src/intset.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include "intset.h"
   5 #include "zmalloc.h"
   6 #include "endian.h"
   7
   8 /* Note that these encodings are ordered, so:
   9  * INTSET_ENC_INT16 < INTSET_ENC_INT32 < INTSET_ENC_INT64. */
  10 #define INTSET_ENC_INT16 (sizeof(int16_t))
  11 #define INTSET_ENC_INT32 (sizeof(int32_t))
  12 #define INTSET_ENC_INT64 (sizeof(int64_t))
  13
  14 /* Return the required encoding for the provided value. */
  15 static uint8_t _intsetValueEncoding(int64_t v) {
  16     if (v < INT32_MIN || v > INT32_MAX)
  17         return INTSET_ENC_INT64;
  18     else if (v < INT16_MIN || v > INT16_MAX)
  19         return INTSET_ENC_INT32;
  20     else
  21         return INTSET_ENC_INT16;
  22 }
  23
  24 /* Return the value at pos, given an encoding. */
  25 static int64_t _intsetGetEncoded(intset *is, int pos, uint8_t enc) {
  26     int64_t v64;
  27     int32_t v32;
  28     int16_t v16;
  29
  30     if (enc == INTSET_ENC_INT64) {
  31         memcpy(&v64,((int64_t*)is->contents)+pos,sizeof(v64));
  32         memrev64ifbe(&v64);
  33         return v64;
  34     } else if (enc == INTSET_ENC_INT32) {
  35         memcpy(&v32,((int32_t*)is->contents)+pos,sizeof(v32));
  36         memrev32ifbe(&v32);
  37         return v32;
  38     } else {
  39         memcpy(&v16,((int16_t*)is->contents)+pos,sizeof(v16));
  40         memrev16ifbe(&v16);
  41         return v16;
  42     }
  43 }
  44
  45 /* Return the value at pos, using the configured encoding. */
  46 static int64_t _intsetGet(intset *is, int pos) {
  47     return _intsetGetEncoded(is,pos,intrev32ifbe(is->encoding));
  48 }
  49
  50 /* Set the value at pos, using the configured encoding. */
  51 static void _intsetSet(intset *is, int pos, int64_t value) {
  52     uint32_t encoding = intrev32ifbe(is->encoding);
  53
  54     if (encoding == INTSET_ENC_INT64) {
  55         ((int64_t*)is->contents)[pos] = value;
  56         memrev64ifbe(((int64_t*)is->contents)+pos);
  57     } else if (encoding == INTSET_ENC_INT32) {
  58         ((int32_t*)is->contents)[pos] = value;
  59         memrev32ifbe(((int32_t*)is->contents)+pos);
  60     } else {
  61         ((int16_t*)is->contents)[pos] = value;
  62         memrev16ifbe(((int16_t*)is->contents)+pos);
  63     }
  64 }
  65
  66 /* Create an empty intset. */
  67 intset *intsetNew(void) {
  68     intset *is = zmalloc(sizeof(intset));
  69     is->encoding = intrev32ifbe(INTSET_ENC_INT16);
  70     is->length = 0;
  71     return is;
  72 }
  73
  74 /* Resize the intset */
  75 static intset *intsetResize(intset *is, uint32_t len) {
  76     uint32_t size = len*intrev32ifbe(is->encoding);
  77     is = zrealloc(is,sizeof(intset)+size);
  78     return is;
  79 }
  80
  81 /* Search for the position of "value". Return 1 when the value was found and
  82  * sets "pos" to the position of the value within the intset. Return 0 when
  83  * the value is not present in the intset and sets "pos" to the position
  84  * where "value" can be inserted. */
  85 static uint8_t intsetSearch(intset *is, int64_t value, uint32_t *pos) {
  86     int min = 0, max = intrev32ifbe(is->length)-1, mid = -1;
  87     int64_t cur = -1;
  88
  89     /* The value can never be found when the set is empty */
  90     if (intrev32ifbe(is->length) == 0) {
  91         if (pos) *pos = 0;
  92         return 0;
  93     } else {
  94         /* Check for the case where we know we cannot find the value,
  95          * but do know the insert position. */
  96         if (value > _intsetGet(is,intrev32ifbe(is->length)-1)) {
  97             if (pos) *pos = intrev32ifbe(is->length);
  98             return 0;
  99         } else if (value < _intsetGet(is,0)) {
 100             if (pos) *pos = 0;
 101             return 0;
 102         }
 103     }
 104
 105     while(max >= min) {
 106         mid = (min+max)/2;
 107         cur = _intsetGet(is,mid);
 108         if (value > cur) {
 109             min = mid+1;
 110         } else if (value < cur) {
 111             max = mid-1;
 112         } else {
 113             break;
 114         }
 115     }
 116
 117     if (value == cur) {
 118         if (pos) *pos = mid;
 119         return 1;
 120     } else {
 121         if (pos) *pos = min;
 122         return 0;
 123     }
 124 }
 125
 126 /* Upgrades the intset to a larger encoding and inserts the given integer. */
 127 static intset *intsetUpgradeAndAdd(intset *is, int64_t value) {
 128     uint8_t curenc = intrev32ifbe(is->encoding);
 129     uint8_t newenc = _intsetValueEncoding(value);
 130     int length = intrev32ifbe(is->length);
 131     int prepend = value < 0 ? 1 : 0;
 132
 133     /* First set new encoding and resize */
 134     is->encoding = intrev32ifbe(newenc);
 135     is = intsetResize(is,intrev32ifbe(is->length)+1);
 136
 137     /* Upgrade back-to-front so we don't overwrite values.
