/* 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 __ltpowerset
 *
 * parameters:
 *	left		powerset
 *	right		powerset
 *	bitlength	length of powerset
 *
 * returns:
 *	int		1 .. left is proper subset of right
 *                           (excludes case where left == right)
 *			0 .. not
 *
 * abstract:
 *  check if one powerset is included in another
 *
 */
int
__ltpowerset (left, right, bitlength)
     SET_WORD      *left;
     SET_WORD      *right;
     unsigned long  bitlength;
{
  if (bitlength <= SET_CHAR_SIZE)
    {
      if ((*((SET_CHAR *)left) & *((SET_CHAR *)right))
	  != *((SET_CHAR *)left))
	return 0;
      if (*((SET_CHAR *)left) != *((SET_CHAR *)right))
	return 1;
      return 0;
    }
  else if (bitlength <= SET_SHORT_SIZE)
    {
      if ((*((SET_SHORT *)left) & *((SET_SHORT *)right))
	  != *((SET_SHORT *)left))
	return 0;
      if (*((SET_SHORT *)left) != *((SET_SHORT *)right))
	return 1;
      return 0;
    }
  else
    {
      SET_WORD	*endp = left + BITS_TO_WORDS(bitlength);
      int all_equal = 1;              /* assume all bits are equal */
    
      while (left < endp)
	{
	  if ((*right & *left) != *left)
	    return 0;
	  if (*left != *right)
	    all_equal = 0;
	  left++;
	  right++;
	}
      if (left == endp && all_equal)    /* exclude TRUE return for == case */
	return 0;
      return 1;
    }
}