1/*
2 * Copyright (c) 2009-2012, Pieter Noordhuis <pcnoordhuis at gmail dot com>
3 * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * * Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 * * Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * * Neither the name of Redis nor the names of its contributors may be used
15 * to endorse or promote products derived from this software without
16 * specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <stdio.h>
32#include <stdlib.h>
33#include <string.h>
34#include "intset.h"
35#include "zmalloc.h"
36#include "endianconv.h"
37#include "redisassert.h"
38
39/* Note that these encodings are ordered, so:
40 * INTSET_ENC_INT16 < INTSET_ENC_INT32 < INTSET_ENC_INT64. */
41#define INTSET_ENC_INT16 (sizeof(int16_t))
42#define INTSET_ENC_INT32 (sizeof(int32_t))
43#define INTSET_ENC_INT64 (sizeof(int64_t))
44
45/* Return the required encoding for the provided value. */
46static uint8_t _intsetValueEncoding(int64_t v) {
47 if (v < INT32_MIN || v > INT32_MAX)
48 return INTSET_ENC_INT64;
49 else if (v < INT16_MIN || v > INT16_MAX)
50 return INTSET_ENC_INT32;
51 else
52 return INTSET_ENC_INT16;
53}
54
55/* Return the value at pos, given an encoding. */
56static int64_t _intsetGetEncoded(intset *is, int pos, uint8_t enc) {
57 int64_t v64;
58 int32_t v32;
59 int16_t v16;
60
61 if (enc == INTSET_ENC_INT64) {
62 memcpy(&v64,((int64_t*)is->contents)+pos,sizeof(v64));
63 memrev64ifbe(&v64);
64 return v64;
65 } else if (enc == INTSET_ENC_INT32) {
66 memcpy(&v32,((int32_t*)is->contents)+pos,sizeof(v32));
67 memrev32ifbe(&v32);
68 return v32;
69 } else {
70 memcpy(&v16,((int16_t*)is->contents)+pos,sizeof(v16));
71 memrev16ifbe(&v16);
72 return v16;
73 }
74}
75
76/* Return the value at pos, using the configured encoding. */
77static int64_t _intsetGet(intset *is, int pos) {
78 return _intsetGetEncoded(is,pos,intrev32ifbe(is->encoding));
79}
80
81/* Set the value at pos, using the configured encoding. */
82static void _intsetSet(intset *is, int pos, int64_t value) {
83 uint32_t encoding = intrev32ifbe(is->encoding);
84
85 if (encoding == INTSET_ENC_INT64) {
86 ((int64_t*)is->contents)[pos] = value;
87 memrev64ifbe(((int64_t*)is->contents)+pos);
88 } else if (encoding == INTSET_ENC_INT32) {
89 ((int32_t*)is->contents)[pos] = value;
90 memrev32ifbe(((int32_t*)is->contents)+pos);
91 } else {
92 ((int16_t*)is->contents)[pos] = value;
93 memrev16ifbe(((int16_t*)is->contents)+pos);
94 }
95}
96
97/* Create an empty intset. */
98intset *intsetNew(void) {
99 intset *is = zmalloc(sizeof(intset));
100 is->encoding = intrev32ifbe(INTSET_ENC_INT16);
101 is->length = 0;
102 return is;
103}
104
105/* Resize the intset */
106static intset *intsetResize(intset *is, uint32_t len) {
107 uint64_t size = (uint64_t)len*intrev32ifbe(is->encoding);
108 assert(size <= SIZE_MAX - sizeof(intset));
109 is = zrealloc(is,sizeof(intset)+size);
110 return is;
111}
112
113/* Search for the position of "value". Return 1 when the value was found and
114 * sets "pos" to the position of the value within the intset. Return 0 when
115 * the value is not present in the intset and sets "pos" to the position
116 * where "value" can be inserted. */
117static uint8_t intsetSearch(intset *is, int64_t value, uint32_t *pos) {
118 int min = 0, max = intrev32ifbe(is->length)-1, mid = -1;
119 int64_t cur = -1;
120
121 /* The value can never be found when the set is empty */
122 if (intrev32ifbe(is->length) == 0) {
123 if (pos) *pos = 0;
124 return 0;
125 } else {
126 /* Check for the case where we know we cannot find the value,
127 * but do know the insert position. */
128 if (value > _intsetGet(is,max)) {
129 if (pos) *pos = intrev32ifbe(is->length);
130 return 0;
131 } else if (value < _intsetGet(is,0)) {
132 if (pos) *pos = 0;
133 return 0;
134 }
135 }
136
137 while(max >= min) {
138 mid = ((unsigned int)min + (unsigned int)max) >> 1;
139 cur = _intsetGet(is,mid);
140 if (value > cur) {
141 min = mid+1;
142 } else if (value < cur) {
143 max = mid-1;
144 } else {
145 break;
146 }
147 }
148
149 if (value == cur) {
150 if (pos) *pos = mid;
151 return 1;
152 } else {
153 if (pos) *pos = min;
154 return 0;
155 }
156}
157
158/* Upgrades the intset to a larger encoding and inserts the given integer. */
159static intset *intsetUpgradeAndAdd(intset *is, int64_t value) {
160 uint8_t curenc = intrev32ifbe(is->encoding);
161 uint8_t newenc = _intsetValueEncoding(value);
162 int length = intrev32ifbe(is->length);
163 int prepend = value < 0 ? 1 : 0;
164
165 /* First set new encoding and resize */
166 is->encoding = intrev32ifbe(newenc);
167 is = intsetResize(is,intrev32ifbe(is->length)+1);
168
169 /* Upgrade back-to-front so we don't overwrite values.
