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- /* An expandable hash tables datatype.
- Copyright (C) 1999, 2000, 2002, 2003, 2004, 2005, 2009, 2010
- Free Software Foundation, Inc.
- Contributed by Vladimir Makarov (vmakarov@cygnus.com).
- 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 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, write to the Free Software
- Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
- /* This package implements basic hash table functionality. It is possible
- to search for an entry, create an entry and destroy an entry.
- Elements in the table are generic pointers.
- The size of the table is not fixed; if the occupancy of the table
- grows too high the hash table will be expanded.
- The abstract data implementation is based on generalized Algorithm D
- from Knuth's book "The art of computer programming". Hash table is
- expanded by creation of new hash table and transferring elements from
- the old table to the new table. */
- #ifndef __HASHTAB_H__
- #define __HASHTAB_H__
- #ifdef __cplusplus
- extern "C" {
- #endif /* __cplusplus */
- #include "ansidecl.h"
- /* The type for a hash code. */
- typedef unsigned int hashval_t;
- /* Callback function pointer types. */
- /* Calculate hash of a table entry. */
- typedef hashval_t (*htab_hash) (const void *);
- /* Compare a table entry with a possible entry. The entry already in
- the table always comes first, so the second element can be of a
- different type (but in this case htab_find and htab_find_slot
- cannot be used; instead the variants that accept a hash value
- must be used). */
- typedef int (*htab_eq) (const void *, const void *);
- /* Cleanup function called whenever a live element is removed from
- the hash table. */
- typedef void (*htab_del) (void *);
-
- /* Function called by htab_traverse for each live element. The first
- arg is the slot of the element (which can be passed to htab_clear_slot
- if desired), the second arg is the auxiliary pointer handed to
- htab_traverse. Return 1 to continue scan, 0 to stop. */
- typedef int (*htab_trav) (void **, void *);
- /* Memory-allocation function, with the same functionality as calloc().
- Iff it returns NULL, the hash table implementation will pass an error
- code back to the user, so if your code doesn't handle errors,
- best if you use xcalloc instead. */
- typedef void *(*htab_alloc) (size_t, size_t);
- /* We also need a free() routine. */
- typedef void (*htab_free) (void *);
- /* Memory allocation and deallocation; variants which take an extra
- argument. */
- typedef void *(*htab_alloc_with_arg) (void *, size_t, size_t);
- typedef void (*htab_free_with_arg) (void *, void *);
- /* This macro defines reserved value for empty table entry. */
- #define HTAB_EMPTY_ENTRY ((PTR) 0)
- /* This macro defines reserved value for table entry which contained
- a deleted element. */
- #define HTAB_DELETED_ENTRY ((PTR) 1)
- /* Hash tables are of the following type. The structure
- (implementation) of this type is not needed for using the hash
- tables. All work with hash table should be executed only through
- functions mentioned below. The size of this structure is subject to
- change. */
- struct htab {
- /* Pointer to hash function. */
- htab_hash hash_f;
- /* Pointer to comparison function. */
- htab_eq eq_f;
- /* Pointer to cleanup function. */
- htab_del del_f;
- /* Table itself. */
- void **entries;
- /* Current size (in entries) of the hash table. */
- size_t size;
- /* Current number of elements including also deleted elements. */
- size_t n_elements;
- /* Current number of deleted elements in the table. */
- size_t n_deleted;
- /* The following member is used for debugging. Its value is number
- of all calls of `htab_find_slot' for the hash table. */
- unsigned int searches;
- /* The following member is used for debugging. Its value is number
- of collisions fixed for time of work with the hash table. */
- unsigned int collisions;
- /* Pointers to allocate/free functions. */
- htab_alloc alloc_f;
- htab_free free_f;
- /* Alternate allocate/free functions, which take an extra argument. */
- void *alloc_arg;
- htab_alloc_with_arg alloc_with_arg_f;
- htab_free_with_arg free_with_arg_f;
- /* Current size (in entries) of the hash table, as an index into the
- table of primes. */
- unsigned int size_prime_index;
- };
- typedef struct htab *htab_t;
- /* An enum saying whether we insert into the hash table or not. */
- enum insert_option {NO_INSERT, INSERT};
- /* The prototypes of the package functions. */
- extern htab_t htab_create_alloc (size_t, htab_hash,
- htab_eq, htab_del,
- htab_alloc, htab_free);
- extern htab_t htab_create_alloc_ex (size_t, htab_hash,
- htab_eq, htab_del,
- void *, htab_alloc_with_arg,
- htab_free_with_arg);
- extern htab_t htab_create_typed_alloc (size_t, htab_hash, htab_eq, htab_del,
- htab_alloc, htab_alloc, htab_free);
- /* Backward-compatibility functions. */
- extern htab_t htab_create (size_t, htab_hash, htab_eq, htab_del);
- extern htab_t htab_try_create (size_t, htab_hash, htab_eq, htab_del);
- extern void htab_set_functions_ex (htab_t, htab_hash,
- htab_eq, htab_del,
- void *, htab_alloc_with_arg,
- htab_free_with_arg);
- extern void htab_delete (htab_t);
- extern void htab_empty (htab_t);
- extern void * htab_find (htab_t, const void *);
- extern void ** htab_find_slot (htab_t, const void *, enum insert_option);
- extern void * htab_find_with_hash (htab_t, const void *, hashval_t);
- extern void ** htab_find_slot_with_hash (htab_t, const void *,
- hashval_t, enum insert_option);
- extern void htab_clear_slot (htab_t, void **);
- extern void htab_remove_elt (htab_t, void *);
- extern void htab_remove_elt_with_hash (htab_t, void *, hashval_t);
- extern void htab_traverse (htab_t, htab_trav, void *);
- extern void htab_traverse_noresize (htab_t, htab_trav, void *);
- extern size_t htab_size (htab_t);
- extern size_t htab_elements (htab_t);
- extern double htab_collisions (htab_t);
- /* A hash function for pointers. */
- extern htab_hash htab_hash_pointer;
- /* An equality function for pointers. */
- extern htab_eq htab_eq_pointer;
- /* A hash function for null-terminated strings. */
- extern hashval_t htab_hash_string (const void *);
- /* An iterative hash function for arbitrary data. */
- extern hashval_t iterative_hash (const void *, size_t, hashval_t);
- /* Shorthand for hashing something with an intrinsic size. */
- #define iterative_hash_object(OB,INIT) iterative_hash (&OB, sizeof (OB), INIT)
- #ifdef __cplusplus
- }
- #endif /* __cplusplus */
- #endif /* __HASHTAB_H */
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