nsz Git - libfirm/blob - ir/adt/set.c

   1 /*
   2  * Copyright (C) 1995-2011 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief       implementation of set
  23  * @author      Markus Armbruster
  24  */
  25
  26 /*  This code is derived from:
  27
  28     From: ejp@ausmelb.oz.AU (Esmond Pitt)
  29     Date: Tue, 7 Mar 1989 22:06:26 GMT
  30     Subject: v06i042: dynamic hashing version of hsearch(3)
  31     Message-ID: <1821@basser.oz>
  32     Newsgroups: comp.sources.misc
  33     Sender: msgs@basser.oz
  34
  35     Posting-number: Volume 6, Issue 42
  36     Submitted-By: Esmond Pitt <ejp@ausmelb.oz.AU>
  37     Archive-name: dynamic-hash
  38
  39     * Dynamic hashing, after CACM April 1988 pp 446-457, by Per-Ake Larson.
  40     * Coded into C, with minor code improvements, and with hsearch(3) interface,
  41     * by ejp@ausmelb.oz, Jul 26, 1988: 13:16;
  42
  43     TODO: Fix Esmond's ugly MixedCapsIdentifiers ;->
  44  */
  45 #include "config.h"
  46
  47 #ifdef PSET
  48 # define SET pset
  49 # define PMANGLE(pre) pre##_pset
  50 # define MANGLEP(post) pset_##post
  51 # define MANGLE(pre, post) pre##pset##post
  52 # define EQUAL(cmp, elt, key, siz) (!(cmp) ((elt)->entry.dptr, (key)))
  53 #else
  54 # define SET set
  55 # define PMANGLE(pre) pre##_set
  56 # define MANGLEP(post) set_##post
  57 # define MANGLE(pre, post) pre##set##post
  58 # define EQUAL(cmp, elt, key, siz) \
  59     (((elt)->entry.size == (siz)) && !(cmp) ((elt)->entry.dptr, (key), (siz)))
  60 #endif
  61
  62 #include <assert.h>
  63 #include <stdlib.h>
  64 #include <stdio.h>
  65 #include <string.h>
  66 #include "xmalloc.h"
  67 #include "lc_printf.h"
  68 #ifdef PSET
  69 # include "pset.h"
  70 #else
  71 # include "set.h"
  72 #endif
  73
  74
  75 #define TOBSTACK_ID MANGLEP(tag)
  76 #include "obst.h"
  77
  78
  79 #define SEGMENT_SIZE_SHIFT   8
  80 #define SEGMENT_SIZE         (1 << SEGMENT_SIZE_SHIFT)
  81 #define DIRECTORY_SIZE_SHIFT 8
  82 #define DIRECTORY_SIZE       (1 << DIRECTORY_SIZE_SHIFT)
  83 #define MAX_LOAD_FACTOR      4
  84
  85
  86 typedef struct element {
  87         struct element *chain;    /**< for chaining Elements */
  88         MANGLEP (entry) entry;
  89 } Element, *Segment;
  90
  91
  92 struct SET {
  93         size_t p;             /**< Next bucket to be split */
  94         size_t maxp;          /**< upper bound on p during expansion */
  95         size_t nkey;          /**< current # keys */
  96         size_t nseg;          /**< current # segments */
  97         Segment *dir[DIRECTORY_SIZE];
  98         MANGLEP(cmp_fun) cmp;     /**< function comparing entries */
  99         unsigned iter_i, iter_j;
 100         Element *iter_tail;       /**< non-NULL while iterating over elts */
 101 #ifdef PSET
 102         Element *free_list;       /**< list of free Elements */
 103 #endif
 104         struct obstack obst;      /**< obstack for allocation all data */
 105 #ifdef STATS
 106         size_t naccess, ncollision, ndups;
 107         size_t max_chain_len;
 108 #endif
 109 };
 110
 111
 112 #ifdef STATS
 113
 114 void MANGLEP(stats) (SET *table)
 115 {
 116         size_t nfree = 0;
 117 #ifdef PSET
 118         Element *q = table->free_list;
 119         while (q) { q = q->chain; ++nfree; }
 120 #endif
 121         lc_printf("     accesses  collisions        keys  duplicates     longest      wasted\n%12zu%12zu%12zu%12zu%12zu%12zu\n",
 122                         table->naccess, table->ncollision, table->nkey, table->ndups, table->max_chain_len, nfree);
 123 }
 124
 125 static inline void stat_chain_len(SET *table, size_t chain_len)
 126 {
 127         table->ncollision += chain_len;
 128         if (table->max_chain_len < chain_len) table->max_chain_len = chain_len;
 129 }
 130
 131 # define stat_access(table) (++(table)->naccess)
 132 # define stat_dup(table) (++(table)->ndups)
 133
 134 #else /* !STATS */
 135
 136 # define stat_chain_len(table, chain_len) ((void)chain_len)
 137 # define stat_access(table) ((void)0)
 138 # define stat_dup(table) ((void)0)
 139
 140 #endif /* !STATS */
