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_GET_RANGE_INSIDE_WORD(x, b, e) \
211 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
212 (((x)[BITSET_BITWORD(b)] >> (b % BITSET_WORDBITS)) & \
213 BITSET_MASK((e) - (b) + 1)) : \
214 (assert (!"BITSET_TEST_RANGE: bit range crosses word boundary"), 0))
215 #define BITSET_TEST_RANGE_INSIDE_WORD(x, b, e, mask) \
216 (BITSET_GET_RANGE_INSIDE_WORD(x, b, e) == (mask))
217 #define BITSET_SET_RANGE_INSIDE_WORD(x, b, e) \
218 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
219 ((x)[BITSET_BITWORD(b)] |= BITSET_RANGE(b, e)) : \
220 (assert (!"BITSET_SET_RANGE_INSIDE_WORD: bit range crosses word boundary"), 0))
221 #define BITSET_CLEAR_RANGE_INSIDE_WORD(x, b, e) \
222 (BITSET_BITWORD(b) == BITSET_BITWORD(e) ? \
223 ((x)[BITSET_BITWORD(b)] &= ~BITSET_RANGE(b, e)) : \
224 (assert (!"BITSET_CLEAR_RANGE: bit range crosses word boundary"), 0))
225
226 static inline bool
__bitset_test_range(const BITSET_WORD * r,unsigned start,unsigned end)227 __bitset_test_range(const BITSET_WORD *r, unsigned start, unsigned end)
228 {
229 const unsigned size = end - start + 1;
230 const unsigned start_mod = start % BITSET_WORDBITS;
231
232 if (start_mod + size <= BITSET_WORDBITS) {
233 return !BITSET_TEST_RANGE_INSIDE_WORD(r, start, end, 0);
234 } else {
235 const unsigned first_size = BITSET_WORDBITS - start_mod;
236
237 return __bitset_test_range(r, start, start + first_size - 1) ||
238 __bitset_test_range(r, start + first_size, end);
239 }
240 }
241
242 #define BITSET_TEST_RANGE(x, b, e) \
243 __bitset_test_range(x, b, e)
244
245 static inline void
__bitset_set_range(BITSET_WORD * r,unsigned start,unsigned end)246 __bitset_set_range(BITSET_WORD *r, unsigned start, unsigned end)
247 {
248 const unsigned size = end - start + 1;
249 const unsigned start_mod = start % BITSET_WORDBITS;
250
251 if (start_mod + size <= BITSET_WORDBITS) {
252 BITSET_SET_RANGE_INSIDE_WORD(r, start, end);
253 } else {
254 const unsigned first_size = BITSET_WORDBITS - start_mod;
255
256 __bitset_set_range(r, start, start + first_size - 1);
257 __bitset_set_range(r, start + first_size, end);
258 }
259 }
260
261 #define BITSET_SET_RANGE(x, b, e) \
262 __bitset_set_range(x, b, e)
263
264 static inline void
__bitclear_clear_range(BITSET_WORD * r,unsigned start,unsigned end)265 __bitclear_clear_range(BITSET_WORD *r, unsigned start, unsigned end)
266 {
267 const unsigned size = end - start + 1;
268 const unsigned start_mod = start % BITSET_WORDBITS;
269
270 if (start_mod + size <= BITSET_WORDBITS) {
271 BITSET_CLEAR_RANGE_INSIDE_WORD(r, start, end);
272 } else {
273 const unsigned first_size = BITSET_WORDBITS - start_mod;
274
275 __bitclear_clear_range(r, start, start + first_size - 1);
276 __bitclear_clear_range(r, start + first_size, end);
277 }
278 }
279
280 #define BITSET_CLEAR_RANGE(x, b, e) \
281 __bitclear_clear_range(x, b, e)
282
283 static inline unsigned
__bitset_prefix_sum(const BITSET_WORD * x,unsigned b,unsigned n)284 __bitset_prefix_sum(const BITSET_WORD *x, unsigned b, unsigned n)
285 {
286 unsigned prefix = 0;
287
288 for (unsigned i = 0; i < n; i++) {
289 if ((i + 1) * BITSET_WORDBITS <= b) {
290 prefix += util_bitcount(x[i]);
291 } else {
292 prefix += util_bitcount(x[i] & BITFIELD_MASK(b - i * BITSET_WORDBITS));
293 break;
294 }
295 }
296 return prefix;
297 }
298
299 /* Count set bits in the bitset (compute the size/cardinality of the bitset).
300 * This is a special case of prefix sum, but this convenience method is more
301 * natural when applicable.
