2 * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
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.
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.
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
22 * @brief implementation of set
23 * @author Markus Armbruster
27 /* This code is derived from:
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
36 Posting-number: Volume 6, Issue 42
37 Submitted-By: Esmond Pitt <ejp@ausmelb.oz.AU>
38 Archive-name: dynamic-hash
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;
44 TODO: Fix Esmond's ugly MixedCapsIdentifiers ;->
52 # define PMANGLE(pre) pre##_pset
53 # define MANGLEP(post) pset_##post
54 # define MANGLE(pre, post) pre##pset##post
55 # define EQUAL(cmp, elt, key, siz) (!(cmp) ((elt)->entry.dptr, (key)))
58 # define PMANGLE(pre) pre##_set
59 # define MANGLEP(post) set_##post
60 # define MANGLE(pre, post) pre##set##post
61 # define EQUAL(cmp, elt, key, siz) \
62 (((elt)->entry.size == (siz)) && !(cmp) ((elt)->entry.dptr, (key), (siz)))
77 #define TOBSTACK_ID MANGLEP(tag)
81 #define SEGMENT_SIZE_SHIFT 8
82 #define SEGMENT_SIZE (1 << SEGMENT_SIZE_SHIFT)
83 #define DIRECTORY_SIZE_SHIFT 8
84 #define DIRECTORY_SIZE (1 << DIRECTORY_SIZE_SHIFT)
85 #define MAX_LOAD_FACTOR 4
88 typedef struct element {
89 struct element *chain; /**< for chaining Elements */
90 MANGLEP (entry) entry;
95 unsigned p; /**< Next bucket to be split */
96 unsigned maxp; /**< upper bound on p during expansion */
97 unsigned nkey; /**< current # keys */
98 unsigned nseg; /**< current # segments */
99 Segment *dir[DIRECTORY_SIZE];
100 MANGLEP(cmp_fun) cmp; /**< function comparing entries */
101 unsigned iter_i, iter_j;
102 Element *iter_tail; /**< non-NULL while iterating over elts */
104 Element *free_list; /**< list of free Elements */
106 struct obstack obst; /**< obstack for allocation all data */
108 int naccess, ncollision, ndups;
112 const char *tag; /**< an optionally tag for distinguishing sets */
120 MANGLEP(stats) (SET *table)
124 Element *q = table->free_list;
125 while (q) { q = q->chain; ++nfree; }
127 printf (" accesses collisions keys duplicates longest wasted\n%12d%12d%12d%12d%12d%12d\n",
128 table->naccess, table->ncollision, table->nkey, table->ndups, table->max_chain_len, nfree);
132 stat_chain_len (SET *table, int chain_len)
134 table->ncollision += chain_len;
135 if (table->max_chain_len < chain_len) table->max_chain_len = chain_len;
138 # define stat_access(table) (++(table)->naccess)
139 # define stat_dup(table) (++(table)->ndups)
143 # define stat_chain_len(table, chain_len) ((void)0)
144 # define stat_access(table) ((void)0)
145 # define stat_dup(table) ((void)0)
151 const char *MANGLEP(tag);
155 MANGLEP(describe) (SET *table)
157 unsigned i, j, collide;
161 printf ("p=%u maxp=%u nkey=%u nseg=%u\n",
162 table->p, table->maxp, table->nkey, table->nseg);
163 for (i = 0; i < table->nseg; i++) {
165 for (j = 0; j < SEGMENT_SIZE; j++) {
169 if (collide) printf ("<%3d>", collide);
170 else printf ("table");
171 printf ("[%d][%3d]: %u %p\n", i, j, ptr->entry.hash, (void *)ptr->entry.dptr);
178 MANGLEP(stats)(table);
186 (PMANGLE(new)) (MANGLEP(cmp_fun) cmp, int nslots)
189 SET *table = xmalloc(sizeof(*table));
191 if (nslots > SEGMENT_SIZE * DIRECTORY_SIZE)
192 nslots = DIRECTORY_SIZE;
194 assert (nslots >= 0);
195 /* Adjust nslots up to next power of 2, minimum SEGMENT_SIZE */
196 for (i = SEGMENT_SIZE; i < nslots; i <<= 1);
197 nslots = i >> SEGMENT_SIZE_SHIFT;
200 table->nseg = table->p = table->nkey = 0;
