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f52a7d75 | 1 | |
2 | /* | |
262a0e14 | 3 | * $Id$ |
f52a7d75 | 4 | * |
b510f3a1 | 5 | * DEBUG: section 00 Hash Tables |
f52a7d75 | 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 | ||
f7f3304a | 36 | #include "squid.h" |
25f98340 AJ |
37 | #include "hash.h" |
38 | #include "profiler/Profiler.h" | |
f52a7d75 | 39 | |
40 | #if HAVE_STDIO_H | |
41 | #include <stdio.h> | |
42 | #endif | |
43 | #if HAVE_STDLIB_H | |
44 | #include <stdlib.h> | |
45 | #endif | |
46 | #if HAVE_STRING_H | |
47 | #include <string.h> | |
48 | #endif | |
49 | #if HAVE_UNISTD_H | |
50 | #include <unistd.h> | |
51 | #endif | |
52 | #if HAVE_GNUMALLLOC_H | |
53 | #include <gnumalloc.h> | |
482aa790 | 54 | #elif HAVE_MALLOC_H |
f52a7d75 | 55 | #include <malloc.h> |
56 | #endif | |
57 | #if HAVE_ASSERT_H | |
58 | #include <assert.h> | |
59 | #endif | |
e880cefa | 60 | #if HAVE_MATH_H |
61 | #include <math.h> | |
62 | #endif | |
f52a7d75 | 63 | |
f52a7d75 | 64 | static void hash_next_bucket(hash_table * hid); |
65 | ||
66 | unsigned int | |
67 | hash_string(const void *data, unsigned int size) | |
68 | { | |
209663bb | 69 | const unsigned char *s = static_cast<const unsigned char *>(data); |
f52a7d75 | 70 | unsigned int n = 0; |
71 | unsigned int j = 0; | |
72 | unsigned int i = 0; | |
73 | while (*s) { | |
26ac0430 | 74 | j++; |
209663bb | 75 | n ^= 271 * (*s++); |
f52a7d75 | 76 | } |
77 | i = n ^ (j * 271); | |
78 | return i % size; | |
79 | } | |
80 | ||
81 | /* the following function(s) were adapted from | |
82 | * usr/src/lib/libc/db/hash_func.c, 4.4 BSD lite */ | |
83 | ||
84 | /* Hash function from Chris Torek. */ | |
85 | unsigned int | |
86 | hash4(const void *data, unsigned int size) | |
87 | { | |
209663bb | 88 | const char *key = static_cast<const char *>(data); |
f52a7d75 | 89 | size_t loop; |
90 | unsigned int h; | |
91 | size_t len; | |
92 | ||
93 | #define HASH4a h = (h << 5) - h + *key++; | |
94 | #define HASH4b h = (h << 5) + h + *key++; | |
95 | #define HASH4 HASH4b | |
96 | ||
97 | h = 0; | |
98 | len = strlen(key); | |
99 | loop = len >> 3; | |
100 | switch (len & (8 - 1)) { | |
101 | case 0: | |
26ac0430 | 102 | break; |
f52a7d75 | 103 | case 7: |
26ac0430 AJ |
104 | HASH4; |
105 | /* FALLTHROUGH */ | |
f52a7d75 | 106 | case 6: |
26ac0430 AJ |
107 | HASH4; |
108 | /* FALLTHROUGH */ | |
f52a7d75 | 109 | case 5: |
26ac0430 AJ |
110 | HASH4; |
111 | /* FALLTHROUGH */ | |
f52a7d75 | 112 | case 4: |
26ac0430 AJ |
113 | HASH4; |
114 | /* FALLTHROUGH */ | |
f52a7d75 | 115 | case 3: |
26ac0430 AJ |
116 | HASH4; |
117 | /* FALLTHROUGH */ | |
f52a7d75 | 118 | case 2: |
26ac0430 AJ |
119 | HASH4; |
120 | /* FALLTHROUGH */ | |
f52a7d75 | 121 | case 1: |
26ac0430 | 122 | HASH4; |
f52a7d75 | 123 | } |
124 | while (loop--) { | |
26ac0430 AJ |
125 | HASH4; |
126 | HASH4; | |
127 | HASH4; | |
128 | HASH4; | |
129 | HASH4; | |
130 | HASH4; | |
131 | HASH4; | |
132 | HASH4; | |
f52a7d75 | 133 | } |
134 | return h % size; | |
135 | } | |
136 | ||
209663bb | 137 | /** |
f52a7d75 | 138 | * hash_create - creates a new hash table, uses the cmp_func |
