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616915dd | 1 | /* |
11db3170 | 2 | ** Splint - annotation-assisted static program checker |
616915dd | 3 | ** Copyright (C) 1994-2000 University of Virginia, |
4 | ** Massachusetts Institute of Technology | |
5 | ** | |
6 | ** This program is free software; you can redistribute it and/or modify it | |
7 | ** under the terms of the GNU General Public License as published by the | |
8 | ** Free Software Foundation; either version 2 of the License, or (at your | |
9 | ** option) any later version. | |
10 | ** | |
11 | ** This program is distributed in the hope that it will be useful, but | |
12 | ** WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | ** General Public License for more details. | |
15 | ** | |
16 | ** The GNU General Public License is available from http://www.gnu.org/ or | |
17 | ** the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
18 | ** MA 02111-1307, USA. | |
19 | ** | |
1b8ae690 | 20 | ** For information on splint: splint@cs.virginia.edu |
21 | ** To report a bug: splint-bug@cs.virginia.edu | |
11db3170 | 22 | ** For more information: http://www.splint.org |
616915dd | 23 | */ |
24 | /* | |
25 | ** hashTable.c | |
26 | ** | |
27 | ** Since hsearch defined in <search.h> only allows one hash table, | |
28 | ** I'll implement my own. | |
29 | ** | |
30 | ** Try to find a decent hash function, etc. later... | |
31 | ** | |
32 | ** hashTable is from string -> unsigned | |
33 | ** | |
34 | */ | |
35 | ||
1b8ae690 | 36 | # include "splintMacros.nf" |
616915dd | 37 | # include "basic.h" |
38 | ||
39 | /*@constant null hbucket hbucket_undefined; @*/ | |
40 | # define hbucket_undefined 0 | |
41 | ||
42 | static /*@truenull@*/ bool hbucket_isNull (/*@null@*/ hbucket h) | |
43 | { | |
44 | return (h == hbucket_undefined); | |
45 | } | |
46 | ||
47 | static hentry | |
48 | hentry_create (cstring key, int val) | |
49 | { | |
50 | hentry h; | |
51 | ||
52 | h.key = key; | |
53 | h.val = val; | |
54 | return (h); | |
55 | } | |
56 | ||
57 | static bool | |
58 | hbucket_isEmpty (hbucket h) | |
59 | { | |
60 | return (h == hbucket_undefined || h->size == 0); | |
61 | } | |
62 | ||
63 | static cstring | |
64 | hbucket_unparse (hbucket h) | |
65 | { | |
66 | cstring s = cstring_undefined; | |
67 | ||
68 | if (!hbucket_isNull (h)) | |
69 | { | |
70 | int i; | |
71 | ||
72 | for (i = 0; i < h->size; i++) | |
73 | { | |
74 | s = message ("%q %s:%d", s, h->entries[i].key, h->entries[i].val); | |
75 | } | |
76 | } | |
77 | ||
78 | return s; | |
79 | } | |
80 | ||
81 | static hbucket | |
82 | hbucket_single (hentry e) | |
83 | { | |
84 | hbucket h = (hbucket) dmalloc (sizeof (*h)); | |
85 | ||
86 | h->size = 1; | |
87 | h->nspace = HBUCKET_BASESIZE - 1; | |
88 | h->entries = (hentry *) dmalloc (HBUCKET_BASESIZE * sizeof (*h->entries)); | |
89 | h->entries[0] = e; | |
90 | ||
91 | return (h); | |
92 | } | |
93 | ||
94 | static void | |
95 | hbucket_grow (/*@notnull@*/ hbucket h) | |
96 | { | |
97 | int i; | |
