text: /* $OpenBSD: ohash.h,v 1.2 2014/06/02 18:52:03 deraadt Exp $ */
  
  /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #ifndef OHASH_H
  #define OHASH_H
  
  /* Open hashing support. 
   * Open hashing was chosen because it is much lighter than other hash
   * techniques, and more efficient in most cases.
   */
  
  /* user-visible data structure */
  struct ohash_info {
  	ptrdiff_t key_offset;
  	void *data;	/* user data */
  	void *(*calloc)(size_t, size_t, void *);
  	void (*free)(void *, void *);
  	void *(*alloc)(size_t, void *);
  };
  
  struct _ohash_record;
  
  /* private structure. It's there just so you can do a sizeof */
  struct ohash {
  	struct _ohash_record 	*t;
  	struct ohash_info 	info;
  	unsigned int 		size;
  	unsigned int 		total;
  	unsigned int 		deleted;
  };
  
  /* For this to be tweakable, we use small primitives, and leave part of the
   * logic to the client application.  e.g., hashing is left to the client
   * application.  We also provide a simple table entry lookup that yields
   * a hashing table index (opaque) to be used in find/insert/remove.
   * The keys are stored at a known position in the client data.
   */
  void ohash_init(struct ohash *, unsigned, struct ohash_info *);
  void ohash_delete(struct ohash *);
  
  unsigned int ohash_lookup_interval(struct ohash *, const char *,
  	    const char *, uint32_t);
  unsigned int ohash_lookup_memory(struct ohash *, const char *,
  	    size_t, uint32_t)
  		__attribute__ ((__bounded__(__string__,2,3)));
  void *ohash_find(struct ohash *, unsigned int);
  void *ohash_remove(struct ohash *, unsigned int);
  void *ohash_insert(struct ohash *, unsigned int, void *);
  void *ohash_first(struct ohash *, unsigned int *);
  void *ohash_next(struct ohash *, unsigned int *);
  unsigned int ohash_entries(struct ohash *);
  
  void *ohash_create_entry(struct ohash_info *, const char *, const char **);
  uint32_t ohash_interval(const char *, const char **);
  
  unsigned int ohash_qlookupi(struct ohash *, const char *, const char **);
  unsigned int ohash_qlookup(struct ohash *, const char *);
  #endif
  