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1 /* $OpenBSD: ohash.h,v 1.2 2014/06/02 18:52:03 deraadt Exp $ */
3 /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
4 *
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.
8 *
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.
16 */
18 #ifndef OHASH_H
19 #define OHASH_H
21 /* Open hashing support.
22 * Open hashing was chosen because it is much lighter than other hash
23 * techniques, and more efficient in most cases.
24 */
26 /* user-visible data structure */
27 struct ohash_info {
28 ptrdiff_t key_offset;
29 void *data; /* user data */
30 void *(*calloc)(size_t, size_t, void *);
31 void (*free)(void *, void *);
32 void *(*alloc)(size_t, void *);
33 };
35 struct _ohash_record;
37 /* private structure. It's there just so you can do a sizeof */
38 struct ohash {
39 struct _ohash_record *t;
40 struct ohash_info info;
41 unsigned int size;
42 unsigned int total;
43 unsigned int deleted;
44 };
46 /* For this to be tweakable, we use small primitives, and leave part of the
47 * logic to the client application. e.g., hashing is left to the client
48 * application. We also provide a simple table entry lookup that yields
49 * a hashing table index (opaque) to be used in find/insert/remove.
50 * The keys are stored at a known position in the client data.
51 */
52 void ohash_init(struct ohash *, unsigned, struct ohash_info *);
53 void ohash_delete(struct ohash *);
55 unsigned int ohash_lookup_interval(struct ohash *, const char *,
56 const char *, uint32_t);
57 unsigned int ohash_lookup_memory(struct ohash *, const char *,
58 size_t, uint32_t);
59 void *ohash_find(struct ohash *, unsigned int);
60 void *ohash_remove(struct ohash *, unsigned int);
61 void *ohash_insert(struct ohash *, unsigned int, void *);
62 void *ohash_first(struct ohash *, unsigned int *);
63 void *ohash_next(struct ohash *, unsigned int *);
64 unsigned int ohash_entries(struct ohash *);
66 void *ohash_create_entry(struct ohash_info *, const char *, const char **);
67 uint32_t ohash_interval(const char *, const char **);
69 unsigned int ohash_qlookupi(struct ohash *, const char *, const char **);
70 unsigned int ohash_qlookup(struct ohash *, const char *);
71 #endif