coreutils/lib/hash.h
2003-10-25 15:29:56 +00:00

89 lines
3.1 KiB
C

/* hash - hashing table processing.
Copyright (C) 1998, 1999, 2001, 2003 Free Software Foundation, Inc.
Written by Jim Meyering <meyering@ascend.com>, 1998.
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, 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. */
/* A generic hash table package. */
/* Make sure USE_OBSTACK is defined to 1 if you want the allocator to use
obstacks instead of malloc, and recompile `hash.c' with same setting. */
#ifndef HASH_H_
# define HASH_H_
# include <stdio.h>
# include <stdbool.h>
typedef size_t (*Hash_hasher) (const void *, size_t);
typedef bool (*Hash_comparator) (const void *, const void *);
typedef void (*Hash_data_freer) (void *);
typedef bool (*Hash_processor) (void *, void *);
struct hash_entry
{
void *data;
struct hash_entry *next;
};
struct hash_tuning
{
/* This structure is mainly used for `hash_initialize', see the block
documentation of `hash_reset_tuning' for more complete comments. */
float shrink_threshold; /* ratio of used buckets to trigger a shrink */
float shrink_factor; /* ratio of new smaller size to original size */
float growth_threshold; /* ratio of used buckets to trigger a growth */
float growth_factor; /* ratio of new bigger size to original size */
bool is_n_buckets; /* if CANDIDATE really means table size */
};
typedef struct hash_tuning Hash_tuning;
struct hash_table;
typedef struct hash_table Hash_table;
/* Information and lookup. */
size_t hash_get_n_buckets (const Hash_table *);
size_t hash_get_n_buckets_used (const Hash_table *);
size_t hash_get_n_entries (const Hash_table *);
size_t hash_get_max_bucket_length (const Hash_table *);
bool hash_table_ok (const Hash_table *);
void hash_print_statistics (const Hash_table *, FILE *);
void *hash_lookup (const Hash_table *, const void *);
/* Walking. */
void *hash_get_first (const Hash_table *);
void *hash_get_next (const Hash_table *, const void *);
size_t hash_get_entries (const Hash_table *, void **, size_t);
size_t hash_do_for_each (const Hash_table *, Hash_processor, void *);
/* Allocation and clean-up. */
size_t hash_string (const char *, size_t);
void hash_reset_tuning (Hash_tuning *);
Hash_table *hash_initialize (size_t, const Hash_tuning *,
Hash_hasher, Hash_comparator,
Hash_data_freer);
void hash_clear (Hash_table *);
void hash_free (Hash_table *);
/* Insertion and deletion. */
bool hash_rehash (Hash_table *, size_t);
void *hash_insert (Hash_table *, const void *);
void *hash_delete (Hash_table *, const void *);
#endif