader_bits::Section*> Sections;

    Sections _sections;

    bool _use_nodes;

    bool _use_edges;

    int line_num;

    std::istringstream line;

  public:

    /// \brief Constructor

    ///

    /// Construct a undirected graph reader, which reads from the given

    /// input stream.

    GraphReader(std::istream& is, Graph& graph) 

      : _is(&is), local_is(false), _graph(graph),

    /// \brief Constructor

    ///

    /// Construct a undirected graph reader, which reads from the given

    /// file.

    GraphReader(const std::string& fn, Graph& graph) 

      : _is(new std::ifstream(fn.c_str())), local_is(true), _graph(graph),

    /// \brief Constructor

    ///

    /// Construct a undirected graph reader, which reads from the given

    /// file.

    GraphReader(const char* fn, Graph& graph) 

      : _is(new std::ifstream(fn)), local_is(true), _graph(graph),

    /// \brief Copy constructor

    ///

    /// The copy constructor transfers all data from the other reader,

    /// therefore the copied reader will not be usable more. 

    GraphReader(GraphReader& other) 

      : _is(other._is), local_is(other.local_is), _graph(other._graph),

      other._is = 0;

      other.local_is = false;

      _node_index.swap(other._node_index);

      _edge_index.swap(other._edge_index);

      _node_maps.swap(other._node_maps);

      _edge_maps.swap(other._edge_maps);

      _attributes.swap(other._attributes);

      _nodes_caption = other._nodes_caption;

      _edges_caption = other._edges_caption;

      _attributes_caption = other._attributes_caption;

      _sections.swap(other._sections);

    }

    /// \brief Destructor

    ~GraphReader() {

      for (typename NodeMaps::iterator it = _node_maps.begin(); 

	   it != _node_maps.end(); ++it) {

	delete it->second;

      }

      for (typename EdgeMaps::iterator it = _edge_maps.begin(); 

	   it != _edge_maps.end(); ++it) {

	delete it->second;

      }

      for (typename Attributes::iterator it = _attributes.begin(); 

	   it != _attributes.end(); ++it) {

	delete it->second;

      }

      for (typename Sections::iterator it = _sections.begin(); 

	   it != _sections.end(); ++it) {

	delete it->second;

      }

      if (local_is) {

	delete _is;

      }

    }

  private:

    GraphReader& operator=(const GraphReader&);

  public:

    /// \name Reading rules

    /// @{

    /// \brief Node map reading rule

    ///

    /// Add a node map reading rule to the reader.

    template <typename Map>

    GraphReader& nodeMap(const std::string& caption, Map& map) {

      checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();

      _reader_bits::MapStorageBase<Node>* storage = 

	new _reader_bits::MapStorage<Node, Map>(map);

      _node_maps.push_back(std::make_pair(caption, storage));

      return *this;

    }

    /// \brief Node map reading rule

    ///

    /// Add a node map reading rule with specialized converter to the

    /// reader.

    template <typename Map, typename Converter>

    GraphReader& nodeMap(const std::string& caption, Map& map, 

			   const Converter& converter = Converter()) {

      checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();

      _reader_bits::MapStorageBase<Node>* storage = 

	new _reader_bits::MapStorage<Node, Map, Converter>(map, converter);

      _node_maps.push_back(std::make_pair(caption, storage));

      return *this;

    }

    /// \brief Edge map reading rule

    ///

    /// Add an edge map reading rule to the reader.

    template <typename Map>

    GraphReader& edgeMap(const std::string& caption, Map& map) {

      checkConcept<concepts::WriteMap<Edge, typename Map::Value>, Map>();

      _reader_bits::MapStorageBase<Edge>* storage = 

	new _reader_bits::MapStorage<Edge, Map>(map);

      _edge_maps.push_back(std::make_pair(caption, storage));

      return *this;

    }

    /// \brief Edge map reading rule

    ///

    /// Add an edge map reading rule with specialized converter to the

    }

    /// \brief Add a section processor with stream oriented reading

    ///

    /// In the \e LGF file extra sections can be placed, which contain

    /// any data in arbitrary format. These sections can be read

    /// directly with this function. The first parameter is the type

    /// of the section, the second is a functor, which takes an \c

    /// std::istream& and an int& parameter, the latter regard to the

    /// line number of stream. The functor can read the input while

    /// the section go on, and the line number should be modified

    /// accordingly.

    template <typename Functor>

    GraphReader& sectionStream(const std::string& type, Functor functor) {

      LEMON_ASSERT(!type.empty(), "Type is not empty.");

      LEMON_ASSERT(_sections.find(type) == _sections.end(), 

		   "Multiple reading of section.");

      LEMON_ASSERT(type != "nodes" && type != "arcs" && type != "edges" &&

		   type != "attributes", "Multiple reading of section.");

      _sections.insert(std::make_pair(type, 

	 new _reader_bits::StreamSection<Functor>(functor)));

      return *this;

    }    

    /// @}

    /// \name Using previously constructed node or edge set

    /// @{

    /// \brief Use previously constructed node set

    ///

    /// Use previously constructed node set, and specify the node

    /// label map.

    template <typename Map>

    GraphReader& useNodes(const Map& map) {

      checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();

      LEMON_ASSERT(!_use_nodes, "Multiple usage of useNodes() member"); 

      _use_nodes = true;

      _writer_bits::DefaultConverter<typename Map::Value> converter;

      for (NodeIt n(_graph); n != INVALID; ++n) {

	_node_index.insert(std::make_pair(converter(map[n]), n));

      }

      return *this;

