129 lines
4.3 KiB
C
129 lines
4.3 KiB
C
/* An expandable hash tables datatype.
|
|
Copyright (C) 1999 Free Software Foundation, Inc.
|
|
Contributed by Vladimir Makarov (vmakarov@cygnus.com).
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
|
|
|
|
/* This package implements basic hash table functionality. It is possible
|
|
to search for an entry, create an entry and destroy an entry.
|
|
|
|
Elements in the table are generic pointers.
|
|
|
|
The size of the table is not fixed; if the occupancy of the table
|
|
grows too high the hash table will be expanded.
|
|
|
|
The abstract data implementation is based on generalized Algorithm D
|
|
from Knuth's book "The art of computer programming". Hash table is
|
|
expanded by creation of new hash table and transferring elements from
|
|
the old table to the new table. */
|
|
|
|
#ifndef __HASHTAB_H__
|
|
#define __HASHTAB_H__
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif /* __cplusplus */
|
|
|
|
#include <ansidecl.h>
|
|
|
|
/* Callback function pointer types. */
|
|
|
|
/* Calculate hash of a table entry. */
|
|
typedef unsigned int (*htab_hash) PARAMS ((const void *));
|
|
|
|
/* Compare a table entry with a possible entry. The entry already in
|
|
the table always comes first, so the second element can be of a
|
|
different type (but in this case htab_find and htab_find_slot
|
|
cannot be used; instead the variants that accept a hash value
|
|
must be used). */
|
|
typedef int (*htab_eq) PARAMS ((const void *, const void *));
|
|
|
|
/* Cleanup function called whenever a live element is removed from
|
|
the hash table. */
|
|
typedef void (*htab_del) PARAMS ((void *));
|
|
|
|
/* Function called by htab_traverse for each live element. The first
|
|
arg is the slot of the element (which can be passed to htab_clear_slot
|
|
if desired), the second arg is the auxiliary pointer handed to
|
|
htab_traverse. Return 1 to continue scan, 0 to stop. */
|
|
typedef int (*htab_trav) PARAMS ((void **, void *));
|
|
|
|
/* Hash tables are of the following type. The structure
|
|
(implementation) of this type is not needed for using the hash
|
|
tables. All work with hash table should be executed only through
|
|
functions mentioned below. */
|
|
|
|
struct htab
|
|
{
|
|
/* Pointer to hash function. */
|
|
htab_hash hash_f;
|
|
|
|
/* Pointer to comparison function. */
|
|
htab_eq eq_f;
|
|
|
|
/* Pointer to cleanup function. */
|
|
htab_del del_f;
|
|
|
|
/* Table itself. */
|
|
void **entries;
|
|
|
|
/* Current size (in entries) of the hash table */
|
|
size_t size;
|
|
|
|
/* Current number of elements including also deleted elements */
|
|
size_t n_elements;
|
|
|
|
/* Current number of deleted elements in the table */
|
|
size_t n_deleted;
|
|
|
|
/* The following member is used for debugging. Its value is number
|
|
of all calls of `htab_find_slot' for the hash table. */
|
|
unsigned int searches;
|
|
|
|
/* The following member is used for debugging. Its value is number
|
|
of collisions fixed for time of work with the hash table. */
|
|
unsigned int collisions;
|
|
};
|
|
|
|
typedef struct htab *htab_t;
|
|
|
|
/* The prototypes of the package functions. */
|
|
|
|
extern htab_t htab_create PARAMS ((size_t, htab_hash,
|
|
htab_eq, htab_del));
|
|
extern void htab_delete PARAMS ((htab_t));
|
|
extern void htab_empty PARAMS ((htab_t));
|
|
|
|
extern void *htab_find PARAMS ((htab_t, const void *));
|
|
extern void **htab_find_slot PARAMS ((htab_t, const void *, int));
|
|
extern void *htab_find_with_hash PARAMS ((htab_t, const void *,
|
|
unsigned int));
|
|
extern void **htab_find_slot_with_hash PARAMS ((htab_t, const void *,
|
|
unsigned int, int));
|
|
extern void htab_clear_slot PARAMS ((htab_t, void **));
|
|
extern void htab_remove_elt PARAMS ((htab_t, void *));
|
|
|
|
extern void htab_traverse PARAMS ((htab_t, htab_trav, void *));
|
|
|
|
extern size_t htab_size PARAMS ((htab_t));
|
|
extern size_t htab_elements PARAMS ((htab_t));
|
|
extern double htab_collisions PARAMS ((htab_t));
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif /* __cplusplus */
|
|
|
|
#endif /* __HASHTAB_H */
|