aboutsummaryrefslogtreecommitdiffstats
path: root/src/util/bitset.h
blob: 7f116214b920c0b8431e76f8093d8829428dc80c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
/*
 * Mesa 3-D graphics library
 *
 * Copyright (C) 2006  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file bitset.h
 * \brief Bitset of arbitrary size definitions.
 * \author Michal Krol
 */

#ifndef BITSET_H
#define BITSET_H

#include "util/bitscan.h"
#include "util/macros.h"

/****************************************************************************
 * generic bitset implementation
 */

#define BITSET_WORD unsigned int
#define BITSET_WORDBITS (sizeof (BITSET_WORD) * 8)

/* bitset declarations
 */
#define BITSET_WORDS(bits) (((bits) + BITSET_WORDBITS - 1) / BITSET_WORDBITS)
#define BITSET_DECLARE(name, bits) BITSET_WORD name[BITSET_WORDS(bits)]

/* bitset operations
 */
#define BITSET_COPY(x, y) memcpy( (x), (y), sizeof (x) )
#define BITSET_EQUAL(x, y) (memcmp( (x), (y), sizeof (x) ) == 0)
#define BITSET_ZERO(x) memset( (x), 0, sizeof (x) )
#define BITSET_ONES(x) memset( (x), 0xff, sizeof (x) )

#define BITSET_BITWORD(b) ((b) / BITSET_WORDBITS)
#define BITSET_BIT(b) (1u << ((b) % BITSET_WORDBITS))

/* single bit operations
 */
#define BITSET_TEST(x, b) (((x)[BITSET_BITWORD(b)] & BITSET_BIT(b)) != 0)
#define BITSET_SET(x, b) ((x)[BITSET_BITWORD(b)] |= BITSET_BIT(b))
#define BITSET_CLEAR(x, b) ((x)[BITSET_BITWORD(b)] &= ~BITSET_BIT(b))

#define BITSET_MASK(b) (((b) % BITSET_WORDBITS == 0) ? ~0 : BITSET_BIT(b) - 1)
#define BITSET_RANGE(b, e) ((BITSET_MASK((e) + 1)) & ~(BITSET_BIT(b) - 1))

/* bit range operations
 */
#define BITSET_TEST_RANGE(x, b, e) \
   (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
   (((x)[BITSET_BITWORD(b)] & BITSET_RANGE(b, e)) != 0) : \
   (assert (!"BITSET_TEST_RANGE: bit range crosses word boundary"), 0))
#define BITSET_SET_RANGE(x, b, e) \
   (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
   ((x)[BITSET_BITWORD(b)] |= BITSET_RANGE(b, e)) : \
   (assert (!"BITSET_SET_RANGE: bit range crosses word boundary"), 0))
#define BITSET_CLEAR_RANGE(x, b, e) \
   (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
   ((x)[BITSET_BITWORD(b)] &= ~BITSET_RANGE(b, e)) : \
   (assert (!"BITSET_CLEAR_RANGE: bit range crosses word boundary"), 0))

/* Get first bit set in a bitset.
 */
static inline int
__bitset_ffs(const BITSET_WORD *x, int n)
{
   int i;

   for (i = 0; i < n; i++) {
      if (x[i])
	 return ffs(x[i]) + BITSET_WORDBITS * i;
   }

   return 0;
}

#define BITSET_FFS(x) __bitset_ffs(x, ARRAY_SIZE(x))

static inline unsigned
__bitset_next_set(unsigned i, BITSET_WORD *tmp,
                  const BITSET_WORD *set, unsigned size)
{
   unsigned bit, word;

   /* NOTE: The initial conditions for this function are very specific.  At
    * the start of the loop, the tmp variable must be set to *set and the
    * initial i value set to 0.  This way, if there is a bit set in the first
    * word, we ignore the i-value and just grab that bit (so 0 is ok, even
    * though 0 may be returned).  If the first word is 0, then the value of
    * `word` will be 0 and we will go on to look at the second word.
    */
   word = BITSET_BITWORD(i);
   while (*tmp == 0) {
      word++;

      if (word >= BITSET_WORDS(size))
         return size;

