1 b4252034 2021-07-22 op /* $OpenBSD: ohash.c,v 1.1 2014/06/02 18:52:03 deraadt Exp $ */
3 b4252034 2021-07-22 op /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
5 b4252034 2021-07-22 op * Permission to use, copy, modify, and distribute this software for any
6 b4252034 2021-07-22 op * purpose with or without fee is hereby granted, provided that the above
7 b4252034 2021-07-22 op * copyright notice and this permission notice appear in all copies.
9 b4252034 2021-07-22 op * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 b4252034 2021-07-22 op * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 b4252034 2021-07-22 op * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 b4252034 2021-07-22 op * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 b4252034 2021-07-22 op * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 b4252034 2021-07-22 op * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 b4252034 2021-07-22 op * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 b4252034 2021-07-22 op #include "compat.h"
20 b4252034 2021-07-22 op #include <stddef.h>
21 b4252034 2021-07-22 op #include <stdint.h>
22 b4252034 2021-07-22 op #include <stdlib.h>
23 b4252034 2021-07-22 op #include <string.h>
24 b4252034 2021-07-22 op #include <limits.h>
25 b4252034 2021-07-22 op #include "ohash.h"
27 b4252034 2021-07-22 op struct _ohash_record {
29 b4252034 2021-07-22 op const char *p;
32 b4252034 2021-07-22 op #define DELETED ((const char *)h)
33 b4252034 2021-07-22 op #define NONE (h->size)
35 b4252034 2021-07-22 op /* Don't bother changing the hash table if the change is small enough. */
36 b4252034 2021-07-22 op #define MINSIZE (1UL << 4)
37 b4252034 2021-07-22 op #define MINDELETED 4
39 b4252034 2021-07-22 op static void ohash_resize(struct ohash *);
42 b4252034 2021-07-22 op /* This handles the common case of variable length keys, where the
43 b4252034 2021-07-22 op * key is stored at the end of the record.
46 b4252034 2021-07-22 op ohash_create_entry(struct ohash_info *i, const char *start, const char **end)
51 b4252034 2021-07-22 op *end = start + strlen(start);
52 b4252034 2021-07-22 op p = (i->alloc)(i->key_offset + (*end - start) + 1, i->data);
54 b4252034 2021-07-22 op memcpy(p+i->key_offset, start, *end-start);
55 b4252034 2021-07-22 op p[i->key_offset + (*end - start)] = '\0';
57 b4252034 2021-07-22 op return (void *)p;
60 b4252034 2021-07-22 op /* hash_delete only frees the hash structure. Use hash_first/hash_next
61 b4252034 2021-07-22 op * to free entries as well. */
63 b4252034 2021-07-22 op ohash_delete(struct ohash *h)
65 b4252034 2021-07-22 op (h->info.free)(h->t, h->info.data);
66 b4252034 2021-07-22 op #ifndef NDEBUG
72 b4252034 2021-07-22 op ohash_resize(struct ohash *h)
74 b4252034 2021-07-22 op struct _ohash_record *n;
76 b4252034 2021-07-22 op unsigned int j;
77 b4252034 2021-07-22 op unsigned int i, incr;
79 b4252034 2021-07-22 op if (4 * h->deleted < h->total) {
80 b4252034 2021-07-22 op if (h->size >= (UINT_MAX >> 1U))
81 b4252034 2021-07-22 op ns = UINT_MAX;
83 b4252034 2021-07-22 op ns = h->size << 1U;
84 b4252034 2021-07-22 op } else if (3 * h->deleted > 2 * h->total)
85 b4252034 2021-07-22 op ns = h->size >> 1U;
88 b4252034 2021-07-22 op if (ns < MINSIZE)
90 b4252034 2021-07-22 op #ifdef STATS_HASH
91 b4252034 2021-07-22 op STAT_HASH_EXPAND++;
92 b4252034 2021-07-22 op STAT_HASH_SIZE += ns - h->size;
95 b4252034 2021-07-22 op n = (h->info.calloc)(ns, sizeof(struct _ohash_record), h->info.data);
