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
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 ;->
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)))
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)))
68 #include "lc_printf.h"
76 #define TOBSTACK_ID MANGLEP(tag)
80 #define SEGMENT_SIZE_SHIFT 8
81 #define SEGMENT_SIZE (1 << SEGMENT_SIZE_SHIFT)
82 #define DIRECTORY_SIZE_SHIFT 8
83 #define DIRECTORY_SIZE (1 << DIRECTORY_SIZE_SHIFT)
84 #define MAX_LOAD_FACTOR 4
87 typedef struct element {
88 struct element *chain; /**< for chaining Elements */
89 MANGLEP (entry) entry;
94 size_t p; /**< Next bucket to be split */
95 size_t maxp; /**< upper bound on p during expansion */
96 size_t nkey; /**< current # keys */
97 size_t nseg; /**< current # segments */
98 Segment *dir[DIRECTORY_SIZE];
99 MANGLEP(cmp_fun) cmp; /**< function comparing entries */
100 unsigned iter_i, iter_j;
101 Element *iter_tail; /**< non-NULL while iterating over elts */
103 Element *free_list; /**< list of free Elements */
105 struct obstack obst; /**< obstack for allocation all data */
107 size_t naccess, ncollision, ndups;
108 size_t max_chain_len;
111 const char *tag; /**< an optionally tag for distinguishing sets */
118 void MANGLEP(stats) (SET *table)
122 Element *q = table->free_list;
123 while (q) { q = q->chain; ++nfree; }
125 lc_printf(" accesses collisions keys duplicates longest wasted\n%12zu%12zu%12zu%12zu%12zu%12zu\n",
126 table->naccess, table->ncollision, table->nkey, table->ndups, table->max_chain_len, nfree);
129 static inline void stat_chain_len(SET *table, size_t chain_len)
131 table->ncollision += chain_len;
132 if (table->max_chain_len < chain_len) table->max_chain_len = chain_len;
135 # define stat_access(table) (++(table)->naccess)
136 # define stat_dup(table) (++(table)->ndups)
140 # define stat_chain_len(table, chain_len) ((void)chain_len)
141 # define stat_access(table) ((void)0)
142 # define stat_dup(table) ((void)0)
148 const char *MANGLEP(tag);
151 void MANGLEP(describe) (SET *table)
153 size_t i, j, collide;
157 lc_printf("p=%zu maxp=%zu nkey=%zu nseg=%zu\n",
158 table->p, table->maxp, table->nkey, table->nseg);
159 for (i = 0; i < table->nseg; i++) {
161 for (j = 0; j < SEGMENT_SIZE; j++) {
165 if (collide) lc_printf("<%3zu>", collide);
166 else printf ("table");
167 lc_printf("[%zd][%3zd]: %u %p\n", i, j, ptr->entry.hash, (void *)ptr->entry.dptr);
174 MANGLEP(stats)(table);
181 SET *(PMANGLE(new)) (MANGLEP(cmp_fun) cmp, size_t nslots)
184 SET *table = XMALLOC(SET);
186 if (nslots > SEGMENT_SIZE * DIRECTORY_SIZE)
187 nslots = DIRECTORY_SIZE;
189 /* Adjust nslots up to next power of 2, minimum SEGMENT_SIZE */
190 for (i = SEGMENT_SIZE; i < nslots; i <<= 1) {
192 nslots = i >> SEGMENT_SIZE_SHIFT;
195 table->nseg = table->p = table->nkey = 0;
196 table->maxp = nslots << SEGMENT_SIZE_SHIFT;
198 table->iter_tail = NULL;
200 table->free_list = NULL;
202 obstack_init (&table->obst);
205 for (i = 0; i < nslots; ++i) {
206 table->dir[i] = OALLOCNZ(&table->obst, Segment, SEGMENT_SIZE);
211 table->naccess = table->ncollision = table->ndups = 0;
212 table->max_chain_len = 0;
215 table->tag = MANGLEP(tag);
221 void PMANGLE(del) (SET *table)
224 MANGLEP(tag) = table->tag;
226 obstack_free (&table->obst, NULL);
230 size_t MANGLEP(count) (SET *table)
236 * do one iteration step, return 1
237 * if still data in the set, 0 else
239 static inline int iter_step(SET *table)
241 if (++table->iter_j >= SEGMENT_SIZE) {
243 if (++table->iter_i >= table->nseg) {
252 * finds the first entry in the table
254 void * MANGLEP(first) (SET *table)
256 assert (!table->iter_tail);
259 while (!table->dir[table->iter_i][table->iter_j]) {
260 if (!iter_step (table)) return NULL;
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;
268 * returns next entry in the table
270 void *MANGLEP(next) (SET *table)
272 if (!table->iter_tail)
275 /* follow collision chain */
276 table->iter_tail = table->iter_tail->chain;
277 if (!table->iter_tail) {
278 /* go to next segment */
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];
284 assert (table->iter_tail->entry.dptr);
285 return table->iter_tail->entry.dptr;
288 void MANGLEP(break) (SET *table)
290 table->iter_tail = NULL;
294 * limit the hash value
296 static inline unsigned Hash(SET *table, unsigned h)
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) */
306 * returns non-zero if the number of elements in
307 * the set is greater then number of segments * MAX_LOAD_FACTOR
309 static inline int loaded(SET *table)
311 return ( ++table->nkey
312 > (table->nseg << SEGMENT_SIZE_SHIFT) * MAX_LOAD_FACTOR);
316 * expand the hash-table: the algorithm is split, so on every
317 * insert, only ONE segment is rehashed!
