cnf_clause_list.h

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/*******************************************************************\
 
Module: CNF Generation
 
Author: Daniel Kroening, kroening@kroening.com
 
\*******************************************************************/

 
#ifndef CPROVER_SOLVERS_SAT_CNF_CLAUSE_LIST_H
#define CPROVER_SOLVERS_SAT_CNF_CLAUSE_LIST_H
 
#include <list>
 
#include <util/threeval.h>
 
#include "cnf.h"
 
// CNF given as a list of clauses
 
class cnf_clause_listt:public cnft
{
public:
  explicit cnf_clause_listt(message_handlert &message_handler)
    : cnft(message_handler)
  {
  }
  virtual ~cnf_clause_listt() { }
 
  void lcnf(const bvt &bv) override;
 
  std::string solver_text() const override
  { return "CNF clause list"; }
 
  tvt l_get(literalt) const override
  {
    return tvt::unknown();
  }
 
  size_t no_clauses() const override
  {
    return clauses.size();
  }
 
  typedef std::list<bvt> clausest;
 
  clausest &get_clauses() { return clauses; }
 
  void copy_to(cnft &cnf) const
  {
    cnf.set_no_variables(_no_variables);
    for(clausest::const_iterator
        it=clauses.begin();
        it!=clauses.end();
        it++)
      cnf.lcnf(*it);
  }
 
  static size_t hash_clause(const bvt &bv)
  {
    size_t result=0;
    for(bvt::const_iterator it=bv.begin(); it!=bv.end(); it++)
      result=((result<<2)^it->get())-result;
 
    return result;
  }
 
  size_t hash() const
  {
    size_t result=0;
    for(clausest::const_iterator it=clauses.begin(); it!=clauses.end(); it++)
      result=((result<<2)^hash_clause(*it))-result;
 
    return result;
  }
 
protected:
  resultt do_prop_solve(const bvt &) override
  {
    return resultt::P_ERROR;
  }
 
  clausest clauses;
};
 
// CNF given as a list of clauses
// PLUS an assignment to the variables
 
class cnf_clause_list_assignmentt:public cnf_clause_listt
{
public:
  explicit cnf_clause_list_assignmentt(message_handlert &message_handler)
    : cnf_clause_listt(message_handler)
  {
  }
 
  typedef std::vector<tvt> assignmentt;
 
  assignmentt &get_assignment()
  {
    return assignment;
  }
 
  tvt l_get(literalt literal) const override
  {
    if(literal.is_true())
      return tvt(true);
    if(literal.is_false())
      return tvt(false);
 
    unsigned v=literal.var_no();
 
    if(v==0 || v>=assignment.size())
      return tvt::unknown();
 
    tvt r=assignment[v];
    return literal.sign()?!r:r;
  }
 
  virtual void copy_assignment_from(const propt &prop);
  void print_assignment(std::ostream &out) const;
 
protected:
  assignmentt assignment;
};
 
#endif // CPROVER_SOLVERS_SAT_CNF_CLAUSE_LIST_H