| /* An expandable hash tables datatype. |
| Copyright (C) 1999 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 hash table element is represented by the following type. */ |
| |
| typedef const void *hash_table_entry_t; |
| |
| /* 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. */ |
| |
| typedef struct hash_table |
| { |
| /* Current size (in entries) of the hash table */ |
| size_t size; |
| /* Current number of elements including also deleted elements */ |
| size_t number_of_elements; |
| /* Current number of deleted elements in the table */ |
| size_t number_of_deleted_elements; |
| /* The following member is used for debugging. Its value is number |
| of all calls of `find_hash_table_entry' for the hash table. */ |
| int searches; |
| /* The following member is used for debugging. Its value is number |
| of collisions fixed for time of work with the hash table. */ |
| int collisions; |
| /* Pointer to function for evaluation of hash value (any unsigned value). |
| This function has one parameter of type hash_table_entry_t. */ |
| unsigned (*hash_function) PARAMS ((hash_table_entry_t)); |
| /* Pointer to function for test on equality of hash table elements (two |
| parameter of type hash_table_entry_t. */ |
| int (*eq_function) PARAMS ((hash_table_entry_t, hash_table_entry_t)); |
| /* Table itself */ |
| hash_table_entry_t *entries; |
| } *hash_table_t; |
| |
| |
| /* The prototypes of the package functions. */ |
| |
| extern hash_table_t create_hash_table |
| PARAMS ((size_t, unsigned (*) (hash_table_entry_t), |
| int (*) (hash_table_entry_t, hash_table_entry_t))); |
| |
| extern void delete_hash_table PARAMS ((hash_table_t)); |
| |
| extern void empty_hash_table PARAMS ((hash_table_t)); |
| |
| extern hash_table_entry_t *find_hash_table_entry |
| PARAMS ((hash_table_t, hash_table_entry_t, int)); |
| |
| extern void remove_element_from_hash_table_entry PARAMS ((hash_table_t, |
| hash_table_entry_t)); |
| |
| extern void clear_hash_table_slot PARAMS ((hash_table_t, hash_table_entry_t *)); |
| |
| extern void traverse_hash_table PARAMS ((hash_table_t, |
| int (*) (hash_table_entry_t, void *), |
| void *)); |
| |
| extern size_t hash_table_size PARAMS ((hash_table_t)); |
| |
| extern size_t hash_table_elements_number PARAMS ((hash_table_t)); |
| |
| extern int hash_table_collisions PARAMS ((hash_table_t)); |
| |
| extern int all_hash_table_collisions PARAMS ((void)); |
| |
| #ifdef __cplusplus |
| } |
| #endif /* __cplusplus */ |
| |
| #endif /* __HASHTAB_H */ |