98 | hentry *newentries; | |
99 | ||
100 | h->nspace += HBUCKET_BASESIZE; | |
101 | ||
102 | newentries = (hentry *) | |
103 | dmalloc ((h->size + HBUCKET_BASESIZE) * sizeof (*newentries)); | |
104 | ||
105 | for (i = 0; i < h->size; i++) | |
106 | { | |
107 | newentries[i] = h->entries[i]; | |
108 | } | |
109 | ||
110 | sfree (h->entries); | |
111 | h->entries = newentries; | |
112 | } | |
113 | ||
114 | static int hbucket_lookup (hbucket p_h, cstring p_key); | |
115 | ||
116 | /* | |
117 | ** bizarre duplicate behaviour | |
118 | ** required for duplicate entries | |
119 | */ | |
120 | ||
121 | static void | |
122 | hbucket_add (/*@notnull@*/ hbucket h, hentry e) | |
123 | { | |
124 | int exloc = hbucket_lookup (h, e.key); | |
125 | ||
126 | ||
127 | if (exloc != HBUCKET_DNE) | |
128 | { | |
129 | h->entries[exloc].key = e.key; | |
130 | h->entries[exloc].val = e.val; | |
131 | return; | |
132 | } | |
133 | ||
134 | if (h->nspace == 0) | |
135 | { | |
136 | hbucket_grow (h); | |
137 | } | |
138 | ||
139 | h->entries[h->size] = e; | |
140 | h->size++; | |
141 | h->nspace--; | |
142 | } | |
143 | ||
144 | static int | |
145 | hbucket_ncollisions (hbucket h) | |
146 | { | |
147 | if (!hbucket_isNull (h) && (h->size > 1)) | |
148 | return (h->size - 1); | |
149 | else | |
150 | return 0; | |
151 | } | |
152 | ||
153 | int | |
154 | hbucket_lookup (hbucket h, cstring key) | |
155 | { | |
156 | if (!hbucket_isNull (h)) | |
157 | { | |
158 | int i; | |
159 | ||
160 | for (i = 0; i < h->size; i++) | |
161 | { | |
162 | if (cstring_equal (h->entries[i].key, key)) | |
163 | { | |
164 | return h->entries[i].val; | |
165 | } | |
166 | } | |
167 | } | |
168 | ||
169 | return HBUCKET_DNE; | |
170 | } | |
171 | ||
172 | static | |
173 | void hbucket_free (/*@only@*/ hbucket h) | |
174 | { | |
175 | if (!hbucket_isNull (h)) | |
176 | { | |
177 | sfree (h->entries); | |
178 | sfree (h); | |
179 | } | |
180 | } | |
181 | ||
182 | void | |
183 | hashTable_free (/*@only@*/ hashTable h) | |
184 | { | |
185 | int i; | |
186 | ||
187 | for (i = 0; i < h->size; i++) | |
188 | { | |
189 | hbucket_free (h->buckets[i]); | |
190 | } | |
191 | ||
192 | sfree (h->buckets); | |
193 | sfree (h); | |
194 | } | |
195 | ||
196 | static int | |
197 | hashTable_countCollisions (hashTable h) | |
198 | { | |
199 | int nc = 0; | |
200 | int i; | |
201 | ||
202 | for (i = 0; i < h->size; i++) | |
203 | { | |
204 | nc += hbucket_ncollisions (h->buckets[i]); | |
205 | } | |
206 | ||
207 | return (nc); | |
208 | } | |
209 | ||
210 | ||
211 | static int | |
212 | hashTable_countEmpty (hashTable h) | |
213 | { | |
214 | int nc = 0; | |
215 | int i; | |
216 | ||
217 | for (i = 0; i < h->size; i++) | |
218 | { | |
219 | if (hbucket_isEmpty (h->buckets[i])) | |
220 | { | |
221 | nc++; | |
222 | } | |
223 | } | |
224 | ||
225 | return (nc); | |
226 | } | |
227 | ||
228 | /* | |
229 | ** hash function snarfed from quake/hash.c Hash_String | |
230 | ** by Stephen Harrison | |
231 | */ | |
232 | ||
