| /* 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> |
| |
| /* Callback function pointer types. */ |
| |
| /* Calculate hash of a table entry. */ |
| typedef unsigned int (*htab_hash) PARAMS ((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) PARAMS ((const void *, const void *)); |
| |
| /* Cleanup function called whenever a live element is removed from |
| the hash table. */ |
| typedef void (*htab_del) PARAMS ((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) PARAMS ((void **, void *)); |
| |
| /* 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. */ |
| |
| 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; |
| }; |
| |
| typedef struct htab *htab_t; |
| |
| /* The prototypes of the package functions. */ |
| |
| extern htab_t htab_create PARAMS ((size_t, htab_hash, |
| htab_eq, htab_del)); |
| extern void htab_delete PARAMS ((htab_t)); |
| extern void htab_empty PARAMS ((htab_t)); |
| |
| extern void *htab_find PARAMS ((htab_t, const void *)); |
| extern void **htab_find_slot PARAMS ((htab_t, const void *, int)); |
| extern void *htab_find_with_hash PARAMS ((htab_t, const void *, |
| unsigned int)); |
| extern void **htab_find_slot_with_hash PARAMS ((htab_t, const void *, |
| unsigned int, int)); |
| extern void htab_clear_slot PARAMS ((htab_t, void **)); |
| extern void htab_remove_elt PARAMS ((htab_t, void *)); |
| |
| extern void htab_traverse PARAMS ((htab_t, htab_trav, void *)); |
| |
| extern size_t htab_size PARAMS ((htab_t)); |
| extern size_t htab_elements PARAMS ((htab_t)); |
| extern double htab_collisions PARAMS ((htab_t)); |
| |
| #ifdef __cplusplus |
| } |
| #endif /* __cplusplus */ |
| |
| #endif /* __HASHTAB_H */ |