 141
 142 SET *(PMANGLE(new)) (MANGLEP(cmp_fun) cmp, size_t nslots)
 143 {
 144         SET   *table = XMALLOC(SET);
 145         size_t i;
 146
 147         if (nslots > SEGMENT_SIZE * DIRECTORY_SIZE)
 148                 nslots = DIRECTORY_SIZE;
 149         else {
 150                 /* Adjust nslots up to next power of 2, minimum SEGMENT_SIZE */
 151                 for (i = SEGMENT_SIZE;  i < nslots;  i <<= 1) {
 152                 }
 153                 nslots = i >> SEGMENT_SIZE_SHIFT;
 154         }
 155
 156         table->nseg = table->p = table->nkey = 0;
 157         table->maxp = nslots << SEGMENT_SIZE_SHIFT;
 158         table->cmp = cmp;
 159         table->iter_tail = NULL;
 160 #ifdef PSET
 161         table->free_list = NULL;
 162 #endif
 163         obstack_init (&table->obst);
 164
 165         /* Make segments */
 166         for (i = 0;  i < nslots;  ++i) {
 167                 table->dir[i] = OALLOCNZ(&table->obst, Segment, SEGMENT_SIZE);
 168                 table->nseg++;
 169         }
 170
 171 #ifdef STATS
 172         table->naccess = table->ncollision = table->ndups = 0;
 173         table->max_chain_len = 0;
 174 #endif
 175         return table;
 176 }
 177
 178
 179 void PMANGLE(del) (SET *table)
 180 {
 181         obstack_free (&table->obst, NULL);
 182         xfree (table);
 183 }
 184
 185 size_t MANGLEP(count) (SET *table)
 186 {
 187         return table->nkey;
 188 }
 189
 190 /*
 191  * do one iteration step, return 1
 192  * if still data in the set, 0 else
 193  */
 194 static inline int iter_step(SET *table)
 195 {
 196         if (++table->iter_j >= SEGMENT_SIZE) {
 197                 table->iter_j = 0;
 198                 if (++table->iter_i >= table->nseg) {
 199                         table->iter_i = 0;
 200                         return 0;
 201                 }
 202         }
 203         return 1;
 204 }
 205
 206 /*
 207  * finds the first entry in the table
 208  */
 209 void * MANGLEP(first) (SET *table)
 210 {
 211         assert (!table->iter_tail);
 212         table->iter_i = 0;
 213         table->iter_j = 0;
 214         while (!table->dir[table->iter_i][table->iter_j]) {
 215                 if (!iter_step (table)) return NULL;
 216         }
 217         table->iter_tail = table->dir[table->iter_i][table->iter_j];
 218         assert (table->iter_tail->entry.dptr);
 219         return table->iter_tail->entry.dptr;
 220 }
 221
 222 /*
 223  * returns next entry in the table
 224  */
 225 void *MANGLEP(next) (SET *table)
 226 {
 227         if (!table->iter_tail)
 228                 return NULL;
 229
 230         /* follow collision chain */
 231         table->iter_tail = table->iter_tail->chain;
 232         if (!table->iter_tail) {
 233                 /* go to next segment */
 234                 do {
 235                         if (!iter_step (table)) return NULL;
 236                 } while (!table->dir[table->iter_i][table->iter_j]);
 237                 table->iter_tail = table->dir[table->iter_i][table->iter_j];
 238         }
 239         assert (table->iter_tail->entry.dptr);
 240         return table->iter_tail->entry.dptr;
 241 }
 242
 243 void MANGLEP(break) (SET *table)
 244 {
 245         table->iter_tail = NULL;
 246 }
 247
 248 /*
 249  * limit the hash value
 250  */
 251 static inline unsigned Hash(SET *table, unsigned h)
 252 {
 253         unsigned address;
 254         address = h & (table->maxp - 1);          /* h % table->maxp */
 255         if (address < (unsigned)table->p)
 256                 address = h & ((table->maxp << 1) - 1); /* h % (2*table->maxp) */
 257         return address;
 258 }
 259
 260 /*
 261  * returns non-zero if the number of elements in
 262  * the set is greater then number of segments * MAX_LOAD_FACTOR
 263  */
 264 static inline int loaded(SET *table)
 265 {
 266         return (  ++table->nkey
 267                         > (table->nseg << SEGMENT_SIZE_SHIFT) * MAX_LOAD_FACTOR);
 268 }
 269
 270 /*
 271  * expand the hash-table: the algorithm is split, so on every
 272  * insert, only ONE segment is rehashed!