233 | /* | |
234 | * Here are 256 random numbers for use in the hash function | |
235 | */ | |
236 | ||
237 | /*@+ignoresigns@*/ | |
238 | static unsigned int RandomNumbers[256] = | |
239 | { | |
240 | #include "256_random_numbers.nf" | |
241 | }; | |
242 | /*@=ignoresigns@*/ | |
243 | ||
244 | static unsigned int | |
245 | hashTable_hashValue (hashTable h, cstring key) | |
246 | { | |
247 | char *p; | |
248 | unsigned int hash_value = 0; | |
249 | ||
250 | for (p = cstring_toCharsSafe (key); *p != '\0'; p++) | |
251 | { | |
252 | hash_value = (hash_value << 1) ^ RandomNumbers[*p % 256]; | |
253 | } | |
254 | ||
255 | return (hash_value % h->size); | |
256 | } | |
257 | ||
258 | static /*@exposed@*/ hbucket | |
259 | hashTable_hash (hashTable h, cstring key) | |
260 | { | |
261 | return h->buckets[hashTable_hashValue (h, key)]; | |
262 | } | |
263 | ||
264 | ||
265 | /*@only@*/ hashTable | |
266 | hashTable_create (int size) | |
267 | { | |
268 | int i; | |
269 | hashTable h = (hashTable) dmalloc (sizeof (*h)); | |
270 | ||
271 | h->size = size; | |
272 | h->nentries = 0; | |
273 | h->buckets = (hbucket *) dmalloc (sizeof (*h->buckets) * size); | |
274 | ||
275 | /*@+loopexec@*/ | |
276 | for (i = 0; i < size; i++) | |
277 | { | |
278 | h->buckets[i] = hbucket_undefined; | |
279 | } | |
280 | /*@-loopexec@*/ | |
281 | return h; | |
282 | } | |
283 | ||
284 | /*@-mustfree@*/ | |
285 | static /*@unused@*/ void | |
286 | hashTable_print (hashTable h) | |
287 | { | |
288 | int i; | |
289 | ||
290 | for (i = 0; i < h->size; i++) | |
291 | { | |
292 | hbucket hb = h->buckets[i]; | |
293 | ||
294 | if (hb != NULL) | |
295 | { | |
296 | llmsg (message ("%d. %s\n", i, hbucket_unparse (hb))); | |
297 | } | |
298 | } | |
299 | ||
300 | llmsg (message ("size: %d, collisions: %d, empty: %d", | |
301 | h->size, | |
302 | hashTable_countCollisions (h), | |
303 | hashTable_countEmpty (h))); | |
304 | } | |
305 | /*@=mustfree@*/ | |
306 | ||
307 | /*@only@*/ cstring | |
308 | hashTable_stats (hashTable h) | |
309 | { | |
310 | return (message ("size: %d, collisions: %d, empty: %d\n", | |
311 | h->size, hashTable_countCollisions (h), | |
312 | hashTable_countEmpty (h))); | |
313 | } | |
314 | ||
315 | static void | |
316 | hashTable_addEntry (hashTable h, hentry e) | |
317 | { | |
318 | unsigned int hindex = hashTable_hashValue (h, e.key); | |
319 | /* | |
320 | ** using | |
321 | ** hbucket hb = h->buckets[hindex]; | |
322 | ** instead reveals a bug I don't want to deal with right now! | |
323 | */ | |
324 | ||
325 | h->nentries++; | |
326 | ||
327 | if (hbucket_isNull (h->buckets[hindex])) | |
328 | { | |
329 | h->buckets[hindex] = hbucket_single (e); | |
330 | } | |
331 | else | |
332 | { | |
333 | hbucket_add (h->buckets[hindex], e); | |
334 | } | |
335 | } | |
336 | ||
337 | void | |
338 | hashTable_insert (hashTable h, cstring key, int value) | |
339 | { | |
340 | unsigned int hindex; | |
341 | hbucket hb; | |
342 | hentry e; | |
343 | ||
344 | ||
345 | h->nentries++; | |
