/// \ingroup io_group

   /// \brief SectionReader for retrieve what is in the file.

   ///

   /// SectionReader for retrieve what is in the file. If you want

   /// to know which sections, maps and items are in the file

   /// use the next code:

   /// \code

   /// LemonReader reader("input.lgf");

   /// ContentReader content(reader);

   /// reader.run();

   /// \endcode

   class ContentReader : public LemonReader::SectionReader {

     typedef LemonReader::SectionReader Parent;

   public:

     /// \brief Constructor.

     ///

     /// Constructor for

     ContentReader(LemonReader& _reader) : Parent(_reader) {}

     /// \brief Desctructor.

     ///

     /// Desctructor.

     virtual ~ContentReader() {}

     /// \brief Gives back how many nodesets are in the file.

     ///

     /// Gives back how many nodesets are in the file.

     int nodeSetNum() const {

       return nodesets.size();

     }

     /// \brief Gives back the name of nodeset on the indiced position.

     ///

     /// Gives back the name of nodeset on the indiced position.

     std::string nodeSetName(int index) const {

       return nodesets[index].name;

     }

     /// \brief Gives back the map names of nodeset on the indiced position.

     ///

     /// Gives back the map names of nodeset on the indiced position.

     const std::vector<std::string>& nodeSetMaps(int index) const {

       return nodesets[index].items;

     }

     /// \brief Gives back how many edgesets are in the file.

     ///

     /// Gives back how many edgesets are in the file.

     int edgeSetNum() const {

       return edgesets.size();

     }

     /// \brief Gives back the name of edgeset on the indiced position.

     ///

     /// Gives back the name of edgeset on the indiced position.

     std::string edgeSetName(int index) const {

       return edgesets[index].name;

     }

     /// \brief Gives back the map names of edgeset on the indiced position.

     ///

     /// Gives back the map names of edgeset on the indiced position.

     const std::vector<std::string>& edgeSetMaps(int index) const {

       return edgesets[index].items;

     }

     /// \brief Gives back how many undirected edgesets are in the file.

     ///

     /// Gives back how many undirected edgesets are in the file.

     int undirEdgeSetNum() const {

       return undiredgesets.size();

     }

     /// \brief Gives back the name of undirected edgeset on the indiced 

     /// position.

     ///

     /// Gives back the name of undirected edgeset on the indiced position.

     std::string undirEdgeSetName(int index) const {

       return undiredgesets[index].name;

     }

     /// \brief Gives back the map names of undirected edgeset on the indiced 

     /// position.

     ///

     /// Gives back the map names of undirected edgeset on the indiced position.

     const std::vector<std::string>& undirEdgeSetMaps(int index) const {

       return undiredgesets[index].items;

     }

     /// \brief Gives back how many labeled nodes section are in the file.

     ///

     /// Gives back how many labeled nodes section are in the file.

     int nodesNum() const {

       return nodes.size();

     }

     /// \brief Gives back the name of labeled nodes section on the indiced 

     /// position.

     ///

     /// Gives back the name of labeled nodes section on the indiced position.

     std::string nodesName(int index) const {

       return nodes[index].name;

     }

     /// \brief Gives back the names of the labeled nodes in the indiced 

     /// section.

     ///

     /// Gives back the names of the labeled nodes in the indiced section.

     const std::vector<std::string>& nodesItems(int index) const {

       return nodes[index].items;

     }

     /// \brief Gives back how many labeled edges section are in the file.

     ///

     /// Gives back how many labeled edges section are in the file.

     int edgesNum() const {

       return edges.size();

     }

     /// \brief Gives back the name of labeled edges section on the indiced 

     /// position.

     ///

     /// Gives back the name of labeled edges section on the indiced position.

     std::string edgesName(int index) const {

       return edges[index].name;

     }

     /// \brief Gives back the names of the labeled edges in the indiced 

     /// section.

     ///

     /// Gives back the names of the labeled edges in the indiced section.

     const std::vector<std::string>& edgesItems(int index) const {

       return edges[index].items;

     }

     /// \brief Gives back how many labeled undirected edges section are 

     /// in the file.

