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 static inline void
__bitset_andnot(BITSET_WORD * r,const BITSET_WORD * x,const BITSET_WORD * y,unsigned n)93 __bitset_andnot(BITSET_WORD *r, const BITSET_WORD *x, const BITSET_WORD *y, unsigned n)
94 {
95 for (unsigned i = 0; i < n; i++)
96 r[i] = x[i] & ~y[i];
97 }
98
99 #define BITSET_AND(r, x, y) \
100 do { \
101 STATIC_ASSERT(ARRAY_SIZE(r) == ARRAY_SIZE(x)); \
102 STATIC_ASSERT(ARRAY_SIZE(r) == ARRAY_SIZE(y)); \
103 __bitset_and(r, x, y, ARRAY_SIZE(r)); \
104 } while (0)
105
106 #define BITSET_OR(r, x, y) \
107 do { \
108 STATIC_ASSERT(ARRAY_SIZE(r) == ARRAY_SIZE(x)); \
109 STATIC_ASSERT(ARRAY_SIZE(r) == ARRAY_SIZE(y)); \
110 __bitset_or(r, x, y, ARRAY_SIZE(r)); \
111 } while (0)
112
113 #define BITSET_NOT(x) \
114 __bitset_not(x, ARRAY_SIZE(x))
115
116 #define BITSET_ANDNOT(r, x, y) \
117 do { \
118 assert(ARRAY_SIZE(r) == ARRAY_SIZE(x)); \
119 assert(ARRAY_SIZE(r) == ARRAY_SIZE(y)); \
120 __bitset_andnot(r, x, y, ARRAY_SIZE(r)); \
121 } while (0)
122
123 static inline void
__bitset_rotate_right(BITSET_WORD * x,unsigned amount,unsigned n)124 __bitset_rotate_right(BITSET_WORD *x, unsigned amount, unsigned n)
125 {
126 assert(amount < BITSET_WORDBITS);
127
128 if (amount == 0)
129 return;
130
131 for (unsigned i = 0; i < n - 1; i++) {
132 x[i] = (x[i] >> amount) | (x[i + 1] << (BITSET_WORDBITS - amount));
133 }
134
135 x[n - 1] = x[n - 1] >> amount;
136 }
137
138 static inline void
__bitset_rotate_left(BITSET_WORD * x,unsigned amount,unsigned n)139 __bitset_rotate_left(BITSET_WORD *x, unsigned amount, unsigned n)
140 {
141 assert(amount < BITSET_WORDBITS);
142
143 if (amount == 0)
144 return;
145
146 for (int i = n - 1; i > 0; i--) {
147 x[i] = (x[i] << amount) | (x[i - 1] >> (BITSET_WORDBITS - amount));
148 }
149
150 x[0] = x[0] << amount;
151 }
152
153 static inline void
__bitset_shr(BITSET_WORD * x,unsigned amount,unsigned n)154 __bitset_shr(BITSET_WORD *x, unsigned amount, unsigned n)
155 {
156 const unsigned int words = amount / BITSET_WORDBITS;
157
158 if (amount == 0)
159 return;
160
161 if (words) {
162 unsigned i;
163
164 for (i = 0; i < n - words; i++)
165 x[i] = x[i + words];
166
167 while (i < n)
168 x[i++] = 0;
169
170 amount %= BITSET_WORDBITS;
171 }
172
173 __bitset_rotate_right(x, amount, n);
174 }
175
176
177 static inline void
__bitset_shl(BITSET_WORD * x,unsigned amount,unsigned n)178 __bitset_shl(BITSET_WORD *x, unsigned amount, unsigned n)
179 {
180 const int words = amount / BITSET_WORDBITS;
181
182 if (amount == 0)
183 return;
184
185 if (words) {
186 int i;
187
188 for (i = n - 1; i >= words; i--) {
189 x[i] = x[i - words];
190 }
191
192 while (i >= 0) {
193 x[i--] = 0;
194 }
195
196 amount %= BITSET_WORDBITS;
197 }
198
199 __bitset_rotate_left(x, amount, n);
200 }
201
202 #define BITSET_SHR(x, n) \
203 __bitset_shr(x, n, ARRAY_SIZE(x));
204
205 #define BITSET_SHL(x, n) \
206 __bitset_shl(x, n, ARRAY_SIZE(x));
207
208 /* bit range operations (e=end is inclusive)
209 */
210 #define BITSET_TEST_RANGE_INSIDE_WORD(x, b, e, mask) \
211 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
212 (((x)[BITSET_BITWORD(b)] & BITSET_RANGE(b, e)) == \
213 (((BITSET_WORD)mask) << (b % BITSET_WORDBITS))) : \