99 b4252034 2021-07-22 op for (j = 0; j < h->size; j++) {
100 b4252034 2021-07-22 op if (h->t[j].p != NULL && h->t[j].p != DELETED) {
101 b4252034 2021-07-22 op i = h->t[j].hv % ns;
102 b4252034 2021-07-22 op incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1;
103 b4252034 2021-07-22 op while (n[i].p != NULL) {
108 b4252034 2021-07-22 op n[i].hv = h->t[j].hv;
109 b4252034 2021-07-22 op n[i].p = h->t[j].p;
112 b4252034 2021-07-22 op (h->info.free)(h->t, h->info.data);
114 b4252034 2021-07-22 op h->size = ns;
115 b4252034 2021-07-22 op h->total -= h->deleted;
116 b4252034 2021-07-22 op h->deleted = 0;
120 b4252034 2021-07-22 op ohash_remove(struct ohash *h, unsigned int i)
122 b4252034 2021-07-22 op void *result = (void *)h->t[i].p;
124 b4252034 2021-07-22 op if (result == NULL || result == DELETED)
127 b4252034 2021-07-22 op #ifdef STATS_HASH
128 b4252034 2021-07-22 op STAT_HASH_ENTRIES--;
130 b4252034 2021-07-22 op h->t[i].p = DELETED;
131 b4252034 2021-07-22 op h->deleted++;
132 b4252034 2021-07-22 op if (h->deleted >= MINDELETED && 4 * h->deleted > h->total)
133 b4252034 2021-07-22 op ohash_resize(h);
134 b4252034 2021-07-22 op return result;
138 b4252034 2021-07-22 op ohash_find(struct ohash *h, unsigned int i)
140 b4252034 2021-07-22 op if (h->t[i].p == DELETED)
143 b4252034 2021-07-22 op return (void *)h->t[i].p;
147 b4252034 2021-07-22 op ohash_insert(struct ohash *h, unsigned int i, void *p)
149 b4252034 2021-07-22 op #ifdef STATS_HASH
150 b4252034 2021-07-22 op STAT_HASH_ENTRIES++;
152 b4252034 2021-07-22 op if (h->t[i].p == DELETED) {
153 b4252034 2021-07-22 op h->deleted--;
154 b4252034 2021-07-22 op h->t[i].p = p;
156 b4252034 2021-07-22 op h->t[i].p = p;
157 b4252034 2021-07-22 op /* Arbitrary resize boundary. Tweak if not efficient enough. */
158 b4252034 2021-07-22 op if (++h->total * 4 > h->size * 3)
159 b4252034 2021-07-22 op ohash_resize(h);
165 b4252034 2021-07-22 op ohash_entries(struct ohash *h)
167 b4252034 2021-07-22 op return h->total - h->deleted;
171 b4252034 2021-07-22 op ohash_first(struct ohash *h, unsigned int *pos)
174 b4252034 2021-07-22 op return ohash_next(h, pos);
178 b4252034 2021-07-22 op ohash_next(struct ohash *h, unsigned int *pos)
180 b4252034 2021-07-22 op for (; *pos < h->size; (*pos)++)
181 b4252034 2021-07-22 op if (h->t[*pos].p != DELETED && h->t[*pos].p != NULL)
182 b4252034 2021-07-22 op return (void *)h->t[(*pos)++].p;
187 b4252034 2021-07-22 op ohash_init(struct ohash *h, unsigned int size, struct ohash_info *info)
189 b4252034 2021-07-22 op h->size = 1UL << size;
190 b4252034 2021-07-22 op if (h->size < MINSIZE)
191 b4252034 2021-07-22 op h->size = MINSIZE;
192 b4252034 2021-07-22 op #ifdef STATS_HASH
193 b4252034 2021-07-22 op STAT_HASH_CREATION++;
194 b4252034 2021-07-22 op STAT_HASH_SIZE += h->size;
196 b4252034 2021-07-22 op /* Copy info so that caller may free it. */
197 b4252034 2021-07-22 op h->info.key_offset = info->key_offset;
198 b4252034 2021-07-22 op h->info.calloc = info->calloc;
199 b4252034 2021-07-22 op h->info.free = info->free;
200 b4252034 2021-07-22 op h->info.alloc = info->alloc;
201 b4252034 2021-07-22 op h->info.data = info->data;
202 b4252034 2021-07-22 op h->t = (h->info.calloc)(h->size, sizeof(struct _ohash_record),
203 b4252034 2021-07-22 op h->info.data);
204 b4252034 2021-07-22 op h->total = h->deleted = 0;
208 b4252034 2021-07-22 op ohash_interval(const char *s, const char **e)
