/* -*- 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