/* -*- C++ -*-

  * src/lemon/dimacs.h - Part of LEMON, a generic C++ optimization library

  *

  * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Combinatorial Optimization Research Group, 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.

  *

  */

 #ifndef LEMON_DIMACS_H

 #define LEMON_DIMACS_H

 #include <iostream>

 #include <string>

 #include <vector>

 #include <lemon/maps.h>

 /// \ingroup misc

 /// \file

 /// \brief Dimacs file format reader.

 namespace lemon {

   /// \addtogroup misc

   /// @{

   /// Dimacs min cost flow reader function.

   /// This function reads a min cost flow instance from dimacs format,

   /// i.e. from dimacs files having a line starting with \c p \c "min".

   /// At the beginning \c g is cleared by \c g.clear(). The edge

   /// capacities are written to \c capacity, \c s and \c t are set to

   /// the source and the target nodes resp. and the cost of the edges

   /// are written to \c cost.

   ///

   /// \author Marton Makai

   template<typename Graph, typename CapacityMap, typename CostMap>

   void readDimacs(std::istream& is, Graph &g, CapacityMap& capacity, 

 		  typename Graph::Node &s, typename Graph::Node &t, 

 		  CostMap& cost) {

     g.clear();

     typename CapacityMap::ValueType _cap;

     typename CostMap::ValueType _cost;

     char d;

     std::string problem;

     char c;

     int i, j;

     std::string str;

     int n, m; 

     typename Graph::Edge e;

     std::vector<typename Graph::Node> nodes;

     while (is>>c) {

       switch (c) {

       case 'c': //comment

 	getline(is, str);

 	break;

       case 'p': //problem definition

 	is >> problem >> n >> m;

 	getline(is, str);

 	nodes.resize(n+1);

 	for (int k=1; k<=n; ++k) nodes[k]=g.addNode();

 	break;

       case 'n': //node definition

 	if (problem=="sp") { //shortest path problem

 	  is >> i;

 	  getline(is, str);

 	  s=nodes[i];

 	}

 	if (problem=="max" || problem=="min") { //((max) or (min cost)) flow problem

 	  is >> i >> d;

 	  getline(is, str);

 	  if (d=='s') s=nodes[i];

 	  if (d=='t') t=nodes[i];

 	}

 	break;

       case 'a':

 	if ( problem == "max" || problem == "sp") {

 	  is >> i >> j >> _cap;

 	  getline(is, str);

 	  e=g.addEdge(nodes[i], nodes[j]);

 	  //capacity.update();

 	  capacity.set(e, _cap);

 	} else {

 	  if ( problem == "min" ) {

 	    is >> i >> j >> _cap >> _cost;

 	    getline(is, str);

 	    e=g.addEdge(nodes[i], nodes[j]);

 	    //capacity.update();

 	    capacity.set(e, _cap);

 	    //cost.update();

 	    cost.set(e, _cost);

 	  } else {

 	    is >> i >> j;

 	    getline(is, str);

 	    g.addEdge(nodes[i], nodes[j]);

 	  }

 	}

 	break;

       }

     }

   }

   /// Dimacs max flow reader function.

   /// This function reads a max flow instance from dimacs format,

   /// i.e. from dimacs files having a line starting with \c p \c

   /// "max".  At the beginning \c g is cleared by \c g.clear(). The

   /// edge capacities are written to \c capacity and \c s and \c t are

   /// set to the source and the target nodes.

   ///

   /// \author Marton Makai

   template<typename Graph, typename CapacityMap>

   void readDimacs(std::istream& is, Graph &g, CapacityMap& capacity, 

 		  typename Graph::Node &s, typename Graph::Node &t) {

     NullMap<typename Graph::Edge, int> n;

     readDimacs(is, g, capacity, s, t, n);

   }

   /// Dimacs shortest path reader function.

   /// This function reads a shortest path instance from dimacs format,

   /// i.e. from dimacs files having a line starting with \c p \c "sp".

   /// At the beginning \c g is cleared by \c g.clear(). The edge

   /// capacities are written to \c capacity and \c s is set to the

   /// source node.

   ///

   /// \author Marton Makai

   template<typename Graph, typename CapacityMap>

   void readDimacs(std::istream& is, Graph &g, CapacityMap& capacity, 

 		  typename Graph::Node &s) {

     NullMap<typename Graph::Edge, int> n;

     readDimacs(is, g, capacity, s, s, n);

   }

   /// Dimacs capacitated graph reader function.

   /// This function reads an edge capacitated graph instance from

   /// dimacs format.  At the beginning \c g is cleared by \c g.clear()

   /// and the edge capacities are written to \c capacity.

   ///

   /// \author Marton Makai

   template<typename Graph, typename CapacityMap>

   void readDimacs(std::istream& is, Graph &g, CapacityMap& capacity) {

     typename Graph::Node u;

     NullMap<typename Graph::Edge, int> n;

     readDimacs(is, g, capacity, u, u, n);

   }

   /// Dimacs plain graph reader function.

   /// This function reads a graph without any designated nodes and

   /// maps from dimacs format, i.e. from dimacs files having a line

   /// starting with \c p \c "mat".  At the beginning \c g is cleared

   /// by \c g.clear().

   ///

   /// \author Marton Makai

   template<typename Graph>

   void readDimacs(std::istream& is, Graph &g) {

     typename Graph::Node u;

     NullMap<typename Graph::Edge, int> n;

     readDimacs(is, g, n, u, u, n);

   }

   /// write matching problem

   template<typename Graph>

   void writeDimacs(std::ostream& os, const Graph &g) {

     typedef typename Graph::NodeIt NodeIt;

     typedef typename Graph::EdgeIt EdgeIt;  

     typename Graph::template NodeMap<int> nodes(g);

     os << "c matching problem" << std::endl;

     int i=1;

     for(NodeIt v(g); v!=INVALID; ++v) {

       nodes.set(v, i);

       ++i;

     }    

     os << "p mat " << g.nodeNum() << " " << g.edgeNum() << std::endl;

     for(EdgeIt e(g); e!=INVALID; ++e) {

       os << "a " << nodes[g.tail(e)] << " " << nodes[g.head(e)] << std::endl; 

     }

   }

   /// @}

 } //namespace lemon

 #endif //LEMON_DIMACS_H