src/lemon/graph_reader.h
changeset 1137 83a48cfd8553
child 1138 f68cb8752d81
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/lemon/graph_reader.h	Mon Feb 07 11:29:25 2005 +0000
     1.3 @@ -0,0 +1,674 @@
     1.4 +/* -*- C++ -*-
     1.5 + * src/lemon/graph_reader.h - Part of LEMON, a generic C++ optimization library
     1.6 + *
     1.7 + * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     1.8 + * (Egervary Combinatorial Optimization Research Group, EGRES).
     1.9 + *
    1.10 + * Permission to use, modify and distribute this software is granted
    1.11 + * provided that this copyright notice appears in all copies. For
    1.12 + * precise terms see the accompanying LICENSE file.
    1.13 + *
    1.14 + * This software is provided "AS IS" with no warranty of any kind,
    1.15 + * express or implied, and with no claim as to its suitability for any
    1.16 + * purpose.
    1.17 + *
    1.18 + */
    1.19 +
    1.20 +///\ingroup gio
    1.21 +///\file
    1.22 +///\brief Graph reader.
    1.23 +
    1.24 +#include <iostream>
    1.25 +#include <sstream>
    1.26 +
    1.27 +#include <map>
    1.28 +#include <vector>
    1.29 +
    1.30 +#include <memory>
    1.31 +
    1.32 +#include <lemon/error.h>
    1.33 +
    1.34 +/// \todo fix exceptions
    1.35 +
    1.36 +
    1.37 +namespace lemon {
    1.38 +
    1.39 +  // Exceptions
    1.40 +
    1.41 +  class IOException {
    1.42 +  public:
    1.43 +    virtual ~IOException() {}
    1.44 +    virtual string what() const = 0;
    1.45 +  };
    1.46 +
    1.47 +  class DataFormatException : public IOException {
    1.48 +    std::string message;
    1.49 +  public:
    1.50 +    DataFormatException(const std::string& _message) 
    1.51 +      : message(_message) {}
    1.52 +    std::string what() const {
    1.53 +      return "DataFormatException: " + message; 
    1.54 +    }
    1.55 +  };
    1.56 +
    1.57 +  template <typename _Exception>
    1.58 +  class StreamException : public _Exception {
    1.59 +  public:
    1.60 +    typedef _Exception Exception;
    1.61 +    StreamException(int _line, Exception _exception) 
    1.62 +      : Exception(_exception), line_num(_line) {}
    1.63 +    virtual int line() const {
    1.64 +      return line_num;
    1.65 +    }
    1.66 +
    1.67 +    virtual ~StreamException() {}
    1.68 +
    1.69 +    virtual std::string what() const {
    1.70 +      ostringstream os;
    1.71 +      os << Exception::what() << " in line " << line();
    1.72 +      return os.str();
    1.73 +    }
    1.74 +  private:
    1.75 +    int line_num;
    1.76 +  };  
    1.77 +
    1.78 +
    1.79 +  /// \brief Standard ReaderTraits for the GraphReader class.
    1.80 +  ///
    1.81 +  /// Standard ReaderTraits for the GraphReader class.
    1.82 +  /// It defines standard reading method for all type of value. 
    1.83 +  struct DefaultReaderTraits {
    1.84 +
    1.85 +    /// \brief Template class for reading an value.
    1.86 +    ///
    1.87 +    /// Template class for reading an value.
    1.88 +    template <typename _Value>
    1.89 +    struct Reader {
    1.90 +      /// The value type.
    1.91 +      typedef _Value Value;
    1.92 +      /// \brief Reads a value from the given stream.
    1.93 +      ///
    1.94 +      /// Reads a value from the given stream.
    1.95 +      void read(std::istream& is, Value& value) {
    1.96 +	if (!(is >> value)) 
    1.97 +	  throw DataFormatException("Default Reader format exception");
    1.98 +      }
    1.99 +    };
   1.100 +
   1.101 +    /// The reader class for the not needed maps.
   1.102 +    typedef Reader<std::string> DefaultReader;
   1.103 +
   1.104 +  };
   1.105 +
   1.106 +  /// \brief Reader class for quoted strings.
   1.107 +  ///
   1.108 +  /// Reader class for quoted strings. It can process the escape
   1.109 +  /// sequences in the string.
