X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fhash.h;h=27b6fa45a67398a93231bd3ddc12e2d2c0e74144;hb=985743b6a147e8c83d1bdd9e6dd87e465a25869b;hp=c0e0ddcea662ac69aa68f6364a69c8e7d01d51b7;hpb=553bf6a0fb409831e87816447bb661fb8d8c77cd;p=gnulib.git diff --git a/lib/hash.h b/lib/hash.h index c0e0ddcea..27b6fa45a 100644 --- a/lib/hash.h +++ b/lib/hash.h @@ -1,161 +1,120 @@ -#ifndef _hash_h_ -# define _hash_h_ 1 - -# include -# include -# include - -# ifdef USE_OBSTACK -# include "obstack.h" +/* hash - hashing table processing. + Copyright (C) 1998, 1999 Free Software Foundation, Inc. + Written by Jim Meyering , 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 -# include "xalloc.h" +#endif -# define obstack_chunk_alloc xmalloc -# define obstack_chunk_free free +typedef unsigned (*Hash_hasher) PARAMS ((const void *, unsigned)); +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_ent +struct hash_entry { - void *key; - struct hash_ent *next; + void *data; + struct hash_entry *next; }; -typedef struct hash_ent HASH_ENT; -/* This is particularly useful to cast uses in hash_initialize of the - system free function. */ -typedef void (*Hash_key_freer_type) (void *key); - -struct HT +struct hash_tuning { - /* User-supplied function for freeing keys. It is specified in - hash_initialize. If non-null, it is used by hash_free, - hash_clear, and hash_rehash. You should specify `free' here - only if you want these functions to free all of your `key' - data. This is typically the case when your key is simply - an auxilliary struct that you have malloc'd to aggregate - several values. */ - Hash_key_freer_type hash_key_freer; - - /* User-supplied hash function that hashes entry E to an integer - in the range 0..TABLE_SIZE-1. */ - unsigned int (*hash_hash) (const void *e, unsigned int table_size); - - /* User-supplied function that determines whether a new entry is - unique by comparing the new entry to entries that hashed to the - same bucket index. It should return zero for a pair of entries - that compare equal, non-zero otherwise. */ - - int (*hash_key_comparator) (const void *, const void *); - - HASH_ENT **hash_table; - unsigned int hash_table_size; - unsigned int hash_n_slots_used; - unsigned int hash_max_chain_length; - - /* Gets set when an entry is deleted from a chain of length - hash_max_chain_length. Indicates that hash_max_chain_length - may no longer be valid. */ - unsigned int hash_dirty_max_chain_length; - - /* Sum of lengths of all chains (not counting any dummy - header entries). */ - unsigned int hash_n_keys; - - /* A linked list of freed HASH_ENT structs. - FIXME: Perhaps this is unnecessary and we should simply free - and reallocate such structs. */ - HASH_ENT *hash_free_entry_list; - - /* FIXME: comment. */ -# ifdef USE_OBSTACK - struct obstack ht_obstack; -# endif + /* 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 HT HT; - -unsigned int - hash_get_n_slots_used (const HT *ht); - -unsigned int - hash_get_max_chain_length (HT *ht); - -int - hash_rehash (HT *ht, unsigned int new_table_size); - -unsigned int - hash_get_table_size (const HT *ht); - -HT * - hash_initialize (unsigned int table_size, - void (*key_freer) (void *key), - unsigned int (*hash) (const void *, unsigned int), - int (*equality_tester) (const void *, const void *)); - -unsigned int - hash_get_n_keys (const HT *ht); - -int - hash_query_in_table (const HT *ht, const void *e); - -void * - hash_lookup (const HT *ht, const void *e); - -void * - hash_insert_if_absent (HT *ht, const void *e, int *failed); - -void * - hash_delete_if_present (HT *ht, const void *e); +typedef struct hash_tuning Hash_tuning; -void - hash_print_statistics (const HT *ht, FILE *stream); - -int - hash_get_statistics (const HT *ht, unsigned int *n_slots_used, - unsigned int *n_keys, - unsigned int *max_chain_length); - -int - hash_table_ok (HT *ht); - -void - hash_do_for_each (HT *ht, void (*f) (void *e, void *aux), void *aux); - -int - hash_do_for_each_2 (HT *ht, int (*f) (void *e, void *aux), void *aux); - -int - hash_do_for_each_in_selected_bucket (HT *ht, const void *key, - int (*f) (const void *bucket_key, - void *e, void *aux), - void *aux); - -void - hash_clear (HT *ht); - -void - hash_free (HT *ht); - -void - hash_get_key_list (const HT *ht, unsigned int bufsize, void **buf); - -void * - hash_get_first (const HT *ht); - -void * - hash_get_next (const HT *ht, const void *e); - -/* This interface to hash_insert_if_absent is used frequently enough to - merit a macro here. */ - -# define HASH_INSERT_NEW_ITEM(ht, item) \ - do \ - { \ - void *already; \ - int _failed; \ - already = hash_insert_if_absent ((ht), (item), &_failed); \ - assert (already == NULL); \ - assert (!_failed); \ - } \ - while (0) +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 n_buckets; + unsigned n_buckets_used; + unsigned n_entries; + + /* Tuning arguments, kept in a physicaly separate structure. */ + const Hash_tuning *tuning; + + /* 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 + }; -#endif /* _hash_h_ */ +typedef struct hash_table Hash_table; + +/* Information and lookup. */ +unsigned hash_get_n_buckets PARAMS ((const Hash_table *)); +unsigned hash_get_n_buckets_used PARAMS ((const Hash_table *)); +unsigned hash_get_n_entries PARAMS ((const Hash_table *)); +unsigned 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 hash_get_entries PARAMS ((const Hash_table *, void **, unsigned)); +unsigned hash_do_for_each PARAMS ((const Hash_table *, Hash_processor, void *)); + +/* Allocation and clean-up. */ +unsigned hash_string PARAMS ((const char *, unsigned)); +void hash_reset_tuning PARAMS ((Hash_tuning *)); +Hash_table *hash_initialize PARAMS ((unsigned, const Hash_tuning *, + 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)); +void *hash_insert PARAMS ((Hash_table *, const void *)); +void *hash_delete PARAMS ((Hash_table *, const void *));