201 table->maxp = nslots << SEGMENT_SIZE_SHIFT;
203 table->iter_tail = NULL;
205 table->free_list = NULL;
207 obstack_init (&table->obst);
210 for (i = 0; i < nslots; ++i) {
211 table->dir[i] = (Segment *)obstack_alloc (&table->obst,
212 sizeof (Segment) * SEGMENT_SIZE);
214 memset(table->dir[i], 0, sizeof (Segment) * SEGMENT_SIZE);
219 table->naccess = table->ncollision = table->ndups = 0;
220 table->max_chain_len = 0;
223 table->tag = MANGLEP(tag);
230 PMANGLE(del) (SET *table)
233 MANGLEP(tag) = table->tag;
235 obstack_free (&table->obst, NULL);
240 MANGLEP(count) (SET *table)
246 * do one iteration step, return 1
247 * if still data in the set, 0 else
250 iter_step (SET *table)
252 if (++table->iter_j >= SEGMENT_SIZE) {
254 if (++table->iter_i >= table->nseg) {
263 * finds the first entry in the table
266 MANGLEP(first) (SET *table)
268 assert (!table->iter_tail);
271 while (!table->dir[table->iter_i][table->iter_j]) {
272 if (!iter_step (table)) return NULL;
274 table->iter_tail = table->dir[table->iter_i][table->iter_j];
275 assert (table->iter_tail->entry.dptr);
276 return table->iter_tail->entry.dptr;
280 * returns next entry in the table
283 MANGLEP(next) (SET *table)
285 if (!table->iter_tail)
288 /* follow collision chain */
289 table->iter_tail = table->iter_tail->chain;
290 if (!table->iter_tail) {
291 /* go to next segment */
293 if (!iter_step (table)) return NULL;
294 } while (!table->dir[table->iter_i][table->iter_j]);
295 table->iter_tail = table->dir[table->iter_i][table->iter_j];
297 assert (table->iter_tail->entry.dptr);
298 return table->iter_tail->entry.dptr;
302 MANGLEP(break) (SET *table)
304 table->iter_tail = NULL;
308 * limit the hash value
310 static INLINE unsigned
311 Hash (SET *table, unsigned h)
314 address = h & (table->maxp - 1); /* h % table->maxp */
315 if (address < (unsigned)table->p)
316 address = h & ((table->maxp << 1) - 1); /* h % (2*table->maxp) */
321 * returns non-zero if the number of elements in
322 * the set is greater then number of segments * MAX_LOAD_FACTOR
327 return ( ++table->nkey
328 > (table->nseg << SEGMENT_SIZE_SHIFT) * MAX_LOAD_FACTOR);
332 * expand the hash-table: the algorithm is split, so on every
333 * insert, only ONE segment is rehashed!
335 * table->p contains the current segment to split
336 * after all segments were split, table->p is set to zero and
337 * table->maxp is duplicated.
340 expand_table (SET *table)
343 int OldSegmentIndex, NewSegmentIndex;
344 int OldSegmentDir, NewSegmentDir;
351 if (table->maxp + table->p < (DIRECTORY_SIZE << SEGMENT_SIZE_SHIFT)) {
352 /* Locate the bucket to be split */
353 OldSegmentDir = table->p >> SEGMENT_SIZE_SHIFT;
354 OldSegment = table->dir[OldSegmentDir];
355 OldSegmentIndex = table->p & (SEGMENT_SIZE-1);
357 /* Expand address space; if necessary create a new segment */
358 NewAddress = table->maxp + table->p;
359 NewSegmentDir = NewAddress >> SEGMENT_SIZE_SHIFT;
360 NewSegmentIndex = NewAddress & (SEGMENT_SIZE-1);
361 if (NewSegmentIndex == 0) {
362 table->dir[NewSegmentDir] =
363 (Segment *)obstack_alloc (&table->obst,
364 sizeof(Segment) * SEGMENT_SIZE);
365 memset(table->dir[NewSegmentDir], 0, sizeof(Segment) * SEGMENT_SIZE);
368 NewSegment = table->dir[NewSegmentDir];
370 /* Adjust state variables */
372 if (table->p == table->maxp) {
373 table->maxp <<= 1; /* table->maxp *= 2 */
377 /* Relocate records to the new bucket */
378 Previous = &OldSegment[OldSegmentIndex];
380 LastOfNew = &NewSegment[NewSegmentIndex];
382 while (Current != NULL) {
