3 * File name: ir/adt/set.c
4 * Purpose: Set --- collection of entries that are unique wrt to a key.
5 * Author: Markus Armbruster
7 * Created: 1999 by getting from fiasco
9 * Copyright: (c) 1995, 1996 Markus Armbruster
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
13 /* This code is derived from:
15 From: ejp@ausmelb.oz.AU (Esmond Pitt)
16 Date: Tue, 7 Mar 1989 22:06:26 GMT
17 Subject: v06i042: dynamic hashing version of hsearch(3)
18 Message-ID: <1821@basser.oz>
19 Newsgroups: comp.sources.misc
20 Sender: msgs@basser.oz
22 Posting-number: Volume 6, Issue 42
23 Submitted-By: Esmond Pitt <ejp@ausmelb.oz.AU>
24 Archive-name: dynamic-hash
26 * Dynamic hashing, after CACM April 1988 pp 446-457, by Per-Ake Larson.
27 * Coded into C, with minor code improvements, and with hsearch(3) interface,
28 * by ejp@ausmelb.oz, Jul 26, 1988: 13:16;
30 TODO: Fix Esmond's ugly MixedCapsIdentifiers ;->
45 /* bcopy is not ISO C *
46 #define bcopy(X, Y, Z) memcpy((Y), (X), (Z))
51 # define PMANGLE(pre) pre##_pset
52 # define MANGLEP(post) pset_##post
53 # define MANGLE(pre, post) pre##pset##post
54 # define EQUAL(cmp, elt, key, siz) (!(cmp) ((elt)->entry.dptr, (key)))
57 # define PMANGLE(pre) pre##_set
58 # define MANGLEP(post) set_##post
59 # define MANGLE(pre, post) pre##set##post
60 # define EQUAL(cmp, elt, key, siz) \
61 (((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;
90 MANGLEP (entry) entry;
95 short p; /* Next bucket to be split */
96 short maxp; /* upper bound on p during expansion */
97 int nkey; /* current # keys */
98 short nseg; /* current # segments */
99 Segment *dir[DIRECTORY_SIZE];
100 MANGLEP(cmp_fun) cmp; /* function comparing entries */
102 Element *iter_tail; /* non-NULL while iterating over elts */
108 int naccess, ncollision, ndups;
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)
161 printf ("p=%d maxp=%d nkey=%d nseg=%d\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, ptr->entry.dptr);
183 (PMANGLE(new)) (MANGLEP(cmp_fun) cmp, int nslots)
186 SET *table = xmalloc (sizeof (SET));
188 /* Adjust nslots up to next power of 2, minimum SEGMENT_SIZE */
189 assert (nslots >= 0);
190 for (i = SEGMENT_SIZE; i < nslots; i <<= 1) assert (i < (i << 1));
191 nslots = i >> SEGMENT_SIZE_SHIFT;
193 table->nseg = table->p = table->nkey = 0;
194 table->maxp = nslots << SEGMENT_SIZE_SHIFT;
196 table->iter_tail = NULL;
198 table->free_list = NULL;
200 obstack_init (&table->obst);
203 for (i = 0; i < nslots; ++i) {
204 table->dir[i] = (Segment *)obstack_alloc (&table->obst,
205 sizeof (Segment) * SEGMENT_SIZE);
207 memset (table->dir[i], 0, sizeof (Segment) * SEGMENT_SIZE);
212 table->naccess = table->ncollision = table->ndups = 0;
213 table->max_chain_len = 0;
216 table->tag = MANGLEP(tag);
223 PMANGLE(del) (SET *table)
226 MANGLEP(tag) = table->tag;
228 obstack_free (&table->obst, NULL);
234 iter_step (SET *table)
236 if (++table->iter_j >= SEGMENT_SIZE) {
238 if (++table->iter_i >= table->nseg) {
248 MANGLEP(first) (SET *table)
250 assert (!table->iter_tail);
253 while (!table->dir[table->iter_i][table->iter_j]) {
254 if (!iter_step (table)) return NULL;
256 table->iter_tail = table->dir[table->iter_i][table->iter_j];
257 assert (table->iter_tail->entry.dptr);
258 return table->iter_tail->entry.dptr;
263 MANGLEP(next) (SET *table)
265 assert (table->iter_tail);
266 table->iter_tail = table->iter_tail->chain;
267 if (!table->iter_tail) {
269 if (!iter_step (table)) return NULL;
270 } while (!table->dir[table->iter_i][table->iter_j]);
271 table->iter_tail = table->dir[table->iter_i][table->iter_j];
273 assert (table->iter_tail->entry.dptr);
274 return table->iter_tail->entry.dptr;
278 MANGLEP(break) (SET *table)
280 assert (table->iter_tail);
281 table->iter_tail = NULL;
285 static INLINE unsigned
286 Hash (SET *table, unsigned h)
290 address = h & (table->maxp - 1);
291 if (address < (unsigned)table->p)
292 address = h & ((table->maxp << 1) - 1); /* h % (2*table->maxp) */
300 return ( ++table->nkey
301 > (table->nseg << SEGMENT_SIZE_SHIFT) * MAX_LOAD_FACTOR);