 273  *
 274  * table->p contains the current segment to split
 275  * after all segments were split, table->p is set to zero and
 276  * table->maxp is duplicated.
 277  */
 278 static void expand_table(SET *table)
 279 {
 280         size_t NewAddress;
 281         size_t OldSegmentIndex, NewSegmentIndex;
 282         size_t OldSegmentDir, NewSegmentDir;
 283         Segment *OldSegment;
 284         Segment *NewSegment;
 285         Element *Current;
 286         Element **Previous;
 287         Element **LastOfNew;
 288
 289         if (table->maxp + table->p < (DIRECTORY_SIZE << SEGMENT_SIZE_SHIFT)) {
 290                 /* Locate the bucket to be split */
 291                 OldSegmentDir   = table->p >> SEGMENT_SIZE_SHIFT;
 292                 OldSegment      = table->dir[OldSegmentDir];
 293                 OldSegmentIndex = table->p & (SEGMENT_SIZE-1);
 294
 295                 /* Expand address space; if necessary create a new segment */
 296                 NewAddress      = table->maxp + table->p;
 297                 NewSegmentDir   = NewAddress >> SEGMENT_SIZE_SHIFT;
 298                 NewSegmentIndex = NewAddress & (SEGMENT_SIZE-1);
 299                 if (NewSegmentIndex == 0) {
 300                         table->dir[NewSegmentDir] = OALLOCNZ(&table->obst, Segment, SEGMENT_SIZE);
 301                         table->nseg++;
 302                 }
 303                 NewSegment = table->dir[NewSegmentDir];
 304
 305                 /* Adjust state variables */
 306                 table->p++;
 307                 if (table->p == table->maxp) {
 308                         table->maxp <<= 1;  /* table->maxp *= 2 */
 309                         table->p = 0;
 310                 }
 311
 312                 /* Relocate records to the new bucket */
 313                 Previous = &OldSegment[OldSegmentIndex];
 314                 Current = *Previous;
 315                 LastOfNew = &NewSegment[NewSegmentIndex];
 316                 *LastOfNew = NULL;
 317                 while (Current != NULL) {
 318                         if (Hash (table, Current->entry.hash) == NewAddress) {
 319                                 /* move to new chain */
 320                                 *LastOfNew = Current;
 321                                 *Previous  = Current->chain;
 322                                 LastOfNew  = &Current->chain;
 323                                 Current    = Current->chain;
 324                                 *LastOfNew = NULL;
 325                         } else {
 326                                 /* leave on old chain */
 327                                 Previous = &Current->chain;
 328                                 Current = Current->chain;
 329                         }
 330                 }
 331         }
 332 }
 333
 334
 335 void * MANGLE(_,_search) (SET *table,
 336                 const void *key,
 337 #ifndef PSET
 338                 size_t size,
 339 #endif
 340                 unsigned hash,
 341                 MANGLE(_,_action) action)
 342 {
 343         unsigned h;
 344         Segment *CurrentSegment;
 345         int SegmentIndex;
 346         MANGLEP(cmp_fun) cmp = table->cmp;
 347         Segment q;
 348         size_t chain_len = 0;
 349
 350         assert (table);
 351         assert (key);
 352         stat_access (table);
 353
 354         /* Find collision chain */
 355         h = Hash (table, hash);
 356         SegmentIndex   = h & (SEGMENT_SIZE-1);
 357         CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
 358         assert (CurrentSegment != NULL);
 359         q = CurrentSegment[SegmentIndex];
 360
 361         /* Follow collision chain */
 362         while (q && !EQUAL (cmp, q, key, size)) {
 363                 q = q->chain;
 364                 ++chain_len;
 365         }
 366
 367         stat_chain_len(table, chain_len);
 368
 369         if (!q && (action != MANGLE(_,_find))) { /* not found, insert */
 370                 assert (!table->iter_tail && "insert an element into a set that is iterated");
 371
 372                 if (CurrentSegment[SegmentIndex]) stat_dup (table);
 373
 374 #ifdef PSET
 375                 if (table->free_list) {
 376                         q = table->free_list;
 377                         table->free_list = table->free_list->chain;
