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