src/Sbitset.c

   1 /* A simple, memory-efficient bitset implementation.
   2
   3    Copyright (C) 2009 Free Software Foundation, Inc.
   4
   5    This file is part of Bison, the GNU Compiler Compiler.
   6
   7    This program 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 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include <config.h>
  21 #include "system.h"
  22
  23 #include "Sbitset.h"
  24
  25 Sbitset
  26 Sbitset__new (Sbitset__Index nbits)
  27 {
  28   /* Some functions, like Sbitset__last_byte_mask, will fail if nbits = 0.  */
  29   aver (nbits);
  30   return xcalloc (1, Sbitset__nbytes (nbits));
  31 }
  32
  33 Sbitset
  34 Sbitset__new_on_obstack (Sbitset__Index nbits, struct obstack *obstackp)
  35 {
  36   char *result;
  37   char *ptr;
  38   char *end;
  39   aver (nbits);
  40   result = obstack_alloc (obstackp, Sbitset__nbytes (nbits));
  41   for (ptr = result, end = result + Sbitset__nbytes (nbits); ptr < end; ++ptr)
  42     *ptr = 0;
  43   return result;
  44 }
  45
  46 void
  47 Sbitset__delete (Sbitset self)
  48 {
  49   free (self);
  50 }
  51
  52 bool
  53 Sbitset__isEmpty (Sbitset self, Sbitset__Index nbits)
  54 {
  55   char *last = self + Sbitset__nbytes (nbits) - 1;
  56   for (; self < last; ++self)
  57     if (*self != 0)
  58       return false;
  59   return ((*last) & Sbitset__last_byte_mask (nbits)) == 0;
  60 }
  61
  62 void
  63 Sbitset__fprint(Sbitset self, Sbitset__Index nbits, FILE *file)
  64 {
  65   Sbitset__Index i;
  66   Sbitset itr;
  67   bool first = true;
  68   fprintf (file, "nbits = %d, set = {", nbits);
  69   SBITSET__FOR_EACH (self, nbits, itr, i)
  70     {
  71       if (first)
  72         first = false;
  73       else
  74         fprintf (file, ",");
  75       fprintf (file, " %d", i);
  76     }
  77   fprintf (file, " }");
  78 }