   1.110 +  class QuotedStringReader {
   1.111 +  public:
   1.112 +    typedef std::string Value;
   1.113 +    
   1.114 +    /// \brief Constructor for the reader.
   1.115 +    ///
   1.116 +    /// Constructor for the reader. If the given parameter is true
   1.117 +    /// the reader processes the escape sequences.
   1.118 +    QuotedStringReader(bool _escaped = true) : escaped(_escaped) {}
   1.119 +    
   1.120 +    /// \brief Reads a quoted string from the given stream.
   1.121 +    ///
   1.122 +    /// Reads a quoted string from the given stream.
   1.123 +    void read(std::istream& is, std::string& value) {
   1.124 +      char c;
   1.125 +      value.clear();
   1.126 +      is >> ws;
   1.127 +      if (!is.get(c) || c != '\"') 
   1.128 +	throw DataFormatException("Quoted string format");
   1.129 +      while (is.get(c) && c != '\"') {
   1.130 +	if (escaped && c == '\\') {
   1.131 +	  value += readEscape(is);
   1.132 +	} else {
   1.133 +	  value += c;
   1.134 +	}
   1.135 +      }
   1.136 +      if (!is) throw DataFormatException("Quoted string format");
   1.137 +    }
   1.138 +
   1.139 +  private:
   1.140 +    
   1.141 +    static char readEscape(std::istream& is) {
   1.142 +      char c;
   1.143 +      switch (is.get(c), c) {
   1.144 +      case '\\':
   1.145 +	return '\\';
   1.146 +      case '\"':
   1.147 +	return '\"';
   1.148 +      case '\'':
   1.149 +	return '\'';
   1.150 +      case '\?':
   1.151 +	return '\?';
   1.152 +      case 'a':
   1.153 +	return '\a';
   1.154 +      case 'b':
   1.155 +	return '\b';
   1.156 +      case 'f':
   1.157 +	return '\f';
   1.158 +      case 'n':
   1.159 +	return '\n';
   1.160 +      case 'r':
   1.161 +	return '\r';
   1.162 +      case 't':
   1.163 +	return '\t';
   1.164 +      case 'v':
   1.165 +	return '\v';
   1.166 +      case 'x':
   1.167 +	{
   1.168 +	  int code;
   1.169 +	  if (!is.get(c) || !isHex(c)) 
   1.170 +	    throw DataFormatException("Escape format exception");
   1.171 +	  else if (code = valueHex(c), !is.get(c) || !isHex(c)) is.putback(c);
   1.172 +	  else code = code * 16 + valueHex(c);
   1.173 +	  return code;
   1.174 +	}
   1.175 +      default:
   1.176 +	{
   1.177 +	  int code;
   1.178 +	  if (!isOct(c)) 
   1.179 +	    throw DataFormatException("Escape format exception");
   1.180 +	  else if (code = valueOct(c), !is.get(c) || !isOct(c)) 
   1.181 +	    is.putback(c);
   1.182 +	  else if (code = code * 8 + valueOct(c), !is.get(c) || !isOct(c)) 
   1.183 +	    is.putback(c);
   1.184 +	  else code = code * 8 + valueOct(c);
   1.185 +	  return code;
   1.186 +	}	      
   1.187 +      } 
   1.188 +    }
   1.189 +
   1.190 +    static bool isOct(char c) {
   1.191 +      return '0' <= c && c <='7'; 
   1.192 +    }
   1.193 +    
   1.194 +    static int valueOct(char c) {
   1.195 +      return c - '0';
   1.196 +    }
   1.197 +
   1.198 +   static bool isHex(char c) {
   1.199 +      return ('0' <= c && c <= '9') || 
   1.200 +	('a' <= c && c <= 'z') || 
   1.201 +	('A' <= c && c <= 'Z'); 
   1.202 +    }
   1.203 +    
   1.204 +    static int valueHex(char c) {
   1.205 +      if ('0' <= c && c <= '9') return c - '0';
   1.206 +      if ('a' <= c && c <= 'z') return c - 'a' + 10;
   1.207 +      return c - 'A' + 10;
   1.208 +    }
   1.209 +
   1.210 +    bool escaped;
   1.211 +  };
   1.212 +
   1.213 +  /// \brief The graph reader class.
   1.214 +  ///
   1.215 +  /// The reader class for the graph input.
