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

   1 /*
   2  * Copyright (C) 1995-2008 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  * @version     $Id$
  25  */
  26
  27 /*  This code is derived from:
  28
  29     From: ejp@ausmelb.oz.AU (Esmond Pitt)
  30     Date: Tue, 7 Mar 1989 22:06:26 GMT
  31     Subject: v06i042: dynamic hashing version of hsearch(3)
  32     Message-ID: <1821@basser.oz>
  33     Newsgroups: comp.sources.misc
  34     Sender: msgs@basser.oz
  35
  36     Posting-number: Volume 6, Issue 42
  37     Submitted-By: Esmond Pitt <ejp@ausmelb.oz.AU>
  38     Archive-name: dynamic-hash
  39
  40     * Dynamic hashing, after CACM April 1988 pp 446-457, by Per-Ake Larson.
  41     * Coded into C, with minor code improvements, and with hsearch(3) interface,
  42     * by ejp@ausmelb.oz, Jul 26, 1988: 13:16;
  43
  44     TODO: Fix Esmond's ugly MixedCapsIdentifiers ;->
  45  */
  46 #include "config.h"
  47
  48 #ifdef PSET
  49 # define SET pset
  50 # define PMANGLE(pre) pre##_pset
  51 # define MANGLEP(post) pset_##post
  52 # define MANGLE(pre, post) pre##pset##post
  53 # define EQUAL(cmp, elt, key, siz) (!(cmp) ((elt)->entry.dptr, (key)))
  54 #else
  55 # define SET set
  56 # define PMANGLE(pre) pre##_set
  57 # define MANGLEP(post) set_##post
  58 # define MANGLE(pre, post) pre##set##post
  59 # define EQUAL(cmp, elt, key, siz) \
  60     (((elt)->entry.size == (siz)) && !(cmp) ((elt)->entry.dptr, (key), (siz)))
  61 #endif
  62
  63 #include <assert.h>
  64 #include <stdlib.h>
  65 #include <stdio.h>
  66 #include <string.h>
  67 #include "xmalloc.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         unsigned p;           /**< Next bucket to be split */
  94         unsigned maxp;        /**< upper bound on p during expansion */
  95         unsigned nkey;        /**< current # keys */
  96         unsigned 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         int naccess, ncollision, ndups;
 107         int max_chain_len;
 108 #endif
 109 #ifdef DEBUG
 110         const char *tag;          /**< an optionally tag for distinguishing sets */
 111 #endif
 112 };
 113
 114
 115 #ifdef STATS
 116
 117 void MANGLEP(stats) (SET *table)
 118 {
 119         int nfree = 0;
 120 #ifdef PSET
 121         Element *q = table->free_list;
 122         while (q) { q = q->chain; ++nfree; }
 123 #endif
 124         printf ("     accesses  collisions        keys  duplicates     longest      wasted\n%12d%12d%12d%12d%12d%12d\n",
 125                         table->naccess, table->ncollision, table->nkey, table->ndups, table->max_chain_len, nfree);
 126 }
 127
 128 static inline void stat_chain_len(SET *table, int chain_len)
 129 {
 130         table->ncollision += chain_len;
 131         if (table->max_chain_len < chain_len) table->max_chain_len = chain_len;
 132 }
 133
 134 # define stat_access(table) (++(table)->naccess)
 135 # define stat_dup(table) (++(table)->ndups)
 136
 137 #else /* !STATS */
 138
 139 # define stat_chain_len(table, chain_len) ((void)chain_len)
 140 # define stat_access(table) ((void)0)
 141 # define stat_dup(table) ((void)0)
 142
 143 #endif /* !STATS */
 144
 145 #ifdef DEBUG
 146
 147 const char *MANGLEP(tag);
 148
 149
 150 void MANGLEP(describe) (SET *table)
 151 {
 152         unsigned i, j, collide;
 153         Element *ptr;
 154         Segment *seg;
 155
 156         printf ("p=%u maxp=%u nkey=%u nseg=%u\n",
 157                         table->p, table->maxp, table->nkey, table->nseg);
 158         for (i = 0;  i < table->nseg;  i++) {
 159                 seg = table->dir[i];
 160                 for (j = 0;  j < SEGMENT_SIZE;  j++) {
 161                         collide = 0;
 162                         ptr = seg[j];
 163                         while (ptr) {
 164                                 if (collide) printf ("<%3d>", collide);
 165                                 else printf ("table");
 166                                 printf ("[%d][%3d]: %u %p\n", i, j, ptr->entry.hash, (void *)ptr->entry.dptr);
 167                                 ptr = ptr->chain;
 168                                 collide++;
 169                         }
 170                 }
 171         }
 172 #ifdef STATS
 173         MANGLEP(stats)(table);
 174 #endif
 175 }
 176