213 b4252034 2021-07-22 op *e = s + strlen(s);
218 b4252034 2021-07-22 op while (s != *e)
219 b4252034 2021-07-22 op k = ((k << 2) | (k >> 30)) ^ *s++;
224 b4252034 2021-07-22 op ohash_lookup_interval(struct ohash *h, const char *start, const char *end,
227 b4252034 2021-07-22 op unsigned int i, incr;
228 b4252034 2021-07-22 op unsigned int empty;
230 b4252034 2021-07-22 op #ifdef STATS_HASH
231 b4252034 2021-07-22 op STAT_HASH_LOOKUP++;
233 b4252034 2021-07-22 op empty = NONE;
234 b4252034 2021-07-22 op i = hv % h->size;
235 b4252034 2021-07-22 op incr = ((hv % (h->size-2)) & ~1) + 1;
236 b4252034 2021-07-22 op while (h->t[i].p != NULL) {
237 b4252034 2021-07-22 op #ifdef STATS_HASH
238 b4252034 2021-07-22 op STAT_HASH_LENGTH++;
240 b4252034 2021-07-22 op if (h->t[i].p == DELETED) {
241 b4252034 2021-07-22 op if (empty == NONE)
243 b4252034 2021-07-22 op } else if (h->t[i].hv == hv &&
244 b4252034 2021-07-22 op strncmp(h->t[i].p+h->info.key_offset, start,
245 b4252034 2021-07-22 op end - start) == 0 &&
246 b4252034 2021-07-22 op (h->t[i].p+h->info.key_offset)[end-start] == '\0') {
247 b4252034 2021-07-22 op if (empty != NONE) {
248 b4252034 2021-07-22 op h->t[empty].hv = hv;
249 b4252034 2021-07-22 op h->t[empty].p = h->t[i].p;
250 b4252034 2021-07-22 op h->t[i].p = DELETED;
251 b4252034 2021-07-22 op return empty;
253 b4252034 2021-07-22 op #ifdef STATS_HASH
254 b4252034 2021-07-22 op STAT_HASH_POSITIVE++;
260 b4252034 2021-07-22 op if (i >= h->size)
261 b4252034 2021-07-22 op i -= h->size;
264 b4252034 2021-07-22 op /* Found an empty position. */
265 b4252034 2021-07-22 op if (empty != NONE)
267 b4252034 2021-07-22 op h->t[i].hv = hv;
272 b4252034 2021-07-22 op ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
274 b4252034 2021-07-22 op unsigned int i, incr;
275 b4252034 2021-07-22 op unsigned int empty;
277 b4252034 2021-07-22 op #ifdef STATS_HASH
278 b4252034 2021-07-22 op STAT_HASH_LOOKUP++;
280 b4252034 2021-07-22 op empty = NONE;
281 b4252034 2021-07-22 op i = hv % h->size;
282 b4252034 2021-07-22 op incr = ((hv % (h->size-2)) & ~1) + 1;
283 b4252034 2021-07-22 op while (h->t[i].p != NULL) {
284 b4252034 2021-07-22 op #ifdef STATS_HASH
285 b4252034 2021-07-22 op STAT_HASH_LENGTH++;
287 b4252034 2021-07-22 op if (h->t[i].p == DELETED) {
288 b4252034 2021-07-22 op if (empty == NONE)
290 b4252034 2021-07-22 op } else if (h->t[i].hv == hv &&
291 b4252034 2021-07-22 op memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
292 b4252034 2021-07-22 op if (empty != NONE) {
293 b4252034 2021-07-22 op h->t[empty].hv = hv;
294 b4252034 2021-07-22 op h->t[empty].p = h->t[i].p;
295 b4252034 2021-07-22 op h->t[i].p = DELETED;
296 b4252034 2021-07-22 op return empty;
298 b4252034 2021-07-22 op #ifdef STATS_HASH
299 b4252034 2021-07-22 op STAT_HASH_POSITIVE++;
304 b4252034 2021-07-22 op if (i >= h->size)
305 b4252034 2021-07-22 op i -= h->size;
308 b4252034 2021-07-22 op /* Found an empty position. */
309 b4252034 2021-07-22 op if (empty != NONE)
311 b4252034 2021-07-22 op h->t[i].hv = hv;
316 b4252034 2021-07-22 op ohash_qlookup(struct ohash *h, const char *s)
318 b4252034 2021-07-22 op const char *e = NULL;
319 b4252034 2021-07-22 op return ohash_qlookupi(h, s, &e);
323 b4252034 2021-07-22 op ohash_qlookupi(struct ohash *h, const char *s, const char **e)
327 b4252034 2021-07-22 op hv = ohash_interval(s, e);
328 b4252034 2021-07-22 op return ohash_lookup_interval(h, s, *e, hv);