1 82550776 2021-03-17 op /* $OpenBSD: ohash.c,v 1.1 2014/06/02 18:52:03 deraadt Exp $ */
3 82550776 2021-03-17 op /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
5 82550776 2021-03-17 op * Permission to use, copy, modify, and distribute this software for any
6 82550776 2021-03-17 op * purpose with or without fee is hereby granted, provided that the above
7 82550776 2021-03-17 op * copyright notice and this permission notice appear in all copies.
9 82550776 2021-03-17 op * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 82550776 2021-03-17 op * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 82550776 2021-03-17 op * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 82550776 2021-03-17 op * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 82550776 2021-03-17 op * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 82550776 2021-03-17 op * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 82550776 2021-03-17 op * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 0ccaf6d8 2021-03-17 op #include "compat.h"
20 82550776 2021-03-17 op #include <stddef.h>
21 82550776 2021-03-17 op #include <stdint.h>
22 82550776 2021-03-17 op #include <stdlib.h>
23 82550776 2021-03-17 op #include <string.h>
24 82550776 2021-03-17 op #include <limits.h>
25 82550776 2021-03-17 op #include "ohash.h"
27 82550776 2021-03-17 op struct _ohash_record {
29 82550776 2021-03-17 op const char *p;
32 82550776 2021-03-17 op #define DELETED ((const char *)h)
33 82550776 2021-03-17 op #define NONE (h->size)
35 82550776 2021-03-17 op /* Don't bother changing the hash table if the change is small enough. */
36 82550776 2021-03-17 op #define MINSIZE (1UL << 4)
37 82550776 2021-03-17 op #define MINDELETED 4
39 82550776 2021-03-17 op static void ohash_resize(struct ohash *);
42 82550776 2021-03-17 op /* This handles the common case of variable length keys, where the
43 82550776 2021-03-17 op * key is stored at the end of the record.
46 82550776 2021-03-17 op ohash_create_entry(struct ohash_info *i, const char *start, const char **end)
51 82550776 2021-03-17 op *end = start + strlen(start);
52 82550776 2021-03-17 op p = (i->alloc)(i->key_offset + (*end - start) + 1, i->data);
54 82550776 2021-03-17 op memcpy(p+i->key_offset, start, *end-start);
55 82550776 2021-03-17 op p[i->key_offset + (*end - start)] = '\0';
57 82550776 2021-03-17 op return (void *)p;
60 82550776 2021-03-17 op /* hash_delete only frees the hash structure. Use hash_first/hash_next
61 82550776 2021-03-17 op * to free entries as well. */
63 82550776 2021-03-17 op ohash_delete(struct ohash *h)
65 82550776 2021-03-17 op (h->info.free)(h->t, h->info.data);
66 82550776 2021-03-17 op #ifndef NDEBUG
72 82550776 2021-03-17 op ohash_resize(struct ohash *h)
74 82550776 2021-03-17 op struct _ohash_record *n;
76 82550776 2021-03-17 op unsigned int j;
77 82550776 2021-03-17 op unsigned int i, incr;
79 82550776 2021-03-17 op if (4 * h->deleted < h->total) {
80 82550776 2021-03-17 op if (h->size >= (UINT_MAX >> 1U))
81 82550776 2021-03-17 op ns = UINT_MAX;
83 82550776 2021-03-17 op ns = h->size << 1U;
84 82550776 2021-03-17 op } else if (3 * h->deleted > 2 * h->total)
85 82550776 2021-03-17 op ns = h->size >> 1U;
88 82550776 2021-03-17 op if (ns < MINSIZE)
90 82550776 2021-03-17 op #ifdef STATS_HASH
91 82550776 2021-03-17 op STAT_HASH_EXPAND++;
92 82550776 2021-03-17 op STAT_HASH_SIZE += ns - h->size;
95 82550776 2021-03-17 op n = (h->info.calloc)(ns, sizeof(struct _ohash_record), h->info.data);
