/* -*- C++ -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library

 *

 * Copyright (C) 2003-2008

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, 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>

#include <lemon/bits/invalid.h>

/// \ingroup dimacs_group

/// \file

/// \brief DIMACS file format reader.

namespace lemon {

  ///@defgroup dimacs_group DIMACS format

  ///\brief Read and write files in DIMACS format

  ///

  ///Tools to read a graph from or write it to a file in DIMACS format

  ///data

  ///\ingroup io_group

  /// \addtogroup dimacs_group

  /// @{

  /// 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

  /// \code

  ///   p min

  /// \endcode

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

  /// amount of the nodes are written to \c supply (signed). The 

  /// lower bounds, capacities and costs of the edges are written to 

  /// \c lower, \c capacity and \c cost.

  ///

  /// \author Marton Makai and Peter Kovacs

  template <typename Graph, typename LowerMap, 

    typename CapacityMap, typename CostMap, 

    typename SupplyMap>

  void readDimacs( std::istream& is,

		   Graph &g,

		   LowerMap& lower, 

		   CapacityMap& capacity, 

		   CostMap& cost,

		   SupplyMap& supply )

  {

    g.clear();

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

    typename Graph::Edge e;

    std::string problem, str;

    char c;

    int n, m; 

    int i, j;

    typename SupplyMap::Value sup;

    typename CapacityMap::Value low;

    typename CapacityMap::Value cap;

    typename CostMap::Value co;

    while (is >> c) {

      switch (c) {

      case 'c': // comment line

	getline(is, str);

	break;

      case 'p': // problem definition line

	is >> problem >> n >> m;

	getline(is, str);

	if (problem != "min") return;

	nodes.resize(n + 1);

	for (int k = 1; k <= n; ++k) {

	  nodes[k] = g.addNode();

	  supply.set(nodes[k], 0);

	}

	break;

      case 'n': // node definition line

	is >> i >> sup;

	getline(is, str);

	supply.set(nodes[i], sup);

	break;

      case 'a': // edge (arc) definition line

	is >> i >> j >> low >> cap >> co;

	getline(is, str);

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

	lower.set(e, low);

	if (cap >= 0)

	  capacity.set(e, cap);

	else

	  capacity.set(e, -1);

	cost.set(e, co);

	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

  /// \code

  ///   p max

  /// \endcode

  /// 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) {

    g.clear();

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

    typename Graph::Edge e;

    std::string problem;

    char c, d;

    int n, m; 

    int i, j;

    typename CapacityMap::Value _cap;

    std::string str;

    while (is >> c) {

      switch (c) {

      case 'c': // comment line

	getline(is, str);

	break;

      case 'p': // problem definition line

	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 line

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

	  is >> i;

	  getline(is, str);

	  s = nodes[i];

	}

	if (problem == "max") { // max flow problem

	  is >> i >> d;

	  getline(is, str);

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

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

	}

	break;

      case 'a': // edge (arc) definition line

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

	  is >> i >> j >> _cap;

	  getline(is, str);

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

	  capacity.set(e, _cap);

	} else {

	  is >> i >> j;

	  getline(is, str);

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

	}

	break;

      }

    }

  }

  /// 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

  /// \code

  ///   p sp

  /// \endcode

  /// 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) {

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

  }

  /// 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;

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

  }

  /// 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

  /// \code

  ///   p mat

  /// \endcode

  /// 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);

  }

  /// DIMACS plain graph writer function.

  ///

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

  /// maps into DIMACS format, i.e. into DIMACS file having a line 

  /// starting with

  /// \code

  ///   p mat

  /// \endcode

  ///

  /// \author Marton Makai

  template<typename Graph>

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

    typedef typename Graph::NodeIt NodeIt;

    typedef typename Graph::EdgeIt EdgeIt;  

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

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

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

    int i = 1;

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

      nodes.set(v, i);

      ++i;

    }    

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

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

    }

  }

  /// @}

} //namespace lemon

#endif //LEMON_DIMACS_H