1 /*
2 * Mesa 3-D graphics library
3 *
4 * Copyright (C) 2006 Brian Paul All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * OTHER DEALINGS IN THE SOFTWARE.
23 */
24
25 /**
26 * \file bitset.h
27 * \brief Bitset of arbitrary size definitions.
28 * \author Michal Krol
29 */
30
31 #ifndef BITSET_H
32 #define BITSET_H
33
34 #include "util/bitscan.h"
35 #include "util/macros.h"
36
37 /****************************************************************************
38 * generic bitset implementation
39 */
40
41 #define BITSET_WORD unsigned int
42 #define BITSET_WORDBITS (sizeof (BITSET_WORD) * 8)
43
44 /* bitset declarations
45 */
46 #define BITSET_WORDS(bits) (((bits) + BITSET_WORDBITS - 1) / BITSET_WORDBITS)
47 #define BITSET_DECLARE(name, bits) BITSET_WORD name[BITSET_WORDS(bits)]
48
49 /* bitset operations
50 */
51 #define BITSET_COPY(x, y) memcpy( (x), (y), sizeof (x) )
52 #define BITSET_EQUAL(x, y) (memcmp( (x), (y), sizeof (x) ) == 0)
53 #define BITSET_ZERO(x) memset( (x), 0, sizeof (x) )
54 #define BITSET_ONES(x) memset( (x), 0xff, sizeof (x) )
55 #define BITSET_SIZE(x) (8 * sizeof(x)) // bitset size in bits
56
57 #define BITSET_BITWORD(b) ((b) / BITSET_WORDBITS)
58 #define BITSET_BIT(b) (1u << ((b) % BITSET_WORDBITS))
59
60 /* single bit operations
61 */
62 #define BITSET_TEST(x, b) (((x)[BITSET_BITWORD(b)] & BITSET_BIT(b)) != 0)
63 #define BITSET_SET(x, b) ((x)[BITSET_BITWORD(b)] |= BITSET_BIT(b))
64 #define BITSET_CLEAR(x, b) ((x)[BITSET_BITWORD(b)] &= ~BITSET_BIT(b))
65
66 #define BITSET_MASK(b) (((b) % BITSET_WORDBITS == 0) ? ~0 : BITSET_BIT(b) - 1)
67 #define BITSET_RANGE(b, e) ((BITSET_MASK((e) + 1)) & ~(BITSET_BIT(b) - 1))
68
69 /* logic bit operations
70 */
71 static inline void
__bitset_and(BITSET_WORD * r,const BITSET_WORD * x,const BITSET_WORD * y,unsigned n)72 __bitset_and(BITSET_WORD *r, const BITSET_WORD *x, const BITSET_WORD *y, unsigned n)
73 {
74 for (unsigned i = 0; i < n; i++)
75 r[i] = x[i] & y[i];
76 }
77
78 static inline void
__bitset_or(BITSET_WORD * r,const BITSET_WORD * x,const BITSET_WORD * y,unsigned n)79 __bitset_or(BITSET_WORD *r, const BITSET_WORD *x, const BITSET_WORD *y, unsigned n)
80 {
81 for (unsigned i = 0; i < n; i++)
82 r[i] = x[i] | y[i];
83 }
84
85 static inline void
__bitset_not(BITSET_WORD * x,unsigned n)86 __bitset_not(BITSET_WORD *x, unsigned n)
87 {
88 for (unsigned i = 0; i < n; i++)
89 x[i] = ~x[i];
90 }
91
92 #define BITSET_AND(r, x, y) \
93 do { \
94 assert(ARRAY_SIZE(r) == ARRAY_SIZE(x)); \
95 assert(ARRAY_SIZE(r) == ARRAY_SIZE(y)); \
96 __bitset_and(r, x, y, ARRAY_SIZE(r)); \
97 } while (0)
98
99 #define BITSET_OR(r, x, y) \
100 do { \
101 assert(ARRAY_SIZE(r) == ARRAY_SIZE(x)); \
102 assert(ARRAY_SIZE(r) == ARRAY_SIZE(y)); \
103 __bitset_or(r, x, y, ARRAY_SIZE(r)); \
104 } while (0)
105
106 #define BITSET_NOT(x) \
107 __bitset_not(x, ARRAY_SIZE(x))