139 | * to compare keys. Returns the identification for the hash table; | |
140 | * otherwise returns a negative number on error. | |
141 | */ | |
142 | hash_table * | |
143 | hash_create(HASHCMP * cmp_func, int hash_sz, HASHHASH * hash_func) | |
144 | { | |
209663bb | 145 | hash_table *hid = (hash_table *)xcalloc(1, sizeof(hash_table)); |
f52a7d75 | 146 | if (!hash_sz) |
26ac0430 | 147 | hid->size = (unsigned int) DEFAULT_HASH_SIZE; |
f52a7d75 | 148 | else |
26ac0430 | 149 | hid->size = (unsigned int) hash_sz; |
f52a7d75 | 150 | /* allocate and null the buckets */ |
209663bb | 151 | hid->buckets = (hash_link **)xcalloc(hid->size, sizeof(hash_link *)); |
f52a7d75 | 152 | hid->cmp = cmp_func; |
153 | hid->hash = hash_func; | |
154 | hid->next = NULL; | |
155 | hid->current_slot = 0; | |
156 | return hid; | |
157 | } | |
158 | ||
209663bb | 159 | /** |
f52a7d75 | 160 | * hash_join - joins a hash_link under its key lnk->key |
26ac0430 | 161 | * into the hash table 'hid'. |
f52a7d75 | 162 | * |
163 | * It does not copy any data into the hash table, only links pointers. | |
164 | */ | |
165 | void | |
166 | hash_join(hash_table * hid, hash_link * lnk) | |
167 | { | |
168 | int i; | |
169 | i = hid->hash(lnk->key, hid->size); | |
170 | lnk->next = hid->buckets[i]; | |
171 | hid->buckets[i] = lnk; | |
172 | hid->count++; | |
173 | } | |
174 | ||
209663bb | 175 | /** |
f52a7d75 | 176 | * hash_lookup - locates the item under the key 'k' in the hash table |
177 | * 'hid'. Returns a pointer to the hash bucket on success; otherwise | |
178 | * returns NULL. | |
179 | */ | |
4a8b20e8 | 180 | hash_link * |
f52a7d75 | 181 | hash_lookup(hash_table * hid, const void *k) |
182 | { | |
f52a7d75 | 183 | int b; |
88bfe092 | 184 | PROF_start(hash_lookup); |
f52a7d75 | 185 | assert(k != NULL); |
186 | b = hid->hash(k, hid->size); | |
209663bb | 187 | for (hash_link *walker = hid->buckets[b]; walker != NULL; walker = walker->next) { |
26ac0430 AJ |
188 | if ((hid->cmp) (k, walker->key) == 0) { |
189 | PROF_stop(hash_lookup); | |
190 | return (walker); | |
191 | } | |
192 | assert(walker != walker->next); | |
f52a7d75 | 193 | } |
88bfe092 | 194 | PROF_stop(hash_lookup); |
f52a7d75 | 195 | return NULL; |
196 | } | |
197 | ||
198 | static void | |
199 | hash_next_bucket(hash_table * hid) | |
200 | { | |
201 | while (hid->next == NULL && ++hid->current_slot < hid->size) | |
26ac0430 | 202 | hid->next = hid->buckets[hid->current_slot]; |
f52a7d75 | 203 | } |
204 | ||
209663bb | 205 | /** |
f52a7d75 | 206 | * hash_first - initializes the hash table for the hash_next() |
207 | * function. | |
208 | */ | |
209 | void | |
210 | hash_first(hash_table * hid) | |
211 | { | |
212 | assert(NULL == hid->next); | |
213 | hid->current_slot = 0; | |
214 | hid->next = hid->buckets[hid->current_slot]; | |
215 | if (NULL == hid->next) | |
26ac0430 | 216 | hash_next_bucket(hid); |
f52a7d75 | 217 | } |
218 | ||
209663bb | 219 | /** |
f52a7d75 | 220 | * hash_next - returns the next item in the hash table 'hid'. |
26ac0430 | 221 | * Otherwise, returns NULL on error or end of list. |
f52a7d75 | 222 | * |