   1.216 +  /// \see graph-io-page
   1.217 +  template <typename _Graph, typename _ReaderTraits = DefaultReaderTraits> 
   1.218 +  class GraphReader {
   1.219 +  public:
   1.220 +    
   1.221 +    typedef _Graph Graph;
   1.222 +    typedef typename Graph::Node Node;
   1.223 +    typedef typename Graph::Edge Edge;
   1.224 +
   1.225 +    typedef _ReaderTraits ReaderTraits;
   1.226 +    typedef typename ReaderTraits::DefaultReader DefaultReader;
   1.227 +
   1.228 +    /// \brief Construct a new GraphReader.
   1.229 +    ///
   1.230 +    /// Construct a new GraphReader. It reads from the given map,
   1.231 +    /// it constructs the given map and it use the given reader as the
   1.232 +    /// default skipper.
   1.233 +    GraphReader(std::istream& _is, Graph& _graph, 
   1.234 +		const DefaultReader& _reader = DefaultReader()) 
   1.235 +      : is(_is), graph(_graph), nodeSkipper(_reader), edgeSkipper(_reader) {}
   1.236 +
   1.237 +    /// \brief Destruct the graph reader.
   1.238 +    ///
   1.239 +    /// Destruct the graph reader.
   1.240 +    ~GraphReader() {
   1.241 +
   1.242 +      for (typename NodeMapReaders::iterator it = node_map_readers.begin(); 
   1.243 +	   it != node_map_readers.end(); ++it) {
   1.244 +	delete it->second;
   1.245 +      }
   1.246 +
   1.247 +      for (typename EdgeMapReaders::iterator it = edge_map_readers.begin(); 
   1.248 +	   it != edge_map_readers.end(); ++it) {
   1.249 +	delete it->second;
   1.250 +      }
   1.251 +
   1.252 +    }
   1.253 +
   1.254 +    /// \brief Add a new node map reader command for the reader.
   1.255 +    ///
   1.256 +    /// Add a new node map reader command for the reader.
   1.257 +    template <typename Map>
   1.258 +    GraphReader& addNodeMap(std::string name, Map& map) {
   1.259 +      return addNodeMap<typename ReaderTraits::template 
   1.260 +	Reader<typename Map::Value>, Map>(name, map);
   1.261 +    }
   1.262 +
   1.263 +    /// \brief Add a new node map reader command for the reader.
   1.264 +    ///
   1.265 +    /// Add a new node map reader command for the reader.
   1.266 +    template <typename Reader, typename Map>
   1.267 +    GraphReader& addNodeMap(std::string name, Map& map, 
   1.268 +			     const Reader& reader = Reader()) {
   1.269 +      if (node_map_readers.find(name) != node_map_readers.end()) {
   1.270 +	throw Exception() << "Multiple read rule for node map: " << name;
   1.271 +      }
   1.272 +      node_map_readers.insert(
   1.273 +        make_pair(name, new MapReader<Node, Map, Reader>(map, reader)));
   1.274 +      return *this;
   1.275 +    }
   1.276 +
   1.277 +    /// \brief Add a new node map skipper command for the reader.
   1.278 +    ///
   1.279 +    /// Add a new node map skipper command for the reader.
   1.280 +    template <typename Reader>
   1.281 +    GraphReader& skipNodeMap(std::string name, 
   1.282 +			     const Reader& reader = Reader()) {
   1.283 +      if (node_map_readers.find(name) != node_map_readers.end()) {
   1.284 +	throw Exception() << "Multiple read rule for node map: " << name;
   1.285 +      }
   1.286 +      node_map_readers.insert(
   1.287 +        make_pair(name, new SkipReader<Node, Reader>(reader)));
   1.288 +      return *this;
   1.289 +    }
   1.290 +
   1.291 +    /// \brief Add a new edge map reader command for the reader.
   1.292 +    ///
   1.293 +    /// Add a new edge map reader command for the reader.
   1.294 +    template <typename Map>
   1.295 +    GraphReader& addEdgeMap(std::string name, Map& map) { 
   1.296 +      return addEdgeMap<typename ReaderTraits::template
   1.297 +	Reader<typename Map::Value>, Map>(name, map);
   1.298 +    }
   1.299 +
   1.300 +
   1.301 +    /// \brief Add a new edge map reader command for the reader.