108
109 static inline void
__bitset_rotate_right(BITSET_WORD * x,unsigned amount,unsigned n)110 __bitset_rotate_right(BITSET_WORD *x, unsigned amount, unsigned n)
111 {
112 assert(amount < BITSET_WORDBITS);
113
114 if (amount == 0)
115 return;
116
117 for (unsigned i = 0; i < n - 1; i++) {
118 x[i] = (x[i] >> amount) | (x[i + 1] << (BITSET_WORDBITS - amount));
119 }
120
121 x[n - 1] = x[n - 1] >> amount;
122 }
123
124 static inline void
__bitset_rotate_left(BITSET_WORD * x,unsigned amount,unsigned n)125 __bitset_rotate_left(BITSET_WORD *x, unsigned amount, unsigned n)
126 {
127 assert(amount < BITSET_WORDBITS);
128
129 if (amount == 0)
130 return;
131
132 for (int i = n - 1; i > 0; i--) {
133 x[i] = (x[i] << amount) | (x[i - 1] >> (BITSET_WORDBITS - amount));
134 }
135
136 x[0] = x[0] << amount;
137 }
138
139 static inline void
__bitset_shr(BITSET_WORD * x,unsigned amount,unsigned n)140 __bitset_shr(BITSET_WORD *x, unsigned amount, unsigned n)
141 {
142 const unsigned int words = amount / BITSET_WORDBITS;
143
144 if (amount == 0)
145 return;
146
147 if (words) {
148 unsigned i;
149
150 for (i = 0; i < n - words; i++)
151 x[i] = x[i + words];
152
153 while (i < n)
154 x[i++] = 0;
155
156 amount %= BITSET_WORDBITS;
157 }
158
159 __bitset_rotate_right(x, amount, n);
160 }
161
162
163 static inline void
__bitset_shl(BITSET_WORD * x,unsigned amount,unsigned n)164 __bitset_shl(BITSET_WORD *x, unsigned amount, unsigned n)
165 {
166 const int words = amount / BITSET_WORDBITS;
167
168 if (amount == 0)
169 return;
170
171 if (words) {
172 int i;
173
174 for (i = n - 1; i >= words; i--) {
175 x[i] = x[i - words];
176 }
177
178 while (i >= 0) {
179 x[i--] = 0;
180 }
181
182 amount %= BITSET_WORDBITS;
183 }
184
185 __bitset_rotate_left(x, amount, n);
186 }
187
188 #define BITSET_SHR(x, n) \
189 __bitset_shr(x, n, ARRAY_SIZE(x));
190
191 #define BITSET_SHL(x, n) \
192 __bitset_shl(x, n, ARRAY_SIZE(x));
193
194 /* bit range operations
195 */
196 #define BITSET_TEST_RANGE_INSIDE_WORD(x, b, e) \
197 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
198 (((x)[BITSET_BITWORD(b)] & BITSET_RANGE(b, e)) != 0) : \
199 (assert (!"BITSET_TEST_RANGE: bit range crosses word boundary"), 0))
200 #define BITSET_SET_RANGE_INSIDE_WORD(x, b, e) \
201 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
202 ((x)[BITSET_BITWORD(b)] |= BITSET_RANGE(b, e)) : \
203 (assert (!"BITSET_SET_RANGE_INSIDE_WORD: bit range crosses word boundary"), 0))
204 #define BITSET_CLEAR_RANGE_INSIDE_WORD(x, b, e) \
205 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
206 ((x)[BITSET_BITWORD(b)] &= ~BITSET_RANGE(b, e)) : \
207 (assert (!"BITSET_CLEAR_RANGE: bit range crosses word boundary"), 0))
208
209 static inline bool
__bitset_test_range(const BITSET_WORD * r,unsigned start,unsigned end)210 __bitset_test_range(const BITSET_WORD *r, unsigned start, unsigned end)
211 {
