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Commit | Line | Data |
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ccc6cda3 | 1 | /* hashlib.c -- functions to manage and access hash tables for bash. */ |
726f6388 | 2 | |
3185942a | 3 | /* Copyright (C) 1987,1989,1991,1995,1998,2001,2003,2005,2006,2008,2009 Free Software Foundation, Inc. |
726f6388 | 4 | |
3185942a | 5 | This file is part of GNU Bash, the Bourne Again SHell. |
726f6388 | 6 | |
3185942a JA |
7 | Bash is free software: you can redistribute it and/or modify |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation, either version 3 of the License, or | |
10 | (at your option) any later version. | |
726f6388 | 11 | |
3185942a JA |
12 | Bash is distributed in the hope that it will be useful, |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
726f6388 | 16 | |
3185942a JA |
17 | You should have received a copy of the GNU General Public License |
18 | along with Bash. If not, see <http://www.gnu.org/licenses/>. | |
19 | */ | |
726f6388 | 20 | |
bb70624e | 21 | #include <config.h> |
726f6388 | 22 | |
d166f048 | 23 | #include "bashansi.h" |
726f6388 | 24 | |
ccc6cda3 | 25 | #if defined (HAVE_UNISTD_H) |
cce855bc JA |
26 | # ifdef _MINIX |
27 | # include <sys/types.h> | |
28 | # endif | |
ccc6cda3 JA |
29 | # include <unistd.h> |
30 | #endif | |
726f6388 | 31 | |
d166f048 JA |
32 | #include <stdio.h> |
33 | ||
ccc6cda3 JA |
34 | #include "shell.h" |
35 | #include "hashlib.h" | |
726f6388 | 36 | |
8868edaf CR |
37 | /* tunable constants for rehashing */ |
38 | #define HASH_REHASH_MULTIPLIER 4 | |
39 | #define HASH_REHASH_FACTOR 2 | |
40 | ||
41 | #define HASH_SHOULDGROW(table) \ | |
42 | ((table)->nentries >= (table)->nbuckets * HASH_REHASH_FACTOR) | |
43 | ||
44 | /* an initial approximation */ | |
45 | #define HASH_SHOULDSHRINK(table) \ | |
46 | (((table)->nbuckets > DEFAULT_HASH_BUCKETS) && \ | |
47 | ((table)->nentries < (table)->nbuckets / HASH_REHASH_MULTIPLIER)) | |
48 | ||
7117c2d2 JA |
49 | /* Rely on properties of unsigned division (unsigned/int -> unsigned) and |
50 | don't discard the upper 32 bits of the value, if present. */ | |
51 | #define HASH_BUCKET(s, t, h) (((h) = hash_string (s)) & ((t)->nbuckets - 1)) | |
f73dda09 | 52 | |
8868edaf CR |
53 | static BUCKET_CONTENTS *copy_bucket_array PARAMS((BUCKET_CONTENTS *, sh_string_func_t *)); |
54 | ||
55 | static void hash_rehash PARAMS((HASH_TABLE *, int)); | |
56 | static void hash_grow PARAMS((HASH_TABLE *)); | |
57 | static void hash_shrink PARAMS((HASH_TABLE *)); | |
726f6388 JA |
58 | |
59 | /* Make a new hash table with BUCKETS number of buckets. Initialize | |
60 | each slot in the table to NULL. */ | |
61 | HASH_TABLE * | |
7117c2d2 | 62 | hash_create (buckets) |
726f6388 JA |
63 | int buckets; |
64 | { | |
ccc6cda3 | 65 | HASH_TABLE *new_table; |
7117c2d2 | 66 | register int i; |
726f6388 | 67 | |
ccc6cda3 | 68 | new_table = (HASH_TABLE *)xmalloc (sizeof (HASH_TABLE)); |
726f6388 JA |
69 | if (buckets == 0) |
70 | buckets = DEFAULT_HASH_BUCKETS; | |