    }

    /// \brief Use previously constructed node set

    ///

    /// Use previously constructed node set, and specify the node

    /// label map and a functor which converts the label map values to

    /// std::string.

    template <typename Map, typename Converter>

    GraphReader& useNodes(const Map& map, 

			    const Converter& converter = Converter()) {

      checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();

      LEMON_ASSERT(!_use_nodes, "Multiple usage of useNodes() member"); 

      _use_nodes = true;

      for (NodeIt n(_graph); n != INVALID; ++n) {

	_node_index.insert(std::make_pair(converter(map[n]), n));

      }

      return *this;

    }

    /// \brief Use previously constructed edge set

    ///

    /// Use previously constructed edge set, and specify the edge

    /// label map.

    template <typename Map>

    GraphReader& useEdges(const Map& map) {

      checkConcept<concepts::ReadMap<Edge, typename Map::Value>, Map>();

      LEMON_ASSERT(!_use_edges, "Multiple usage of useEdges() member");

      _use_edges = true;

      _writer_bits::DefaultConverter<typename Map::Value> converter;

      for (EdgeIt a(_graph); a != INVALID; ++a) {

	_edge_index.insert(std::make_pair(converter(map[a]), a));

      }

      return *this;

    }

    /// \brief Use previously constructed edge set

    ///

    /// Use previously constructed edge set, and specify the edge

    /// label map and a functor which converts the label map values to

    /// std::string.

    template <typename Map, typename Converter>

    GraphReader& useEdges(const Map& map, 

			    const Converter& converter = Converter()) {

      checkConcept<concepts::ReadMap<Edge, typename Map::Value>, Map>();

      LEMON_ASSERT(!_use_edges, "Multiple usage of useEdges() member"); 

      _use_edges = true;

      for (EdgeIt a(_graph); a != INVALID; ++a) {

	_edge_index.insert(std::make_pair(converter(map[a]), a));

      }

      return *this;

    }

    /// @}

  private:

    bool readLine() {

      std::string str;

      while(++line_num, std::getline(*_is, str)) {

	line.clear(); line.str(str);

	char c;

	if (line >> std::ws >> c && c != '#') {

	  line.putback(c);

	  return true;

	}

      }

      return false;

    }

    bool readSuccess() {

      return static_cast<bool>(*_is);

    }

    void skipSection() {

      char c;

      while (readSuccess() && line >> c && c != '@') {

	readLine();

      }

      line.putback(c);

    }

    void readNodes() {

      std::vector<int> map_index(_node_maps.size());

      int map_num, label_index;

      char c;

      if (!readLine() || !(line >> c) || c == '@') {

	if (readSuccess() && line) line.putback(c);

	if (!_node_maps.empty()) 

	  throw DataFormatError("Cannot find map names");

	return;

      }

      line.putback(c);

      {

	std::map<std::string, int> maps;

	std::string map;

	int index = 0;

	while (_reader_bits::readToken(line, map)) {

	  if (maps.find(map) != maps.end()) {

	    std::ostringstream msg;

	    msg << "Multiple occurence of node map: " << map;

	    throw DataFormatError(msg.str().c_str());

	  }

	  maps.insert(std::make_pair(map, index));

	  ++index;

	}

	for (int i = 0; i < static_cast<int>(_node_maps.size()); ++i) {

	  std::map<std::string, int>::iterator jt = 

	    maps.find(_node_maps[i].first);

	  if (jt == maps.end()) {

	    std::ostringstream msg;

	    msg << "Map not found in file: " << _node_maps[i].first;

	    throw DataFormatError(msg.str().c_str());

	  }

	  map_index[i] = jt->second;

	}

	{

	  std::map<std::string, int>::iterator jt = maps.find("label");

	  if (jt != maps.end()) {

	    label_index = jt->second;

	  } else {

	    label_index = -1;

	  }

	}

	map_num = maps.size();

      }

      while (readLine() && line >> c && c != '@') {

	line.putback(c);

	std::vector<std::string> tokens(map_num);

	for (int i = 0; i < map_num; ++i) {

	  if (!_reader_bits::readToken(line, tokens[i])) {

	    std::ostringstream msg;

	    msg << "Column not found (" << i + 1 << ")";

	    throw DataFormatError(msg.str().c_str());

	  }

	}

	if (line >> std::ws >> c)

	  throw DataFormatError("Extra character on the end of line");

	Node n;

	if (!_use_nodes) {

          Node source = it->second;

          it = _node_index.find(target_token);

          if (it == _node_index.end()) {       

            std::ostringstream msg;            

            msg << "Item not found: " << target_token;

            throw DataFormatError(msg.str().c_str());

          }                                          

          Node target = it->second;                            

	  e = _graph.addEdge(source, target);

	  if (label_index != -1) 

	    _edge_index.insert(std::make_pair(tokens[label_index], e));

	} else {

	  if (label_index == -1) 

	    throw DataFormatError("Label map not found in file");

	  typename std::map<std::string, Edge>::iterator it =

	    _edge_index.find(tokens[label_index]);

	  if (it == _edge_index.end()) {

	    std::ostringstream msg;

	    msg << "Edge with label not found: " << tokens[label_index];

	    throw DataFormatError(msg.str().c_str());	    

	  }

	  e = it->second;

	}

	for (int i = 0; i < static_cast<int>(_edge_maps.size()); ++i) {

	  _edge_maps[i].second->set(e, tokens[map_index[i]]);

	}

      }

      if (readSuccess()) {

	line.putback(c);

      }

    }

    void readAttributes() {

      std::set<std::string> read_attr;

      char c;

      while (readLine() && line >> c && c != '@') {