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/* hash - hashing table processing.
Copyright (C) 1998 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 PARAMS
# if PROTOTYPES || __STDC__
# define PARAMS(Args) Args
# else
# define PARAMS(Args) ()
# endif
#endif
typedef unsigned int (*Hash_hasher) PARAMS ((const void *, unsigned int));
typedef bool (*Hash_comparator) PARAMS ((const void *, const void *));
typedef void (*Hash_data_freer) PARAMS ((void *));
typedef bool (*Hash_processor) PARAMS ((void *, void *));
struct hash_entry
{
void *data;
struct hash_entry *next;
};
struct hash_table
{
/* The array of buckets starts at BUCKET and extends to BUCKET_LIMIT-1,
for a possibility of N_BUCKETS. Among those, N_BUCKETS_USED buckets
are not empty, there are N_ENTRIES active entries in the table. */
struct hash_entry *bucket;
struct hash_entry *bucket_limit;
unsigned int n_buckets;
unsigned int n_buckets_used;
unsigned int n_entries;
/* Three functions are given to `hash_initialize', see the documentation
block for this function. In a word, HASHER randomizes a user entry
into a number up from 0 up to some maximum minus 1; COMPARATOR returns
true if two user entries compare equally; and DATA_FREER is the cleanup
function for a user entry. */
Hash_hasher hasher;
Hash_comparator comparator;
Hash_data_freer data_freer;
/* A linked list of freed struct hash_entry structs. */
struct hash_entry *free_entry_list;
#if USE_OBSTACK
/* Whenever obstacks are used, it is possible to allocate all overflowed
entries into a single stack, so they all can be freed in a single
operation. It is not clear if the speedup is worth the trouble. */
struct obstack entry_stack;
#endif
};
typedef struct hash_table Hash_table;
/* Information and lookup. */
unsigned int hash_get_n_buckets PARAMS ((const Hash_table *));
unsigned int hash_get_n_buckets_used PARAMS ((const Hash_table *));
unsigned int hash_get_n_entries PARAMS ((const Hash_table *));
unsigned int hash_get_max_bucket_length PARAMS ((const Hash_table *));
bool hash_table_ok PARAMS ((const Hash_table *));
void hash_print_statistics PARAMS ((const Hash_table *, FILE *));
void *hash_lookup PARAMS ((const Hash_table *, const void *));
/* Walking. */
void *hash_get_first PARAMS ((const Hash_table *));
void *hash_get_next PARAMS ((const Hash_table *, const void *));
unsigned int hash_get_entries PARAMS ((const Hash_table *, void **,
unsigned int));
unsigned int hash_do_for_each PARAMS ((const Hash_table *, Hash_processor,
void *));
/* Allocation and clean-up. */
unsigned int hash_string PARAMS ((const char *, unsigned int));
Hash_table *hash_initialize PARAMS ((unsigned int, Hash_hasher,
Hash_comparator, Hash_data_freer));
void hash_clear PARAMS ((Hash_table *));
void hash_free PARAMS ((Hash_table *));
/* Insertion and deletion. */
bool hash_rehash PARAMS ((Hash_table *, unsigned int));
void *hash_insert PARAMS ((Hash_table *, const void *, bool *));
void *hash_delete PARAMS ((Hash_table *, const void *));
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