 138      * Note that the "prepend" variable is used to make sure we have an empty
 139      * space at either the beginning or the end of the intset. */
 140     while(length--)
 141         _intsetSet(is,length+prepend,_intsetGetEncoded(is,length,curenc));
 142
 143     /* Set the value at the beginning or the end. */
 144     if (prepend)
 145         _intsetSet(is,0,value);
 146     else
 147         _intsetSet(is,intrev32ifbe(is->length),value);
 148     is->length = intrev32ifbe(intrev32ifbe(is->length)+1);
 149     return is;
 150 }
 151
 152 static void intsetMoveTail(intset *is, uint32_t from, uint32_t to) {
 153     void *src, *dst;
 154     uint32_t bytes = intrev32ifbe(is->length)-from;
 155     uint32_t encoding = intrev32ifbe(is->encoding);
 156
 157     if (encoding == INTSET_ENC_INT64) {
 158         src = (int64_t*)is->contents+from;
 159         dst = (int64_t*)is->contents+to;
 160         bytes *= sizeof(int64_t);
 161     } else if (encoding == INTSET_ENC_INT32) {
 162         src = (int32_t*)is->contents+from;
 163         dst = (int32_t*)is->contents+to;
 164         bytes *= sizeof(int32_t);
 165     } else {
 166         src = (int16_t*)is->contents+from;
 167         dst = (int16_t*)is->contents+to;
 168         bytes *= sizeof(int16_t);
 169     }
 170     memmove(dst,src,bytes);
 171 }
 172
 173 /* Insert an integer in the intset */
 174 intset *intsetAdd(intset *is, int64_t value, uint8_t *success) {
 175     uint8_t valenc = _intsetValueEncoding(value);
 176     uint32_t pos;
 177     if (success) *success = 1;
 178
 179     /* Upgrade encoding if necessary. If we need to upgrade, we know that
 180      * this value should be either appended (if > 0) or prepended (if < 0),
 181      * because it lies outside the range of existing values. */
 182     if (valenc > intrev32ifbe(is->encoding)) {
 183         /* This always succeeds, so we don't need to curry *success. */
 184         return intsetUpgradeAndAdd(is,value);
 185     } else {
 186         /* Abort if the value is already present in the set.