71 | ||
72 | new_table->bucket_array = | |
73 | (BUCKET_CONTENTS **)xmalloc (buckets * sizeof (BUCKET_CONTENTS *)); | |
74 | new_table->nbuckets = buckets; | |
75 | new_table->nentries = 0; | |
7117c2d2 JA |
76 | |
77 | for (i = 0; i < buckets; i++) | |
78 | new_table->bucket_array[i] = (BUCKET_CONTENTS *)NULL; | |
79 | ||
726f6388 JA |
80 | return (new_table); |
81 | } | |
82 | ||
f73dda09 | 83 | int |
7117c2d2 | 84 | hash_size (table) |
f73dda09 JA |
85 | HASH_TABLE *table; |
86 | { | |
87 | return (HASH_ENTRIES(table)); | |
88 | } | |
89 | ||
90 | static BUCKET_CONTENTS * | |
91 | copy_bucket_array (ba, cpdata) | |
92 | BUCKET_CONTENTS *ba; | |
93 | sh_string_func_t *cpdata; /* data copy function */ | |
94 | { | |
95 | BUCKET_CONTENTS *new_bucket, *n, *e; | |
96 | ||
97 | if (ba == 0) | |
98 | return ((BUCKET_CONTENTS *)0); | |
99 | ||
100 | for (n = (BUCKET_CONTENTS *)0, e = ba; e; e = e->next) | |
101 | { | |
102 | if (n == 0) | |
103 | { | |
104 | new_bucket = (BUCKET_CONTENTS *)xmalloc (sizeof (BUCKET_CONTENTS)); | |
105 | n = new_bucket; | |
106 | } | |
107 | else | |
108 | { | |
109 | n->next = (BUCKET_CONTENTS *)xmalloc (sizeof (BUCKET_CONTENTS)); | |
110 | n = n->next; | |
111 | } | |
112 | ||
113 | n->key = savestring (e->key); | |
114 | n->data = e->data ? (cpdata ? (*cpdata) (e->data) : savestring (e->data)) | |
7117c2d2 JA |
115 | : NULL; |
116 | n->khash = e->khash; | |
f73dda09 JA |
117 | n->times_found = e->times_found; |
118 | n->next = (BUCKET_CONTENTS *)NULL; | |
119 | } | |
120 | ||
121 | return new_bucket; | |
122 | } | |
123 | ||
8868edaf CR |
124 | static void |
125 | hash_rehash (table, nsize) | |
126 | HASH_TABLE *table; | |
127 | int nsize; | |
128 | { | |
129 | int osize, i, j; | |
130 | BUCKET_CONTENTS **old_bucket_array, *item, *next; | |
131 | ||
132 | if (table == NULL || nsize == table->nbuckets) | |
133 | return; | |
134 | ||
135 | osize = table->nbuckets; | |
136 | old_bucket_array = table->bucket_array; | |
137 | ||
138 | table->nbuckets = nsize; | |
139 | table->bucket_array = (BUCKET_CONTENTS **)xmalloc (table->nbuckets * sizeof (BUCKET_CONTENTS *)); | |
140 | for (i = 0; i < table->nbuckets; i++) | |
141 | table->bucket_array[i] = (BUCKET_CONTENTS *)NULL; | |
142 | ||
143 | for (j = 0; j < osize; j++) | |
144 | { | |
145 | for (item = old_bucket_array[j]; item; item = next) | |
146 | { | |
147 | next = item->next; | |
148 | i = item->khash & (table->nbuckets - 1); | |
149 | item->next = table->bucket_array[i]; | |
150 | table->bucket_array[i] = item; | |
151 | } | |
152 | } | |
153 | ||
154 | free (old_bucket_array); | |
155 | } | |
156 | ||
157 | static void | |
158 | hash_grow (table) | |
159 | HASH_TABLE *table; | |
160 | { | |
161 | int nsize; | |
162 | ||
163 | nsize = table->nbuckets * HASH_REHASH_MULTIPLIER; | |
164 | if (nsize > 0) /* overflow */ | |
165 | hash_rehash (table, nsize); | |
166 | } | |
167 | ||
168 | static void | |
169 | hash_shrink (table) | |
170 | HASH_TABLE *table; | |
171 | { | |
172 | int nsize; | |
173 | ||