212 const unsigned size = end - start + 1;
213 const unsigned start_mod = start % BITSET_WORDBITS;
214
215 if (start_mod + size <= BITSET_WORDBITS) {
216 return BITSET_TEST_RANGE_INSIDE_WORD(r, start, end);
217 } else {
218 const unsigned first_size = BITSET_WORDBITS - start_mod;
219
220 return __bitset_test_range(r, start, start + first_size - 1) ||
221 __bitset_test_range(r, start + first_size, end);
222 }
223 }
224
225 #define BITSET_TEST_RANGE(x, b, e) \
226 __bitset_test_range(x, b, e)
227
228 static inline void
__bitset_set_range(BITSET_WORD * r,unsigned start,unsigned end)229 __bitset_set_range(BITSET_WORD *r, unsigned start, unsigned end)
230 {
231 const unsigned size = end - start + 1;
232 const unsigned start_mod = start % BITSET_WORDBITS;
233
234 if (start_mod + size <= BITSET_WORDBITS) {
235 BITSET_SET_RANGE_INSIDE_WORD(r, start, end);
236 } else {
237 const unsigned first_size = BITSET_WORDBITS - start_mod;
238
239 __bitset_set_range(r, start, start + first_size - 1);
240 __bitset_set_range(r, start + first_size, end);
241 }
242 }
243
244 #define BITSET_SET_RANGE(x, b, e) \
245 __bitset_set_range(x, b, e)
246
247 static inline void
__bitclear_clear_range(BITSET_WORD * r,unsigned start,unsigned end)248 __bitclear_clear_range(BITSET_WORD *r, unsigned start, unsigned end)
249 {
250 const unsigned size = end - start + 1;
251 const unsigned start_mod = start % BITSET_WORDBITS;
252
253 if (start_mod + size <= BITSET_WORDBITS) {
254 BITSET_CLEAR_RANGE_INSIDE_WORD(r, start, end);
255 } else {
256 const unsigned first_size = BITSET_WORDBITS - start_mod;
257
258 __bitclear_clear_range(r, start, start + first_size - 1);
259 __bitclear_clear_range(r, start + first_size, end);
260 }
261 }
262
263 #define BITSET_CLEAR_RANGE(x, b, e) \
264 __bitclear_clear_range(x, b, e)
265
266 static inline unsigned
__bitset_prefix_sum(const BITSET_WORD * x,unsigned b,unsigned n)267 __bitset_prefix_sum(const BITSET_WORD *x, unsigned b, unsigned n)
268 {
269 unsigned prefix = 0;
270
271 for (unsigned i = 0; i < n; i++) {
272 if ((i + 1) * BITSET_WORDBITS <= b) {
273 prefix += util_bitcount(x[i]);
274 } else {
275 prefix += util_bitcount(x[i] & BITFIELD_MASK(b - i * BITSET_WORDBITS));
276 break;
277 }
278 }
279 return prefix;
280 }
281
282 /* Count set bits in the bitset (compute the size/cardinality of the bitset).
283 * This is a special case of prefix sum, but this convenience method is more
284 * natural when applicable.
285 */
286
287 static inline unsigned
__bitset_count(const BITSET_WORD * x,unsigned n)288 __bitset_count(const BITSET_WORD *x, unsigned n)
289 {
290 return __bitset_prefix_sum(x, ~0, n);
291 }
292
293 #define BITSET_PREFIX_SUM(x, b) \
294 __bitset_prefix_sum(x, b, ARRAY_SIZE(x))
295
296 #define BITSET_COUNT(x) \
297 __bitset_count(x, ARRAY_SIZE(x))
298
299 /* Get first bit set in a bitset.
