/* Implement POWERSET runtime actions for CHILL.
   Copyright (C) 1992,1993 Free Software Foundation, Inc.
   Author: Wilfried Moser, et al

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#define __CHILL_LIB__

#include <stdio.h>
#include "powerset.h"

/*
 * function __powerset_copy
 *    This is more general than __psslice, since it
 *    can be told where in the destination powerset (DOFFSET
 *    parameter) to start storing the slice.
 *
 * parameters:
 *      dps             dest powerset
 *      dbl             destination bit length
 *      doffset         offset bit number (zero origin)
 *	sps		sourcepowerset
 *	sbl     	source powerset length in bits
 *      start           starting bit number
 *      end             ending bit number
 *
 * exceptions:
 *  none
 *
 * abstract:
 *  Extract into a powerset a slice of another powerset.
 *
 */
void
__pscpy (dps, dbl, doffset, sps, sbl, start, length)
     SET_WORD      *dps;
     unsigned long  dbl;
     unsigned long  doffset;
     const SET_WORD*sps;
     unsigned long  sbl;
     unsigned long  start;
     unsigned long  length;
{
  unsigned long end = start + length - 1;
  unsigned long src, dst;

  /* assert end >= start;
     assert end - start + 1 <= dbl;
     assert "the sets don't overlap in memory" */

  /* assert doffset >= 0 and < dbl */

  for (src = start, dst = doffset; src <= end; src++, dst++)
    {
      char tmp;

      if (sbl <= SET_CHAR_SIZE)                /* fetch a bit */
	tmp = GET_BIT_IN_CHAR (*((SET_CHAR *)sps), src);
      else if (sbl <= SET_SHORT_SIZE)
	tmp = GET_BIT_IN_SHORT (*((SET_SHORT *)sps), src);
      else
	tmp = GET_BIT_IN_WORD (sps[src / SET_WORD_SIZE], src % SET_WORD_SIZE);

      if (tmp & 1)
	{
	  if (dbl <= SET_CHAR_SIZE)            /* store a 1-bit */
	    SET_BIT_IN_CHAR (*((SET_CHAR *)dps), dst);
	  else if (dbl <= SET_SHORT_SIZE)
	    SET_BIT_IN_SHORT (*((SET_SHORT *)dps), dst);
	  else
	    SET_BIT_IN_WORD (dps[dst / SET_WORD_SIZE], dst % SET_WORD_SIZE);
	}
      else
	{
	  if (dbl <= SET_CHAR_SIZE)            /* store a 0-bit */
	    CLEAR_BIT_IN_CHAR (*((SET_CHAR *)dps), dst);
	  else if (dbl <= SET_SHORT_SIZE)
	    CLEAR_BIT_IN_SHORT (*((SET_SHORT *)dps), dst);
	  else
	    CLEAR_BIT_IN_WORD (dps[dst / SET_WORD_SIZE], dst % SET_WORD_SIZE);
	}
    }
  if (dbl <= SET_CHAR_SIZE)         /* clear unused bits in output bitstring */
    {
      MASK_UNUSED_CHAR_BITS ((SET_CHAR *)dps, dbl);
    }
  else if (dbl <= SET_SHORT_SIZE)
    {
      MASK_UNUSED_SHORT_BITS ((SET_SHORT *)dps, dbl);
    }
  else
    {
      MASK_UNUSED_WORD_BITS ((SET_WORD *)(dps + (dbl/SET_WORD_SIZE)), 
			     dbl % SET_WORD_SIZE);
    }
}