2 * Copyright (C) 1995-2011 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
26 /* This code is derived from:
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
35 Posting-number: Volume 6, Issue 42
36 Submitted-By: Esmond Pitt <ejp@ausmelb.oz.AU>
37 Archive-name: dynamic-hash
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;
43 TODO: Fix Esmond's ugly MixedCapsIdentifiers ;->
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)))
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)))
67 #include "lc_printf.h"
75 #define TOBSTACK_ID MANGLEP(tag)
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
86 typedef struct element {
87 struct element *chain; /**< for chaining Elements */
88 MANGLEP (entry) entry;
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 */
102 Element *free_list; /**< list of free Elements */
104 struct obstack obst; /**< obstack for allocation all data */
106 size_t naccess, ncollision, ndups;
107 size_t max_chain_len;
110 const char *tag; /**< an optionally tag for distinguishing sets */
117 void MANGLEP(stats) (SET *table)
121 Element *q = table->free_list;
122 while (q) { q = q->chain; ++nfree; }
124 lc_printf(" accesses collisions keys duplicates longest wasted\n%12zu%12zu%12zu%12zu%12zu%12zu\n",
125 table->naccess, table->ncollision, table->nkey, table->ndups, table->max_chain_len, nfree);
128 static inline void stat_chain_len(SET *table, size_t chain_len)
130 table->ncollision += chain_len;
131 if (table->max_chain_len < chain_len) table->max_chain_len = chain_len;
134 # define stat_access(table) (++(table)->naccess)
135 # define stat_dup(table) (++(table)->ndups)
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)
147 const char *MANGLEP(tag);
150 void MANGLEP(describe) (SET *table)
152 size_t i, j, collide;
156 lc_printf("p=%zu maxp=%zu nkey=%zu nseg=%zu\n",
157 table->p, table->maxp, table->nkey, table->nseg);
158 for (i = 0; i < table->nseg; i++) {
160 for (j = 0; j < SEGMENT_SIZE; j++) {
164 if (collide) lc_printf("<%3zu>", collide);
165 else printf ("table");
166 lc_printf("[%zd][%3zd]: %u %p\n", i, j, ptr->entry.hash, (void *)ptr->entry.dptr);
173 MANGLEP(stats)(table);
180 SET *(PMANGLE(new)) (MANGLEP(cmp_fun) cmp, size_t nslots)
182 SET *table = XMALLOC(SET);
185 if (nslots > SEGMENT_SIZE * DIRECTORY_SIZE)
186 nslots = DIRECTORY_SIZE;
188 /* Adjust nslots up to next power of 2, minimum SEGMENT_SIZE */
189 for (i = SEGMENT_SIZE; i < nslots; i <<= 1) {
191 nslots = i >> SEGMENT_SIZE_SHIFT;
194 table->nseg = table->p = table->nkey = 0;
195 table->maxp = nslots << SEGMENT_SIZE_SHIFT;
197 table->iter_tail = NULL;
199 table->free_list = NULL;
201 obstack_init (&table->obst);
204 for (i = 0; i < nslots; ++i) {
205 table->dir[i] = OALLOCNZ(&table->obst, Segment, SEGMENT_SIZE);
210 table->naccess = table->ncollision = table->ndups = 0;
211 table->max_chain_len = 0;
214 table->tag = MANGLEP(tag);
220 void PMANGLE(del) (SET *table)
223 MANGLEP(tag) = table->tag;
225 obstack_free (&table->obst, NULL);
229 size_t MANGLEP(count) (SET *table)
235 * do one iteration step, return 1
236 * if still data in the set, 0 else
238 static inline int iter_step(SET *table)
240 if (++table->iter_j >= SEGMENT_SIZE) {
242 if (++table->iter_i >= table->nseg) {
251 * finds the first entry in the table
253 void * MANGLEP(first) (SET *table)
255 assert (!table->iter_tail);
258 while (!table->dir[table->iter_i][table->iter_j]) {
259 if (!iter_step (table)) return NULL;
261 table->iter_tail = table->dir[table->iter_i][table->iter_j];
262 assert (table->iter_tail->entry.dptr);
263 return table->iter_tail->entry.dptr;
267 * returns next entry in the table
269 void *MANGLEP(next) (SET *table)
271 if (!table->iter_tail)
274 /* follow collision chain */
275 table->iter_tail = table->iter_tail->chain;
276 if (!table->iter_tail) {
277 /* go to next segment */
279 if (!iter_step (table)) return NULL;
280 } while (!table->dir[table->iter_i][table->iter_j]);
281 table->iter_tail = table->dir[table->iter_i][table->iter_j];
283 assert (table->iter_tail->entry.dptr);
284 return table->iter_tail->entry.dptr;
287 void MANGLEP(break) (SET *table)
289 table->iter_tail = NULL;
293 * limit the hash value
295 static inline unsigned Hash(SET *table, unsigned h)
298 address = h & (table->maxp - 1); /* h % table->maxp */
299 if (address < (unsigned)table->p)
300 address = h & ((table->maxp << 1) - 1); /* h % (2*table->maxp) */
305 * returns non-zero if the number of elements in
306 * the set is greater then number of segments * MAX_LOAD_FACTOR
308 static inline int loaded(SET *table)
310 return ( ++table->nkey
311 > (table->nseg << SEGMENT_SIZE_SHIFT) * MAX_LOAD_FACTOR);
315 * expand the hash-table: the algorithm is split, so on every
316 * insert, only ONE segment is rehashed!
318 * table->p contains the current segment to split
319 * after all segments were split, table->p is set to zero and
320 * table->maxp is duplicated.