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.
323 static void expand_table(SET *table)
326 size_t OldSegmentIndex, NewSegmentIndex;
327 size_t OldSegmentDir, NewSegmentDir;
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);
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);
348 NewSegment = table->dir[NewSegmentDir];
350 /* Adjust state variables */
352 if (table->p == table->maxp) {
353 table->maxp <<= 1; /* table->maxp *= 2 */
357 /* Relocate records to the new bucket */
358 Previous = &OldSegment[OldSegmentIndex];
360 LastOfNew = &NewSegment[NewSegmentIndex];
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;
371 /* leave on old chain */
372 Previous = &Current->chain;
373 Current = Current->chain;
380 void * MANGLE(_,_search) (SET *table,
386 MANGLE(_,_action) action)
389 Segment *CurrentSegment;
391 MANGLEP(cmp_fun) cmp = table->cmp;
393 size_t chain_len = 0;
398 MANGLEP(tag) = table->tag;
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];
409 /* Follow collision chain */
410 while (q && !EQUAL (cmp, q, key, size)) {
415 stat_chain_len(table, chain_len);
417 if (!q && (action != MANGLE(_,_find))) { /* not found, insert */
418 assert (!table->iter_tail && "insert an element into a set that is iterated");
420 if (CurrentSegment[SegmentIndex]) stat_dup (table);
423 if (table->free_list) {
424 q = table->free_list;
425 table->free_list = table->free_list->chain;
427 q = OALLOC(&table->obst, Element);
429 q->entry.dptr = (void *)key;
431 obstack_blank (&table->obst, offsetof (Element, entry.dptr));
432 if (action == _set_hinsert0)
433 obstack_grow0 (&table->obst, key, size);
435 obstack_grow (&table->obst, key, size);
436 q = (Segment) obstack_finish (&table->obst);
437 q->entry.size = size;
439 q->chain = CurrentSegment[SegmentIndex];
440 q->entry.hash = hash;
441 CurrentSegment[SegmentIndex] = q;
443 if (loaded (table)) {
444 expand_table(table); /* doesn't affect q */
450 if (action == _pset_hinsert) return &q->entry;
452 if (action == _set_hinsert || action == _set_hinsert0) return &q->entry;
454 return q->entry.dptr;
460 int pset_default_ptr_cmp(const void *x, const void *y)
465 void *pset_remove(SET *table, const void *key, unsigned hash)
468 Segment *CurrentSegment;
470 pset_cmp_fun cmp = table->cmp;
475 assert (table && !table->iter_tail);
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];
485 /* Follow collision chain */
486 while (!EQUAL (cmp, *p, key, size)) {
492 stat_chain_len (table, chain_len);
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 */
502 if (!iter_step (table))
504 } while (!table->dir[table->iter_i][table->iter_j]);
505 table->iter_tail = table->dir[table->iter_i][table->iter_j];
510 q->chain = table->free_list;
511 table->free_list = q;
514 return q->entry.dptr;
518 void *(pset_find) (SET *se, const void *key, unsigned hash)
520 return pset_find (se, key, hash);
524 void *(pset_insert) (SET *se, const void *key, unsigned hash)
526 return pset_insert (se, key, hash);
531 (pset_hinsert) (SET *se, const void *key, unsigned hash)
533 return pset_hinsert (se, key, hash);
536 void pset_insert_pset_ptr(pset *target, pset *src)
539 for (elt = pset_first(src); elt; elt = pset_next(src)) {
540 pset_insert_ptr(target, elt);
546 void *(set_find) (set *se, const void *key, size_t size, unsigned hash)
548 return set_find (se, key, size, hash);
552 void *(set_insert) (set *se, const void *key, size_t size, unsigned hash)
554 return set_insert (se, key, size, hash);
558 set_entry *(set_hinsert) (set *se, const void *key, size_t size, unsigned hash)
560 return set_hinsert (se, key, size, hash);