| /* An expandable hash tables datatype. |
| Copyright (C) 1999-2020 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, const void *); |
| extern void htab_remove_elt_with_hash (htab_t, const 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 */ |