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f52a7d75 | 1 | |
2 | /* | |
262a0e14 | 3 | * $Id$ |
f52a7d75 | 4 | * |
5 | * DEBUG: section 0 Hash Tables | |
6 | * AUTHOR: Harvest Derived | |
7 | * | |
2b6662ba | 8 | * SQUID Web Proxy Cache http://www.squid-cache.org/ |
f52a7d75 | 9 | * ---------------------------------------------------------- |
10 | * | |
2b6662ba | 11 | * Squid is the result of efforts by numerous individuals from |
12 | * the Internet community; see the CONTRIBUTORS file for full | |
13 | * details. Many organizations have provided support for Squid's | |
14 | * development; see the SPONSORS file for full details. Squid is | |
15 | * Copyrighted (C) 2001 by the Regents of the University of | |
16 | * California; see the COPYRIGHT file for full details. Squid | |
17 | * incorporates software developed and/or copyrighted by other | |
18 | * sources; see the CREDITS file for full details. | |
f52a7d75 | 19 | * |
20 | * This program is free software; you can redistribute it and/or modify | |
21 | * it under the terms of the GNU General Public License as published by | |
22 | * the Free Software Foundation; either version 2 of the License, or | |
23 | * (at your option) any later version. | |
26ac0430 | 24 | * |
f52a7d75 | 25 | * This program is distributed in the hope that it will be useful, |
26 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
27 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
28 | * GNU General Public License for more details. | |
26ac0430 | 29 | * |
f52a7d75 | 30 | * You should have received a copy of the GNU General Public License |
31 | * along with this program; if not, write to the Free Software | |
32 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. | |
33 | * | |
34 | */ | |
35 | ||
36 | #include "config.h" | |
37 | ||
38 | #if HAVE_STDIO_H | |
39 | #include <stdio.h> | |
40 | #endif | |
41 | #if HAVE_STDLIB_H | |
42 | #include <stdlib.h> | |
43 | #endif | |
44 | #if HAVE_STRING_H | |
45 | #include <string.h> | |
46 | #endif | |
47 | #if HAVE_UNISTD_H | |
48 | #include <unistd.h> | |
49 | #endif | |
50 | #if HAVE_GNUMALLLOC_H | |
51 | #include <gnumalloc.h> | |
482aa790 | 52 | #elif HAVE_MALLOC_H |
f52a7d75 | 53 | #include <malloc.h> |
54 | #endif | |
55 | #if HAVE_ASSERT_H | |
56 | #include <assert.h> | |
57 | #endif | |
e880cefa | 58 | #if HAVE_MATH_H |
59 | #include <math.h> | |
60 | #endif | |
f52a7d75 | 61 | |
62 | #include "hash.h" | |
63 | #include "util.h" | |
88bfe092 | 64 | #include "profiling.h" |
f52a7d75 | 65 | |
66 | static void hash_next_bucket(hash_table * hid); | |
67 | ||
68 | unsigned int | |
69 | hash_string(const void *data, unsigned int size) | |
70 | { | |
71 | const char *s = data; | |
72 | unsigned int n = 0; | |
73 | unsigned int j = 0; | |
74 | unsigned int i = 0; | |
75 | while (*s) { | |
26ac0430 AJ |
76 | j++; |
77 | n ^= 271 * (unsigned) *s++; | |
f52a7d75 | 78 | } |
79 | i = n ^ (j * 271); | |
80 | return i % size; | |
81 | } | |
82 | ||
83 | /* the following function(s) were adapted from | |
84 | * usr/src/lib/libc/db/hash_func.c, 4.4 BSD lite */ | |
85 | ||
86 | /* Hash function from Chris Torek. */ | |
87 | unsigned int | |
88 | hash4(const void *data, unsigned int size) | |
89 | { | |
90 | const char *key = data; | |
91 | size_t loop; | |
92 | unsigned int h; | |
93 | size_t len; | |
94 | ||
95 | #define HASH4a h = (h << 5) - h + *key++; | |
