/* -*- 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>

 #include <lemon/error.h>

 /// \ingroup dimacs_group

 /// \file

 /// \brief DIMACS file format reader.

 namespace lemon {

   /// \addtogroup dimacs_group

   /// @{

   /// DIMACS file type descriptor.

   struct DimacsDescriptor

   {

     ///File type enum

     enum Type

       {

         NONE, MIN, MAX, SP, MAT

       };

     ///The file type

     Type type;

     ///The number of nodes in the graph

     int nodeNum;

     ///The number of edges in the graph

     int edgeNum;

     int lineShift;

     /// Constructor. Sets the type to NONE.

     DimacsDescriptor() : type(NONE) {}

   };

   ///Discover the type of a DIMACS file

   ///It starts seeking the begining of the file for the problem type

   ///and size info. The found data is returned in a special struct

   ///that can be evaluated and passed to the appropriate reader

   ///function.

   DimacsDescriptor dimacsType(std::istream& is)

   {

     DimacsDescriptor r;

     std::string problem,str;

     char c;

     r.lineShift=0;

     while (is >> c)

       switch(c)

         {

         case 'p':

           if(is >> problem >> r.nodeNum >> r.edgeNum)

             {

               getline(is, str);

               r.lineShift++;

               if(problem=="min") r.type=DimacsDescriptor::MIN;

               else if(problem=="max") r.type=DimacsDescriptor::MAX;

               else if(problem=="sp") r.type=DimacsDescriptor::SP;

               else if(problem=="mat") r.type=DimacsDescriptor::MAT;

               else throw FormatError("Unknown problem type");

               return r;

             }

           else

             {

               throw FormatError("Missing or wrong problem type declaration.");

             }

           break;

         case 'c':

           getline(is, str);

           r.lineShift++;

           break;

         default:

           throw FormatError("Unknown DIMACS declaration.");

         }

     throw FormatError("Missing problem type declaration.");

   }

   /// DIMACS minimum cost flow reader function.

   ///

   /// This function reads a minimum cost flow instance from DIMACS format,

   /// i.e. from a DIMACS file 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.

   ///

   /// If the file type was previously evaluated by dimacsType(), then

   /// the descriptor struct should be given by the \c dest parameter.

   template <typename Digraph, typename LowerMap,

             typename CapacityMap, typename CostMap,

             typename SupplyMap>

   void readDimacsMin(std::istream& is,

                      Digraph &g,

                      LowerMap& lower,

                      CapacityMap& capacity,

                      CostMap& cost,

                      SupplyMap& supply,

                      DimacsDescriptor desc=DimacsDescriptor())

   {

     g.clear();

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

     typename Digraph::Arc e;

     std::string problem, str;

     char c;

     int i, j;

     if(desc.type==DimacsDescriptor::NONE) desc=dimacsType(is);

     if(desc.type!=DimacsDescriptor::MIN)

       throw FormatError("Problem type mismatch");

     nodes.resize(desc.nodeNum + 1);

     for (int k = 1; k <= desc.nodeNum; ++k) {

       nodes[k] = g.addNode();

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

     }

     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 '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;

       }

     }

   }

   template<typename Digraph, typename CapacityMap>

   void _readDimacs(std::istream& is,

                    Digraph &g,

                    CapacityMap& capacity,

                    typename Digraph::Node &s,

                    typename Digraph::Node &t,

                    DimacsDescriptor desc=DimacsDescriptor()) {

     g.clear();

     s=t=INVALID;

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

     typename Digraph::Arc e;

     char c, d;

     int i, j;

     typename CapacityMap::Value _cap;

     std::string str;

     nodes.resize(desc.nodeNum + 1);

     for (int k = 1; k <= desc.nodeNum; ++k) {

       nodes[k] = g.addNode();

     }

     while (is >> c) {

       switch (c) {

       case 'c': // comment line

         getline(is, str);

         break;

       case 'n': // node definition line

         if (desc.type==DimacsDescriptor::SP) { // shortest path problem

           is >> i;

           getline(is, str);

           s = nodes[i];

         }

         if (desc.type==DimacsDescriptor::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 (desc.type==DimacsDescriptor::SP ||

             desc.type==DimacsDescriptor::MAX) {

           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 maximum flow reader function.