174 | nsize = table->nbuckets / HASH_REHASH_MULTIPLIER; | |
175 | hash_rehash (table, nsize); | |
176 | } | |
177 | ||
f73dda09 | 178 | HASH_TABLE * |
7117c2d2 | 179 | hash_copy (table, cpdata) |
f73dda09 JA |
180 | HASH_TABLE *table; |
181 | sh_string_func_t *cpdata; | |
182 | { | |
183 | HASH_TABLE *new_table; | |
184 | int i; | |
185 | ||
186 | if (table == 0) | |
187 | return ((HASH_TABLE *)NULL); | |
188 | ||
7117c2d2 | 189 | new_table = hash_create (table->nbuckets); |
f73dda09 JA |
190 | |
191 | for (i = 0; i < table->nbuckets; i++) | |
192 | new_table->bucket_array[i] = copy_bucket_array (table->bucket_array[i], cpdata); | |
193 | ||
194 | new_table->nentries = table->nentries; | |
195 | return new_table; | |
196 | } | |
197 | ||
d233b485 CR |
198 | /* This is the best 32-bit string hash function I found. It's one of the |
199 | Fowler-Noll-Vo family (FNV-1). | |
200 | ||
201 | The magic is in the interesting relationship between the special prime | |
202 | 16777619 (2^24 + 403) and 2^32 and 2^8. */ | |
203 | ||
204 | #define FNV_OFFSET 2166136261 | |
205 | #define FNV_PRIME 16777619 | |
206 | ||
207 | /* If you want to use 64 bits, use | |
208 | FNV_OFFSET 14695981039346656037 | |
8868edaf | 209 | FNV_PRIME 1099511628211 |
d233b485 CR |
210 | */ |
211 | ||
7117c2d2 JA |
212 | /* The `khash' check below requires that strings that compare equally with |
213 | strcmp hash to the same value. */ | |
214 | unsigned int | |
215 | hash_string (s) | |
216 | const char *s; | |
217 | { | |
218 | register unsigned int i; | |
726f6388 | 219 | |
d233b485 | 220 | for (i = FNV_OFFSET; *s; s++) |
7117c2d2 | 221 | { |
8868edaf CR |
222 | /* FNV-1a has the XOR first, traditional FNV-1 has the multiply first */ |
223 | ||
224 | /* was i *= FNV_PRIME */ | |
225 | i += (i<<1) + (i<<4) + (i<<7) + (i<<8) + (i<<24); | |
7117c2d2 JA |
226 | i ^= *s; |
227 | } | |
228 | ||
229 | return i; | |
230 | } | |
231 | ||
232 | /* Return the location of the bucket which should contain the data | |
233 | for STRING. TABLE is a pointer to a HASH_TABLE. */ | |
726f6388 JA |
234 | |
235 | int | |
7117c2d2 | 236 | hash_bucket (string, table) |
f73dda09 | 237 | const char *string; |
726f6388 JA |
238 | HASH_TABLE *table; |
239 | { | |
7117c2d2 | 240 | unsigned int h; |
726f6388 | 241 | |
7117c2d2 | 242 | return (HASH_BUCKET (string, table, h)); |
726f6388 JA |
243 | } |
244 | ||
7117c2d2 JA |
245 | /* Return a pointer to the hashed item. If the HASH_CREATE flag is passed, |
246 | create a new hash table entry for STRING, otherwise return NULL. */ | |
726f6388 | 247 | BUCKET_CONTENTS * |
7117c2d2 | 248 | hash_search (string, table, flags) |
f73dda09 | 249 | const char *string; |
726f6388 | 250 | HASH_TABLE *table; |
7117c2d2 | 251 | int flags; |
726f6388 JA |
252 | { |
253 | BUCKET_CONTENTS *list; | |
7117c2d2 JA |
254 | int bucket; |
255 | unsigned int hv; | |
726f6388 | 256 | |
7117c2d2 | 257 | if (table == 0 || ((flags & HASH_CREATE) == 0 && HASH_ENTRIES (table) == 0)) |
726f6388 JA |
258 | return (BUCKET_CONTENTS *)NULL; |