 177 #endif /* !DEBUG */
 178
 179
 180 SET *(PMANGLE(new)) (MANGLEP(cmp_fun) cmp, int nslots)
 181 {
 182         int i;
 183         SET *table = XMALLOC(SET);
 184
 185         if (nslots > SEGMENT_SIZE * DIRECTORY_SIZE)
 186                 nslots = DIRECTORY_SIZE;
 187         else {
 188                 assert (nslots >= 0);
 189                 /* Adjust nslots up to next power of 2, minimum SEGMENT_SIZE */
 190                 for (i = SEGMENT_SIZE;  i < nslots;  i <<= 1) {
 191                 }
 192                 nslots = i >> SEGMENT_SIZE_SHIFT;
 193         }
 194
 195         table->nseg = table->p = table->nkey = 0;
 196         table->maxp = nslots << SEGMENT_SIZE_SHIFT;
 197         table->cmp = cmp;
 198         table->iter_tail = NULL;
 199 #ifdef PSET
 200         table->free_list = NULL;
 201 #endif
 202         obstack_init (&table->obst);
 203
 204         /* Make segments */
 205         for (i = 0;  i < nslots;  ++i) {
 206                 table->dir[i] = OALLOCNZ(&table->obst, Segment, SEGMENT_SIZE);
 207                 table->nseg++;
 208         }
 209
 210 #ifdef STATS
 211         table->naccess = table->ncollision = table->ndups = 0;
 212         table->max_chain_len = 0;
 213 #endif
 214 #ifdef DEBUG
 215         table->tag = MANGLEP(tag);
 216 #endif
 217         return table;
 218 }
 219
 220
 221 void PMANGLE(del) (SET *table)
 222 {
 223 #ifdef DEBUG
 224         MANGLEP(tag) = table->tag;
 225 #endif
 226         obstack_free (&table->obst, NULL);
 227         xfree (table);
 228 }
 229
 230 int MANGLEP(count) (SET *table)
 231 {
 232         return table->nkey;
 233 }
 234
 235 /*
 236  * do one iteration step, return 1
 237  * if still data in the set, 0 else
 238  */
 239 static inline int iter_step(SET *table)
 240 {
 241         if (++table->iter_j >= SEGMENT_SIZE) {
 242                 table->iter_j = 0;
 243                 if (++table->iter_i >= table->nseg) {
 244                         table->iter_i = 0;
 245                         return 0;
 246                 }
 247         }
 248         return 1;
 249 }
 250
 251 /*
 252  * finds the first entry in the table
 253  */
 254 void * MANGLEP(first) (SET *table)
 255 {
 256         assert (!table->iter_tail);
 257         table->iter_i = 0;
 258         table->iter_j = 0;
 259         while (!table->dir[table->iter_i][table->iter_j]) {
 260                 if (!iter_step (table)) return NULL;
 261         }
 262         table->iter_tail = table->dir[table->iter_i][table->iter_j];
 263         assert (table->iter_tail->entry.dptr);
 264         return table->iter_tail->entry.dptr;
 265 }
 266
 267 /*
 268  * returns next entry in the table
 269  */
 270 void *MANGLEP(next) (SET *table)
 271 {
 272         if (!table->iter_tail)
 273                 return NULL;
 274
 275         /* follow collision chain */
 276         table->iter_tail = table->iter_tail->chain;
 277         if (!table->iter_tail) {
 278                 /* go to next segment */
 279                 do {
 280                         if (!iter_step (table)) return NULL;
 281                 } while (!table->dir[table->iter_i][table->iter_j]);
 282                 table->iter_tail = table->dir[table->iter_i][table->iter_j];
 283         }
 284         assert (table->iter_tail->entry.dptr);
 285         return table->iter_tail->entry.dptr;
 286 }
 287
 288 void MANGLEP(break) (SET *table)
 289 {
 290         table->iter_tail = NULL;
 291 }
 292
 293 /*
 294  * limit the hash value
 295  */
 296 static inline unsigned Hash(SET *table, unsigned h)
 297 {
 298         unsigned address;
 299         address = h & (table->maxp - 1);          /* h % table->maxp */
 300         if (address < (unsigned)table->p)
 301                 address = h & ((table->maxp << 1) - 1); /* h % (2*table->maxp) */
 302         return address;
 303 }
 304
 305 /*
 306  * returns non-zero if the number of elements in
 307  * the set is greater then number of segments * MAX_LOAD_FACTOR
 308  */
 309 static inline int loaded(SET *table)
 310 {
 311         return (  ++table->nkey
 312                         > (table->nseg << SEGMENT_SIZE_SHIFT) * MAX_LOAD_FACTOR);
 313 }
 314
 315 /*
 316  * expand the hash-table: the algorithm is split, so on every
 317  * insert, only ONE segment is rehashed!
