src/intset.c

   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
  38 /* Note that these encodings are ordered, so:
  39  * INTSET_ENC_INT16 < INTSET_ENC_INT32 < INTSET_ENC_INT64. */
  40 #define INTSET_ENC_INT16 (sizeof(int16_t))
  41 #define INTSET_ENC_INT32 (sizeof(int32_t))
  42 #define INTSET_ENC_INT64 (sizeof(int64_t))
  43
  44 /* Return the required encoding for the provided value. */
  45 static uint8_t _intsetValueEncoding(int64_t v) {
  46     if (v < INT32_MIN || v > INT32_MAX)
  47         return INTSET_ENC_INT64;
  48     else if (v < INT16_MIN || v > INT16_MAX)
  49         return INTSET_ENC_INT32;
  50     else
  51         return INTSET_ENC_INT16;
  52 }
  53
  54 /* Return the value at pos, given an encoding. */
  55 static int64_t _intsetGetEncoded(intset *is, int pos, uint8_t enc) {
  56     int64_t v64;
  57     int32_t v32;
  58     int16_t v16;
  59
  60     if (enc == INTSET_ENC_INT64) {
  61         memcpy(&v64,((int64_t*)is->contents)+pos,sizeof(v64));
  62         memrev64ifbe(&v64);
  63         return v64;
  64     } else if (enc == INTSET_ENC_INT32) {
  65         memcpy(&v32,((int32_t*)is->contents)+pos,sizeof(v32));
  66         memrev32ifbe(&v32);
  67         return v32;
  68     } else {
  69         memcpy(&v16,((int16_t*)is->contents)+pos,sizeof(v16));
  70         memrev16ifbe(&v16);
  71         return v16;
  72     }
  73 }
  74
  75 /* Return the value at pos, using the configured encoding. */
  76 static int64_t _intsetGet(intset *is, int pos) {
  77     return _intsetGetEncoded(is,pos,intrev32ifbe(is->encoding));
  78 }
  79
  80 /* Set the value at pos, using the configured encoding. */
  81 static void _intsetSet(intset *is, int pos, int64_t value) {
  82     uint32_t encoding = intrev32ifbe(is->encoding);
  83
  84     if (encoding == INTSET_ENC_INT64) {
  85         ((int64_t*)is->contents)[pos] = value;
  86         memrev64ifbe(((int64_t*)is->contents)+pos);
  87     } else if (encoding == INTSET_ENC_INT32) {
  88         ((int32_t*)is->contents)[pos] = value;
  89         memrev32ifbe(((int32_t*)is->contents)+pos);
  90     } else {
  91         ((int16_t*)is->contents)[pos] = value;
  92         memrev16ifbe(((int16_t*)is->contents)+pos);
  93     }
  94 }
  95
  96 /* Create an empty intset. */
  97 intset *intsetNew(void) {
  98     intset *is = zmalloc(sizeof(intset));
  99     is->encoding = intrev32ifbe(INTSET_ENC_INT16);
 100     is->length = 0;
 101     return is;
 102 }
 103
 104 /* Resize the intset */
 105 static intset *intsetResize(intset *is, uint32_t len) {
 106     uint32_t size = len*intrev32ifbe(is->encoding);
 107     is = zrealloc(is,sizeof(intset)+size);
 108     return is;
 109 }
 110
 111 /* Search for the position of "value". Return 1 when the value was found and
 112  * sets "pos" to the position of the value within the intset. Return 0 when
 113  * the value is not present in the intset and sets "pos" to the position
 114  * where "value" can be inserted. */
 115 static uint8_t intsetSearch(intset *is, int64_t value, uint32_t *pos) {
 116     int min = 0, max = intrev32ifbe(is->length)-1, mid = -1;
 117     int64_t cur = -1;
 118
 119     /* The value can never be found when the set is empty */
 120     if (intrev32ifbe(is->length) == 0) {
 121         if (pos) *pos = 0;
 122         return 0;
 123     } else {
 124         /* Check for the case where we know we cannot find the value,
 125          * but do know the insert position. */
 126         if (value > _intsetGet(is,intrev32ifbe(is->length)-1)) {
 127             if (pos) *pos = intrev32ifbe(is->length);
 128             return 0;
 129         } else if (value < _intsetGet(is,0)) {
 130             if (pos) *pos = 0;
 131             return 0;
 132         }
 133     }
 134
 135     while(max >= min) {
 136         mid = (min+max)/2;
 137         cur = _intsetGet(is,mid);
 138         if (value > cur) {
 139             min = mid+1;
 140         } else if (value < cur) {
 141             max = mid-1;
 142         } else {
 143             break;
 144         }
 145     }
 146
 147     if (value == cur) {
 148         if (pos) *pos = mid;
 149         return 1;
 150     } else {
 151         if (pos) *pos = min;
 152         return 0;
 153     }
 154 }
 155
 156 /* Upgrades the intset to a larger encoding and inserts the given integer. */
 157 static intset *intsetUpgradeAndAdd(intset *is, int64_t value) {
 158     uint8_t curenc = intrev32ifbe(is->encoding);
 159     uint8_t newenc = _intsetValueEncoding(value);
 160     int length = intrev32ifbe(is->length);
 161     int prepend = value < 0 ? 1 : 0;
 162
 163     /* First set new encoding and resize */
 164     is->encoding = intrev32ifbe(newenc);
 165     is = intsetResize(is,intrev32ifbe(is->length)+1);
 166
 167     /* Upgrade back-to-front so we don't overwrite values.