223 | * MUST call hash_first() before hash_next(). | |
224 | */ | |
4a8b20e8 | 225 | hash_link * |
f52a7d75 | 226 | hash_next(hash_table * hid) |
227 | { | |
209663bb AJ |
228 | hash_link *p = hid->next; |
229 | if (NULL == p) | |
26ac0430 | 230 | return NULL; |
209663bb | 231 | hid->next = p->next; |
f52a7d75 | 232 | if (NULL == hid->next) |
26ac0430 | 233 | hash_next_bucket(hid); |
209663bb | 234 | return p; |
f52a7d75 | 235 | } |
236 | ||
209663bb | 237 | /** |
2c4f7ab2 | 238 | * hash_last - resets hash traversal state to NULL |
239 | * | |
240 | */ | |
241 | void | |
ab96e65c | 242 | hash_last(hash_table * hid) |
2c4f7ab2 | 243 | { |
137a13ea | 244 | assert(hid != NULL); |
2c4f7ab2 | 245 | hid->next = NULL; |
246 | hid->current_slot = 0; | |
247 | } | |
248 | ||
209663bb | 249 | /** |
26ac0430 | 250 | * hash_remove_link - deletes the given hash_link node from the |
f52a7d75 | 251 | * hash table 'hid'. Does not free the item, only removes it |
252 | * from the list. | |
253 | * | |
4fba1a24 | 254 | * An assertion is triggered if the hash_link is not found in the |
255 | * list. | |
f52a7d75 | 256 | */ |
257 | void | |
258 | hash_remove_link(hash_table * hid, hash_link * hl) | |
259 | { | |
f52a7d75 | 260 | assert(hl != NULL); |
209663bb AJ |
261 | int i = hid->hash(hl->key, hid->size); |
262 | for (hash_link **P = &hid->buckets[i]; *P; P = &(*P)->next) { | |
26ac0430 AJ |
263 | if (*P != hl) |
264 | continue; | |
265 | *P = hl->next; | |
266 | if (hid->next == hl) { | |
267 | hid->next = hl->next; | |
268 | if (NULL == hid->next) | |
269 | hash_next_bucket(hid); | |
270 | } | |
271 | hid->count--; | |
272 | return; | |
f52a7d75 | 273 | } |
e530de6c | 274 | assert(0); |
f52a7d75 | 275 | } |
276 | ||
209663bb | 277 | /** |
26ac0430 | 278 | * hash_get_bucket - returns the head item of the bucket |
f52a7d75 | 279 | * in the hash table 'hid'. Otherwise, returns NULL on error. |
280 | */ | |
281 | hash_link * | |
282 | hash_get_bucket(hash_table * hid, unsigned int bucket) | |
283 | { | |
284 | if (bucket >= hid->size) | |
26ac0430 | 285 | return NULL; |
f52a7d75 | 286 | return (hid->buckets[bucket]); |
287 | } | |
288 | ||
289 | void | |
290 | hashFreeItems(hash_table * hid, HASHFREE * free_func) | |
291 | { | |
292 | hash_link *l; | |
f52a7d75 | 293 | int i = 0; |
209663bb | 294 | hash_link **list = (hash_link **)xcalloc(hid->count, sizeof(hash_link *)); |
f52a7d75 | 295 | hash_first(hid); |
296 | while ((l = hash_next(hid)) && i < hid->count) { | |
26ac0430 AJ |
297 | *(list + i) = l; |
298 | i++; | |
f52a7d75 | 299 | } |
209663bb | 300 | for (int j = 0; j < i; j++) |
26ac0430 | 301 | free_func(*(list + j)); |
f52a7d75 | 302 | xfree(list); |
303 | } | |
304 | ||
305 | void | |
306 | hashFreeMemory(hash_table * hid) | |
307 | { | |
04f7fd38 | 308 | if (hid == NULL) |
928b6c10 | 309 | return; |
efacbef0 | 310 | if (hid->buckets) |
26ac0430 | 311 | xfree(hid->buckets); |
f52a7d75 | 312 | xfree(hid); |
313 | } | |
314 | ||
26ac0430 | 315 | static int hash_primes[] = { |
f52a7d75 | 316 | 103, |
317 | 229, | |
318 | 467, | |
319 | 977, | |
320 | 1979, | |