 318  *
 319  * table->p contains the current segment to split
 320  * after all segments were split, table->p is set to zero and
 321  * table->maxp is duplicated.
 322  */
 323 static void expand_table(SET *table)
 324 {
 325         unsigned NewAddress;
 326         int OldSegmentIndex, NewSegmentIndex;
 327         int OldSegmentDir, NewSegmentDir;
 328         Segment *OldSegment;
 329         Segment *NewSegment;
 330         Element *Current;
 331         Element **Previous;
 332         Element **LastOfNew;
 333
 334         if (table->maxp + table->p < (DIRECTORY_SIZE << SEGMENT_SIZE_SHIFT)) {
 335                 /* Locate the bucket to be split */
 336                 OldSegmentDir   = table->p >> SEGMENT_SIZE_SHIFT;
 337                 OldSegment      = table->dir[OldSegmentDir];
 338                 OldSegmentIndex = table->p & (SEGMENT_SIZE-1);
 339
 340                 /* Expand address space; if necessary create a new segment */
 341                 NewAddress      = table->maxp + table->p;
 342                 NewSegmentDir   = NewAddress >> SEGMENT_SIZE_SHIFT;
 343                 NewSegmentIndex = NewAddress & (SEGMENT_SIZE-1);
 344                 if (NewSegmentIndex == 0) {
 345                         table->dir[NewSegmentDir] = OALLOCNZ(&table->obst, Segment, SEGMENT_SIZE);
 346                         table->nseg++;
 347                 }
 348                 NewSegment = table->dir[NewSegmentDir];
 349
 350                 /* Adjust state variables */
 351                 table->p++;
 352                 if (table->p == table->maxp) {
 353                         table->maxp <<= 1;  /* table->maxp *= 2 */
 354                         table->p = 0;
 355                 }
 356
 357                 /* Relocate records to the new bucket */
 358                 Previous = &OldSegment[OldSegmentIndex];
 359                 Current = *Previous;
 360                 LastOfNew = &NewSegment[NewSegmentIndex];
 361                 *LastOfNew = NULL;
 362                 while (Current != NULL) {
 363                         if (Hash (table, Current->entry.hash) == NewAddress) {
 364                                 /* move to new chain */
 365                                 *LastOfNew = Current;
 366                                 *Previous  = Current->chain;
 367                                 LastOfNew  = &Current->chain;
 368                                 Current    = Current->chain;
 369                                 *LastOfNew = NULL;
 370                         } else {
 371                                 /* leave on old chain */
 372                                 Previous = &Current->chain;
 373                                 Current = Current->chain;
 374                         }
 375                 }
 376         }
 377 }
 378
 379
 380 void * MANGLE(_,_search) (SET *table,
 381                 const void *key,
 382 #ifndef PSET
 383                 size_t size,
 384 #endif
 385                 unsigned hash,
 386                 MANGLE(_,_action) action)
 387 {
 388         unsigned h;
 389         Segment *CurrentSegment;
 390         int SegmentIndex;
 391         MANGLEP(cmp_fun) cmp = table->cmp;
 392         Segment q;
 393         int chain_len = 0;
 394
 395         assert (table);
 396         assert (key);
 397 #ifdef DEBUG
 398         MANGLEP(tag) = table->tag;
 399 #endif
 400         stat_access (table);
 401
 402         /* Find collision chain */
 403         h = Hash (table, hash);
 404         SegmentIndex   = h & (SEGMENT_SIZE-1);
 405         CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
 406         assert (CurrentSegment != NULL);
 407         q = CurrentSegment[SegmentIndex];
 408
 409         /* Follow collision chain */
 410         while (q && !EQUAL (cmp, q, key, size)) {
 411                 q = q->chain;
 412                 ++chain_len;
 413         }
 414
 415         stat_chain_len (table, chain_len);
 416
 417         if (!q && (action != MANGLE(_,_find))) { /* not found, insert */
 418                 assert (!table->iter_tail && "insert an element into a set that is iterated");
 419
 420                 if (CurrentSegment[SegmentIndex]) stat_dup (table);
 421
 422 #ifdef PSET
 423                 if (table->free_list) {
 424                         q = table->free_list;
