text: /**************************************************************************************************
  MiniSat -- Copyright (c) 2005, Niklas Sorensson
  http://www.cs.chalmers.se/Cs/Research/FormalMethods/MiniSat/
  
  Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
  associated documentation files (the "Software"), to deal in the Software without restriction,
  including without limitation the rights to use, copy, modify, merge, publish, distribute,
  sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  
  The above copyright notice and this permission notice shall be included in all copies or
  substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
  NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
  DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
  OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  **************************************************************************************************/
  // Modified to compile with MS Visual Studio 6.0 by Alan Mishchenko
  
  #ifndef solver_h
  #define solver_h
  
  #ifdef _WIN32
  #define inline __inline // compatible with MS VS 6.0
  #endif
  
  #include "vec.h"
  
  //=================================================================================================
  // Simple types:
  
  // does not work for c++
  typedef int  bool;
  static const bool  true      = 1;
  static const bool  false     = 0;
  
  typedef int                lit;
  typedef char               lbool;
  
  #ifdef _WIN32
  typedef signed __int64     uint64;   // compatible with MS VS 6.0
  #else
  typedef unsigned long long uint64;
  #endif
  
  static const int   var_Undef = -1;
  static const lit   lit_Undef = -2;
  
  static const lbool l_Undef   =  0;
  static const lbool l_True    =  1;
  static const lbool l_False   = -1;
  
  static inline lit  toLit   (int v) { return v + v; }
  static inline lit  lit_neg (lit l) { return l ^ 1; }
  static inline int  lit_var (lit l) { return l >> 1; }
  static inline int  lit_sign(lit l) { return (l & 1); }
  
  
  //=================================================================================================
  // Public interface:
  
  struct solver_t;
  typedef struct solver_t solver;
  
  extern solver* solver_new(void);
  extern void    solver_delete(solver* s);
  
  extern bool    solver_addclause(solver* s, lit* begin, lit* end);
  extern bool    solver_simplify(solver* s);
  extern bool    solver_solve(solver* s, lit* begin, lit* end);
  
  extern int     solver_nvars(solver* s);
  extern int     solver_nclauses(solver* s);
  extern int     solver_nconflicts(solver* s);
  
  extern void    solver_setnvars(solver* s,int n);
  
  struct stats_t
  {
      long long   starts, decisions, propagations, inspects, conflicts;
      long long   clauses, clauses_literals, learnts, learnts_literals, max_literals, tot_literals;
  };
  typedef struct stats_t stats;
  
  //=================================================================================================
  // Solver representation:
  
  struct clause_t;
  typedef struct clause_t clause;
  
  struct solver_t
  {
      int      size;          // nof variables
      int      cap;           // size of varmaps
      int      qhead;         // Head index of queue.
      int      qtail;         // Tail index of queue.
  
      // clauses
      vecp     clauses;       // List of problem constraints. (contains: clause*)
      vecp     learnts;       // List of learnt clauses. (contains: clause*)
  
      // activities
      uint64   var_inc;       // Amount to bump next variable with.
      uint64   var_decay;     // INVERSE decay factor for variable activity: stores 1/decay. 
      uint64    cla_inc;       // Amount to bump next clause with.
      uint64    cla_decay;     // INVERSE decay factor for clause activity: stores 1/decay.
  
      vecp*    wlists;        // 
      uint64*  activity;      // A heuristic measurement of the activity of a variable.
      lbool*   assigns;       // Current values of variables.
      int*     orderpos;      // Index in variable order.
      clause** reasons;       //
      int*     levels;        //
      lit*     trail;
  
      clause*  binary;        // A temporary binary clause
      lbool*   tags;          //
      veci     tagged;        // (contains: var)
      veci     stack;         // (contains: var)
  
      veci     order;         // Variable order. (heap) (contains: var)
      veci     trail_lim;     // Separator indices for different decision levels in 'trail'. (contains: int)
      veci     model;         // If problem is solved, this vector contains the model (contains: lbool).
  
      int      root_level;    // Level of first proper decision.
      int      simpdb_assigns;// Number of top-level assignments at last 'simplifyDB()'.
      int      simpdb_props;  // Number of propagations before next 'simplifyDB()'.
      //double   random_seed;
      //double   progress_estimate;
      int      verbosity;     // Verbosity level. 0=silent, 1=some progress report, 2=everything
  
      stats    stats;
  };
  
  #endif
  