 168      * Note that the "prepend" variable is used to make sure we have an empty
 169      * space at either the beginning or the end of the intset. */
 170     while(length--)
 171         _intsetSet(is,length+prepend,_intsetGetEncoded(is,length,curenc));
 172
 173     /* Set the value at the beginning or the end. */
 174     if (prepend)
 175         _intsetSet(is,0,value);
 176     else
 177         _intsetSet(is,intrev32ifbe(is->length),value);
 178     is->length = intrev32ifbe(intrev32ifbe(is->length)+1);
 179     return is;
 180 }
 181
 182 static void intsetMoveTail(intset *is, uint32_t from, uint32_t to) {
 183     void *src, *dst;
 184     uint32_t bytes = intrev32ifbe(is->length)-from;
 185     uint32_t encoding = intrev32ifbe(is->encoding);
 186
 187     if (encoding == INTSET_ENC_INT64) {
 188         src = (int64_t*)is->contents+from;
 189         dst = (int64_t*)is->contents+to;
 190         bytes *= sizeof(int64_t);
 191     } else if (encoding == INTSET_ENC_INT32) {
 192         src = (int32_t*)is->contents+from;
 193         dst = (int32_t*)is->contents+to;
 194         bytes *= sizeof(int32_t);
 195     } else {
 196         src = (int16_t*)is->contents+from;
 197         dst = (int16_t*)is->contents+to;
 198         bytes *= sizeof(int16_t);
 199     }
 200     memmove(dst,src,bytes);
 201 }
 202
 203 /* Insert an integer in the intset */
 204 intset *intsetAdd(intset *is, int64_t value, uint8_t *success) {
 205     uint8_t valenc = _intsetValueEncoding(value);
 206     uint32_t pos;
 207     if (success) *success = 1;
 208
 209     /* Upgrade encoding if necessary. If we need to upgrade, we know that
 210      * this value should be either appended (if > 0) or prepended (if < 0),
 211      * because it lies outside the range of existing values. */
 212     if (valenc > intrev32ifbe(is->encoding)) {
 213         /* This always succeeds, so we don't need to curry *success. */
 214         return intsetUpgradeAndAdd(is,value);
 215     } else {
 216         /* Abort if the value is already present in the set.