      *tmp = set[word];
   }

   /* Find the next set bit in the non-zero word */
   bit = ffs(*tmp) - 1;

   /* Unset the bit */
   *tmp &= ~(1ull << bit);

   return word * BITSET_WORDBITS + bit;
}

#define BITSET_FOREACH_SET(__i, __tmp, __set, __size) \
   for (__tmp = *(__set), __i = 0; \
        (__i = __bitset_next_set(__i, &__tmp, __set, __size)) < __size;)

#ifdef __cplusplus

/**
 * Simple C++ wrapper of a bitset type of static size, with value semantics
 * and basic bitwise arithmetic operators.  The operators defined below are
 * expected to have the same semantics as the same operator applied to other
 * fundamental integer types.  T is the name of the struct to instantiate
 * it as, and N is the number of bits in the bitset.
 */
#define DECLARE_BITSET_T(T, N) struct T {                       \
      EXPLICIT_CONVERSION                                       \
      operator bool() const                                     \
      {                                                         \
         for (unsigned i = 0; i < BITSET_WORDS(N); i++)         \
            if (words[i])                                       \
               return true;                                     \
         return false;                                          \
      }                                                         \
                                                                \
      T &                                                       \
      operator=(int x)                                          \
      {                                                         \
         const T c = {{ (BITSET_WORD)x }};                      \
         return *this = c;                                      \
      }                                                         \
                                                                \
      friend bool                                               \
      operator==(const T &b, const T &c)                        \
      {                                                         \
         return BITSET_EQUAL(b.words, c.words);                 \
      }                                                         \
                                                                \
      friend bool                                               \
      operator!=(const T &b, const T &c)                        \
      {                                                         \
         return !(b == c);                                      \
      }                                                         \
                                                                \
      friend bool                                               \
      operator==(const T &b, int x)                             \
      {                                                         \
         const T c = {{ (BITSET_WORD)x }};                      \
         return b == c;                                         \
      }                                                         \
                                                                \
      friend bool                                               \
      operator!=(const T &b, int x)                             \
      {                                                         \
         return !(b == x);                                      \
      }                                                         \
                                                                \
      friend T                                                  \
      operator~(const T &b)                                     \
      {                                                         \
         T c;                                                   \
         for (unsigned i = 0; i < BITSET_WORDS(N); i++)         \
            c.words[i] = ~b.words[i];                           \
         return c;                                              \
      }                                                         \
                                                                \
      T &                                                       \
      operator|=(const T &b)                                    \
      {                                                         \
         for (unsigned i = 0; i < BITSET_WORDS(N); i++)         \
            words[i] |= b.words[i];                             \
         return *this;                                          \
      }                                                         \
                                                                \
      friend T                                                  \
      operator|(const T &b, const T &c)                         \
      {                                                         \
         T d = b;                                               \
         d |= c;                                                \
         return d;                                              \
      }                                                         \
                                                                \
      T &                                                       \
      operator&=(const T &b)                                    \
      {                                                         \
         for (unsigned i = 0; i < BITSET_WORDS(N); i++)         \
            words[i] &= b.words[i];                             \
         return *this;                                          \
      }                                                         \
                                                                \
      friend T                                                  \
      operator&(const T &b, const T &c)                         \
      {                                                         \
         T d = b;                                               \
         d &= c;                                                \
         return d;                                              \
      }                                                         \
                                                                \
      bool                                                      \
      test(unsigned i) const                                    \
      {                                                         \
         return BITSET_TEST(words, i);                          \
      }                                                         \
                                                                \
      T &                                                       \
      set(unsigned i)                                           \
      {                                                         \
         BITSET_SET(words, i);                                  \
         return *this;                                          \
      }                                                         \
                                                                \
      T &                                                       \
      clear(unsigned i)                                         \
      {                                                         \
         BITSET_CLEAR(words, i);                                \
         return *this;                                          \
      }                                                         \
                                                                \
      BITSET_WORD words[BITSET_WORDS(N)];                       \
   }

#endif

#endif