libchill/ltps.c

   1 /* Implement POWERSET runtime actions for CHILL.
   2    Copyright (C) 1992,1993 Free Software Foundation, Inc.
   3    Author: Wilfried Moser, et al
   4
   5 This file is part of GNU CC.
   6
   7 GNU CC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU CC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU CC; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 #define __CHILL_LIB__
  22
  23 #include <stdio.h>
  24 #include "powerset.h"
  25
  26 /*
  27  * function __ltpowerset
  28  *
  29  * parameters:
  30  *      left            powerset
  31  *      right           powerset
  32  *      bitlength       length of powerset
  33  *
  34  * returns:
  35  *      int             1 .. left is proper subset of right
  36  *                           (excludes case where left == right)
  37  *                      0 .. not
  38  *
  39  * abstract:
  40  *  check if one powerset is included in another
  41  *
  42  */
  43 int
  44 __ltpowerset (left, right, bitlength)
  45      SET_WORD      *left;
  46      SET_WORD      *right;
  47      unsigned long  bitlength;
  48 {
  49   if (bitlength <= SET_CHAR_SIZE)
  50     {
  51       if ((*((SET_CHAR *)left) & *((SET_CHAR *)right))
  52           != *((SET_CHAR *)left))
  53         return 0;
  54       if (*((SET_CHAR *)left) != *((SET_CHAR *)right))
  55         return 1;
  56       return 0;
  57     }
  58   else if (bitlength <= SET_SHORT_SIZE)
  59     {
  60       if ((*((SET_SHORT *)left) & *((SET_SHORT *)right))
  61           != *((SET_SHORT *)left))
  62         return 0;
  63       if (*((SET_SHORT *)left) != *((SET_SHORT *)right))
  64         return 1;
  65       return 0;
  66     }
  67   else
  68     {
  69       SET_WORD  *endp = left + BITS_TO_WORDS(bitlength);
  70       int all_equal = 1;              /* assume all bits are equal */
  71
  72       while (left < endp)
  73         {
  74           if ((*right & *left) != *left)
  75             return 0;
  76           if (*left != *right)
  77             all_equal = 0;
  78           left++;
  79           right++;
  80         }
  81       if (left == endp && all_equal)    /* exclude TRUE return for == case */
  82         return 0;
  83       return 1;
  84     }
  85 }