214 (assert (!"BITSET_TEST_RANGE: bit range crosses word boundary"), 0))
215 #define BITSET_SET_RANGE_INSIDE_WORD(x, b, e) \
216 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
217 ((x)[BITSET_BITWORD(b)] |= BITSET_RANGE(b, e)) : \
218 (assert (!"BITSET_SET_RANGE_INSIDE_WORD: bit range crosses word boundary"), 0))
219 #define BITSET_CLEAR_RANGE_INSIDE_WORD(x, b, e) \
220 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
221 ((x)[BITSET_BITWORD(b)] &= ~BITSET_RANGE(b, e)) : \
222 (assert (!"BITSET_CLEAR_RANGE: bit range crosses word boundary"), 0))
223
224 static inline bool
__bitset_test_range(const BITSET_WORD * r,unsigned start,unsigned end)225 __bitset_test_range(const BITSET_WORD *r, unsigned start, unsigned end)
226 {
227 const unsigned size = end - start + 1;
228 const unsigned start_mod = start % BITSET_WORDBITS;
229
230 if (start_mod + size <= BITSET_WORDBITS) {
231 return !BITSET_TEST_RANGE_INSIDE_WORD(r, start, end, 0);
232 } else {
233 const unsigned first_size = BITSET_WORDBITS - start_mod;
234
235 return __bitset_test_range(r, start, start + first_size - 1) ||
236 __bitset_test_range(r, start + first_size, end);
237 }
238 }
239
240 #define BITSET_TEST_RANGE(x, b, e) \
241 __bitset_test_range(x, b, e)
242
243 static inline void
__bitset_set_range(BITSET_WORD * r,unsigned start,unsigned end)244 __bitset_set_range(BITSET_WORD *r, unsigned start, unsigned end)
245 {
246 const unsigned size = end - start + 1;
247 const unsigned start_mod = start % BITSET_WORDBITS;
248
249 if (start_mod + size <= BITSET_WORDBITS) {
250 BITSET_SET_RANGE_INSIDE_WORD(r, start, end);
251 } else {
252 const unsigned first_size = BITSET_WORDBITS - start_mod;
253
254 __bitset_set_range(r, start, start + first_size - 1);
255 __bitset_set_range(r, start + first_size, end);
256 }
257 }
258
259 #define BITSET_SET_RANGE(x, b, e) \
260 __bitset_set_range(x, b, e)
261
262 static inline void
__bitclear_clear_range(BITSET_WORD * r,unsigned start,unsigned end)263 __bitclear_clear_range(BITSET_WORD *r, unsigned start, unsigned end)
264 {
265 const unsigned size = end - start + 1;
266 const unsigned start_mod = start % BITSET_WORDBITS;
267
268 if (start_mod + size <= BITSET_WORDBITS) {
269 BITSET_CLEAR_RANGE_INSIDE_WORD(r, start, end);
270 } else {
271 const unsigned first_size = BITSET_WORDBITS - start_mod;
272
273 __bitclear_clear_range(r, start, start + first_size - 1);
274 __bitclear_clear_range(r, start + first_size, end);
275 }
276 }
277
278 #define BITSET_CLEAR_RANGE(x, b, e) \
279 __bitclear_clear_range(x, b, e)
280
281 static inline unsigned
__bitset_prefix_sum(const BITSET_WORD * x,unsigned b,unsigned n)282 __bitset_prefix_sum(const BITSET_WORD *x, unsigned b, unsigned n)
283 {
284 unsigned prefix = 0;
285
286 for (unsigned i = 0; i < n; i++) {
287 if ((i + 1) * BITSET_WORDBITS <= b) {
288 prefix += util_bitcount(x[i]);
289 } else {
290 prefix += util_bitcount(x[i] & BITFIELD_MASK(b - i * BITSET_WORDBITS));
291 break;
292 }
293 }
294 return prefix;
295 }
296
297 /* Count set bits in the bitset (compute the size/cardinality of the bitset).
298 * This is a special case of prefix sum, but this convenience method is more
299 * natural when applicable.
