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ohash.h revision 1.1 
      1 #ifndef OHASH_H
      2 #define OHASH_H
      3 /* $OpenBSD: ohash.h,v 1.8 2005/12/29 18:54:47 jaredy Exp $ */
      4 /* ex:ts=8 sw=4:
      5  */
      6 
      7 /* Copyright (c) 1999, 2004 Marc Espie <espie (at) 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 *, u_int32_t);
     57 unsigned int ohash_lookup_memory(struct ohash *, const char *,
     58 	    size_t, u_int32_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 *);
     65 
     66 void *ohash_create_entry(struct ohash_info *, const char *, const char **);
     67 u_int32_t ohash_interval(const char *, const char **);
     68 
     69 unsigned int ohash_qlookupi(struct ohash *, const char *, const char **);
     70 unsigned int ohash_qlookup(struct ohash *, const char *);
     71 __END_DECLS
     72 #endif
     73 
     74