 217          * This call will populate "pos" with the right position to insert
 218          * the value when it cannot be found. */
 219         if (intsetSearch(is,value,&pos)) {
 220             if (success) *success = 0;
 221             return is;
 222         }
 223
 224         is = intsetResize(is,intrev32ifbe(is->length)+1);
 225         if (pos < intrev32ifbe(is->length)) intsetMoveTail(is,pos,pos+1);
 226     }
 227
 228     _intsetSet(is,pos,value);
 229     is->length = intrev32ifbe(intrev32ifbe(is->length)+1);
 230     return is;
 231 }
 232
 233 /* Delete integer from intset */
 234 intset *intsetRemove(intset *is, int64_t value, int *success) {
 235     uint8_t valenc = _intsetValueEncoding(value);
 236     uint32_t pos;
 237     if (success) *success = 0;
 238
 239     if (valenc <= intrev32ifbe(is->encoding) && intsetSearch(is,value,&pos)) {
 240         uint32_t len = intrev32ifbe(is->length);
 241
 242         /* We know we can delete */
 243         if (success) *success = 1;
 244
 245         /* Overwrite value with tail and update length */
 246         if (pos < (len-1)) intsetMoveTail(is,pos+1,pos);
 247         is = intsetResize(is,len-1);
 248         is->length = intrev32ifbe(len-1);
 249     }
 250     return is;
 251 }
 252
 253 /* Determine whether a value belongs to this set */
 254 uint8_t intsetFind(intset *is, int64_t value) {
 255     uint8_t valenc = _intsetValueEncoding(value);
 256     return valenc <= intrev32ifbe(is->encoding) && intsetSearch(is,value,NULL);
 257 }
 258
 259 /* Return random member */
 260 int64_t intsetRandom(intset *is) {
 261     return _intsetGet(is,rand()%intrev32ifbe(is->length));
 262 }
 263
 264 /* Sets the value to the value at the given position. When this position is
 265  * out of range the function returns 0, when in range it returns 1. */
 266 uint8_t intsetGet(intset *is, uint32_t pos, int64_t *value) {
 267     if (pos < intrev32ifbe(is->length)) {
 268         *value = _intsetGet(is,pos);
 269         return 1;
 270     }
 271     return 0;
 272 }
 273
 274 /* Return intset length */
 275 uint32_t intsetLen(intset *is) {
 276     return intrev32ifbe(is->length);
 277 }
 278
 279 /* Return intset blob size in bytes. */
 280 size_t intsetBlobLen(intset *is) {
 281     return sizeof(intset)+intrev32ifbe(is->length)*intrev32ifbe(is->encoding);
 282 }
 283
 284 #ifdef INTSET_TEST_MAIN
 285 #include <sys/time.h>
 286
 287 void intsetRepr(intset *is) {
 288     int i;
 289     for (i = 0; i < intrev32ifbe(is->length); i++) {
 290         printf("%lld\n", (uint64_t)_intsetGet(is,i));
 291     }
 292     printf("\n");
 293 }
 294
 295 void error(char *err) {
 296     printf("%s\n", err);
 297     exit(1);
 298 }
 299
 300 void ok(void) {
 301     printf("OK\n");
 302 }
 303
 304 long long usec(void) {
 305     struct timeval tv;
 306     gettimeofday(&tv,NULL);
 307     return (((long long)tv.tv_sec)*1000000)+tv.tv_usec;
 308 }
 309
 310 #define assert(_e) ((_e)?(void)0:(_assert(#_e,__FILE__,__LINE__),exit(1)))
 311 void _assert(char *estr, char *file, int line) {
 312     printf("\n\n=== ASSERTION FAILED ===\n");
 313     printf("==> %s:%d '%s' is not true\n",file,line,estr);
 314 }
 315
 316 intset *createSet(int bits, int size) {
 317     uint64_t mask = (1<<bits)-1;
 318     uint64_t i, value;
 319     intset *is = intsetNew();
 320
 321     for (i = 0; i < size; i++) {
 322         if (bits > 32) {
 323             value = (rand()*rand()) & mask;
 324         } else {
 325             value = rand() & mask;
 326         }
 327         is = intsetAdd(is,value,NULL);
 328     }
 329     return is;
 330 }
 331
 332 void checkConsistency(intset *is) {
 333     int i;
 334
 335     for (i = 0; i < (intrev32ifbe(is->length)-1); i++) {
 336         uint32_t encoding = intrev32ifbe(is->encoding);
 337
 338         if (encoding == INTSET_ENC_INT16) {
 339             int16_t *i16 = (int16_t*)is->contents;
 340             assert(i16[i] < i16[i+1]);
 341         } else if (encoding == INTSET_ENC_INT32) {
 342             int32_t *i32 = (int32_t*)is->contents;
 343             assert(i32[i] < i32[i+1]);
 344         } else {
 345             int64_t *i64 = (int64_t*)is->contents;
 346             assert(i64[i] < i64[i+1]);
 347         }
 348     }
 349 }
 350
 351 int main(int argc, char **argv) {
 352     uint8_t success;
 353     int i;
 354     intset *is;
 355     sranddev();
 356
 357     printf("Value encodings: "); {
 358         assert(_intsetValueEncoding(-32768) == INTSET_ENC_INT16);
 359         assert(_intsetValueEncoding(+32767) == INTSET_ENC_INT16);
 360         assert(_intsetValueEncoding(-32769) == INTSET_ENC_INT32);
 361         assert(_intsetValueEncoding(+32768) == INTSET_ENC_INT32);