300 */
301
302 static inline unsigned
__bitset_count(const BITSET_WORD * x,unsigned n)303 __bitset_count(const BITSET_WORD *x, unsigned n)
304 {
305 return __bitset_prefix_sum(x, ~0, n);
306 }
307
308 #define BITSET_PREFIX_SUM(x, b) \
309 __bitset_prefix_sum(x, b, ARRAY_SIZE(x))
310
311 #define BITSET_COUNT(x) \
312 __bitset_count(x, ARRAY_SIZE(x))
313
314 /* Return true if the bitset has no bits set.
315 */
316 static inline bool
__bitset_is_empty(const BITSET_WORD * x,int n)317 __bitset_is_empty(const BITSET_WORD *x, int n)
318 {
319 for (int i = 0; i < n; i++) {
320 if (x[i])
321 return false;
322 }
323
324 return true;
325 }
326
327 /* Get first bit set in a bitset.
328 */
329 static inline int
__bitset_ffs(const BITSET_WORD * x,int n)330 __bitset_ffs(const BITSET_WORD *x, int n)
331 {
332 for (int i = 0; i < n; i++) {
333 if (x[i])
334 return ffs(x[i]) + BITSET_WORDBITS * i;
335 }
336
337 return 0;
338 }
339
340 /* Get the last bit set in a bitset.
341 */
342 static inline int
__bitset_last_bit(const BITSET_WORD * x,int n)343 __bitset_last_bit(const BITSET_WORD *x, int n)
344 {
345 for (int i = n - 1; i >= 0; i--) {
346 if (x[i])
347 return util_last_bit(x[i]) + BITSET_WORDBITS * i;
348 }
349
350 return 0;
351 }
352
353 #define BITSET_FFS(x) __bitset_ffs(x, ARRAY_SIZE(x))
354 #define BITSET_LAST_BIT(x) __bitset_last_bit(x, ARRAY_SIZE(x))
355 #define BITSET_LAST_BIT_SIZED(x, size) __bitset_last_bit(x, size)
356 #define BITSET_IS_EMPTY(x) __bitset_is_empty(x, ARRAY_SIZE(x))
357
358 static inline unsigned
__bitset_next_set(unsigned i,BITSET_WORD * tmp,const BITSET_WORD * set,unsigned size)359 __bitset_next_set(unsigned i, BITSET_WORD *tmp,
360 const BITSET_WORD *set, unsigned size)
361 {
362 unsigned bit, word;
363
364 /* NOTE: The initial conditions for this function are very specific. At
365 * the start of the loop, the tmp variable must be set to *set and the
366 * initial i value set to 0. This way, if there is a bit set in the first
367 * word, we ignore the i-value and just grab that bit (so 0 is ok, even
368 * though 0 may be returned). If the first word is 0, then the value of
369 * `word` will be 0 and we will go on to look at the second word.
370 */
371 word = BITSET_BITWORD(i);
372 while (*tmp == 0) {
373 word++;
374
375 if (word >= BITSET_WORDS(size))
376 return size;
377
378 *tmp = set[word];
379 }
380
381 /* Find the next set bit in the non-zero word */
382 bit = ffs(*tmp) - 1;
383
384 /* Unset the bit */
385 *tmp &= ~(1ull << bit);
386
387 return word * BITSET_WORDBITS + bit;
388 }
389
390 /**
391 * Iterates over each set bit in a set
392 *
393 * @param __i iteration variable, bit number
394 * @param __set the bitset to iterate (will not be modified)
395 * @param __size number of bits in the set to consider
396 */
397 #define BITSET_FOREACH_SET(__i, __set, __size) \
398 for (BITSET_WORD __tmp = (__size) == 0 ? 0 : *(__set), *__foo = &__tmp; __foo != NULL; __foo = NULL) \
399 for (__i = 0; \
400 (__i = __bitset_next_set(__i, &__tmp, __set, __size)) < __size;)
401
402 static inline void
__bitset_next_range(unsigned * start,unsigned * end,const BITSET_WORD * set,unsigned size)403 __bitset_next_range(unsigned *start, unsigned *end, const BITSET_WORD *set,
404 unsigned size)
405 {
406 /* To find the next start, start searching from end. In the first iteration
407 * it will be at 0, in every subsequent iteration it will be at the first
408 * 0-bit after the range.
