1 /* $OpenBSD: src/lib/libutil/ohash.c,v 1.1 2014/06/02 18:52:03 deraadt Exp $ */
3 /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 #include <sys/cdefs.h>
19 __FBSDID("$FreeBSD$");
28 struct _ohash_record {
33 #define DELETED ((const char *)h)
34 #define NONE (h->size)
36 /* Don't bother changing the hash table if the change is small enough. */
37 #define MINSIZE (1UL << 4)
40 static void ohash_resize(struct ohash *);
43 /* This handles the common case of variable length keys, where the
44 * key is stored at the end of the record.
47 ohash_create_entry(struct ohash_info *i, const char *start, const char **end)
52 *end = start + strlen(start);
53 p = (i->alloc)(i->key_offset + (*end - start) + 1, i->data);
55 memcpy(p+i->key_offset, start, *end-start);
56 p[i->key_offset + (*end - start)] = '\0';
61 /* hash_delete only frees the hash structure. Use hash_first/hash_next
62 * to free entries as well. */
64 ohash_delete(struct ohash *h)
66 (h->info.free)(h->t, h->info.data);
73 ohash_resize(struct ohash *h)
75 struct _ohash_record *n;
80 if (4 * h->deleted < h->total) {
81 if (h->size >= (UINT_MAX >> 1U))
85 } else if (3 * h->deleted > 2 * h->total)
93 STAT_HASH_SIZE += ns - h->size;
96 n = (h->info.calloc)(ns, sizeof(struct _ohash_record), h->info.data);
100 for (j = 0; j < h->size; j++) {
101 if (h->t[j].p != NULL && h->t[j].p != DELETED) {
103 incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1;
104 while (n[i].p != NULL) {
109 n[i].hv = h->t[j].hv;
113 (h->info.free)(h->t, h->info.data);
116 h->total -= h->deleted;
121 ohash_remove(struct ohash *h, unsigned int i)
123 void *result = (void *)h->t[i].p;
125 if (result == NULL || result == DELETED)
133 if (h->deleted >= MINDELETED && 4 * h->deleted > h->total)
139 ohash_find(struct ohash *h, unsigned int i)
141 if (h->t[i].p == DELETED)
144 return (void *)h->t[i].p;
148 ohash_insert(struct ohash *h, unsigned int i, void *p)
153 if (h->t[i].p == DELETED) {
158 /* Arbitrary resize boundary. Tweak if not efficient enough. */
159 if (++h->total * 4 > h->size * 3)
166 ohash_entries(struct ohash *h)
168 return h->total - h->deleted;
172 ohash_first(struct ohash *h, unsigned int *pos)
175 return ohash_next(h, pos);
179 ohash_next(struct ohash *h, unsigned int *pos)
181 for (; *pos < h->size; (*pos)++)
182 if (h->t[*pos].p != DELETED && h->t[*pos].p != NULL)
183 return (void *)h->t[(*pos)++].p;
188 ohash_init(struct ohash *h, unsigned int size, struct ohash_info *info)
190 h->size = 1UL << size;
191 if (h->size < MINSIZE)
194 STAT_HASH_CREATION++;
195 STAT_HASH_SIZE += h->size;
197 /* Copy info so that caller may free it. */
198 h->info.key_offset = info->key_offset;
199 h->info.calloc = info->calloc;
200 h->info.free = info->free;
201 h->info.alloc = info->alloc;
202 h->info.data = info->data;
203 h->t = (h->info.calloc)(h->size, sizeof(struct _ohash_record),
205 h->total = h->deleted = 0;
209 ohash_interval(const char *s, const char **e)
220 k = ((k << 2) | (k >> 30)) ^ *s++;
225 ohash_lookup_interval(struct ohash *h, const char *start, const char *end,
228 unsigned int i, incr;
236 incr = ((hv % (h->size-2)) & ~1) + 1;
237 while (h->t[i].p != NULL) {
241 if (h->t[i].p == DELETED) {
244 } else if (h->t[i].hv == hv &&
245 strncmp(h->t[i].p+h->info.key_offset, start,
247 (h->t[i].p+h->info.key_offset)[end-start] == '\0') {
250 h->t[empty].p = h->t[i].p;
255 STAT_HASH_POSITIVE++;
265 /* Found an empty position. */
273 ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
275 unsigned int i, incr;
283 incr = ((hv % (h->size-2)) & ~1) + 1;
284 while (h->t[i].p != NULL) {
288 if (h->t[i].p == DELETED) {
291 } else if (h->t[i].hv == hv &&
292 memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
295 h->t[empty].p = h->t[i].p;
300 STAT_HASH_POSITIVE++;
309 /* Found an empty position. */
317 ohash_qlookup(struct ohash *h, const char *s)
319 const char *e = NULL;
320 return ohash_qlookupi(h, s, &e);
324 ohash_qlookupi(struct ohash *h, const char *s, const char **e)
328 hv = ohash_interval(s, e);
329 return ohash_lookup_interval(h, s, *e, hv);