170 * Note that the "prepend" variable is used to make sure we have an empty
171 * space at either the beginning or the end of the intset. */
172 while(length--)
173 _intsetSet(is,length+prepend,_intsetGetEncoded(is,length,curenc));
174
175 /* Set the value at the beginning or the end. */
176 if (prepend)
177 _intsetSet(is,0,value);
178 else
179 _intsetSet(is,intrev32ifbe(is->length),value);
180 is->length = intrev32ifbe(intrev32ifbe(is->length)+1);
181 return is;
182}
183
184static void intsetMoveTail(intset *is, uint32_t from, uint32_t to) {
185 void *src, *dst;
186 uint32_t bytes = intrev32ifbe(is->length)-from;
187 uint32_t encoding = intrev32ifbe(is->encoding);
188
189 if (encoding == INTSET_ENC_INT64) {
190 src = (int64_t*)is->contents+from;
191 dst = (int64_t*)is->contents+to;
192 bytes *= sizeof(int64_t);
193 } else if (encoding == INTSET_ENC_INT32) {
194 src = (int32_t*)is->contents+from;
195 dst = (int32_t*)is->contents+to;
196 bytes *= sizeof(int32_t);
197 } else {
198 src = (int16_t*)is->contents+from;
199 dst = (int16_t*)is->contents+to;
200 bytes *= sizeof(int16_t);
201 }
202 memmove(dst,src,bytes);
203}
204
205/* Insert an integer in the intset */
206intset *intsetAdd(intset *is, int64_t value, uint8_t *success) {
207 uint8_t valenc = _intsetValueEncoding(value);
208 uint32_t pos;
209 if (success) *success = 1;
210
211 /* Upgrade encoding if necessary. If we need to upgrade, we know that
212 * this value should be either appended (if > 0) or prepended (if < 0),
213 * because it lies outside the range of existing values. */
214 if (valenc > intrev32ifbe(is->encoding)) {
215 /* This always succeeds, so we don't need to curry *success. */
216 return intsetUpgradeAndAdd(is,value);
217 } else {
218 /* Abort if the value is already present in the set.
219 * This call will populate "pos" with the right position to insert
220 * the value when it cannot be found. */
221 if (intsetSearch(is,value,&pos)) {
222 if (success) *success = 0;
223 return is;
224 }
225
226 is = intsetResize(is,intrev32ifbe(is->length)+1);
227 if (pos < intrev32ifbe(is->length)) intsetMoveTail(is,pos,pos+1);
228 }
229
230 _intsetSet(is,pos,value);
231 is->length = intrev32ifbe(intrev32ifbe(is->length)+1);
232 return is;
233}
234
235/* Delete integer from intset */
236intset *intsetRemove(intset *is, int64_t value, int *success) {
237 uint8_t valenc = _intsetValueEncoding(value);
238 uint32_t pos;
239 if (success) *success = 0;
240
241 if (valenc <= intrev32ifbe(is->encoding) && intsetSearch(is,value,&pos)) {
242 uint32_t len = intrev32ifbe(is->length);
243
244 /* We know we can delete */
245 if (success) *success = 1;
246
247 /* Overwrite value with tail and update length */
248 if (pos < (len-1)) intsetMoveTail(is,pos+1,pos);
249 is = intsetResize(is,len-1);
250 is->length = intrev32ifbe(len-1);
251 }
252 return is;
253}
254
255/* Determine whether a value belongs to this set */
256uint8_t intsetFind(intset *is, int64_t value) {
257 uint8_t valenc = _intsetValueEncoding(value);
258 return valenc <= intrev32ifbe(is->encoding) && intsetSearch(is,value,NULL);
259}
260
261/* Return random member */
262int64_t intsetRandom(intset *is) {
263 uint32_t len = intrev32ifbe(is->length);
264 assert(len); /* avoid division by zero on corrupt intset payload. */
265 return _intsetGet(is,rand()%len);
266}
267
268/* Get the value at the given position. When this position is
269 * out of range the function returns 0, when in range it returns 1. */
270uint8_t intsetGet(intset *is, uint32_t pos, int64_t *value) {
271 if (pos < intrev32ifbe(is->length)) {
272 *value = _intsetGet(is,pos);
273 return 1;
274 }
275 return 0;
276}
277
278/* Return intset length */
279uint32_t intsetLen(const intset *is) {
280 return intrev32ifbe(is->length);
281}
282
283/* Return intset blob size in bytes. */
284size_t intsetBlobLen(intset *is) {
285 return sizeof(intset)+(size_t)intrev32ifbe(is->length)*intrev32ifbe(is->encoding);
286}
287
288/* Validate the integrity of the data structure.
