/*-----------------------------------------------------------------------

File  : ccl_clausepos.h

Author: Stephan Schulz

Contents
 
  Positions of subterms in clauses (and in equations).

  Copyright 1998, 1999 by the author.
  This code is released under the GNU General Public Licence and
  the GNU Lesser General Public License.
  See the file COPYING in the main E directory for details..
  Run "eprover -h" for contact information.

Changes

<1> Wed May 20 03:34:54 MET DST 1998
    New

-----------------------------------------------------------------------*/

#ifndef CLAUSEPOS

#define CLAUSEPOS

#include <cte_termpos.h>
#include <ccl_clauses.h>


/*---------------------------------------------------------------------*/
/*                    Data type declarations                           */
/*---------------------------------------------------------------------*/



typedef struct clauseposcell
{
   Clause_p  clause;
   Eqn_p     literal;
   EqnSide   side;
   TermPos_p pos;
}ClausePosCell, *ClausePos_p;



/*---------------------------------------------------------------------*/
/*                Exported Functions and Variables                     */
/*---------------------------------------------------------------------*/


#define ClausePosCellAlloc() (ClausePosCell*)SizeMalloc(sizeof(ClausePosCell))
#define ClausePosCellFree(junk)         SizeFree(junk, sizeof(ClausePosCell))

#ifdef CONSTANT_MEM_ESTIMATE
#define CLAUSEPOSCELL_MEM 20
#else
#define CLAUSEPOSCELL_MEM MEMSIZE(ClausePosCell)
#endif

static __inline__ ClausePos_p ClausePosAlloc(void);
static __inline__ void        ClausePosFree(ClausePos_p junk);

static __inline__ Term_p   ClausePosGetSide(ClausePos_p pos);
static __inline__ Term_p   ClausePosGetOtherSide(ClausePos_p pos);
static __inline__ Term_p   ClausePosGetSubterm(ClausePos_p pos);
#define ClausePosIsTop(position) ((PStackEmpty((position)->pos)))

      
void     ClausePosPrint(FILE* out, ClausePos_p pos);
Eqn_p    ClausePosFindPosLiteral(ClausePos_p pos, bool maximal);
Eqn_p    ClausePosFindMaxLiteral(ClausePos_p pos, bool positive);
Term_p   ClausePosFindFirstMaximalSide(ClausePos_p pos, bool positive);
Term_p   ClausePosFindNextMaximalSide(ClausePos_p pos, bool positive);
Term_p   ClausePosFindFirstMaximalSubterm(ClausePos_p pos);
Term_p   ClausePosFindNextMaximalSubterm(ClausePos_p pos);

/*---------------------------------------------------------------------*/
/*                Inline Functions                                     */
/*---------------------------------------------------------------------*/


/*-----------------------------------------------------------------------
//
// Function: ClausePosAlloc()
//
//   Allocate an empty, semi-initialized ClausePosCell.
//
// Global Variables: -
//
// Side Effects    : Memory operations
//
/----------------------------------------------------------------------*/

static __inline__ ClausePos_p ClausePosAlloc(void)
{
   ClausePos_p handle = ClausePosCellAlloc();
   
   handle->literal = NULL;
   handle->side    = LeftSide;
   handle->pos     = TermPosAlloc();

   return handle;
}


/*-----------------------------------------------------------------------
//
// Function:  ClausePosFree()
//
//   Free a clausepos.
//
// Global Variables: -
//
// Side Effects    : Memory operations
//
/----------------------------------------------------------------------*/

static __inline__ void ClausePosFree(ClausePos_p junk)
{
   assert(junk);

   TermPosFree(junk->pos);
   ClausePosCellFree(junk);
}


/*-----------------------------------------------------------------------
//
// Function: ClausePosGetSide()
//
//   Given a clause position, return the designated side of the
//   literal. 
//
// Global Variables: -
//
// Side Effects    : -
//
/----------------------------------------------------------------------*/

static __inline__ Term_p ClausePosGetSide(ClausePos_p pos)
{
   if(pos->side == LeftSide)
   {
      return pos->literal->lterm;
   }
   return pos->literal->rterm;
}


/*-----------------------------------------------------------------------
//
// Function: ClausePosGetOtherSide()
//
//   Given a clause position, return the _not_ designated side of the
//   literal - don't ask, this has it's use!
//
// Global Variables: -
//
// Side Effects    : -
//
/----------------------------------------------------------------------*/

static __inline__ Term_p ClausePosGetOtherSide(ClausePos_p pos)
{
   if(pos->side == LeftSide)
   {
      return pos->literal->rterm;
   }
   return pos->literal->lterm;
}



/*-----------------------------------------------------------------------
//
// Function: ClausePosGetSubterm()
//
//   Given a clause position, return the designated subterm of the
//   literal. 
//
// Global Variables: -
//
// Side Effects    : -
//
/----------------------------------------------------------------------*/

static __inline__ Term_p ClausePosGetSubterm(ClausePos_p pos)
{
   return TermPosGetSubterm(ClausePosGetSide(pos), pos->pos);
}


#endif

/*---------------------------------------------------------------------*/
/*                        End of File                                  */
/*---------------------------------------------------------------------*/