99 82550776 2021-03-17 op for (j = 0; j < h->size; j++) {
100 82550776 2021-03-17 op if (h->t[j].p != NULL && h->t[j].p != DELETED) {
101 82550776 2021-03-17 op i = h->t[j].hv % ns;
102 82550776 2021-03-17 op incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1;
103 82550776 2021-03-17 op while (n[i].p != NULL) {
108 82550776 2021-03-17 op n[i].hv = h->t[j].hv;
109 82550776 2021-03-17 op n[i].p = h->t[j].p;
112 82550776 2021-03-17 op (h->info.free)(h->t, h->info.data);
114 82550776 2021-03-17 op h->size = ns;
115 82550776 2021-03-17 op h->total -= h->deleted;
116 82550776 2021-03-17 op h->deleted = 0;
120 82550776 2021-03-17 op ohash_remove(struct ohash *h, unsigned int i)
122 82550776 2021-03-17 op void *result = (void *)h->t[i].p;
124 82550776 2021-03-17 op if (result == NULL || result == DELETED)
127 82550776 2021-03-17 op #ifdef STATS_HASH
128 82550776 2021-03-17 op STAT_HASH_ENTRIES--;
130 82550776 2021-03-17 op h->t[i].p = DELETED;
131 82550776 2021-03-17 op h->deleted++;
132 82550776 2021-03-17 op if (h->deleted >= MINDELETED && 4 * h->deleted > h->total)
133 82550776 2021-03-17 op ohash_resize(h);
134 82550776 2021-03-17 op return result;
138 82550776 2021-03-17 op ohash_find(struct ohash *h, unsigned int i)
140 82550776 2021-03-17 op if (h->t[i].p == DELETED)
143 82550776 2021-03-17 op return (void *)h->t[i].p;
147 82550776 2021-03-17 op ohash_insert(struct ohash *h, unsigned int i, void *p)
149 82550776 2021-03-17 op #ifdef STATS_HASH
150 82550776 2021-03-17 op STAT_HASH_ENTRIES++;
152 82550776 2021-03-17 op if (h->t[i].p == DELETED) {
153 82550776 2021-03-17 op h->deleted--;
154 82550776 2021-03-17 op h->t[i].p = p;
156 82550776 2021-03-17 op h->t[i].p = p;
157 82550776 2021-03-17 op /* Arbitrary resize boundary. Tweak if not efficient enough. */
158 82550776 2021-03-17 op if (++h->total * 4 > h->size * 3)
159 82550776 2021-03-17 op ohash_resize(h);
165 82550776 2021-03-17 op ohash_entries(struct ohash *h)
167 82550776 2021-03-17 op return h->total - h->deleted;
171 82550776 2021-03-17 op ohash_first(struct ohash *h, unsigned int *pos)
174 82550776 2021-03-17 op return ohash_next(h, pos);
178 82550776 2021-03-17 op ohash_next(struct ohash *h, unsigned int *pos)
180 82550776 2021-03-17 op for (; *pos < h->size; (*pos)++)
181 82550776 2021-03-17 op if (h->t[*pos].p != DELETED && h->t[*pos].p != NULL)
182 82550776 2021-03-17 op return (void *)h->t[(*pos)++].p;
187 82550776 2021-03-17 op ohash_init(struct ohash *h, unsigned int size, struct ohash_info *info)
189 82550776 2021-03-17 op h->size = 1UL << size;
190 82550776 2021-03-17 op if (h->size < MINSIZE)
191 82550776 2021-03-17 op h->size = MINSIZE;
192 82550776 2021-03-17 op #ifdef STATS_HASH
193 82550776 2021-03-17 op STAT_HASH_CREATION++;
194 82550776 2021-03-17 op STAT_HASH_SIZE += h->size;
196 82550776 2021-03-17 op /* Copy info so that caller may free it. */
197 82550776 2021-03-17 op h->info.key_offset = info->key_offset;
198 82550776 2021-03-17 op h->info.calloc = info->calloc;
199 82550776 2021-03-17 op h->info.free = info->free;
200 82550776 2021-03-17 op h->info.alloc = info->alloc;
201 82550776 2021-03-17 op h->info.data = info->data;
202 82550776 2021-03-17 op h->t = (h->info.calloc)(h->size, sizeof(struct _ohash_record),
203 82550776 2021-03-17 op h->info.data);
204 82550776 2021-03-17 op h->total = h->deleted = 0;
208 82550776 2021-03-17 op ohash_interval(const char *s, const char **e)
