src/Sbitset.h

   1 /* A simple, memory-efficient bitset implementation.
   2
   3    Copyright (C) 2009, 2010 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 #ifndef SBITSET_H_
  21 # define SBITSET_H_
  22
  23 typedef unsigned char *Sbitset;
  24 typedef size_t Sbitset__Index;
  25 #define SBITSET__INDEX__CONVERSION_SPEC "zu"
  26
  27 #define Sbitset__nbytes(NBITS) \
  28   (((NBITS) + CHAR_BIT - 1) / CHAR_BIT)
  29 #define Sbitset__byteAddress(SELF, INDEX) \
  30   (((SELF) + (INDEX) / CHAR_BIT))
  31 #define Sbitset__bit_mask(INDEX) \
  32   (1 << (CHAR_BIT - 1 - (INDEX) % CHAR_BIT))
  33 #define Sbitset__last_byte_mask(NBITS) \
  34   (UCHAR_MAX << (CHAR_BIT - 1 - ((NBITS) - 1) % CHAR_BIT))
  35
  36 /* nbits must not be 0.  */
  37 Sbitset Sbitset__new (Sbitset__Index nbits);
  38 Sbitset Sbitset__new_on_obstack (Sbitset__Index nbits,
  39                                  struct obstack *obstackp);
  40 void Sbitset__delete (Sbitset self);
  41
  42 #define Sbitset__test(SELF, INDEX)                                            \
  43   ((*Sbitset__byteAddress ((SELF), (INDEX)) & Sbitset__bit_mask (INDEX)) != 0)
  44
  45 bool Sbitset__isEmpty (Sbitset self, Sbitset__Index nbits);
  46
  47 void Sbitset__fprint(Sbitset self, Sbitset__Index nbits, FILE *file);
  48
  49 #define Sbitset__set(SELF, INDEX)                                             \
  50 do {                                                                          \
  51   *Sbitset__byteAddress ((SELF), (INDEX)) =                                   \
  52     *Sbitset__byteAddress ((SELF), (INDEX)) | Sbitset__bit_mask (INDEX);      \
  53 } while(0)
  54
  55 #define Sbitset__reset(SELF, INDEX)                                           \
  56 do {                                                                          \
  57   *Sbitset__byteAddress ((SELF), (INDEX)) =                                   \
  58     *Sbitset__byteAddress ((SELF), (INDEX)) & ~Sbitset__bit_mask (INDEX);     \
  59 } while(0)
  60
  61 /* NBITS is the size of the bitset.  More than NBITS bits might be reset.  */
  62 #define Sbitset__zero(SELF, NBITS)                                            \
  63 do {                                                                          \
  64   memset (SELF, 0, Sbitset__nbytes (NBITS));                                  \
  65 } while(0)
  66
  67 /* NBITS is the size of the bitset.  More than NBITS bits might be set.  */
  68 #define Sbitset__ones(SELF, NBITS)                                            \
  69 do {                                                                          \
  70   memset (SELF, UCHAR_MAX, Sbitset__nbytes (NBITS));                          \
  71 } while(0)
  72
  73 /* NBITS is the size of every bitset.  More than NBITS bits might be set.  */
  74 #define Sbitset__or(SELF, OTHER1, OTHER2, NBITS)                              \
  75 do {                                                                          \
  76   Sbitset ptr_self = (SELF);                                                  \
  77   Sbitset ptr_other1 = (OTHER1);                                              \
  78   Sbitset ptr_other2 = (OTHER2);                                              \
  79   Sbitset end_self = ptr_self + Sbitset__nbytes (NBITS);                      \
  80   for (; ptr_self < end_self; ++ptr_self, ++ptr_other1, ++ptr_other2)         \
  81     *ptr_self = *ptr_other1 | *ptr_other2;                                    \
  82 } while(0)
  83
  84 #define SBITSET__FOR_EACH(SELF, NBITS, ITER, INDEX)                           \
  85   for ((ITER) = (SELF); (ITER) < (SELF) + Sbitset__nbytes (NBITS); ++(ITER))  \
  86     if (*(ITER) != 0)                                                         \
  87       for ((INDEX) = ((ITER)-(SELF))*CHAR_BIT;                                \
  88            (INDEX) < (NBITS) && (SELF)+(INDEX)/CHAR_BIT < (ITER)+1;           \
  89            ++(INDEX))                                                         \
  90         if (((*ITER) & Sbitset__bit_mask (INDEX)) != 0)
  91
  92 #endif /* !SBITSET_H_ */