src/Sbitset.h

   1 /* A simple, memory-efficient bitset implementation.
   2
   3    Copyright (C) 2009-2015, 2018-2021 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 <https://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 /* ATTENTION: there are *two* loops here, "break" and "continue" will
  85    not apply to the whole loop, just the inner one.  */
  86 # define SBITSET__FOR_EACH(SELF, NBITS, ITER, INDEX)                    \
  87   for ((ITER) = (SELF); (ITER) < (SELF) + Sbitset__nbytes (NBITS); ++(ITER)) \
  88     if (*(ITER) != 0)                                                   \
  89       for ((INDEX) = ((ITER)-(SELF))*CHAR_BIT;                          \
  90            (INDEX) < (NBITS) && (SELF)+(INDEX)/CHAR_BIT < (ITER)+1;     \
  91            ++(INDEX))                                                   \
  92         if (((*ITER) & Sbitset__bit_mask (INDEX)) != 0)
  93
  94 #endif /* !SBITSET_H_ */