289 * when `deep` is 0, only the integrity of the header is validated.
290 * when `deep` is 1, we make sure there are no duplicate or out of order records. */
291int intsetValidateIntegrity(const unsigned char *p, size_t size, int deep) {
292 intset *is = (intset *)p;
293 /* check that we can actually read the header. */
294 if (size < sizeof(*is))
295 return 0;
296
297 uint32_t encoding = intrev32ifbe(is->encoding);
298
299 size_t record_size;
300 if (encoding == INTSET_ENC_INT64) {
301 record_size = INTSET_ENC_INT64;
302 } else if (encoding == INTSET_ENC_INT32) {
303 record_size = INTSET_ENC_INT32;
304 } else if (encoding == INTSET_ENC_INT16){
305 record_size = INTSET_ENC_INT16;
306 } else {
307 return 0;
308 }
309
310 /* check that the size matches (all records are inside the buffer). */
311 uint32_t count = intrev32ifbe(is->length);
312 if (sizeof(*is) + count*record_size != size)
313 return 0;
314
315 /* check that the set is not empty. */
316 if (count==0)
317 return 0;
318
319 if (!deep)
320 return 1;
321
322 /* check that there are no dup or out of order records. */
323 int64_t prev = _intsetGet(is,0);
324 for (uint32_t i=1; i<count; i++) {
325 int64_t cur = _intsetGet(is,i);
326 if (cur <= prev)
327 return 0;
328 prev = cur;
329 }
330
331 return 1;
332}
333
334#ifdef REDIS_TEST
335#include <sys/time.h>
336#include <time.h>
337
338#if 0
339static void intsetRepr(intset *is) {
340 for (uint32_t i = 0; i < intrev32ifbe(is->length); i++) {
341 printf("%lld\n", (uint64_t)_intsetGet(is,i));
342 }
343 printf("\n");
344}
345
346static void error(char *err) {
347 printf("%s\n", err);
348 exit(1);
349}
350#endif
351
352static void ok(void) {
353 printf("OK\n");
354}
355
356static long long usec(void) {
357 struct timeval tv;
358 gettimeofday(&tv,NULL);
359 return (((long long)tv.tv_sec)*1000000)+tv.tv_usec;
360}
361
362static intset *createSet(int bits, int size) {
363 uint64_t mask = (1<<bits)-1;
364 uint64_t value;
365 intset *is = intsetNew();
366
367 for (int i = 0; i < size; i++) {
368 if (bits > 32) {
369 value = (rand()*rand()) & mask;
370 } else {
371 value = rand() & mask;
372 }
373 is = intsetAdd(is,value,NULL);
374 }
375 return is;
376}
377
378static void checkConsistency(intset *is) {
379 for (uint32_t i = 0; i < (intrev32ifbe(is->length)-1); i++) {
380 uint32_t encoding = intrev32ifbe(is->encoding);
381
382 if (encoding == INTSET_ENC_INT16) {
383 int16_t *i16 = (int16_t*)is->contents;
384 assert(i16[i] < i16[i+1]);
385 } else if (encoding == INTSET_ENC_INT32) {
386 int32_t *i32 = (int32_t*)is->contents;
387 assert(i32[i] < i32[i+1]);
388 } else {
389 int64_t *i64 = (int64_t*)is->contents;
390 assert(i64[i] < i64[i+1]);
391 }
392 }
393}
394
395#define UNUSED(x) (void)(x)
396int intsetTest(int argc, char **argv, int flags) {
397 uint8_t success;
398 int i;
399 intset *is;
400 srand(time(NULL));
401
402 UNUSED(argc);
403 UNUSED(argv);
404 UNUSED(flags);
405
406 printf("Value encodings: "); {
407 assert(_intsetValueEncoding(-32768) == INTSET_ENC_INT16);
408 assert(_intsetValueEncoding(+32767) == INTSET_ENC_INT16);
409 assert(_intsetValueEncoding(-32769) == INTSET_ENC_INT32);
410 assert(_intsetValueEncoding(+32768) == INTSET_ENC_INT32);
411 assert(_intsetValueEncoding(-2147483648) == INTSET_ENC_INT32);
412 assert(_intsetValueEncoding(+2147483647) == INTSET_ENC_INT32);
413 assert(_intsetValueEncoding(-2147483649) == INTSET_ENC_INT64);
414 assert(_intsetValueEncoding(+2147483648) == INTSET_ENC_INT64);
415 assert(_intsetValueEncoding(-9223372036854775808ull) ==
416 INTSET_ENC_INT64);
417 assert(_intsetValueEncoding(+9223372036854775807ull) ==