 378                 } else {
 379                         q = OALLOC(&table->obst, Element);
 380                 }
 381                 q->entry.dptr = (void *)key;
 382 #else
 383                 obstack_blank (&table->obst, offsetof (Element, entry.dptr));
 384                 if (action == _set_hinsert0)
 385                         obstack_grow0 (&table->obst, key, size);
 386                 else
 387                         obstack_grow (&table->obst, key, size);
 388                 q = (Segment) obstack_finish (&table->obst);
 389                 q->entry.size = size;
 390 #endif
 391                 q->chain = CurrentSegment[SegmentIndex];
 392                 q->entry.hash = hash;
 393                 CurrentSegment[SegmentIndex] = q;
 394
 395                 if (loaded (table)) {
 396                         expand_table(table);    /* doesn't affect q */
 397                 }
 398         }
 399
 400         if (!q) return NULL;
 401 #ifdef PSET
 402         if (action == _pset_hinsert) return &q->entry;
 403 #else
 404         if (action == _set_hinsert || action == _set_hinsert0) return &q->entry;
 405 #endif
 406         return q->entry.dptr;
 407 }
 408
 409
 410 #ifdef PSET
 411
 412 int pset_default_ptr_cmp(const void *x, const void *y)
 413 {
 414         return x != y;
 415 }
 416
 417 void *pset_remove(SET *table, const void *key, unsigned hash)
 418 {
 419         unsigned h;
 420         Segment *CurrentSegment;
 421         int SegmentIndex;
 422         pset_cmp_fun cmp = table->cmp;
 423         Segment *p;
 424         Segment q;
 425         int chain_len = 0;
 426
 427         assert (table && !table->iter_tail);
 428         stat_access (table);
 429
 430         /* Find collision chain */
 431         h = Hash (table, hash);
 432         SegmentIndex = h & (SEGMENT_SIZE-1);
 433         CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
 434         assert (CurrentSegment != NULL);
 435         p = &CurrentSegment[SegmentIndex];
 436
 437         /* Follow collision chain */
 438         while (!EQUAL (cmp, *p, key, size)) {
 439                 p = &(*p)->chain;
 440                 assert (*p);
 441                 ++chain_len;
 442         }
 443
 444         stat_chain_len (table, chain_len);
 445
 446         q = *p;
 447
 448         if (q == table->iter_tail) {
 449                 /* removing current element */
 450                 table->iter_tail = q->chain;
 451                 if (!table->iter_tail) {
 452                         /* go to next segment */
 453                         do {
 454                                 if (!iter_step (table))
 455                                         break;
 456                         } while (!table->dir[table->iter_i][table->iter_j]);
 457                         table->iter_tail = table->dir[table->iter_i][table->iter_j];
 458                 }
 459         }
 460
 461         *p = (*p)->chain;
 462         q->chain = table->free_list;
 463         table->free_list = q;
 464         --table->nkey;
 465
 466         return q->entry.dptr;
 467 }
 468
 469
 470 void *(pset_find) (SET *se, const void *key, unsigned hash)
 471 {
 472         return pset_find (se, key, hash);
 473 }
 474
 475
 476 void *(pset_insert) (SET *se, const void *key, unsigned hash)
 477 {
 478         return pset_insert (se, key, hash);
 479 }
 480
 481
 482         MANGLEP(entry) *
 483 (pset_hinsert) (SET *se, const void *key, unsigned hash)
 484 {
 485         return pset_hinsert (se, key, hash);
 486 }
 487
 488 void pset_insert_pset_ptr(pset *target, pset *src)
 489 {
 490         void *elt;
 491         for (elt = pset_first(src); elt; elt = pset_next(src)) {
 492                 pset_insert_ptr(target, elt);
 493         }
 494 }
 495
 496 #else /* !PSET */
 497
 498 void *(set_find) (set *se, const void *key, size_t size, unsigned hash)
 499 {
 500         return set_find (se, key, size, hash);
 501 }
 502
 503
 504 void *(set_insert) (set *se, const void *key, size_t size, unsigned hash)
 505 {
 506         return set_insert (se, key, size, hash);
 507 }
 508
 509
 510 set_entry *(set_hinsert) (set *se, const void *key, size_t size, unsigned hash)
 511 {
 512         return set_hinsert (se, key, size, hash);
 513 }
 514
 515 #endif /* !PSET */