300 */
301 static inline int
__bitset_ffs(const BITSET_WORD * x,int n)302 __bitset_ffs(const BITSET_WORD *x, int n)
303 {
304 for (int i = 0; i < n; i++) {
305 if (x[i])
306 return ffs(x[i]) + BITSET_WORDBITS * i;
307 }
308
309 return 0;
310 }
311
312 /* Get the last bit set in a bitset.
313 */
314 static inline int
__bitset_last_bit(const BITSET_WORD * x,int n)315 __bitset_last_bit(const BITSET_WORD *x, int n)
316 {
317 for (int i = n - 1; i >= 0; i--) {
318 if (x[i])
319 return util_last_bit(x[i]) + BITSET_WORDBITS * i;
320 }
321
322 return 0;
323 }
324
325 #define BITSET_FFS(x) __bitset_ffs(x, ARRAY_SIZE(x))
326 #define BITSET_LAST_BIT(x) __bitset_last_bit(x, ARRAY_SIZE(x))
327 #define BITSET_LAST_BIT_SIZED(x, size) __bitset_last_bit(x, size)
328
329 static inline unsigned
__bitset_next_set(unsigned i,BITSET_WORD * tmp,const BITSET_WORD * set,unsigned size)330 __bitset_next_set(unsigned i, BITSET_WORD *tmp,
331 const BITSET_WORD *set, unsigned size)
332 {
333 unsigned bit, word;
334
335 /* NOTE: The initial conditions for this function are very specific. At
336 * the start of the loop, the tmp variable must be set to *set and the
337 * initial i value set to 0. This way, if there is a bit set in the first
338 * word, we ignore the i-value and just grab that bit (so 0 is ok, even
339 * though 0 may be returned). If the first word is 0, then the value of
340 * `word` will be 0 and we will go on to look at the second word.
341 */
342 word = BITSET_BITWORD(i);
343 while (*tmp == 0) {
344 word++;
345
346 if (word >= BITSET_WORDS(size))
347 return size;
348
349 *tmp = set[word];
350 }
351
352 /* Find the next set bit in the non-zero word */
353 bit = ffs(*tmp) - 1;
354
355 /* Unset the bit */
356 *tmp &= ~(1ull << bit);
357
358 return word * BITSET_WORDBITS + bit;
359 }
360
361 /**
362 * Iterates over each set bit in a set
363 *
364 * @param __i iteration variable, bit number
365 * @param __set the bitset to iterate (will not be modified)
366 * @param __size number of bits in the set to consider
367 */
368 #define BITSET_FOREACH_SET(__i, __set, __size) \
369 for (BITSET_WORD __tmp = (__size) == 0 ? 0 : *(__set), *__foo = &__tmp; __foo != NULL; __foo = NULL) \
370 for (__i = 0; \
371 (__i = __bitset_next_set(__i, &__tmp, __set, __size)) < __size;)
372
373 static inline void
__bitset_next_range(unsigned * start,unsigned * end,const BITSET_WORD * set,unsigned size)374 __bitset_next_range(unsigned *start, unsigned *end, const BITSET_WORD *set,
375 unsigned size)
376 {
377 /* To find the next start, start searching from end. In the first iteration
378 * it will be at 0, in every subsequent iteration it will be at the first
379 * 0-bit after the range.
380 */
381 unsigned word = BITSET_BITWORD(*end);
382 if (word >= BITSET_WORDS(size)) {
383 *start = *end = size;
384 return;
385 }
386 BITSET_WORD tmp = set[word] & ~(BITSET_BIT(*end) - 1);
387 while (!tmp) {
388 word++;
389 if (word >= BITSET_WORDS(size)) {
390 *start = *end = size;
391 return;
392 }
393 tmp = set[word];
394 }
395
396 *start = word * BITSET_WORDBITS + ffs(tmp) - 1;
397
398 /* Now do the opposite to find end. Here we can start at start + 1, because
399 * we know that the bit at start is 1 and we're searching for the first
400 * 0-bit.