306 expand_table (SET *table)
309 int OldSegmentIndex, NewSegmentIndex;
310 int OldSegmentDir, NewSegmentDir;
317 if (table->maxp + table->p < (DIRECTORY_SIZE << SEGMENT_SIZE_SHIFT)) {
318 /* Locate the bucket to be split */
319 OldSegmentDir = table->p >> SEGMENT_SIZE_SHIFT;
320 OldSegment = table->dir[OldSegmentDir];
321 OldSegmentIndex = table->p & (SEGMENT_SIZE-1);
323 /* Expand address space; if necessary create a new segment */
324 NewAddress = table->maxp + table->p;
325 NewSegmentDir = NewAddress >> SEGMENT_SIZE_SHIFT;
326 NewSegmentIndex = NewAddress & (SEGMENT_SIZE-1);
327 if (NewSegmentIndex == 0) {
328 table->dir[NewSegmentDir] =
329 (Segment *)obstack_alloc (&table->obst,
330 sizeof(Segment) * SEGMENT_SIZE);
332 NewSegment = table->dir[NewSegmentDir];
334 /* Adjust state variables */
336 if (table->p == table->maxp) {
337 table->maxp <<= 1; /* table->maxp *= 2 */
342 /* Relocate records to the new bucket */
343 Previous = &OldSegment[OldSegmentIndex];
345 LastOfNew = &NewSegment[NewSegmentIndex];
347 while (Current != NULL) {
348 if (Hash (table, Current->entry.hash) == NewAddress) {
349 /* move to new chain */
350 *LastOfNew = Current;
351 *Previous = Current->chain;
352 LastOfNew = &Current->chain;
353 Current = Current->chain;
356 /* leave on old chain */
357 Previous = &Current->chain;
358 Current = Current->chain;
366 MANGLE(_,_search) (SET *table,
372 MANGLE(_,_action) action)
375 Segment *CurrentSegment;
377 MANGLEP(cmp_fun) cmp = table->cmp;
382 assert (!table->iter_tail);
385 MANGLEP(tag) = table->tag;
389 /* Find collision chain */
390 h = Hash (table, hash);
391 SegmentIndex = h & (SEGMENT_SIZE-1);
392 CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
393 assert (CurrentSegment != NULL);
394 q = CurrentSegment[SegmentIndex];
396 /* Follow collision chain */
397 while (q && !EQUAL (cmp, q, key, size)) {
402 stat_chain_len (table, chain_len);
404 if (!q && (action != MANGLE(_,_find))) { /* not found, insert */
405 if (CurrentSegment[SegmentIndex]) stat_dup (table);
408 if (table->free_list) {
409 q = table->free_list;
410 table->free_list = table->free_list->chain;
412 q = obstack_alloc (&table->obst, sizeof (Element));
414 q->entry.dptr = (void *)key;
416 obstack_blank (&table->obst, offsetof (Element, entry.dptr));
417 if (action == _set_hinsert0)
418 obstack_grow0 (&table->obst, key, size);
420 obstack_grow (&table->obst, key, size);
421 q = obstack_finish (&table->obst);
422 q->entry.size = size;
424 q->chain = CurrentSegment[SegmentIndex];
425 q->entry.hash = hash;
426 CurrentSegment[SegmentIndex] = q;
428 if (loaded (table)) {
429 expand_table(table); /* doesn't affect q */
435 if (action == _pset_hinsert) return &q->entry;
437 if (action == _set_hinsert || action == _set_hinsert0) return &q->entry;
439 return q->entry.dptr;
446 pset_remove (SET *table, const void *key, unsigned hash)
449 Segment *CurrentSegment;
451 pset_cmp_fun cmp = table->cmp;
456 assert (table && !table->iter_tail);
459 /* Find collision chain */
460 h = Hash (table, hash);
461 SegmentIndex = h & (SEGMENT_SIZE-1);
462 CurrentSegment = table->dir[h >> SEGMENT_SIZE_SHIFT];
463 assert (CurrentSegment != NULL);
464 p = &CurrentSegment[SegmentIndex];
466 /* Follow collision chain */
467 while (!EQUAL (cmp, *p, key, size)) {
473 stat_chain_len (table, chain_len);
477 q->chain = table->free_list;
478 table->free_list = q;
480 return q->entry.dptr;
485 (pset_find) (SET *se, const void *key, unsigned hash)
487 return pset_find (se, key, hash);
492 (pset_insert) (SET *se, const void *key, unsigned hash)
494 return pset_insert (se, key, hash);
499 (pset_hinsert) (SET *se, const void *key, unsigned hash)
501 return pset_hinsert (se, key, hash);
507 (set_find) (set *se, const void *key, size_t size, unsigned hash)
509 return set_find (se, key, size, hash);
514 (set_insert) (set *se, const void *key, size_t size, unsigned hash)
516 return set_insert (se, key, size, hash);
521 (set_hinsert) (set *se, const void *key, size_t size, unsigned hash)
523 return set_hinsert (se, key, size, hash);