302 */
303
304 static inline unsigned
__bitset_count(const BITSET_WORD * x,unsigned n)305 __bitset_count(const BITSET_WORD *x, unsigned n)
306 {
307 return __bitset_prefix_sum(x, ~0, n);
308 }
309
310 #define BITSET_PREFIX_SUM(x, b) \
311 __bitset_prefix_sum(x, b, ARRAY_SIZE(x))
312
313 #define BITSET_COUNT(x) \
314 __bitset_count(x, ARRAY_SIZE(x))
315
316 /* Return true if the bitset has no bits set.
317 */
318 static inline bool
__bitset_is_empty(const BITSET_WORD * x,int n)319 __bitset_is_empty(const BITSET_WORD *x, int n)
320 {
321 for (int i = 0; i < n; i++) {
322 if (x[i])
323 return false;
324 }
325
326 return true;
327 }
328
329 /* Get first bit set in a bitset.
330 */
331 static inline int
__bitset_ffs(const BITSET_WORD * x,int n)332 __bitset_ffs(const BITSET_WORD *x, int n)
333 {
334 for (int i = 0; i < n; i++) {
335 if (x[i])
336 return ffs(x[i]) + BITSET_WORDBITS * i;
337 }
338
339 return 0;
340 }
341
342 /* Get the last bit set in a bitset.
343 */
344 static inline int
__bitset_last_bit(const BITSET_WORD * x,int n)345 __bitset_last_bit(const BITSET_WORD *x, int n)
346 {
347 for (int i = n - 1; i >= 0; i--) {
348 if (x[i])
349 return util_last_bit(x[i]) + BITSET_WORDBITS * i;
350 }
351
352 return 0;
353 }
354
355 /* Get the last bit set in a bitset before last_bit.
356 */
357 static inline int
__bitset_last_bit_before(const BITSET_WORD * x,int last_bit)358 __bitset_last_bit_before(const BITSET_WORD *x, int last_bit)
359 {
360 int n = last_bit / BITSET_WORDBITS;
361 int reminder = last_bit % BITSET_WORDBITS;
362 if (reminder) {
363 BITSET_WORD last = x[n] & BITFIELD_MASK(reminder);
364 if (last)
365 return util_last_bit(last) + n * BITSET_WORDBITS;
366 }
367 return __bitset_last_bit(x, n);
368 }
369
370 #define BITSET_FFS(x) __bitset_ffs(x, ARRAY_SIZE(x))
371 #define BITSET_LAST_BIT(x) __bitset_last_bit(x, ARRAY_SIZE(x))
372 #define BITSET_LAST_BIT_SIZED(x, size) __bitset_last_bit(x, size)
373 #define BITSET_LAST_BIT_BEFORE(x, last_bit) __bitset_last_bit_before(x, last_bit)
374 #define BITSET_IS_EMPTY(x) __bitset_is_empty(x, ARRAY_SIZE(x))
375
376 static inline unsigned
__bitset_next_set(unsigned i,BITSET_WORD * tmp,const BITSET_WORD * set,unsigned size)377 __bitset_next_set(unsigned i, BITSET_WORD *tmp,
378 const BITSET_WORD *set, unsigned size)
379 {
380 unsigned bit, word;
381
382 /* NOTE: The initial conditions for this function are very specific. At
383 * the start of the loop, the tmp variable must be set to *set and the
384 * initial i value set to 0. This way, if there is a bit set in the first
385 * word, we ignore the i-value and just grab that bit (so 0 is ok, even
386 * though 0 may be returned). If the first word is 0, then the value of
387 * `word` will be 0 and we will go on to look at the second word.
388 */
389 word = BITSET_BITWORD(i);
390 while (*tmp == 0) {
391 word++;
392
393 if (word >= BITSET_WORDS(size))
394 return size;
395
396 *tmp = set[word];
397 }
398
399 /* Find the next set bit in the non-zero word */
400 bit = ffs(*tmp) - 1;
401
402 /* Unset the bit */
403 *tmp &= ~(1ull << bit);
404
405 return word * BITSET_WORDBITS + bit;
406 }
407
408 /**
409 * Iterates over each set bit in a set
410 *
411 * @param __i iteration variable, bit number
412 * @param __set the bitset to iterate (will not be modified)
413 * @param __size number of bits in the set to consider
414 */
415 #define BITSET_FOREACH_SET(__i, __set, __size) \
416 for (BITSET_WORD __tmp = (__size) == 0 ? 0 : *(__set), *__foo = &__tmp; __foo != NULL; __foo = NULL) \
417 for (__i = 0; \
418 (__i = __bitset_next_set(__i, &__tmp, __set, __size)) < __size;)
419
420 static inline void
__bitset_next_range(unsigned * start,unsigned * end,const BITSET_WORD * set,unsigned size)421 __bitset_next_range(unsigned *start, unsigned *end, const BITSET_WORD *set,
422 unsigned size)
423 {
424 /* To find the next start, start searching from end. In the first iteration
425 * it will be at 0, in every subsequent iteration it will be at the first
426 * 0-bit after the range.