 187          * This call will populate "pos" with the right position to insert
 188          * the value when it cannot be found. */
 189         if (intsetSearch(is,value,&pos)) {
 190             if (success) *success = 0;
 191             return is;
 192         }
 193
 194         is = intsetResize(is,intrev32ifbe(is->length)+1);
 195         if (pos < intrev32ifbe(is->length)) intsetMoveTail(is,pos,pos+1);
 196     }
 197
 198     _intsetSet(is,pos,value);
 199     is->length = intrev32ifbe(intrev32ifbe(is->length)+1);
 200     return is;
 201 }
 202
 203 /* Delete integer from intset */
 204 intset *intsetRemove(intset *is, int64_t value, int *success) {
 205     uint8_t valenc = _intsetValueEncoding(value);
 206     uint32_t pos;
 207     if (success) *success = 0;
 208
 209     if (valenc <= intrev32ifbe(is->encoding) && intsetSearch(is,value,&pos)) {
 210         uint32_t len = intrev32ifbe(is->length);
 211
 212         /* We know we can delete */
 213         if (success) *success = 1;
 214
 215         /* Overwrite value with tail and update length */
 216         if (pos < (len-1)) intsetMoveTail(is,pos+1,pos);
 217         is = intsetResize(is,len-1);
 218         is->length = intrev32ifbe(len-1);
 219     }
 220     return is;
 221 }
 222
 223 /* Determine whether a value belongs to this set */
 224 uint8_t intsetFind(intset *is, int64_t value) {
 225     uint8_t valenc = _intsetValueEncoding(value);
 226     return valenc <= intrev32ifbe(is->encoding) && intsetSearch(is,value,NULL);
 227 }
 228
 229 /* Return random member */
 230 int64_t intsetRandom(intset *is) {
 231     return _intsetGet(is,rand()%intrev32ifbe(is->length));
 232 }
 233
 234 /* Sets the value to the value at the given position. When this position is
 235  * out of range the function returns 0, when in range it returns 1. */
 236 uint8_t intsetGet(intset *is, uint32_t pos, int64_t *value) {
 237     if (pos < intrev32ifbe(is->length)) {
 238         *value = _intsetGet(is,pos);
 239         return 1;
 240     }
 241     return 0;
 242 }
 243
 244 /* Return intset length */
 245 uint32_t intsetLen(intset *is) {
 246     return intrev32ifbe(is->length);
 247 }
 248
 249 /* Return intset blob size in bytes. */
 250 size_t intsetBlobLen(intset *is) {
 251     return sizeof(intset)+intrev32ifbe(is->length)*intrev32ifbe(is->encoding);
 252 }
 253
 254 #ifdef INTSET_TEST_MAIN
 255 #include <sys/time.h>
 256
 257 void intsetRepr(intset *is) {
 258     int i;
 259     for (i = 0; i < intrev32ifbe(is->length); i++) {
 260         printf("%lld\n", (uint64_t)_intsetGet(is,i));
 261     }
 262     printf("\n");
 263 }
 264
 265 void error(char *err) {
 266     printf("%s\n", err);
 267     exit(1);
 268 }
 269
 270 void ok(void) {
 271     printf("OK\n");
 272 }
 273
 274 long long usec(void) {
 275     struct timeval tv;
 276     gettimeofday(&tv,NULL);
 277     return (((long long)tv.tv_sec)*1000000)+tv.tv_usec;
 278 }
 279
 280 #define assert(_e) ((_e)?(void)0:(_assert(#_e,__FILE__,__LINE__),exit(1)))
 281 void _assert(char *estr, char *file, int line) {
 282     printf("\n\n=== ASSERTION FAILED ===\n");
 283     printf("==> %s:%d '%s' is not true\n",file,line,estr);
 284 }
 285
 286 intset *createSet(int bits, int size) {
 287     uint64_t mask = (1<<bits)-1;
 288     uint64_t i, value;
 289     intset *is = intsetNew();
 290
 291     for (i = 0; i < size; i++) {
 292         if (bits > 32) {
 293             value = (rand()*rand()) & mask;
 294         } else {
 295             value = rand() & mask;
 296         }
 297         is = intsetAdd(is,value,NULL);
 298     }
 299     return is;
 300 }
 301
 302 void checkConsistency(intset *is) {
 303     int i;
 304
 305     for (i = 0; i < (intrev32ifbe(is->length)-1); i++) {
 306         uint32_t encoding = intrev32ifbe(is->encoding);
 307
 308         if (encoding == INTSET_ENC_INT16) {
 309             int16_t *i16 = (int16_t*)is->contents;
 310             assert(i16[i] < i16[i+1]);
 311         } else if (encoding == INTSET_ENC_INT32) {
 312             int32_t *i32 = (int32_t*)is->contents;
 313             assert(i32[i] < i32[i+1]);
 314         } else {
 315             int64_t *i64 = (int64_t*)is->contents;
 316             assert(i64[i] < i64[i+1]);
 317         }
 318     }
 319 }
 320
 321 int main(int argc, char **argv) {
 322     uint8_t success;
 323     int i;
 324     intset *is;
 325     sranddev();
 326
 327     printf("Value encodings: "); {
 328         assert(_intsetValueEncoding(-32768) == INTSET_ENC_INT16);
 329         assert(_intsetValueEncoding(+32767) == INTSET_ENC_INT16);
 330         assert(_intsetValueEncoding(-32769) == INTSET_ENC_INT32);
 331         assert(_intsetValueEncoding(+32768) == INTSET_ENC_INT32);
