1/* $OpenBSD: src/lib/libutil/ohash.h,v 1.2 2014/06/02 18:52:03 deraadt Exp $ */
2
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 *
17 * $FreeBSD$
18 */
19
20#ifndef OHASH_H
21#define OHASH_H
22
23#include <stddef.h>
24
25/* Open hashing support.
26 * Open hashing was chosen because it is much lighter than other hash
27 * techniques, and more efficient in most cases.
28 */
29
30/* user-visible data structure */
31struct ohash_info {
32	ptrdiff_t key_offset;
33	void *data;	/* user data */
34	void *(*calloc)(size_t, size_t, void *);
35	void (*free)(void *, void *);
36	void *(*alloc)(size_t, void *);
37};
38
39struct _ohash_record;
40
41/* private structure. It's there just so you can do a sizeof */
42struct ohash {
43	struct _ohash_record 	*t;
44	struct ohash_info 	info;
45	unsigned int 		size;
46	unsigned int 		total;
47	unsigned int 		deleted;
48};
49
50/* For this to be tweakable, we use small primitives, and leave part of the
51 * logic to the client application.  e.g., hashing is left to the client
52 * application.  We also provide a simple table entry lookup that yields
53 * a hashing table index (opaque) to be used in find/insert/remove.
54 * The keys are stored at a known position in the client data.
55 */
56__BEGIN_DECLS
57void ohash_init(struct ohash *, unsigned, struct ohash_info *);
58void ohash_delete(struct ohash *);
59
60unsigned int ohash_lookup_interval(struct ohash *, const char *,
61	    const char *, uint32_t);
62unsigned int ohash_lookup_memory(struct ohash *, const char *,
63	    size_t, uint32_t);
64void *ohash_find(struct ohash *, unsigned int);
65void *ohash_remove(struct ohash *, unsigned int);
66void *ohash_insert(struct ohash *, unsigned int, void *);
67void *ohash_first(struct ohash *, unsigned int *);
68void *ohash_next(struct ohash *, unsigned int *);
69unsigned int ohash_entries(struct ohash *);
70
71void *ohash_create_entry(struct ohash_info *, const char *, const char **);
72uint32_t ohash_interval(const char *, const char **);
73
74unsigned int ohash_qlookupi(struct ohash *, const char *, const char **);
75unsigned int ohash_qlookup(struct ohash *, const char *);
76__END_DECLS
77#endif
78