   1.302 +    ///
   1.303 +    /// Add a new edge map reader command for the reader.
   1.304 +    template <typename Reader, typename Map>
   1.305 +    GraphReader& addEdgeMap(std::string name, Map& map,
   1.306 +			     const Reader& reader = Reader()) {
   1.307 +      if (edge_map_readers.find(name) != edge_map_readers.end()) {
   1.308 +	throw Exception() << "Multiple read rule for edge map: " << name;
   1.309 +      }
   1.310 +      edge_map_readers.insert(
   1.311 +        make_pair(name, new MapReader<Edge, Map, Reader>(map, reader)));
   1.312 +      return *this;
   1.313 +    }
   1.314 +
   1.315 +    /// \brief Add a new edge map skipper command for the reader.
   1.316 +    ///
   1.317 +    /// Add a new edge map skipper command for the reader.
   1.318 +    template <typename Reader>
   1.319 +    GraphReader& skipEdgeMap(std::string name,
   1.320 +			     const Reader& reader = Reader()) {
   1.321 +      if (edge_map_readers.find(name) != edge_map_readers.end()) {
   1.322 +	throw Exception() << "Multiple read rule for edge map: " << name;
   1.323 +      }
   1.324 +      edge_map_readers.insert(
   1.325 +        make_pair(name, new SkipReader<Edge, Reader>(reader)));
   1.326 +      return *this;
   1.327 +    }
   1.328 +
   1.329 +    /// \brief Add a new labeled node reader for the reader.
   1.330 +    ///
   1.331 +    /// Add a new labeled node reader for the reader.
   1.332 +    GraphReader& addNode(std::string name, Node& node) {
   1.333 +      if (node_readers.find(name) != node_readers.end()) {
   1.334 +	throw Exception() << "Multiple read rule for node";
   1.335 +      }
   1.336 +      node_readers.insert(make_pair(name, &node));
   1.337 +      return *this;
   1.338 +    }
   1.339 +
   1.340 +    /// \brief Add a new labeled edge reader for the reader.
   1.341 +    ///
   1.342 +    /// Add a new labeled edge reader for the reader.
   1.343 +    GraphReader& addEdge(std::string name, Edge& edge) {
   1.344 +      if (edge_readers.find(name) != edge_readers.end()) {
   1.345 +	throw Exception() << "Multiple read rule for edge";
   1.346 +      }
   1.347 +      edge_readers.insert(make_pair(name, &edge));
   1.348 +      return *this;
   1.349 +    }
   1.350 +
   1.351 +    /// \brief Executes the reader commands.
   1.352 +    ///
   1.353 +    /// Executes the reader commands.
   1.354 +    void run() {
   1.355 +      int line_num = 0;
   1.356 +      std::auto_ptr<InverterBase<Node> > nodeInverter;
   1.357 +      std::auto_ptr<InverterBase<Edge> > edgeInverter;
   1.358 +      try {
   1.359 +	std::string line = readNotEmptyLine(is, line_num);
   1.360 +	if (line.find("@nodeset") == 0) {
   1.361 +	  line = readNodeSet(line_num, nodeInverter);
   1.362 +	} 
   1.363 +	if (line.find("@edgeset") == 0) {
   1.364 +	  line = readEdgeSet(line_num, edgeInverter, nodeInverter);
   1.365 +	}
   1.366 +	if (line.find("@nodes") == 0) {
   1.367 +	  line = readNodes(line_num, nodeInverter);
   1.368 +	}
   1.369 +	if (line.find("@edges") == 0) {
   1.370 +	  line = readEdges(line_num, edgeInverter);
   1.371 +	}
   1.372 +	if (line.find("@end") != 0) {
   1.373 +	  throw DataFormatException("Invalid control sequence: " + line);
   1.374 +	}
   1.375 +      } catch (DataFormatException e) {
   1.376 +	throw StreamException<DataFormatException>(line_num, e);
   1.377 +      }
   1.378 +    }
   1.379 +
   1.380 +  private:
   1.381 +
   1.382 +    template <typename Item> class InverterBase;
   1.383 +
   1.384 +    std::string readNodeSet(int& line_num, 
   1.385 +			    auto_ptr<InverterBase<Node> > & nodeInverter) {
   1.386 +      std::vector<ReaderBase<Node>* > index;
   1.387 +      {
   1.388 +	std::string line = readNotEmptyLine(is, line_num);    
   1.389 +	std::string id;
   1.390 +	std::istringstream ls(line);	
   1.391 +	while (ls >> id) {
   1.392 +	  if (id[0] == '#') break;
   1.393 +	  typename NodeMapReaders::iterator it = node_map_readers.find(id);
   1.394 +	  if (it != node_map_readers.end()) {
   1.395 +	    index.push_back(it->second);