     ///

     /// Gives back how many labeled undirected edges section are in the file.

     int undirEdgesNum() const {

       return undiredges.size();

     }

     /// \brief Gives back the name of labeled undirected edges section 

     /// on the indiced position.

     ///

     /// Gives back the name of labeled undirected edges section on the 

     /// indiced position.

     std::string undirEdgesName(int index) const {

       return undiredges[index].name;

     }

     /// \brief Gives back the names of the labeled undirected edges in 

     /// the indiced section.

     ///

     /// Gives back the names of the labeled undirected edges in the 

     /// indiced section.

     const std::vector<std::string>& undirEdgesItems(int index) const {

       return undiredges[index].items;

     }

     /// \brief Gives back how many attributes section are in the file.

     ///

     /// Gives back how many attributes section are in the file.

     int attributesNum() const {

       return attributes.size();

     }

     /// \brief Gives back the name of attributes section on the indiced 

     /// position.

     ///

     /// Gives back the name of attributes section on the indiced position.

     std::string attributesName(int index) const {

       return attributes[index].name;

     }

     /// \brief Gives back the names of the attributes in the indiced section.

     ///

     /// Gives back the names of the attributes in the indiced section.

     const std::vector<std::string>& attributesItems(int index) const {

       return attributes[index].items;

     }

     const std::vector<std::string>& otherSections() const {

       return sections;

     }

   protected:

     /// \brief Gives back true when the SectionReader can process 

     /// the section with the given header line.

     ///

     /// It gives back true when the section is common section.

     bool header(const std::string& line) {

       std::istringstream ls(line);

       std::string command, name;

       ls >> command >> name;

       if (command == "@nodeset") {

 	current = command;

 	nodesets.push_back(SectionInfo(name));

       } else if (command == "@edgeset") {

 	current = command;

 	edgesets.push_back(SectionInfo(name));

       } else if (command == "@undiredgeset") {

 	current = command;

 	undiredgesets.push_back(SectionInfo(name));

       } else if (command == "@nodes") {

 	current = command;

 	nodes.push_back(SectionInfo(name));

       } else if (command == "@edges") {

 	current = command;

 	edges.push_back(SectionInfo(name));

       } else if (command == "@undiredges") {

 	current = command;

 	undiredges.push_back(SectionInfo(name));

       } else if (command == "@attributes") {

 	current = command;

 	attributes.push_back(SectionInfo(name));

       } else {

 	sections.push_back(line);

 	return false;

       }

       return true;

     }

     /// \brief Retrieve the items from various sections.

     ///

     /// Retrieve the items from various sections.

     void read(std::istream& is) {

       if (current == "@nodeset") {

 	readMapNames(is, nodesets.back().items);

       } else if (current == "@edgeset") {

 	readMapNames(is, edgesets.back().items);

       } else if (current == "@undiredgeset") {

 	readMapNames(is, undiredgesets.back().items);

       } else if (current == "@nodes") {

 	readItemNames(is, nodes.back().items);

       } else if (current == "@edges") {

 	readItemNames(is, edges.back().items);

       } else if (current == "@undiredges") {

 	readItemNames(is, undiredges.back().items);

       } else if (current == "@attributes") {

 	readItemNames(is, attributes.back().items);

       }

     }    

   private:

     void readMapNames(std::istream& is, std::vector<std::string>& maps) {

       std::string line, id;

       std::getline(is, line);

       std::istringstream ls(line);

       while (ls >> id) {

 	maps.push_back(id);

       }

       while (getline(is, line));

     }

     void readItemNames(std::istream& is, std::vector<std::string>& maps) {

       std::string line, id;

       while (std::getline(is, line)) {

 	std::istringstream ls(line);

 	ls >> id;

 	maps.push_back(id);

       }

     }

     struct SectionInfo {

       std::string name;

       std::vector<std::string> items;

       SectionInfo(const std::string& _name) : name(_name) {}

     };

     std::vector<SectionInfo> nodesets;

     std::vector<SectionInfo> edgesets;

     std::vector<SectionInfo> undiredgesets;

     std::vector<SectionInfo> nodes;

     std::vector<SectionInfo> edges;

     std::vector<SectionInfo> undiredges;

     std::vector<SectionInfo> attributes;

     std::vector<std::string> sections;

     std::string current;

   };