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      1 /* A simple, memory-efficient bitset implementation.
      2 
      3    Copyright (C) 2009-2012 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_ */
     93