418 INTSET_ENC_INT64);
419 ok();
420 }
421
422 printf("Basic adding: "); {
423 is = intsetNew();
424 is = intsetAdd(is,5,&success); assert(success);
425 is = intsetAdd(is,6,&success); assert(success);
426 is = intsetAdd(is,4,&success); assert(success);
427 is = intsetAdd(is,4,&success); assert(!success);
428 ok();
429 zfree(is);
430 }
431
432 printf("Large number of random adds: "); {
433 uint32_t inserts = 0;
434 is = intsetNew();
435 for (i = 0; i < 1024; i++) {
436 is = intsetAdd(is,rand()%0x800,&success);
437 if (success) inserts++;
438 }
439 assert(intrev32ifbe(is->length) == inserts);
440 checkConsistency(is);
441 ok();
442 zfree(is);
443 }
444
445 printf("Upgrade from int16 to int32: "); {
446 is = intsetNew();
447 is = intsetAdd(is,32,NULL);
448 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
449 is = intsetAdd(is,65535,NULL);
450 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
451 assert(intsetFind(is,32));
452 assert(intsetFind(is,65535));
453 checkConsistency(is);
454 zfree(is);
455
456 is = intsetNew();
457 is = intsetAdd(is,32,NULL);
458 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
459 is = intsetAdd(is,-65535,NULL);
460 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
461 assert(intsetFind(is,32));
462 assert(intsetFind(is,-65535));
463 checkConsistency(is);
464 ok();
465 zfree(is);
466 }
467
468 printf("Upgrade from int16 to int64: "); {
469 is = intsetNew();
470 is = intsetAdd(is,32,NULL);
471 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
472 is = intsetAdd(is,4294967295,NULL);
473 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
474 assert(intsetFind(is,32));
475 assert(intsetFind(is,4294967295));
476 checkConsistency(is);
477 zfree(is);
478
479 is = intsetNew();
480 is = intsetAdd(is,32,NULL);
481 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
482 is = intsetAdd(is,-4294967295,NULL);
483 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
484 assert(intsetFind(is,32));
485 assert(intsetFind(is,-4294967295));
486 checkConsistency(is);
487 ok();
488 zfree(is);
489 }
490
491 printf("Upgrade from int32 to int64: "); {
492 is = intsetNew();
493 is = intsetAdd(is,65535,NULL);
494 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
495 is = intsetAdd(is,4294967295,NULL);
496 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
497 assert(intsetFind(is,65535));
498 assert(intsetFind(is,4294967295));
499 checkConsistency(is);
500 zfree(is);
501
502 is = intsetNew();
503 is = intsetAdd(is,65535,NULL);
504 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
505 is = intsetAdd(is,-4294967295,NULL);
506 assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
507 assert(intsetFind(is,65535));
508 assert(intsetFind(is,-4294967295));
509 checkConsistency(is);
510 ok();
511 zfree(is);
512 }
513
514 printf("Stress lookups: "); {
515 long num = 100000, size = 10000;
516 int i, bits = 20;
517 long long start;
518 is = createSet(bits,size);
519 checkConsistency(is);
520
521 start = usec();
522 for (i = 0; i < num; i++) intsetSearch(is,rand() % ((1<<bits)-1),NULL);
523 printf("%ld lookups, %ld element set, %lldusec\n",
524 num,size,usec()-start);
525 zfree(is);
526 }
527
528 printf("Stress add+delete: "); {
529 int i, v1, v2;
530 is = intsetNew();
531 for (i = 0; i < 0xffff; i++) {
532 v1 = rand() % 0xfff;
533 is = intsetAdd(is,v1,NULL);
534 assert(intsetFind(is,v1));
535
536 v2 = rand() % 0xfff;
537 is = intsetRemove(is,v2,NULL);
538 assert(!intsetFind(is,v2));
539 }
540 checkConsistency(is);
541 ok();
542 zfree(is);
543 }
544
545 return 0;
546}
547#endif
548