 362         assert(_intsetValueEncoding(-2147483648) == INTSET_ENC_INT32);
 363         assert(_intsetValueEncoding(+2147483647) == INTSET_ENC_INT32);
 364         assert(_intsetValueEncoding(-2147483649) == INTSET_ENC_INT64);
 365         assert(_intsetValueEncoding(+2147483648) == INTSET_ENC_INT64);
 366         assert(_intsetValueEncoding(-9223372036854775808ull) == INTSET_ENC_INT64);
 367         assert(_intsetValueEncoding(+9223372036854775807ull) == INTSET_ENC_INT64);
 368         ok();
 369     }
 370
 371     printf("Basic adding: "); {
 372         is = intsetNew();
 373         is = intsetAdd(is,5,&success); assert(success);
 374         is = intsetAdd(is,6,&success); assert(success);
 375         is = intsetAdd(is,4,&success); assert(success);
 376         is = intsetAdd(is,4,&success); assert(!success);
 377         ok();
 378     }
 379
 380     printf("Large number of random adds: "); {
 381         int inserts = 0;
 382         is = intsetNew();
 383         for (i = 0; i < 1024; i++) {
 384             is = intsetAdd(is,rand()%0x800,&success);
 385             if (success) inserts++;
 386         }
 387         assert(intrev32ifbe(is->length) == inserts);
 388         checkConsistency(is);
 389         ok();
 390     }
 391
 392     printf("Upgrade from int16 to int32: "); {
 393         is = intsetNew();
 394         is = intsetAdd(is,32,NULL);
 395         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
 396         is = intsetAdd(is,65535,NULL);
 397         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
 398         assert(intsetFind(is,32));
 399         assert(intsetFind(is,65535));
 400         checkConsistency(is);
 401
 402         is = intsetNew();
 403         is = intsetAdd(is,32,NULL);
 404         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
 405         is = intsetAdd(is,-65535,NULL);
 406         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
 407         assert(intsetFind(is,32));
 408         assert(intsetFind(is,-65535));
 409         checkConsistency(is);
 410         ok();
 411     }
 412
 413     printf("Upgrade from int16 to int64: "); {
 414         is = intsetNew();
 415         is = intsetAdd(is,32,NULL);
 416         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
 417         is = intsetAdd(is,4294967295,NULL);
 418         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
 419         assert(intsetFind(is,32));
 420         assert(intsetFind(is,4294967295));
 421         checkConsistency(is);
 422
 423         is = intsetNew();
 424         is = intsetAdd(is,32,NULL);
 425         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
 426         is = intsetAdd(is,-4294967295,NULL);
 427         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
 428         assert(intsetFind(is,32));
 429         assert(intsetFind(is,-4294967295));
 430         checkConsistency(is);
 431         ok();
 432     }
 433
 434     printf("Upgrade from int32 to int64: "); {
 435         is = intsetNew();
 436         is = intsetAdd(is,65535,NULL);
 437         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
 438         is = intsetAdd(is,4294967295,NULL);
 439         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
 440         assert(intsetFind(is,65535));
 441         assert(intsetFind(is,4294967295));
 442         checkConsistency(is);
 443
 444         is = intsetNew();
 445         is = intsetAdd(is,65535,NULL);
 446         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
 447         is = intsetAdd(is,-4294967295,NULL);
 448         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
 449         assert(intsetFind(is,65535));
 450         assert(intsetFind(is,-4294967295));
 451         checkConsistency(is);
 452         ok();
 453     }
 454
 455     printf("Stress lookups: "); {
 456         long num = 100000, size = 10000;
 457         int i, bits = 20;
 458         long long start;
 459         is = createSet(bits,size);
 460         checkConsistency(is);
 461
 462         start = usec();
 463         for (i = 0; i < num; i++) intsetSearch(is,rand() % ((1<<bits)-1),NULL);
 464         printf("%ld lookups, %ld element set, %lldusec\n",num,size,usec()-start);
 465     }
 466
 467     printf("Stress add+delete: "); {
 468         int i, v1, v2;
 469         is = intsetNew();
 470         for (i = 0; i < 0xffff; i++) {
 471             v1 = rand() % 0xfff;
 472             is = intsetAdd(is,v1,NULL);
 473             assert(intsetFind(is,v1));
 474
 475             v2 = rand() % 0xfff;
 476             is = intsetRemove(is,v2,NULL);
 477             assert(!intsetFind(is,v2));
 478         }
 479         checkConsistency(is);
 480         ok();
 481     }
 482 }
 483 #endif