409 */
410 unsigned word = BITSET_BITWORD(*end);
411 if (word >= BITSET_WORDS(size)) {
412 *start = *end = size;
413 return;
414 }
415 BITSET_WORD tmp = set[word] & ~(BITSET_BIT(*end) - 1);
416 while (!tmp) {
417 word++;
418 if (word >= BITSET_WORDS(size)) {
419 *start = *end = size;
420 return;
421 }
422 tmp = set[word];
423 }
424
425 *start = word * BITSET_WORDBITS + ffs(tmp) - 1;
426
427 /* Now do the opposite to find end. Here we can start at start + 1, because
428 * we know that the bit at start is 1 and we're searching for the first
429 * 0-bit.
430 */
431 word = BITSET_BITWORD(*start + 1);
432 if (word >= BITSET_WORDS(size)) {
433 *end = size;
434 return;
435 }
436 tmp = set[word] | (BITSET_BIT(*start + 1) - 1);
437 while (~tmp == 0) {
438 word++;
439 if (word >= BITSET_WORDS(size)) {
440 *end = size;
441 return;
442 }
443 tmp = set[word];
444 }
445
446 /* Cap "end" at "size" in case there are extra bits past "size" set in the
447 * word. This is only necessary for "end" because we terminate the loop if
448 * "start" goes past "size".
449 */
450 *end = MIN2(word * BITSET_WORDBITS + ffs(~tmp) - 1, size);
451 }
452
453 /**
454 * Iterates over each contiguous range of set bits in a set
455 *
456 * @param __start the first 1 bit of the current range
457 * @param __end the bit after the last 1 bit of the current range
458 * @param __set the bitset to iterate (will not be modified)
459 * @param __size number of bits in the set to consider
460 */
461 #define BITSET_FOREACH_RANGE(__start, __end, __set, __size) \
462 for (__start = 0, __end = 0, \
463 __bitset_next_range(&__start, &__end, __set, __size); \
464 __start < __size; \
465 __bitset_next_range(&__start, &__end, __set, __size))
466
467
468 #ifdef __cplusplus
469
470 /**
471 * Simple C++ wrapper of a bitset type of static size, with value semantics
472 * and basic bitwise arithmetic operators. The operators defined below are
473 * expected to have the same semantics as the same operator applied to other
474 * fundamental integer types. T is the name of the struct to instantiate
475 * it as, and N is the number of bits in the bitset.
476 */
477 #define DECLARE_BITSET_T(T, N) struct T { \
478 explicit \
479 operator bool() const \
480 { \
481 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
482 if (words[i]) \
483 return true; \
484 return false; \
485 } \
486 \
487 T & \
488 operator=(int x) \
489 { \
490 const T c = {{ (BITSET_WORD)x }}; \
491 return *this = c; \
492 } \
493 \
494 friend bool \
495 operator==(const T &b, const T &c) \
496 { \
497 return BITSET_EQUAL(b.words, c.words); \
498 } \
499 \
500 friend bool \
501 operator!=(const T &b, const T &c) \
502 { \
503 return !(b == c); \
504 } \
505 \
506 friend bool \
507 operator==(const T &b, int x) \
508 { \
509 const T c = {{ (BITSET_WORD)x }}; \
510 return b == c; \
511 } \
512 \
513 friend bool \
514 operator!=(const T &b, int x) \
515 { \
516 return !(b == x); \
517 } \
518 \
519 friend T \
520 operator~(const T &b) \
521 { \
522 T c; \
523 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
524 c.words[i] = ~b.words[i]; \
525 return c; \
526 } \
527 \
528 T & \
529 operator|=(const T &b) \
530 { \
531 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
532 words[i] |= b.words[i]; \
533 return *this; \
534 } \
535 \
536 friend T \
537 operator|(const T &b, const T &c) \
538 { \
539 T d = b; \
540 d |= c; \
541 return d; \
542 } \
543 \
544 T & \
545 operator&=(const T &b) \
546 { \
547 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
548 words[i] &= b.words[i]; \
549 return *this; \
550 } \
551 \
552 friend T \
553 operator&(const T &b, const T &c) \
554 { \
555 T d = b; \
556 d &= c; \
557 return d; \
558 } \
559 \
560 bool \
561 test(unsigned i) const \
562 { \
563 return BITSET_TEST(words, i); \
564 } \
565 \
566 T & \
567 set(unsigned i) \
568 { \
569 BITSET_SET(words, i); \
570 return *this; \
571 } \
572 \
573 T & \
574 clear(unsigned i) \
575 { \
576 BITSET_CLEAR(words, i); \
577 return *this; \
578 } \
579 \
580 BITSET_WORD words[BITSET_WORDS(N)]; \
581 }
582
583 #endif
584
585 #endif
586