259 | ||
7117c2d2 | 260 | bucket = HASH_BUCKET (string, table, hv); |
726f6388 | 261 | |
0001803f | 262 | for (list = table->bucket_array ? table->bucket_array[bucket] : 0; list; list = list->next) |
726f6388 | 263 | { |
a0c0a00f | 264 | /* This is the comparison function */ |
7117c2d2 | 265 | if (hv == list->khash && STREQ (list->key, string)) |
726f6388 JA |
266 | { |
267 | list->times_found++; | |
268 | return (list); | |
269 | } | |
726f6388 | 270 | } |
7117c2d2 JA |
271 | |
272 | if (flags & HASH_CREATE) | |
273 | { | |
8868edaf CR |
274 | if (HASH_SHOULDGROW (table)) |
275 | { | |
276 | hash_grow (table); | |
277 | bucket = HASH_BUCKET (string, table, hv); | |
278 | } | |
279 | ||
7117c2d2 JA |
280 | list = (BUCKET_CONTENTS *)xmalloc (sizeof (BUCKET_CONTENTS)); |
281 | list->next = table->bucket_array[bucket]; | |
282 | table->bucket_array[bucket] = list; | |
283 | ||
284 | list->data = NULL; | |
285 | list->key = (char *)string; /* XXX fix later */ | |
286 | list->khash = hv; | |
287 | list->times_found = 0; | |
288 | ||
289 | table->nentries++; | |
290 | return (list); | |
291 | } | |
292 | ||
726f6388 JA |
293 | return (BUCKET_CONTENTS *)NULL; |
294 | } | |
295 | ||
296 | /* Remove the item specified by STRING from the hash table TABLE. | |
297 | The item removed is returned, so you can free its contents. If | |
298 | the item isn't in this table NULL is returned. */ | |
299 | BUCKET_CONTENTS * | |
7117c2d2 | 300 | hash_remove (string, table, flags) |
f73dda09 | 301 | const char *string; |
726f6388 | 302 | HASH_TABLE *table; |
7117c2d2 | 303 | int flags; |
726f6388 | 304 | { |
7117c2d2 | 305 | int bucket; |
726f6388 | 306 | BUCKET_CONTENTS *prev, *temp; |
7117c2d2 | 307 | unsigned int hv; |
726f6388 | 308 | |
7117c2d2 | 309 | if (table == 0 || HASH_ENTRIES (table) == 0) |
726f6388 JA |
310 | return (BUCKET_CONTENTS *)NULL; |
311 | ||
7117c2d2 | 312 | bucket = HASH_BUCKET (string, table, hv); |
726f6388 | 313 | prev = (BUCKET_CONTENTS *)NULL; |
7117c2d2 | 314 | for (temp = table->bucket_array[bucket]; temp; temp = temp->next) |
726f6388 | 315 | { |
7117c2d2 | 316 | if (hv == temp->khash && STREQ (temp->key, string)) |
726f6388 JA |
317 | { |
318 | if (prev) | |
319 | prev->next = temp->next; | |
320 | else | |
7117c2d2 | 321 | table->bucket_array[bucket] = temp->next; |
726f6388 JA |
322 | |
323 | table->nentries--; | |
324 | return (temp); | |
325 | } | |
326 | prev = temp; | |
726f6388 JA |
327 | } |
328 | return ((BUCKET_CONTENTS *) NULL); | |
329 | } | |
330 | ||
331 | /* Create an entry for STRING, in TABLE. If the entry already | |
7117c2d2 | 332 | exists, then return it (unless the HASH_NOSRCH flag is set). */ |
726f6388 | 333 | BUCKET_CONTENTS * |
7117c2d2 | 334 | hash_insert (string, table, flags) |
726f6388 JA |
335 | char *string; |
336 | HASH_TABLE *table; | |
7117c2d2 | 337 | int flags; |
726f6388 JA |
338 | { |
339 | BUCKET_CONTENTS *item; | |
ccc6cda3 | 340 | int bucket; |
7117c2d2 | 341 | unsigned int hv; |
726f6388 | 342 | |
ccc6cda3 | 343 | if (table == 0) |