321 | 4019, | |
322 | 6037, | |
323 | 7951, | |
324 | 12149, | |
325 | 16231, | |
326 | 33493, | |
327 | 65357 | |
328 | }; | |
329 | ||
330 | int | |
331 | hashPrime(int n) | |
332 | { | |
333 | int I = sizeof(hash_primes) / sizeof(int); | |
f52a7d75 | 334 | int best_prime = hash_primes[0]; |
d87ebd78 | 335 | double min = fabs(log((double) n) - log((double) hash_primes[0])); |
f52a7d75 | 336 | double d; |
209663bb | 337 | for (int i = 0; i < I; i++) { |
26ac0430 AJ |
338 | d = fabs(log((double) n) - log((double) hash_primes[i])); |
339 | if (d > min) | |
340 | continue; | |
341 | min = d; | |
342 | best_prime = hash_primes[i]; | |
f52a7d75 | 343 | } |
344 | return best_prime; | |
345 | } | |
346 | ||
209663bb | 347 | /** |
186477c1 | 348 | * return the key of a hash_link as a const string |
349 | */ | |
350 | const char * | |
351 | hashKeyStr(hash_link * hl) | |
352 | { | |
353 | return (const char *) hl->key; | |
354 | } | |
355 | ||
f52a7d75 | 356 | |
32d002cb | 357 | #if USE_HASH_DRIVER |
209663bb | 358 | /** |
f52a7d75 | 359 | * hash-driver - Run with a big file as stdin to insert each line into the |
360 | * hash table, then prints the whole hash table, then deletes a random item, | |
361 | * and prints the table again... | |
362 | */ | |
363 | int | |
364 | main(void) | |
365 | { | |
366 | hash_table *hid; | |
f52a7d75 | 367 | LOCAL_ARRAY(char, buf, BUFSIZ); |
368 | LOCAL_ARRAY(char, todelete, BUFSIZ); | |
369 | hash_link *walker = NULL; | |
370 | ||
371 | todelete[0] = '\0'; | |
372 | printf("init\n"); | |
373 | ||
374 | printf("creating hash table\n"); | |
375 | if ((hid = hash_create((HASHCMP *) strcmp, 229, hash4)) < 0) { | |
26ac0430 AJ |
376 | printf("hash_create error.\n"); |
377 | exit(1); | |
f52a7d75 | 378 | } |
379 | printf("done creating hash table: %d\n", hid); | |
380 | ||
381 | while (fgets(buf, BUFSIZ, stdin)) { | |
26ac0430 AJ |
382 | buf[strlen(buf) - 1] = '\0'; |
383 | printf("Inserting '%s' for item %p to hash table: %d\n", | |
384 | buf, buf, hid); | |
385 | hash_insert(hid, xstrdup(buf), (void *) 0x12345678); | |
386 | if (random() % 17 == 0) | |
387 | strcpy(todelete, buf); | |
f52a7d75 | 388 | } |
389 | ||
390 | printf("walking hash table...\n"); | |
209663bb | 391 | for (int i = 0, walker = hash_first(hid); walker; walker = hash_next(hid)) { |
26ac0430 AJ |
392 | printf("item %5d: key: '%s' item: %p\n", i++, walker->key, |
393 | walker->item); | |
f52a7d75 | 394 | } |
395 | printf("done walking hash table...\n"); | |
396 | ||
397 | if (todelete[0]) { | |
26ac0430 AJ |
398 | printf("deleting %s from %d\n", todelete, hid); |
399 | if (hash_delete(hid, todelete)) | |
400 | printf("hash_delete error\n"); | |
f52a7d75 | 401 | } |
402 | printf("walking hash table...\n"); | |
209663bb | 403 | for (int i = 0, walker = hash_first(hid); walker; walker = hash_next(hid)) { |
26ac0430 AJ |
404 | printf("item %5d: key: '%s' item: %p\n", i++, walker->key, |
405 | walker->item); | |
f52a7d75 | 406 | } |
407 | printf("done walking hash table...\n"); | |
408 | ||
409 | ||
410 | printf("driver finished.\n"); | |
411 | exit(0); | |
412 | } | |
413 | #endif |