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_ */