   1.396 +	    node_map_readers.erase(it);
   1.397 +	  } else {
   1.398 +	    index.push_back(&nodeSkipper);
   1.399 +	  }
   1.400 +	}
   1.401 +      }
   1.402 +
   1.403 +      if (index.size() == 0) {
   1.404 +	throw DataFormatException("No node map found");
   1.405 +      }
   1.406 +
   1.407 +      nodeInverter = auto_ptr<InverterBase<Node> >(index[0]->getInverter());
   1.408 +      std::string line;
   1.409 +      while (line = readNotEmptyLine(is, line_num), line[0] != '@') {
   1.410 +	Node node = graph.addNode();
   1.411 +	std::istringstream ls(line);
   1.412 +	nodeInverter->read(ls, node);
   1.413 +	for (int i = 1; i < (int)index.size(); ++i) {
   1.414 +	  index[i]->read(ls, node);
   1.415 +	}
   1.416 +      }
   1.417 +      return line;
   1.418 +    }
   1.419 +
   1.420 +    std::string readEdgeSet(int& line_num, 
   1.421 +			    auto_ptr<InverterBase<Edge> > & edgeInverter, 
   1.422 +			    auto_ptr<InverterBase<Node> > & nodeInverter) {
   1.423 +      std::vector<ReaderBase<Edge>*> index;
   1.424 +      {
   1.425 +	std::string line = readNotEmptyLine(is, line_num);    
   1.426 +	std::string id;
   1.427 +	std::istringstream ls(line);	
   1.428 +	while (ls >> id) {
   1.429 +	  if (id[0] == '#') break;
   1.430 +	  typename EdgeMapReaders::iterator it = edge_map_readers.find(id);
   1.431 +	  if (it != edge_map_readers.end()) {
   1.432 +	    index.push_back(it->second);
   1.433 +	    edge_map_readers.erase(it);
   1.434 +	  } else {
   1.435 +	    index.push_back(&edgeSkipper);
   1.436 +	  }
   1.437 +	}
   1.438 +      }
   1.439 +
   1.440 +      if (index.size() == 0) {
   1.441 +	throw DataFormatException("No edge map found");
   1.442 +      }
   1.443 +
   1.444 +      edgeInverter = auto_ptr<InverterBase<Edge> >(index[0]->getInverter());
   1.445 +      std::string line;
   1.446 +      while (line = readNotEmptyLine(is, line_num), line[0] != '@') {	
   1.447 +	std::istringstream ls(line);
   1.448 +	Node source = nodeInverter->read(ls);
   1.449 +	Node target = nodeInverter->read(ls);
   1.450 +	Edge edge = graph.addEdge(source, target);
   1.451 +	edgeInverter->read(ls, edge);
   1.452 +	for (int i = 1; i < (int)index.size(); ++i) {
   1.453 +	  index[i]->read(ls, edge);
   1.454 +	}
   1.455 +      }      
   1.456 +      return line;
   1.457 +    }
   1.458 +
   1.459 +    std::string readNodes(int& line_num, 
   1.460 +			  auto_ptr<InverterBase<Node> >& nodeInverter) {
   1.461 +      std::string line;
   1.462 +      while (line = readNotEmptyLine(is, line_num), line[0] != '@') {
   1.463 +	std::istringstream ls(line);
   1.464 +	std::string name;
   1.465 +	ls >> name;
   1.466 +	typename NodeReaders::iterator it = node_readers.find(name);
   1.467 +	if (it != node_readers.end()) {
   1.468 +	  *(it -> second) = nodeInverter->read(ls);
   1.469 +	} 
   1.470 +      }        
   1.471 +      return line;
   1.472 +    }
   1.473 +
   1.474 +    std::string readEdges(int& line_num, 
   1.475 +			  auto_ptr<InverterBase<Edge> >& edgeInverter) {
   1.476 +      std::string line;
   1.477 +      while (line = readNotEmptyLine(is, line_num), line[0] != '@') {
   1.478 +	std::istringstream ls(line);
   1.479 +	std::string name;
   1.480 +	ls >> name;
   1.481 +	typename EdgeReaders::iterator it = edge_readers.find(name);
   1.482 +	if (it != edge_readers.end()) {
   1.483 +	  *(it -> second) = edgeInverter->read(ls);
   1.484 +	} 
   1.485 +      }        
   1.486 +      return line;    
   1.487 +    }
   1.488 +
   1.489 +    std::string readNotEmptyLine(std::istream& is, int& line_num) {
   1.490 +      std::string line;
   1.491 +      while (++line_num, getline(is, line)) {	
   1.492 +	int vi = line.find_first_not_of(" \t");
   1.493 +	if (vi != (int)string::npos && line[vi] != '#') {
   1.494 +	  return line.substr(vi);
   1.495 +	}
   1.496 +      }
   1.497 +      throw DataFormatException("End of stream");
   1.498 +    }
   1.499 +    
   1.500 +    // Inverters store and give back the Item from the id,
   1.501 +    // and may put the ids into a map.