96 | #define HASH4b h = (h << 5) + h + *key++; | |
97 | #define HASH4 HASH4b | |
98 | ||
99 | h = 0; | |
100 | len = strlen(key); | |
101 | loop = len >> 3; | |
102 | switch (len & (8 - 1)) { | |
103 | case 0: | |
26ac0430 | 104 | break; |
f52a7d75 | 105 | case 7: |
26ac0430 AJ |
106 | HASH4; |
107 | /* FALLTHROUGH */ | |
f52a7d75 | 108 | case 6: |
26ac0430 AJ |
109 | HASH4; |
110 | /* FALLTHROUGH */ | |
f52a7d75 | 111 | case 5: |
26ac0430 AJ |
112 | HASH4; |
113 | /* FALLTHROUGH */ | |
f52a7d75 | 114 | case 4: |
26ac0430 AJ |
115 | HASH4; |
116 | /* FALLTHROUGH */ | |
f52a7d75 | 117 | case 3: |
26ac0430 AJ |
118 | HASH4; |
119 | /* FALLTHROUGH */ | |
f52a7d75 | 120 | case 2: |
26ac0430 AJ |
121 | HASH4; |
122 | /* FALLTHROUGH */ | |
f52a7d75 | 123 | case 1: |
26ac0430 | 124 | HASH4; |
f52a7d75 | 125 | } |
126 | while (loop--) { | |
26ac0430 AJ |
127 | HASH4; |
128 | HASH4; | |
129 | HASH4; | |
130 | HASH4; | |
131 | HASH4; | |
132 | HASH4; | |
133 | HASH4; | |
134 | HASH4; | |
f52a7d75 | 135 | } |
136 | return h % size; | |
137 | } | |
138 | ||
139 | /* | |
140 | * hash_create - creates a new hash table, uses the cmp_func | |
141 | * to compare keys. Returns the identification for the hash table; | |
142 | * otherwise returns a negative number on error. | |
143 | */ | |
144 | hash_table * | |
145 | hash_create(HASHCMP * cmp_func, int hash_sz, HASHHASH * hash_func) | |
146 | { | |
147 | hash_table *hid = xcalloc(1, sizeof(hash_table)); | |
148 | if (!hash_sz) | |
26ac0430 | 149 | hid->size = (unsigned int) DEFAULT_HASH_SIZE; |
f52a7d75 | 150 | else |
26ac0430 | 151 | hid->size = (unsigned int) hash_sz; |
f52a7d75 | 152 | /* allocate and null the buckets */ |
153 | hid->buckets = xcalloc(hid->size, sizeof(hash_link *)); | |
154 | hid->cmp = cmp_func; | |
155 | hid->hash = hash_func; | |
156 | hid->next = NULL; | |
157 | hid->current_slot = 0; | |
158 | return hid; | |
159 | } | |
160 | ||
161 | /* | |
162 | * hash_join - joins a hash_link under its key lnk->key | |
26ac0430 | 163 | * into the hash table 'hid'. |
f52a7d75 | 164 | * |
165 | * It does not copy any data into the hash table, only links pointers. | |
166 | */ | |
167 | void | |
168 | hash_join(hash_table * hid, hash_link * lnk) | |
169 | { | |
170 | int i; | |
171 | i = hid->hash(lnk->key, hid->size); | |
172 | lnk->next = hid->buckets[i]; | |
173 | hid->buckets[i] = lnk; | |
174 | hid->count++; | |
175 | } | |
176 | ||
177 | /* | |
178 | * hash_lookup - locates the item under the key 'k' in the hash table | |
179 | * 'hid'. Returns a pointer to the hash bucket on success; otherwise | |
180 | * returns NULL. | |
181 | */ | |
4a8b20e8 | 182 | hash_link * |
f52a7d75 | 183 | hash_lookup(hash_table * hid, const void *k) |
184 | { | |
185 | hash_link *walker; | |
186 | int b; | |
88bfe092 | 187 | PROF_start(hash_lookup); |
f52a7d75 | 188 | assert(k != NULL); |
189 | b = hid->hash(k, hid->size); | |
190 | for (walker = hid->buckets[b]; walker != NULL; walker = walker->next) { | |
26ac0430 AJ |
191 | if ((hid->cmp) (k, walker->key) == 0) { |
192 | PROF_stop(hash_lookup); | |
193 | return (walker); | |
194 | } | |
195 | assert(walker != walker->next); | |
f52a7d75 | 196 | } |
88bfe092 | 197 | PROF_stop(hash_lookup); |
f52a7d75 | 198 | return NULL; |
199 | } | |
200 | ||
201 | static void | |
202 | hash_next_bucket(hash_table * hid) | |
203 | { | |
204 | while (hid->next == NULL && ++hid->current_slot < hid->size) | |