7117c2d2 | 344 | table = hash_create (0); |
726f6388 | 345 | |
7117c2d2 JA |
346 | item = (flags & HASH_NOSRCH) ? (BUCKET_CONTENTS *)NULL |
347 | : hash_search (string, table, 0); | |
348 | ||
349 | if (item == 0) | |
726f6388 | 350 | { |
8868edaf CR |
351 | if (HASH_SHOULDGROW (table)) |
352 | hash_grow (table); | |
353 | ||
7117c2d2 | 354 | bucket = HASH_BUCKET (string, table, hv); |
726f6388 | 355 | |
7117c2d2 JA |
356 | item = (BUCKET_CONTENTS *)xmalloc (sizeof (BUCKET_CONTENTS)); |
357 | item->next = table->bucket_array[bucket]; | |
358 | table->bucket_array[bucket] = item; | |
726f6388 | 359 | |
7117c2d2 | 360 | item->data = NULL; |
726f6388 | 361 | item->key = string; |
7117c2d2 | 362 | item->khash = hv; |
726f6388 | 363 | item->times_found = 0; |
7117c2d2 JA |
364 | |
365 | table->nentries++; | |
726f6388 JA |
366 | } |
367 | ||
368 | return (item); | |
369 | } | |
370 | ||
ccc6cda3 JA |
371 | /* Remove and discard all entries in TABLE. If FREE_DATA is non-null, it |
372 | is a function to call to dispose of a hash item's data. Otherwise, | |
373 | free() is called. */ | |
374 | void | |
7117c2d2 | 375 | hash_flush (table, free_data) |
ccc6cda3 | 376 | HASH_TABLE *table; |
f73dda09 | 377 | sh_free_func_t *free_data; |
ccc6cda3 JA |
378 | { |
379 | int i; | |
380 | register BUCKET_CONTENTS *bucket, *item; | |
381 | ||
7117c2d2 | 382 | if (table == 0 || HASH_ENTRIES (table) == 0) |
d166f048 JA |
383 | return; |
384 | ||
ccc6cda3 JA |
385 | for (i = 0; i < table->nbuckets; i++) |
386 | { | |
387 | bucket = table->bucket_array[i]; | |
388 | ||
389 | while (bucket) | |
390 | { | |
391 | item = bucket; | |
392 | bucket = bucket->next; | |
393 | ||
394 | if (free_data) | |
395 | (*free_data) (item->data); | |
396 | else | |
397 | free (item->data); | |
398 | free (item->key); | |
399 | free (item); | |
400 | } | |
401 | table->bucket_array[i] = (BUCKET_CONTENTS *)NULL; | |
402 | } | |
7117c2d2 JA |
403 | |
404 | table->nentries = 0; | |
ccc6cda3 JA |
405 | } |
406 | ||
d166f048 JA |
407 | /* Free the hash table pointed to by TABLE. */ |
408 | void | |
7117c2d2 | 409 | hash_dispose (table) |
d166f048 JA |
410 | HASH_TABLE *table; |
411 | { | |
412 | free (table->bucket_array); | |
413 | free (table); | |
414 | } | |
415 | ||
7117c2d2 JA |
416 | void |
417 | hash_walk (table, func) | |
726f6388 | 418 | HASH_TABLE *table; |
7117c2d2 | 419 | hash_wfunc *func; |
726f6388 | 420 | { |
7117c2d2 JA |
421 | register int i; |
422 | BUCKET_CONTENTS *item; | |
423 | ||
424 | if (table == 0 || HASH_ENTRIES (table) == 0) | |
425 | return; | |
426 | ||
427 | for (i = 0; i < table->nbuckets; i++) | |
428 | { | |
429 | for (item = hash_items (i, table); item; item = item->next) | |
430 | if ((*func) (item) < 0) | |
431 | return; | |
432 | } | |
726f6388 JA |
433 | } |
434 | ||
7117c2d2 | 435 | #if defined (DEBUG) || defined (TEST_HASHING) |
cce855bc | 436 | void |
7117c2d2 | 437 | hash_pstats (table, name) |
d166f048 JA |
438 | HASH_TABLE *table; |
439 | char *name; | |
440 | { | |
441 | register int slot, bcount; | |