427 */
428 unsigned word = BITSET_BITWORD(*end);
429 if (word >= BITSET_WORDS(size)) {
430 *start = *end = size;
431 return;
432 }
433 BITSET_WORD tmp = set[word] & ~(BITSET_BIT(*end) - 1);
434 while (!tmp) {
435 word++;
436 if (word >= BITSET_WORDS(size)) {
437 *start = *end = size;
438 return;
439 }
440 tmp = set[word];
441 }
442
443 *start = word * BITSET_WORDBITS + ffs(tmp) - 1;
444
445 /* Now do the opposite to find end. Here we can start at start + 1, because
446 * we know that the bit at start is 1 and we're searching for the first
447 * 0-bit.
448 */
449 word = BITSET_BITWORD(*start + 1);
450 if (word >= BITSET_WORDS(size)) {
451 *end = size;
452 return;
453 }
454 tmp = set[word] | (BITSET_BIT(*start + 1) - 1);
455 while (~tmp == 0) {
456 word++;
457 if (word >= BITSET_WORDS(size)) {
458 *end = size;
459 return;
460 }
461 tmp = set[word];
462 }
463
464 /* Cap "end" at "size" in case there are extra bits past "size" set in the
465 * word. This is only necessary for "end" because we terminate the loop if
466 * "start" goes past "size".
467 */
468 *end = MIN2(word * BITSET_WORDBITS + ffs(~tmp) - 1, size);
469 }
470
471 /**
472 * Iterates over each contiguous range of set bits in a set
473 *
474 * @param __start the first 1 bit of the current range
475 * @param __end the bit after the last 1 bit of the current range
476 * @param __set the bitset to iterate (will not be modified)
477 * @param __size number of bits in the set to consider
478 */
479 #define BITSET_FOREACH_RANGE(__start, __end, __set, __size) \
480 for (__start = 0, __end = 0, \
481 __bitset_next_range(&__start, &__end, __set, __size); \
482 __start < __size; \
483 __bitset_next_range(&__start, &__end, __set, __size))
484
485
486 #ifdef __cplusplus
487
488 /**
489 * Simple C++ wrapper of a bitset type of static size, with value semantics
490 * and basic bitwise arithmetic operators. The operators defined below are
491 * expected to have the same semantics as the same operator applied to other
492 * fundamental integer types. T is the name of the struct to instantiate
493 * it as, and N is the number of bits in the bitset.
494 */
495 #define DECLARE_BITSET_T(T, N) struct T { \
496 explicit \
497 operator bool() const \
498 { \
499 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
500 if (words[i]) \
501 return true; \
502 return false; \
503 } \
504 \
505 T & \
506 operator=(int x) \
507 { \
508 const T c = {{ (BITSET_WORD)x }}; \
509 return *this = c; \
510 } \
511 \
512 friend bool \
513 operator==(const T &b, const T &c) \
514 { \
515 return BITSET_EQUAL(b.words, c.words); \
516 } \
517 \
518 friend bool \
519 operator!=(const T &b, const T &c) \
520 { \
521 return !(b == c); \
522 } \
523 \
524 friend bool \
525 operator==(const T &b, int x) \
526 { \
527 const T c = {{ (BITSET_WORD)x }}; \
528 return b == c; \
529 } \
530 \
531 friend bool \
532 operator!=(const T &b, int x) \
533 { \
534 return !(b == x); \
535 } \
536 \
537 friend T \
538 operator~(const T &b) \
539 { \
540 T c; \
541 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
542 c.words[i] = ~b.words[i]; \
543 return c; \
544 } \
545 \
546 T & \
547 operator|=(const T &b) \
548 { \
549 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
550 words[i] |= b.words[i]; \
551 return *this; \
552 } \
553 \
554 friend T \
555 operator|(const T &b, const T &c) \
556 { \
557 T d = b; \
558 d |= c; \
559 return d; \
560 } \
561 \
562 T & \
563 operator&=(const T &b) \
564 { \
565 for (unsigned i = 0; i < BITSET_WORDS(N); i++) \
566 words[i] &= b.words[i]; \
567 return *this; \
568 } \
569 \
570 friend T \
571 operator&(const T &b, const T &c) \
572 { \
573 T d = b; \
574 d &= c; \
575 return d; \
576 } \
577 \
578 bool \
579 test(unsigned i) const \
580 { \
581 return BITSET_TEST(words, i); \
582 } \
583 \
584 T & \
585 set(unsigned i) \
586 { \
587 BITSET_SET(words, i); \
588 return *this; \
589 } \
590 \
591 T & \
592 clear(unsigned i) \
593 { \
594 BITSET_CLEAR(words, i); \
595 return *this; \
596 } \
597 \
598 BITSET_WORD words[BITSET_WORDS(N)]; \
599 }
600
601 #endif
602
603 #endif
604