401 */
402 word = BITSET_BITWORD(*start + 1);
403 if (word >= BITSET_WORDS(size)) {
404 *end = size;
405 return;
406 }
407 tmp = set[word] | (BITSET_BIT(*start + 1) - 1);
408 while (~tmp == 0) {
409 word++;
410 if (word >= BITSET_WORDS(size)) {
411 *end = size;
412 return;
413 }
414 tmp = set[word];
415 }
416
417 /* Cap "end" at "size" in case there are extra bits past "size" set in the
418 * word. This is only necessary for "end" because we terminate the loop if
419 * "start" goes past "size".
420 */
421 *end = MIN2(word * BITSET_WORDBITS + ffs(~tmp) - 1, size);
422 }
423
424 /**
425 * Iterates over each contiguous range of set bits in a set
426 *
427 * @param __start the first 1 bit of the current range
428 * @param __end the bit after the last 1 bit of the current range
429 * @param __set the bitset to iterate (will not be modified)
430 * @param __size number of bits in the set to consider
431 */
432 #define BITSET_FOREACH_RANGE(__start, __end, __set, __size) \
433 for (__start = 0, __end = 0, \
434 __bitset_next_range(&__start, &__end, __set, __size); \
435 __start < __size; \
436 __bitset_next_range(&__start, &__end, __set, __size))
437
438
439 #ifdef __cplusplus
440
441 /**
442 * Simple C++ wrapper of a bitset type of static size, with value semantics
443 * and basic bitwise arithmetic operators. The operators defined below are
444 * expected to have the same semantics as the same operator applied to other
445 * fundamental integer types. T is the name of the struct to instantiate
446 * it as, and N is the number of bits in the bitset.
447 */
448 #define DECLARE_BITSET_T(T, N) struct T { \
449 EXPLICIT_CONVERSION \
450 operator bool() const \
451 { \
452 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
453 if (words[i]) \
454 return true; \
455 return false; \
456 } \
457 \
458 T & \
459 operator=(int x) \
460 { \
461 const T c = {{ (BITSET_WORD)x }}; \
462 return *this = c; \
463 } \
464 \
465 friend bool \
466 operator==(const T &b, const T &c) \
467 { \
468 return BITSET_EQUAL(b.words, c.words); \
469 } \
470 \
471 friend bool \
472 operator!=(const T &b, const T &c) \
473 { \
474 return !(b == c); \
475 } \
476 \
477 friend bool \
478 operator==(const T &b, int x) \
479 { \
480 const T c = {{ (BITSET_WORD)x }}; \
481 return b == c; \
482 } \
483 \
484 friend bool \
485 operator!=(const T &b, int x) \
486 { \
487 return !(b == x); \
488 } \
489 \
490 friend T \
491 operator~(const T &b) \
492 { \
493 T c; \
494 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
495 c.words[i] = ~b.words[i]; \
496 return c; \
497 } \
498 \
499 T & \
500 operator|=(const T &b) \
501 { \
502 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
503 words[i] |= b.words[i]; \
504 return *this; \
505 } \
506 \
507 friend T \
508 operator|(const T &b, const T &c) \
509 { \
510 T d = b; \
511 d |= c; \
512 return d; \
513 } \
514 \
515 T & \
516 operator&=(const T &b) \
517 { \
518 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
519 words[i] &= b.words[i]; \
520 return *this; \
521 } \
522 \
523 friend T \
524 operator&(const T &b, const T &c) \
525 { \
526 T d = b; \
527 d &= c; \
528 return d; \
529 } \
530 \
531 bool \
532 test(unsigned i) const \
533 { \
534 return BITSET_TEST(words, i); \
535 } \
536 \
537 T & \
538 set(unsigned i) \
539 { \
540 BITSET_SET(words, i); \
541 return *this; \
542 } \
543 \
544 T & \
545 clear(unsigned i) \
546 { \
547 BITSET_CLEAR(words, i); \
548 return *this; \
549 } \
550 \
551 BITSET_WORD words[BITSET_WORDS(N)]; \
552 }
553
554 #endif
555
556 #endif
557