213 82550776 2021-03-17 op *e = s + strlen(s);
218 82550776 2021-03-17 op while (s != *e)
219 82550776 2021-03-17 op k = ((k << 2) | (k >> 30)) ^ *s++;
224 82550776 2021-03-17 op ohash_lookup_interval(struct ohash *h, const char *start, const char *end,
227 82550776 2021-03-17 op unsigned int i, incr;
228 82550776 2021-03-17 op unsigned int empty;
230 82550776 2021-03-17 op #ifdef STATS_HASH
231 82550776 2021-03-17 op STAT_HASH_LOOKUP++;
233 82550776 2021-03-17 op empty = NONE;
234 82550776 2021-03-17 op i = hv % h->size;
235 82550776 2021-03-17 op incr = ((hv % (h->size-2)) & ~1) + 1;
236 82550776 2021-03-17 op while (h->t[i].p != NULL) {
237 82550776 2021-03-17 op #ifdef STATS_HASH
238 82550776 2021-03-17 op STAT_HASH_LENGTH++;
240 82550776 2021-03-17 op if (h->t[i].p == DELETED) {
241 82550776 2021-03-17 op if (empty == NONE)
243 82550776 2021-03-17 op } else if (h->t[i].hv == hv &&
244 82550776 2021-03-17 op strncmp(h->t[i].p+h->info.key_offset, start,
245 82550776 2021-03-17 op end - start) == 0 &&
246 82550776 2021-03-17 op (h->t[i].p+h->info.key_offset)[end-start] == '\0') {
247 82550776 2021-03-17 op if (empty != NONE) {
248 82550776 2021-03-17 op h->t[empty].hv = hv;
249 82550776 2021-03-17 op h->t[empty].p = h->t[i].p;
250 82550776 2021-03-17 op h->t[i].p = DELETED;
251 82550776 2021-03-17 op return empty;
253 82550776 2021-03-17 op #ifdef STATS_HASH
254 82550776 2021-03-17 op STAT_HASH_POSITIVE++;
260 82550776 2021-03-17 op if (i >= h->size)
261 82550776 2021-03-17 op i -= h->size;
264 82550776 2021-03-17 op /* Found an empty position. */
265 82550776 2021-03-17 op if (empty != NONE)
267 82550776 2021-03-17 op h->t[i].hv = hv;
272 82550776 2021-03-17 op ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
274 82550776 2021-03-17 op unsigned int i, incr;
275 82550776 2021-03-17 op unsigned int empty;
277 82550776 2021-03-17 op #ifdef STATS_HASH
278 82550776 2021-03-17 op STAT_HASH_LOOKUP++;
280 82550776 2021-03-17 op empty = NONE;
281 82550776 2021-03-17 op i = hv % h->size;
282 82550776 2021-03-17 op incr = ((hv % (h->size-2)) & ~1) + 1;
283 82550776 2021-03-17 op while (h->t[i].p != NULL) {
284 82550776 2021-03-17 op #ifdef STATS_HASH
285 82550776 2021-03-17 op STAT_HASH_LENGTH++;
287 82550776 2021-03-17 op if (h->t[i].p == DELETED) {
288 82550776 2021-03-17 op if (empty == NONE)
290 82550776 2021-03-17 op } else if (h->t[i].hv == hv &&
291 82550776 2021-03-17 op memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
292 82550776 2021-03-17 op if (empty != NONE) {
293 82550776 2021-03-17 op h->t[empty].hv = hv;
294 82550776 2021-03-17 op h->t[empty].p = h->t[i].p;
295 82550776 2021-03-17 op h->t[i].p = DELETED;
296 82550776 2021-03-17 op return empty;
298 82550776 2021-03-17 op #ifdef STATS_HASH
299 82550776 2021-03-17 op STAT_HASH_POSITIVE++;
304 82550776 2021-03-17 op if (i >= h->size)
305 82550776 2021-03-17 op i -= h->size;
308 82550776 2021-03-17 op /* Found an empty position. */
309 82550776 2021-03-17 op if (empty != NONE)
311 82550776 2021-03-17 op h->t[i].hv = hv;
316 82550776 2021-03-17 op ohash_qlookup(struct ohash *h, const char *s)
318 82550776 2021-03-17 op const char *e = NULL;
319 82550776 2021-03-17 op return ohash_qlookupi(h, s, &e);
323 82550776 2021-03-17 op ohash_qlookupi(struct ohash *h, const char *s, const char **e)
327 82550776 2021-03-17 op hv = ohash_interval(s, e);
328 82550776 2021-03-17 op return ohash_lookup_interval(h, s, *e, hv);