/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

 * 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>

/// \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 digraph 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 arcs are written to

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

  template <typename Digraph, typename LowerMap,

    typename CapacityMap, typename CostMap,

    typename SupplyMap>

  void readDimacs( std::istream& is,

                   Digraph &g,

                   LowerMap& lower,

                   CapacityMap& capacity,

                   CostMap& cost,

                   SupplyMap& supply )

  {

    g.clear();

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

    typename Digraph::Arc 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': // arc (arc) definition line

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

        getline(is, str);

        e = g.addArc(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 arc

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

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

  template<typename Digraph, typename CapacityMap>

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

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

    g.clear();

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

    typename Digraph::Arc 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': // arc (arc) definition line

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

          is >> i >> j >> _cap;

          getline(is, str);

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

          capacity.set(e, _cap);

        } else {

          is >> i >> j;

          getline(is, str);

          g.addArc(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 arc

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

  /// source node.

  template<typename Digraph, typename CapacityMap>

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

                  typename Digraph::Node &s) {

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

  }

  /// DIMACS capacitated digraph reader function.

  ///

  /// This function reads an arc capacitated digraph instance from

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

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

  template<typename Digraph, typename CapacityMap>

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

    typename Digraph::Node u;

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

  }

  /// DIMACS plain digraph reader function.

  ///

  /// This function reads a digraph 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().

  template<typename Digraph>

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

    typename Digraph::Node u;

    NullMap<typename Digraph::Arc, int> n;

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

  }

  /// DIMACS plain digraph writer function.

  ///

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

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

  /// starting with

  /// \code

  ///   p mat

  /// \endcode

  template<typename Digraph>

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

    typedef typename Digraph::NodeIt NodeIt;

    typedef typename Digraph::ArcIt ArcIt;

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

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

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

    int i = 1;

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

      nodes.set(v, i);

      ++i;

    }

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

      os << "a " << nodes[g.source(e)] << " " << nodes[g.target(e)]

         << std::endl;

    }

  }

  /// @}

} //namespace lemon

#endif //LEMON_DIMACS_H