   1.502 +    
   1.503 +    template <typename _Item>
   1.504 +    class InverterBase {
   1.505 +    public:
   1.506 +      typedef _Item Item;
   1.507 +      virtual void read(std::istream&, const Item&) = 0;
   1.508 +      virtual Item read(std::istream&) = 0;
   1.509 +    };
   1.510 +
   1.511 +    template <typename _Item, typename _Map, typename _Reader>
   1.512 +    class MapReaderInverter : public InverterBase<_Item> {
   1.513 +    public:
   1.514 +      typedef _Item Item;
   1.515 +      typedef _Reader Reader;
   1.516 +      typedef typename Reader::Value Value;
   1.517 +      typedef _Map Map;
   1.518 +      typedef std::map<Value, Item> Inverse;
   1.519 +
   1.520 +      Map& map;
   1.521 +      Reader reader;
   1.522 +      Inverse inverse;
   1.523 +
   1.524 +      MapReaderInverter(Map& _map, const Reader& _reader) 
   1.525 +	: map(_map), reader(_reader) {}
   1.526 +
   1.527 +      virtual ~MapReaderInverter() {}
   1.528 +
   1.529 +      virtual void read(std::istream& is, const Item& item) {
   1.530 +	Value value;
   1.531 +	reader.read(is, value);
   1.532 +	map.set(item, value);
   1.533 +	typename Inverse::iterator it = inverse.find(value);
   1.534 +	if (it == inverse.end()) {
   1.535 +	  inverse.insert(make_pair(value, item));
   1.536 +	} else {
   1.537 +	  throw DataFormatException("Multiple ID occurence");
   1.538 +	}
   1.539 +      }
   1.540 +
   1.541 +      virtual Item read(std::istream& is) {
   1.542 +	Value value;
   1.543 +	reader.read(is, value);	
   1.544 +	typename Inverse::const_iterator it = inverse.find(value);
   1.545 +	if (it != inverse.end()) {
   1.546 +	  return it->second;
   1.547 +	} else {
   1.548 +	  throw DataFormatException("Invalid ID");
   1.549 +	}
   1.550 +      }      
   1.551 +    };
   1.552 +
   1.553 +    template <typename _Item, typename _Reader>
   1.554 +    class SkipReaderInverter : public InverterBase<_Item> {
   1.555 +    public:
   1.556 +      typedef _Item Item;
   1.557 +      typedef _Reader Reader;
   1.558 +      typedef typename Reader::Value Value;
   1.559 +      typedef std::map<Value, Item> Inverse;
   1.560 +
   1.561 +      Reader reader;
   1.562 +
   1.563 +      SkipReaderInverter(const Reader& _reader) 
   1.564 +	: reader(_reader) {}
   1.565 +
   1.566 +      virtual ~SkipReaderInverter() {}
   1.567 +
   1.568 +      virtual void read(std::istream& is, const Item& item) {
   1.569 +	Value value;
   1.570 +	reader.read(is, value);
   1.571 +	typename Inverse::iterator it = inverse.find(value);
   1.572 +	if (it == inverse.end()) {
   1.573 +	  inverse.insert(make_pair(value, item));
   1.574 +	} else {
   1.575 +	  throw DataFormatException("Multiple ID occurence");
   1.576 +	}
   1.577 +      }
   1.578 +
   1.579 +      virtual Item read(std::istream& is) {
   1.580 +	Value value;
   1.581 +	reader.read(is, value);	
   1.582 +	typename Inverse::const_iterator it = inverse.find(value);
   1.583 +	if (it != inverse.end()) {
   1.584 +	  return it->second;
   1.585 +	} else {