346 | ||
347 | /* | |
348 | ** rehashing based (loosely) on code by Steve Harrison | |
349 | */ | |
350 | ||
351 | if (h->nentries * 162 > h->size * 100) | |
352 | { | |
353 | int i; | |
354 | int oldsize = h->size; | |
355 | int newsize = 1 + ((oldsize * 26244) / 10000); /* 26244 = 162^2 */ | |
356 | hbucket *oldbuckets = h->buckets; | |
357 | ||
358 | ||
359 | h->size = newsize; | |
360 | h->nentries = 0; | |
361 | h->buckets = (hbucket *) dmalloc (sizeof (*h->buckets) * newsize); | |
362 | ||
363 | /*@+loopexec@*/ | |
364 | for (i = 0; i < newsize; i++) | |
365 | { | |
366 | h->buckets[i] = hbucket_undefined; | |
367 | } | |
368 | /*@=loopexec@*/ | |
369 | ||
370 | for (i = 0; i < oldsize; i++) | |
371 | { | |
372 | hbucket bucket = oldbuckets[i]; | |
373 | ||
374 | if (!hbucket_isNull (bucket)) | |
375 | { | |
376 | int j; | |
377 | ||
378 | for (j = 0; j < bucket->size; j++) | |
379 | { | |
380 | hashTable_addEntry (h, bucket->entries[j]); | |
381 | } | |
382 | ||
383 | sfree (bucket); | |
384 | } | |
385 | } | |
386 | ||
387 | sfree (oldbuckets); | |
388 | } | |
389 | ||
390 | ||
391 | e = hentry_create (key, value); | |
392 | hindex = hashTable_hashValue (h, key); | |
393 | hb = h->buckets[hindex]; | |
394 | ||
395 | if (hbucket_isNull (hb)) | |
396 | { | |
397 | h->buckets[hindex] = hbucket_single (e); | |
398 | } | |
399 | else | |
400 | { | |
401 | hbucket_add (hb, e); | |
402 | } | |
403 | ||
404 | } | |
405 | ||
406 | int | |
407 | hashTable_lookup (hashTable h, cstring key) | |
408 | { | |
409 | hbucket hb = hashTable_hash (h, key); | |
410 | ||
411 | return (hbucket_lookup (hb, key)); | |
412 | } | |
413 | ||
414 | /* | |
415 | ** This is needed if oldkey is going to be released. | |
416 | */ | |
417 | ||
418 | void | |
419 | hashTable_replaceKey (hashTable h, cstring oldkey, /*@dependent@*/ cstring newkey) | |
420 | { | |
421 | hbucket hb = hashTable_hash (h, oldkey); | |
422 | ||
423 | llassert (cstring_equal (oldkey, newkey)); | |
424 | ||
425 | if (!hbucket_isNull (hb)) | |
426 | { | |
427 | int i; | |
428 | ||
429 | for (i = 0; i < hb->size; i++) | |
430 | { | |
431 | if (cstring_equal (hb->entries[i].key, oldkey)) | |
432 | { | |
433 | hb->entries[i].key = newkey; | |
434 | return; | |
435 | } | |
436 | } | |
437 | } | |
438 | ||
439 | llbug (message ("hashTable_replaceKey: %s not found", oldkey)); | |
440 | } | |
441 | ||
442 | void | |
443 | hashTable_remove (hashTable h, cstring key) | |
444 | { | |
445 | hbucket hb = hashTable_hash (h, key); | |
446 | ||
447 | if (!hbucket_isNull (hb)) | |
448 | { | |
449 | int i; | |
450 | ||
451 | for (i = 0; i < hb->size; i++) | |
452 | { | |
453 | if (cstring_equal (hb->entries[i].key, key)) | |
454 | { | |
455 | if (i < hb->size - 1) | |
456 | { | |
457 | hb->entries[i] = hb->entries[hb->size - 1]; | |
458 | } | |
459 | ||
460 | hb->size--; | |
461 | return; | |
462 | } | |
463 | } | |
464 | } | |
465 | ||
466 | llbug (message ("hashTable_removeKey: %s not found", key)); | |
467 | } | |
468 | ||
469 |