include/ohash.h

   1 #ifndef OHASH_H
   2 #define OHASH_H
   3 /* $OpenBSD: ohash.h,v 1.10 2012/09/23 15:05:23 espie Exp $ */
   4 /* ex:ts=8 sw=4:
   5  */
   6
   7 /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
   8  *
   9  * Permission to use, copy, modify, and distribute this software for any
  10  * purpose with or without fee is hereby granted, provided that the above
  11  * copyright notice and this permission notice appear in all copies.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  14  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  15  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  16  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  17  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  18  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  19  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  20  */
  21
  22 /* Open hashing support.
  23  * Open hashing was chosen because it is much lighter than other hash
  24  * techniques, and more efficient in most cases.
  25  */
  26
  27 struct ohash_info {
  28         ptrdiff_t key_offset;
  29         void *data;     /* user data */
  30         void *(*halloc)(size_t, void *);
  31         void (*hfree)(void *, size_t, void *);
  32         void *(*alloc)(size_t, void *);
  33 };
  34
  35 struct _ohash_record;
  36
  37 struct ohash {
  38         struct _ohash_record    *t;
  39         struct ohash_info       info;
  40         unsigned int            size;
  41         unsigned int            total;
  42         unsigned int            deleted;
  43 };
  44
  45 /* For this to be tweakable, we use small primitives, and leave part of the
  46  * logic to the client application.  e.g., hashing is left to the client
  47  * application.  We also provide a simple table entry lookup that yields
  48  * a hashing table index (opaque) to be used in find/insert/remove.
  49  * The keys are stored at a known position in the client data.
  50  */
  51 __BEGIN_DECLS
  52 void ohash_init(struct ohash *, unsigned, struct ohash_info *);
  53 void ohash_delete(struct ohash *);
  54
  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                 __attribute__ ((__bounded__(__string__,2,3)));
  60 void *ohash_find(struct ohash *, unsigned int);
  61 void *ohash_remove(struct ohash *, unsigned int);
  62 void *ohash_insert(struct ohash *, unsigned int, void *);
  63 void *ohash_first(struct ohash *, unsigned int *);
  64 void *ohash_next(struct ohash *, unsigned int *);
  65 unsigned int ohash_entries(struct ohash *);
  66
  67 void *ohash_create_entry(struct ohash_info *, const char *, const char **);
  68 uint32_t ohash_interval(const char *, const char **);
  69
  70 unsigned int ohash_qlookupi(struct ohash *, const char *, const char **);
  71 unsigned int ohash_qlookup(struct ohash *, const char *);
  72 __END_DECLS
  73 #endif