 425                         table->free_list = table->free_list->chain;
 426                 } else {
 427                         q = OALLOC(&table->obst, Element);
 428                 }
 429                 q->entry.dptr = (void *)key;
 430 #else
 431                 obstack_blank (&table->obst, offsetof (Element, entry.dptr));
 432                 if (action == _set_hinsert0)
 433                         obstack_grow0 (&table->obst, key, size);
 434                 else
 435                         obstack_grow (&table->obst, key, size);
 436                 q = (Segment) obstack_finish (&table->obst);
 437                 q->entry.size = size;
 438 #endif
 439                 q->chain = CurrentSegment[SegmentIndex];
 440                 q->entry.hash = hash;
 441                 CurrentSegment[SegmentIndex] = q;
 442
 443                 if (loaded (table)) {
 444                         expand_table(table);    /* doesn't affect q */
 445                 }
 446         }
 447
 448         if (!q) return NULL;
 449 #ifdef PSET
 450         if (action == _pset_hinsert) return &q->entry;
 451 #else
 452         if (action == _set_hinsert || action == _set_hinsert0) return &q->entry;
 453 #endif
 454         return q->entry.dptr;
 455 }
 456
 457
 458 #ifdef PSET
 459
 460 int pset_default_ptr_cmp(const void *x, const void *y)
 461 {
 462         return x != y;
 463 }
 464
 465 void *pset_remove(SET *table, const void *key, unsigned hash)
 466 {
 467         unsigned h;
 468         Segment *CurrentSegment;
 469         int SegmentIndex;
 470         pset_cmp_fun cmp = table->cmp;
 471         Segment *p;
 472         Segment q;
 473         int chain_len = 0;
 474
 475         assert (table && !table->iter_tail);
 476         stat_access (table);
 477
 478         /* Find collision chain */
 479         h = Hash (table, hash);
 480         SegmentIndex = h & (SEGMENT_SIZE-1);
 481         CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
 482         assert (CurrentSegment != NULL);
 483         p = &CurrentSegment[SegmentIndex];
 484
 485         /* Follow collision chain */
 486         while (!EQUAL (cmp, *p, key, size)) {
 487                 p = &(*p)->chain;
 488                 assert (*p);
 489                 ++chain_len;
 490         }
 491
 492         stat_chain_len (table, chain_len);
 493
 494         q = *p;
 495
 496         if (q == table->iter_tail) {
 497                 /* removing current element */
 498                 table->iter_tail = q->chain;
 499                 if (!table->iter_tail) {
 500                         /* go to next segment */
 501                         do {
 502                                 if (!iter_step (table))
 503                                         break;
 504                         } while (!table->dir[table->iter_i][table->iter_j]);
 505                         table->iter_tail = table->dir[table->iter_i][table->iter_j];
 506                 }
 507         }
 508
 509         *p = (*p)->chain;
 510         q->chain = table->free_list;
 511         table->free_list = q;
 512         --table->nkey;
 513
 514         return q->entry.dptr;
 515 }
 516
 517
 518 void *(pset_find) (SET *se, const void *key, unsigned hash)
 519 {
 520         return pset_find (se, key, hash);
 521 }
 522
 523
 524 void *(pset_insert) (SET *se, const void *key, unsigned hash)
 525 {
 526         return pset_insert (se, key, hash);
 527 }
 528
 529
 530         MANGLEP(entry) *
 531 (pset_hinsert) (SET *se, const void *key, unsigned hash)
 532 {
 533         return pset_hinsert (se, key, hash);
 534 }
 535
 536 void pset_insert_pset_ptr(pset *target, pset *src)
 537 {
 538         void *elt;
 539         for (elt = pset_first(src); elt; elt = pset_next(src)) {
 540                 pset_insert_ptr(target, elt);
 541         }
 542 }
 543
 544 #else /* !PSET */
 545
 546 void *(set_find) (set *se, const void *key, size_t size, unsigned hash)
 547 {
 548         return set_find (se, key, size, hash);
 549 }
 550
 551
 552 void *(set_insert) (set *se, const void *key, size_t size, unsigned hash)
 553 {
 554         return set_insert (se, key, size, hash);
 555 }
 556
 557
 558 set_entry *(set_hinsert) (set *se, const void *key, size_t size, unsigned hash)
 559 {
 560         return set_hinsert (se, key, size, hash);
 561 }
 562
 563 #endif /* !PSET */