 332         assert(_intsetValueEncoding(-2147483648) == INTSET_ENC_INT32);
 333         assert(_intsetValueEncoding(+2147483647) == INTSET_ENC_INT32);
 334         assert(_intsetValueEncoding(-2147483649) == INTSET_ENC_INT64);
 335         assert(_intsetValueEncoding(+2147483648) == INTSET_ENC_INT64);
 336         assert(_intsetValueEncoding(-9223372036854775808ull) == INTSET_ENC_INT64);
 337         assert(_intsetValueEncoding(+9223372036854775807ull) == INTSET_ENC_INT64);
 338         ok();
 339     }
 340
 341     printf("Basic adding: "); {
 342         is = intsetNew();
 343         is = intsetAdd(is,5,&success); assert(success);
 344         is = intsetAdd(is,6,&success); assert(success);
 345         is = intsetAdd(is,4,&success); assert(success);
 346         is = intsetAdd(is,4,&success); assert(!success);
 347         ok();
 348     }
 349
 350     printf("Large number of random adds: "); {
 351         int inserts = 0;
 352         is = intsetNew();
 353         for (i = 0; i < 1024; i++) {
 354             is = intsetAdd(is,rand()%0x800,&success);
 355             if (success) inserts++;
 356         }
 357         assert(intrev32ifbe(is->length) == inserts);
 358         checkConsistency(is);
 359         ok();
 360     }
 361
 362     printf("Upgrade from int16 to int32: "); {
 363         is = intsetNew();
 364         is = intsetAdd(is,32,NULL);
 365         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
 366         is = intsetAdd(is,65535,NULL);
 367         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
 368         assert(intsetFind(is,32));
 369         assert(intsetFind(is,65535));
 370         checkConsistency(is);
 371
 372         is = intsetNew();
 373         is = intsetAdd(is,32,NULL);
 374         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
 375         is = intsetAdd(is,-65535,NULL);
 376         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
 377         assert(intsetFind(is,32));
 378         assert(intsetFind(is,-65535));
 379         checkConsistency(is);
 380         ok();
 381     }
 382
 383     printf("Upgrade from int16 to int64: "); {
 384         is = intsetNew();
 385         is = intsetAdd(is,32,NULL);
 386         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
 387         is = intsetAdd(is,4294967295,NULL);
 388         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
 389         assert(intsetFind(is,32));
 390         assert(intsetFind(is,4294967295));
 391         checkConsistency(is);
 392
 393         is = intsetNew();
 394         is = intsetAdd(is,32,NULL);
 395         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT16);
 396         is = intsetAdd(is,-4294967295,NULL);
 397         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
 398         assert(intsetFind(is,32));
 399         assert(intsetFind(is,-4294967295));
 400         checkConsistency(is);
 401         ok();
 402     }
 403
 404     printf("Upgrade from int32 to int64: "); {
 405         is = intsetNew();
 406         is = intsetAdd(is,65535,NULL);
 407         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
 408         is = intsetAdd(is,4294967295,NULL);
 409         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
 410         assert(intsetFind(is,65535));
 411         assert(intsetFind(is,4294967295));
 412         checkConsistency(is);
 413
 414         is = intsetNew();
 415         is = intsetAdd(is,65535,NULL);
 416         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT32);
 417         is = intsetAdd(is,-4294967295,NULL);
 418         assert(intrev32ifbe(is->encoding) == INTSET_ENC_INT64);
 419         assert(intsetFind(is,65535));
 420         assert(intsetFind(is,-4294967295));
 421         checkConsistency(is);
 422         ok();
 423     }
 424
 425     printf("Stress lookups: "); {
 426         long num = 100000, size = 10000;
 427         int i, bits = 20;
 428         long long start;
 429         is = createSet(bits,size);
 430         checkConsistency(is);
 431
 432         start = usec();
 433         for (i = 0; i < num; i++) intsetSearch(is,rand() % ((1<<bits)-1),NULL);
 434         printf("%ld lookups, %ld element set, %lldusec\n",num,size,usec()-start);
 435     }
 436
 437     printf("Stress add+delete: "); {
 438         int i, v1, v2;
 439         is = intsetNew();
 440         for (i = 0; i < 0xffff; i++) {
 441             v1 = rand() % 0xfff;
 442             is = intsetAdd(is,v1,NULL);
 443             assert(intsetFind(is,v1));
 444
 445             v2 = rand() % 0xfff;
 446             is = intsetRemove(is,v2,NULL);
 447             assert(!intsetFind(is,v2));
 448         }
 449         checkConsistency(is);
 450         ok();
 451     }
 452 }
 453 #endif