322 static void expand_table(SET *table)
325 size_t OldSegmentIndex, NewSegmentIndex;
326 size_t OldSegmentDir, NewSegmentDir;
333 if (table->maxp + table->p < (DIRECTORY_SIZE << SEGMENT_SIZE_SHIFT)) {
334 /* Locate the bucket to be split */
335 OldSegmentDir = table->p >> SEGMENT_SIZE_SHIFT;
336 OldSegment = table->dir[OldSegmentDir];
337 OldSegmentIndex = table->p & (SEGMENT_SIZE-1);
339 /* Expand address space; if necessary create a new segment */
340 NewAddress = table->maxp + table->p;
341 NewSegmentDir = NewAddress >> SEGMENT_SIZE_SHIFT;
342 NewSegmentIndex = NewAddress & (SEGMENT_SIZE-1);
343 if (NewSegmentIndex == 0) {
344 table->dir[NewSegmentDir] = OALLOCNZ(&table->obst, Segment, SEGMENT_SIZE);
347 NewSegment = table->dir[NewSegmentDir];
349 /* Adjust state variables */
351 if (table->p == table->maxp) {
352 table->maxp <<= 1; /* table->maxp *= 2 */
356 /* Relocate records to the new bucket */
357 Previous = &OldSegment[OldSegmentIndex];
359 LastOfNew = &NewSegment[NewSegmentIndex];
361 while (Current != NULL) {
362 if (Hash (table, Current->entry.hash) == NewAddress) {
363 /* move to new chain */
364 *LastOfNew = Current;
365 *Previous = Current->chain;
366 LastOfNew = &Current->chain;
367 Current = Current->chain;
370 /* leave on old chain */
371 Previous = &Current->chain;
372 Current = Current->chain;
379 void * MANGLE(_,_search) (SET *table,
385 MANGLE(_,_action) action)
388 Segment *CurrentSegment;
390 MANGLEP(cmp_fun) cmp = table->cmp;
392 size_t chain_len = 0;
397 MANGLEP(tag) = table->tag;
401 /* Find collision chain */
402 h = Hash (table, hash);
403 SegmentIndex = h & (SEGMENT_SIZE-1);
404 CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
405 assert (CurrentSegment != NULL);
406 q = CurrentSegment[SegmentIndex];
408 /* Follow collision chain */
409 while (q && !EQUAL (cmp, q, key, size)) {
414 stat_chain_len(table, chain_len);
416 if (!q && (action != MANGLE(_,_find))) { /* not found, insert */
417 assert (!table->iter_tail && "insert an element into a set that is iterated");
419 if (CurrentSegment[SegmentIndex]) stat_dup (table);
422 if (table->free_list) {
423 q = table->free_list;
424 table->free_list = table->free_list->chain;
426 q = OALLOC(&table->obst, Element);
428 q->entry.dptr = (void *)key;
430 obstack_blank (&table->obst, offsetof (Element, entry.dptr));
431 if (action == _set_hinsert0)
432 obstack_grow0 (&table->obst, key, size);
434 obstack_grow (&table->obst, key, size);
435 q = (Segment) obstack_finish (&table->obst);
436 q->entry.size = size;
438 q->chain = CurrentSegment[SegmentIndex];
439 q->entry.hash = hash;
440 CurrentSegment[SegmentIndex] = q;
442 if (loaded (table)) {
443 expand_table(table); /* doesn't affect q */
449 if (action == _pset_hinsert) return &q->entry;
451 if (action == _set_hinsert || action == _set_hinsert0) return &q->entry;
453 return q->entry.dptr;
459 int pset_default_ptr_cmp(const void *x, const void *y)
464 void *pset_remove(SET *table, const void *key, unsigned hash)
467 Segment *CurrentSegment;
469 pset_cmp_fun cmp = table->cmp;
474 assert (table && !table->iter_tail);
477 /* Find collision chain */
478 h = Hash (table, hash);
479 SegmentIndex = h & (SEGMENT_SIZE-1);
480 CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
481 assert (CurrentSegment != NULL);
482 p = &CurrentSegment[SegmentIndex];
484 /* Follow collision chain */
485 while (!EQUAL (cmp, *p, key, size)) {
491 stat_chain_len (table, chain_len);
495 if (q == table->iter_tail) {
496 /* removing current element */
497 table->iter_tail = q->chain;
498 if (!table->iter_tail) {
499 /* go to next segment */
501 if (!iter_step (table))
503 } while (!table->dir[table->iter_i][table->iter_j]);
504 table->iter_tail = table->dir[table->iter_i][table->iter_j];
509 q->chain = table->free_list;
510 table->free_list = q;
513 return q->entry.dptr;
517 void *(pset_find) (SET *se, const void *key, unsigned hash)
519 return pset_find (se, key, hash);
523 void *(pset_insert) (SET *se, const void *key, unsigned hash)
525 return pset_insert (se, key, hash);
530 (pset_hinsert) (SET *se, const void *key, unsigned hash)
532 return pset_hinsert (se, key, hash);
535 void pset_insert_pset_ptr(pset *target, pset *src)
538 for (elt = pset_first(src); elt; elt = pset_next(src)) {
539 pset_insert_ptr(target, elt);
545 void *(set_find) (set *se, const void *key, size_t size, unsigned hash)
547 return set_find (se, key, size, hash);
551 void *(set_insert) (set *se, const void *key, size_t size, unsigned hash)
553 return set_insert (se, key, size, hash);
557 set_entry *(set_hinsert) (set *se, const void *key, size_t size, unsigned hash)
559 return set_hinsert (se, key, size, hash);