442 | register BUCKET_CONTENTS *bc; | |
443 | ||
444 | if (name == 0) | |
445 | name = "unknown hash table"; | |
446 | ||
447 | fprintf (stderr, "%s: %d buckets; %d items\n", name, table->nbuckets, table->nentries); | |
448 | ||
449 | /* Print out a count of how many strings hashed to each bucket, so we can | |
450 | see how even the distribution is. */ | |
451 | for (slot = 0; slot < table->nbuckets; slot++) | |
452 | { | |
7117c2d2 | 453 | bc = hash_items (slot, table); |
d166f048 JA |
454 | |
455 | fprintf (stderr, "\tslot %3d: ", slot); | |
456 | for (bcount = 0; bc; bc = bc->next) | |
28ef6c31 | 457 | bcount++; |
d166f048 JA |
458 | |
459 | fprintf (stderr, "%d\n", bcount); | |
460 | } | |
461 | } | |
cce855bc | 462 | #endif |
d166f048 | 463 | |
726f6388 JA |
464 | #ifdef TEST_HASHING |
465 | ||
7117c2d2 | 466 | /* link with xmalloc.o and lib/malloc/libmalloc.a */ |
726f6388 JA |
467 | #undef NULL |
468 | #include <stdio.h> | |
469 | ||
f73dda09 JA |
470 | #ifndef NULL |
471 | #define NULL 0 | |
472 | #endif | |
473 | ||
474 | HASH_TABLE *table, *ntable; | |
726f6388 | 475 | |
7117c2d2 | 476 | int interrupt_immediately = 0; |
8868edaf | 477 | int running_trap = 0; |
7117c2d2 JA |
478 | |
479 | int | |
480 | signal_is_trapped (s) | |
481 | int s; | |
726f6388 | 482 | { |
7117c2d2 JA |
483 | return (0); |
484 | } | |
485 | ||
486 | void | |
487 | programming_error (const char *format, ...) | |
488 | { | |
489 | abort(); | |
490 | } | |
491 | ||
492 | void | |
493 | fatal_error (const char *format, ...) | |
494 | { | |
495 | abort(); | |
726f6388 JA |
496 | } |
497 | ||
a0c0a00f CR |
498 | void |
499 | internal_warning (const char *format, ...) | |
500 | { | |
501 | } | |
502 | ||
8868edaf | 503 | int |
726f6388 JA |
504 | main () |
505 | { | |
506 | char string[256]; | |
507 | int count = 0; | |
508 | BUCKET_CONTENTS *tt; | |
509 | ||
a0c0a00f CR |
510 | #if defined (TEST_NBUCKETS) |
511 | table = hash_create (TEST_NBUCKETS); | |
512 | #else | |
7117c2d2 | 513 | table = hash_create (0); |
a0c0a00f | 514 | #endif |
ccc6cda3 | 515 | |
726f6388 JA |
516 | for (;;) |
517 | { | |
518 | char *temp_string; | |
519 | if (fgets (string, sizeof (string), stdin) == 0) | |
28ef6c31 | 520 | break; |
726f6388 | 521 | if (!*string) |
28ef6c31 | 522 | break; |
726f6388 | 523 | temp_string = savestring (string); |
7117c2d2 | 524 | tt = hash_insert (temp_string, table, 0); |
726f6388 JA |
525 | if (tt->times_found) |
526 | { | |
527 | fprintf (stderr, "You have already added item `%s'\n", string); | |
528 | free (temp_string); | |
529 | } | |
530 | else | |
531 | { | |
532 | count++; | |
533 | } | |
534 | } | |
ccc6cda3 | 535 | |
7117c2d2 | 536 | hash_pstats (table, "hash test"); |
f73dda09 | 537 | |
7117c2d2 JA |
538 | ntable = hash_copy (table, (sh_string_func_t *)NULL); |
539 | hash_flush (table, (sh_free_func_t *)NULL); | |
540 | hash_pstats (ntable, "hash copy test"); | |
f73dda09 | 541 | |
d166f048 | 542 | exit (0); |
726f6388 JA |
543 | } |
544 | ||
545 | #endif /* TEST_HASHING */ |