   ///

   /// This function reads a maximum flow instance from DIMACS format,

   /// i.e. from a DIMACS file 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.

   ///

   /// If the file type was previously evaluated by dimacsType(), then

   /// the descriptor struct should be given by the \c dest parameter.

   template<typename Digraph, typename CapacityMap>

   void readDimacsMax(std::istream& is,

                      Digraph &g,

                      CapacityMap& capacity,

                      typename Digraph::Node &s,

                      typename Digraph::Node &t,

                      DimacsDescriptor desc=DimacsDescriptor()) {

     if(desc.type==DimacsDescriptor::NONE) desc=dimacsType(is);

     if(desc.type!=DimacsDescriptor::MAX)

       throw FormatError("Problem type mismatch");

     _readDimacs(is,g,capacity,s,t,desc);

   }

   /// DIMACS shortest path reader function.

   ///

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

   /// i.e. from a DIMACS file having a line starting with

   /// \code

   ///   p sp

   /// \endcode

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

   /// lengths are written to \c length and \c s is set to the

   /// source node.

   ///

   /// If the file type was previously evaluated by dimacsType(), then

   /// the descriptor struct should be given by the \c dest parameter.

   template<typename Digraph, typename LengthMap>

   void readDimacsSp(std::istream& is,

                     Digraph &g,

                     LengthMap& length,

                     typename Digraph::Node &s,

                     DimacsDescriptor desc=DimacsDescriptor()) {

     typename Digraph::Node t;

     if(desc.type==DimacsDescriptor::NONE) desc=dimacsType(is);

     if(desc.type!=DimacsDescriptor::SP)

       throw FormatError("Problem type mismatch");

     _readDimacs(is, g, length, s, t,desc);

   }

   /// DIMACS capacitated digraph reader function.

   ///

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

   /// DIMACS 'mat' or 'sp' format.

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

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

   ///

   /// If the file type was previously evaluated by dimacsType(), then

   /// the descriptor struct should be given by the \c dest parameter.

   template<typename Digraph, typename CapacityMap>

   void readDimacsCap(std::istream& is,

                      Digraph &g,

                      CapacityMap& capacity,

                      DimacsDescriptor desc=DimacsDescriptor()) {

     typename Digraph::Node u,v;

     if(desc.type==DimacsDescriptor::NONE) desc=dimacsType(is);

     if(desc.type!=DimacsDescriptor::MAX || desc.type!=DimacsDescriptor::SP)

       throw FormatError("Problem type mismatch");

     _readDimacs(is, g, capacity, u, v, desc);

   }

   /// 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().

   ///

   /// If the file type was previously evaluated by dimacsType(), then

   /// the descriptor struct should be given by the \c dest parameter.

   template<typename Digraph>

   void readDimacsMat(std::istream& is, Digraph &g,

                      DimacsDescriptor desc=DimacsDescriptor()) {

     typename Digraph::Node u,v;

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

     if(desc.type==DimacsDescriptor::NONE) desc=dimacsType(is);

     if(desc.type!=DimacsDescriptor::MAT)

       throw FormatError("Problem type mismatch");

     _readDimacs(is, g, n, u, v, desc);

   }

   /// 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

   /// If \c comment is not empty, then it will be printed in the first line

   /// prefixed by 'c'.

   template<typename Digraph>

   void writeDimacsMat(std::ostream& os, const Digraph &g,

                       std::string comment="") {

     typedef typename Digraph::NodeIt NodeIt;

     typedef typename Digraph::ArcIt ArcIt;

     if(!comment.empty()) 

       os << "c " << comment << 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