lib/libopenbsd/ohash.h

   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 */
  31 struct 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
  39 struct _ohash_record;
  40
  41 /* private structure. It's there just so you can do a sizeof */
  42 struct 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
  57 void ohash_init(struct ohash *, unsigned, struct ohash_info *);
  58 void ohash_delete(struct ohash *);
  59
  60 unsigned int ohash_lookup_interval(struct ohash *, const char *,
  61             const char *, uint32_t);
  62 unsigned int ohash_lookup_memory(struct ohash *, const char *,
  63             size_t, uint32_t);
  64 void *ohash_find(struct ohash *, unsigned int);
  65 void *ohash_remove(struct ohash *, unsigned int);
  66 void *ohash_insert(struct ohash *, unsigned int, void *);
  67 void *ohash_first(struct ohash *, unsigned int *);
  68 void *ohash_next(struct ohash *, unsigned int *);
  69 unsigned int ohash_entries(struct ohash *);
  70
  71 void *ohash_create_entry(struct ohash_info *, const char *, const char **);
  72 uint32_t ohash_interval(const char *, const char **);
  73
  74 unsigned int ohash_qlookupi(struct ohash *, const char *, const char **);
  75 unsigned int ohash_qlookup(struct ohash *, const char *);
  76 __END_DECLS
  77 #endif