383 if (Hash (table, Current->entry.hash) == NewAddress) {
384 /* move to new chain */
385 *LastOfNew = Current;
386 *Previous = Current->chain;
387 LastOfNew = &Current->chain;
388 Current = Current->chain;
391 /* leave on old chain */
392 Previous = &Current->chain;
393 Current = Current->chain;
401 MANGLE(_,_search) (SET *table,
407 MANGLE(_,_action) action)
410 Segment *CurrentSegment;
412 MANGLEP(cmp_fun) cmp = table->cmp;
419 MANGLEP(tag) = table->tag;
423 /* Find collision chain */
424 h = Hash (table, hash);
425 SegmentIndex = h & (SEGMENT_SIZE-1);
426 CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
427 assert (CurrentSegment != NULL);
428 q = CurrentSegment[SegmentIndex];
430 /* Follow collision chain */
431 while (q && !EQUAL (cmp, q, key, size)) {
436 stat_chain_len (table, chain_len);
438 if (!q && (action != MANGLE(_,_find))) { /* not found, insert */
439 assert (!table->iter_tail && "insert an element into a set that is iterated");
441 if (CurrentSegment[SegmentIndex]) stat_dup (table);
444 if (table->free_list) {
445 q = table->free_list;
446 table->free_list = table->free_list->chain;
448 q = obstack_alloc (&table->obst, sizeof (Element));
450 q->entry.dptr = (void *)key;
452 obstack_blank (&table->obst, offsetof (Element, entry.dptr));
453 if (action == _set_hinsert0)
454 obstack_grow0 (&table->obst, key, size);
456 obstack_grow (&table->obst, key, size);
457 q = obstack_finish (&table->obst);
458 q->entry.size = size;
460 q->chain = CurrentSegment[SegmentIndex];
461 q->entry.hash = hash;
462 CurrentSegment[SegmentIndex] = q;
464 if (loaded (table)) {
465 expand_table(table); /* doesn't affect q */
471 if (action == _pset_hinsert) return &q->entry;
473 if (action == _set_hinsert || action == _set_hinsert0) return &q->entry;
475 return q->entry.dptr;
481 int pset_default_ptr_cmp(const void *x, const void *y)
487 pset_remove (SET *table, const void *key, unsigned hash)
490 Segment *CurrentSegment;
492 pset_cmp_fun cmp = table->cmp;
497 assert (table && !table->iter_tail);
500 /* Find collision chain */
501 h = Hash (table, hash);
502 SegmentIndex = h & (SEGMENT_SIZE-1);
503 CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
504 assert (CurrentSegment != NULL);
505 p = &CurrentSegment[SegmentIndex];
507 /* Follow collision chain */
508 while (!EQUAL (cmp, *p, key, size)) {
514 stat_chain_len (table, chain_len);
518 if (q == table->iter_tail) {
519 /* removing current element */
520 table->iter_tail = q->chain;
521 if (!table->iter_tail) {
522 /* go to next segment */
524 if (!iter_step (table))
526 } while (!table->dir[table->iter_i][table->iter_j]);
527 table->iter_tail = table->dir[table->iter_i][table->iter_j];
532 q->chain = table->free_list;
533 table->free_list = q;
536 return q->entry.dptr;
541 (pset_find) (SET *se, const void *key, unsigned hash)
543 return pset_find (se, key, hash);
548 (pset_insert) (SET *se, const void *key, unsigned hash)
550 return pset_insert (se, key, hash);
555 (pset_hinsert) (SET *se, const void *key, unsigned hash)
557 return pset_hinsert (se, key, hash);
560 void pset_insert_pset_ptr(pset *target, pset *src) {
562 for (elt = pset_first(src); elt; elt = pset_next(src)) {
563 pset_insert_ptr(target, elt);
570 (set_find) (set *se, const void *key, size_t size, unsigned hash)
572 return set_find (se, key, size, hash);
577 (set_insert) (set *se, const void *key, size_t size, unsigned hash)
579 return set_insert (se, key, size, hash);
584 (set_hinsert) (set *se, const void *key, size_t size, unsigned hash)
586 return set_hinsert (se, key, size, hash);