diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/hash.h | 278 |
1 files changed, 94 insertions, 184 deletions
diff --git a/lib/hash.h b/lib/hash.h index 1dbce5c2c..0cbb27e3a 100644 --- a/lib/hash.h +++ b/lib/hash.h @@ -1,193 +1,103 @@ -#ifndef HASH_H -# define HASH_H 1 - -# if HAVE_CONFIG_H -# include <config.h> -# endif - -# include <stdio.h> -# include <assert.h> - -# ifdef STDC_HEADERS -# include <stdlib.h> -# endif - -# ifndef HAVE_DECL_FREE -void free (); +/* 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 -# ifndef HAVE_DECL_MALLOC -char *malloc (); -# 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 *)); -# ifndef PARAMS -# if defined PROTOTYPES || (defined __STDC__ && __STDC__) -# define PARAMS(Args) Args -# else -# define PARAMS(Args) () -# endif -# endif - -# define USE_OBSTACK -# ifdef USE_OBSTACK -# include "obstack.h" -# endif - -# define obstack_chunk_alloc malloc -# define obstack_chunk_free free - -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) PARAMS((void *key)); -struct HT +struct hash_table { - /* User-supplied function for freeing keys. It is specified in - hash_initialize. If non-null, it is used by hash_free and - hash_clear. 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) PARAMS((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) PARAMS((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 + /* 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 HT HT; - -unsigned int - hash_get_n_slots_used PARAMS((const HT *ht)); - -unsigned int - hash_get_max_chain_length PARAMS((HT *ht)); - -int - hash_rehash PARAMS((HT *ht, unsigned int new_table_size)); - -unsigned int - hash_get_table_size PARAMS((const HT *ht)); - -HT * - hash_initialize PARAMS((unsigned int table_size, - void (*key_freer) PARAMS((void *key)), - unsigned int (*hash) PARAMS((const void *, - unsigned int)), - int (*equality_tester) PARAMS((const void *, - const void *)))); - -unsigned int - hash_get_n_keys PARAMS((const HT *ht)); - -int - hash_query_in_table PARAMS((const HT *ht, const void *e)); - -void * - hash_lookup PARAMS((const HT *ht, const void *e)); - -void * - hash_insert_if_absent PARAMS((HT *ht, - const void *e, - int *failed)); - -void * - hash_delete_if_present PARAMS((HT *ht, const void *e)); - -void - hash_print_statistics PARAMS((const HT *ht, FILE *stream)); - -int - hash_get_statistics PARAMS((const HT *ht, unsigned int *n_slots_used, - unsigned int *n_keys, - unsigned int *max_chain_length)); - -int - hash_table_ok PARAMS((HT *ht)); - -void - hash_do_for_each PARAMS((HT *ht, - void (*f) PARAMS((void *e, void *aux)), - void *aux)); - -int - hash_do_for_each_2 PARAMS((HT *ht, - int (*f) PARAMS((void *e, void *aux)), - void *aux)); - -int - hash_do_for_each_in_selected_bucket PARAMS((HT *ht, - const void *key, - int (*f) PARAMS((const void *bucket_key, - void *e, - void *aux)), - void *aux)); - -void - hash_clear PARAMS((HT *ht)); - -void - hash_free PARAMS((HT *ht)); - -void - hash_get_key_list PARAMS((const HT *ht, - unsigned int bufsize, - void **buf)); - -void * - hash_get_first PARAMS((const HT *ht)); - -void * - hash_get_next PARAMS((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, Failp) \ - do \ - { \ - void *_already; \ - _already = hash_insert_if_absent ((Ht), (Item), Failp); \ - assert (_already == NULL); \ - } \ - while (0) - -#endif /* HASH_H */ +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 *)); |