libchill/eqps.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 "config.h"
  24 #include <stdio.h>
  25 #include "powerset.h"
  26
  27 /*
  28  * function __eqpowerset
  29  *
  30  * parameters:
  31  *      left            left powerset
  32  *      right           right powerset
  33  *      bitlength       length of powerset in bits
  34  *
  35  * returns:
  36  *    1 if powersets are equal, bit for bit
  37  *
  38  * exceptions:
  39  *  none
  40  *
  41  * abstract:
  42  *  compares two powersets for equality
  43  *
  44  */
  45 int
  46 __eqpowerset (left, right, bitlength)
  47      SET_WORD *left;
  48      SET_WORD *right;
  49      unsigned long bitlength;
  50 {
  51 #ifndef USE_CHARS
  52   if (bitlength <= SET_CHAR_SIZE)
  53     {
  54       SET_CHAR c = *(SET_CHAR *)left ^ *(SET_CHAR *)right;
  55       MASK_UNUSED_CHAR_BITS (&c, bitlength);
  56       return (c == 0) ? 1 : 0;
  57     }
  58   else if (bitlength <= SET_SHORT_SIZE)
  59     {
  60       SET_SHORT c = *(SET_SHORT *)left ^ *(SET_SHORT *)right;
  61       MASK_UNUSED_SHORT_BITS (&c, bitlength);
  62       return (c == 0) ? 1 : 0;
  63     }
  64   else if (bitlength <= SET_WORD_SIZE)
  65     {
  66       SET_WORD c = *(SET_WORD *)left ^ *(SET_WORD *)right;
  67       MASK_UNUSED_WORD_BITS (&c, bitlength % SET_WORD_SIZE);
  68       return (c == 0) ? 1 : 0;
  69     }
  70   else
  71 #endif
  72     {
  73       SET_WORD c;
  74       register unsigned long i;
  75       unsigned long len = bitlength / SET_WORD_SIZE;
  76
  77       for (i = 0; i < len; i++) /* a word-oriented memcmp */
  78         if (left[i] != right[i])
  79           return 0;
  80       /* do the last (possibly partial) word */
  81       bitlength %= SET_WORD_SIZE;
  82       if (bitlength == 0)
  83         return 1;
  84       c = left[i] ^ right[i];
  85       MASK_UNUSED_WORD_BITS (&c, bitlength);
  86       return (c == 0) ? 1 : 0;
  87     }
  88 }