26ac0430 | 205 | hid->next = hid->buckets[hid->current_slot]; |
f52a7d75 | 206 | } |
207 | ||
208 | /* | |
209 | * hash_first - initializes the hash table for the hash_next() | |
210 | * function. | |
211 | */ | |
212 | void | |
213 | hash_first(hash_table * hid) | |
214 | { | |
215 | assert(NULL == hid->next); | |
216 | hid->current_slot = 0; | |
217 | hid->next = hid->buckets[hid->current_slot]; | |
218 | if (NULL == hid->next) | |
26ac0430 | 219 | hash_next_bucket(hid); |
f52a7d75 | 220 | } |
221 | ||
222 | /* | |
223 | * hash_next - returns the next item in the hash table 'hid'. | |
26ac0430 | 224 | * Otherwise, returns NULL on error or end of list. |
f52a7d75 | 225 | * |
226 | * MUST call hash_first() before hash_next(). | |
227 | */ | |
4a8b20e8 | 228 | hash_link * |
f52a7d75 | 229 | hash_next(hash_table * hid) |
230 | { | |
231 | hash_link *this = hid->next; | |
232 | if (NULL == this) | |
26ac0430 | 233 | return NULL; |
f52a7d75 | 234 | hid->next = this->next; |
235 | if (NULL == hid->next) | |
26ac0430 | 236 | hash_next_bucket(hid); |
f52a7d75 | 237 | return this; |
238 | } | |
239 | ||
2c4f7ab2 | 240 | /* |
241 | * hash_last - resets hash traversal state to NULL | |
242 | * | |
243 | */ | |
244 | void | |
ab96e65c | 245 | hash_last(hash_table * hid) |
2c4f7ab2 | 246 | { |
137a13ea | 247 | assert(hid != NULL); |
2c4f7ab2 | 248 | hid->next = NULL; |
249 | hid->current_slot = 0; | |
250 | } | |
251 | ||
f52a7d75 | 252 | /* |
26ac0430 | 253 | * hash_remove_link - deletes the given hash_link node from the |
f52a7d75 | 254 | * hash table 'hid'. Does not free the item, only removes it |
255 | * from the list. | |
256 | * | |
4fba1a24 | 257 | * An assertion is triggered if the hash_link is not found in the |
258 | * list. | |
f52a7d75 | 259 | */ |
260 | void | |
261 | hash_remove_link(hash_table * hid, hash_link * hl) | |
262 | { | |
263 | hash_link **P; | |
264 | int i; | |
265 | assert(hl != NULL); | |
266 | i = hid->hash(hl->key, hid->size); | |
267 | for (P = &hid->buckets[i]; *P; P = &(*P)->next) { | |
26ac0430 AJ |
268 | if (*P != hl) |
269 | continue; | |
270 | *P = hl->next; | |
271 | if (hid->next == hl) { | |
272 | hid->next = hl->next; | |
273 | if (NULL == hid->next) | |
274 | hash_next_bucket(hid); | |
275 | } | |
276 | hid->count--; | |
277 | return; | |
f52a7d75 | 278 | } |
e530de6c | 279 | assert(0); |
f52a7d75 | 280 | } |
281 | ||
282 | /* | |
26ac0430 | 283 | * hash_get_bucket - returns the head item of the bucket |
f52a7d75 | 284 | * in the hash table 'hid'. Otherwise, returns NULL on error. |
285 | */ | |
286 | hash_link * | |
287 | hash_get_bucket(hash_table * hid, unsigned int bucket) | |
288 | { | |
289 | if (bucket >= hid->size) | |
26ac0430 | 290 | return NULL; |
f52a7d75 | 291 | return (hid->buckets[bucket]); |
292 | } | |
293 | ||
294 | void | |
295 | hashFreeItems(hash_table * hid, HASHFREE * free_func) | |
296 | { | |
297 | hash_link *l; | |
298 | hash_link **list; | |
299 | int i = 0; | |
300 | int j; | |
301 | list = xcalloc(hid->count, sizeof(hash_link *)); | |
302 | hash_first(hid); | |
303 | while ((l = hash_next(hid)) && i < hid->count) { | |
26ac0430 AJ |
304 | *(list + i) = l; |
305 | i++; | |
f52a7d75 | 306 | } |
307 | for (j = 0; j < i; j++) | |
26ac0430 | 308 | free_func(*(list + j)); |
f52a7d75 | 309 | xfree(list); |
310 | } | |
311 | ||
312 | void | |
