rm_/lib/hash.h
2020-09-02 16:47:03 +08:00

107 lines
4.2 KiB
C

/* hash - hashing table processing.
Copyright (C) 1998-1999, 2001, 2003, 2009-2020 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 3 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, see <https://www.gnu.org/licenses/>. */
/* 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>
/* The __attribute__ feature is available in gcc versions 2.5 and later.
The warn_unused_result attribute appeared first in gcc-3.4.0. */
# if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
# define _GL_ATTRIBUTE_WUR __attribute__ ((__warn_unused_result__))
# else
# define _GL_ATTRIBUTE_WUR /* empty */
# endif
# ifndef _GL_ATTRIBUTE_DEPRECATED
/* The __attribute__((__deprecated__)) feature
is available in gcc versions 3.1 and newer. */
# if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 1)
# define _GL_ATTRIBUTE_DEPRECATED /* empty */
# else
# define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
# endif
# endif
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_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 *) _GL_ATTRIBUTE_PURE;
size_t hash_get_n_buckets_used (const Hash_table *) _GL_ATTRIBUTE_PURE;
size_t hash_get_n_entries (const Hash_table *) _GL_ATTRIBUTE_PURE;
size_t hash_get_max_bucket_length (const Hash_table *) _GL_ATTRIBUTE_PURE;
bool hash_table_ok (const Hash_table *) _GL_ATTRIBUTE_PURE;
void hash_print_statistics (const Hash_table *, FILE *);
void *hash_lookup (const Hash_table *, const void *);
/* Walking. */
void *hash_get_first (const Hash_table *) _GL_ATTRIBUTE_PURE;
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) _GL_ATTRIBUTE_PURE;
void hash_reset_tuning (Hash_tuning *);
Hash_table *hash_initialize (size_t, const Hash_tuning *,
Hash_hasher, Hash_comparator,
Hash_data_freer) _GL_ATTRIBUTE_WUR;
Hash_table *hash_xinitialize (size_t, const Hash_tuning *,
Hash_hasher, Hash_comparator,
Hash_data_freer) _GL_ATTRIBUTE_WUR;
void hash_clear (Hash_table *);
void hash_free (Hash_table *);
/* Insertion and deletion. */
bool hash_rehash (Hash_table *, size_t) _GL_ATTRIBUTE_WUR;
void *hash_insert (Hash_table *, const void *) _GL_ATTRIBUTE_WUR;
int hash_insert_if_absent (Hash_table *table, const void *entry,
const void **matched_ent);
void *hash_delete (Hash_table *, const void *);
#endif