   1.586 +	  throw DataFormatException("Invalid ID");
   1.587 +	}
   1.588 +      }      
   1.589 +    private:
   1.590 +      Inverse inverse;
   1.591 +    };
   1.592 +
   1.593 +    // Readers
   1.594 +
   1.595 +    template <typename _Item>    
   1.596 +    class ReaderBase {
   1.597 +    public:
   1.598 +      typedef _Item Item;
   1.599 +
   1.600 +      //      virtual ~ReaderBase() {}
   1.601 +
   1.602 +      virtual void read(std::istream& is, const Item& item) = 0;
   1.603 +      virtual InverterBase<_Item>* getInverter() = 0;
   1.604 +    };
   1.605 +
   1.606 +    template <typename _Item, typename _Map, typename _Reader>
   1.607 +    class MapReader : public ReaderBase<_Item> {
   1.608 +    public:
   1.609 +      typedef _Map Map;
   1.610 +      typedef _Reader Reader;
   1.611 +      typedef typename Reader::Value Value;
   1.612 +      typedef _Item Item;
   1.613 +      
   1.614 +      Map& map;
   1.615 +      Reader reader;
   1.616 +
   1.617 +      MapReader(Map& _map, const Reader& _reader) 
   1.618 +	: map(_map), reader(_reader) {}
   1.619 +
   1.620 +      virtual ~MapReader() {}
   1.621 +
   1.622 +      virtual void read(std::istream& is, const Item& item) {
   1.623 +	Value value;
   1.624 +	reader.read(is, value);
   1.625 +	map.set(item, value);
   1.626 +      }
   1.627 +
   1.628 +      virtual InverterBase<_Item>* getInverter() {
   1.629 +	return new MapReaderInverter<Item, Map, Reader>(map, reader);
   1.630 +      }
   1.631 +    };
   1.632 +
   1.633 +
   1.634 +    template <typename _Item, typename _Reader>
   1.635 +    class SkipReader : public ReaderBase<_Item> {
   1.636 +    public:
   1.637 +      typedef _Reader Reader;
   1.638 +      typedef typename Reader::Value Value;
   1.639 +      typedef _Item Item;
   1.640 +
   1.641 +      Reader reader;
   1.642 +      SkipReader(const Reader& _reader) : reader(_reader) {}
   1.643 +
   1.644 +      virtual ~SkipReader() {}
   1.645 +
   1.646 +      virtual void read(std::istream& is, const Item& item) {
   1.647 +	Value value;
   1.648 +	reader.read(is, value);
   1.649 +      }      
   1.650 +
   1.651 +      virtual InverterBase<Item>* getInverter() {
   1.652 +	return new SkipReaderInverter<Item, Reader>(reader);
   1.653 +      }
   1.654 +    };
   1.655 +
   1.656 +
   1.657 +    typedef std::map<std::string, ReaderBase<Node>*> NodeMapReaders;
   1.658 +    NodeMapReaders node_map_readers;
   1.659 +
   1.660 +    typedef std::map<std::string, ReaderBase<Edge>*> EdgeMapReaders;
   1.661 +    EdgeMapReaders edge_map_readers;
   1.662 +
   1.663 +    typedef std::map<std::string, Node*> NodeReaders;
   1.664 +    NodeReaders node_readers;
   1.665 +
   1.666 +    typedef std::map<std::string, Edge*> EdgeReaders;
   1.667 +    EdgeReaders edge_readers;
   1.668 +
   1.669 +    std::istream& is;
   1.670 +    Graph& graph;
   1.671 +
   1.672 +    SkipReader<Node, DefaultReader> nodeSkipper;
   1.673 +    SkipReader<Edge, DefaultReader> edgeSkipper;
   1.674 +
   1.675 +  };
   1.676 +
   1.677 +}