313 | hashFreeMemory(hash_table * hid) | |
314 | { | |
137a13ea | 315 | assert(hid != NULL); |
efacbef0 | 316 | if (hid->buckets) |
26ac0430 | 317 | xfree(hid->buckets); |
f52a7d75 | 318 | xfree(hid); |
319 | } | |
320 | ||
26ac0430 | 321 | static int hash_primes[] = { |
f52a7d75 | 322 | 103, |
323 | 229, | |
324 | 467, | |
325 | 977, | |
326 | 1979, | |
327 | 4019, | |
328 | 6037, | |
329 | 7951, | |
330 | 12149, | |
331 | 16231, | |
332 | 33493, | |
333 | 65357 | |
334 | }; | |
335 | ||
336 | int | |
337 | hashPrime(int n) | |
338 | { | |
339 | int I = sizeof(hash_primes) / sizeof(int); | |
340 | int i; | |
341 | int best_prime = hash_primes[0]; | |
d87ebd78 | 342 | double min = fabs(log((double) n) - log((double) hash_primes[0])); |
f52a7d75 | 343 | double d; |
344 | for (i = 0; i < I; i++) { | |
26ac0430 AJ |
345 | d = fabs(log((double) n) - log((double) hash_primes[i])); |
346 | if (d > min) | |
347 | continue; | |
348 | min = d; | |
349 | best_prime = hash_primes[i]; | |
f52a7d75 | 350 | } |
351 | return best_prime; | |
352 | } | |
353 | ||
186477c1 | 354 | /* |
355 | * return the key of a hash_link as a const string | |
356 | */ | |
357 | const char * | |
358 | hashKeyStr(hash_link * hl) | |
359 | { | |
360 | return (const char *) hl->key; | |
361 | } | |
362 | ||
f52a7d75 | 363 | |
364 | #ifdef USE_HASH_DRIVER | |
365 | /* | |
366 | * hash-driver - Run with a big file as stdin to insert each line into the | |
367 | * hash table, then prints the whole hash table, then deletes a random item, | |
368 | * and prints the table again... | |
369 | */ | |
370 | int | |
371 | main(void) | |
372 | { | |
373 | hash_table *hid; | |
374 | int i; | |
375 | LOCAL_ARRAY(char, buf, BUFSIZ); | |
376 | LOCAL_ARRAY(char, todelete, BUFSIZ); | |
377 | hash_link *walker = NULL; | |
378 | ||
379 | todelete[0] = '\0'; | |
380 | printf("init\n"); | |
381 | ||
382 | printf("creating hash table\n"); | |
383 | if ((hid = hash_create((HASHCMP *) strcmp, 229, hash4)) < 0) { | |
26ac0430 AJ |
384 | printf("hash_create error.\n"); |
385 | exit(1); | |
f52a7d75 | 386 | } |
387 | printf("done creating hash table: %d\n", hid); | |
388 | ||
389 | while (fgets(buf, BUFSIZ, stdin)) { | |
26ac0430 AJ |
390 | buf[strlen(buf) - 1] = '\0'; |
391 | printf("Inserting '%s' for item %p to hash table: %d\n", | |
392 | buf, buf, hid); | |
393 | hash_insert(hid, xstrdup(buf), (void *) 0x12345678); | |
394 | if (random() % 17 == 0) | |
395 | strcpy(todelete, buf); | |
f52a7d75 | 396 | } |
397 | ||
398 | printf("walking hash table...\n"); | |
399 | for (i = 0, walker = hash_first(hid); walker; walker = hash_next(hid)) { | |
26ac0430 AJ |
400 | printf("item %5d: key: '%s' item: %p\n", i++, walker->key, |
401 | walker->item); | |
f52a7d75 | 402 | } |
403 | printf("done walking hash table...\n"); | |
404 | ||
405 | if (todelete[0]) { | |
26ac0430 AJ |
406 | printf("deleting %s from %d\n", todelete, hid); |
407 | if (hash_delete(hid, todelete)) | |
408 | printf("hash_delete error\n"); | |
f52a7d75 | 409 | } |
410 | printf("walking hash table...\n"); | |
411 | for (i = 0, walker = hash_first(hid); walker; walker = hash_next(hid)) { | |
26ac0430 AJ |
412 | printf("item %5d: key: '%s' item: %p\n", i++, walker->key, |
413 | walker->item); | |
f52a7d75 | 414 | } |
415 | printf("done walking hash table...\n"); | |
416 | ||
417 | ||
418 | printf("driver finished.\n"); | |
419 | exit(0); | |
420 | } | |
421 | #endif |