5 Author: Pekka Riikonen <priikone@silcnet.org>
7 Copyright (C) 2001 - 2002 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; version 2 of the License.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
20 /****h* silcutil/SILC Hash Table Interface
24 * Implementation of collision resistant hash table. This is a hash table
25 * that provides a reliable (what you add there stays there, and duplicate
26 * keys are allowed) with as fast reference to the key as possible. If
27 * there are a lot of duplicate keys in the hash table the lookup gets
28 * slower of course. However, this is reliable and no data is lost at any
29 * point. If you know that you never have duplicate keys then this is as
30 * fast as any simple hash table.
32 * The interface provides many ways to search the hash table including
33 * an extended interface where caller can specify its own hash and comparison
36 * There are two ways to traverse the entire hash table if this feature
37 * is needed. There exists a foreach function that calls a foreach
38 * callback for each entry in the hash table. Other way is to use
39 * SilcHashTableList structure and traverse the hash table inside while()
40 * using the list structure. Both are equally fast.
44 #ifndef SILCHASHTABLE_H
45 #define SILCHASHTABLE_H
47 /****s* silcutil/SilcHashTableAPI/SilcHashTable
51 * typedef struct SilcHashTableStruct *SilcHashTable;
55 * This context is the actual hash table and is allocated
56 * by silc_hash_table_alloc and given as argument usually to
57 * all silc_hash_table_* functions. It is freed by the
58 * silc_hash_table_free function.
61 typedef struct SilcHashTableStruct *SilcHashTable;
63 /****s* silcutil/SilcHashTableAPI/SilcHashTableList
67 * typedef struct SilcHashTableListStruct SilcHashTableList;
71 * This structure is used to tarverse the hash table. This structure
72 * is given as argument to the silc_hash_table_list function to
73 * initialize it and then used to traverse the hash table with the
74 * silc_hash_table_get function. It needs not be allocated or freed.
78 * SilcHashTableList htl;
79 * silc_hash_table_list(hash_table, &htl);
80 * while (silc_hash_table_get(&htl, (void *)&key, (void *)&context))
82 * silc_hash_table_list_reset(&htl);
86 typedef struct SilcHashTableListStruct SilcHashTableList;
88 /* List structure to traverse the hash table. */
89 struct SilcHashTableListStruct {
97 /****f* silcutil/SilcHashTableAPI/SilcHashFunction
101 * typedef SilcUInt32 (*SilcHashFunction)(void *key, void *user_context);
105 * A type for the hash function. This function is used to hash the
106 * provided key value `key' and return the index for the hash table.
107 * The `user_context' is application specific context and is delivered
111 typedef SilcUInt32 (*SilcHashFunction)(void *key, void *user_context);
113 /****f* silcutil/SilcHashTableAPI/SilcHashCompare
117 * typedef bool (*SilcHashCompare)(void *key1, void *key2,
118 * void *user_context);
122 * A comparison funtion that is called to compare the two keys `key1' and
123 * `key2'. If they are equal this must return TRUE or FALSE otherwise.
124 * The application provides this function when allocating a new hash table.
125 * The `user_context' is application specific context and is delivered
129 typedef bool (*SilcHashCompare)(void *key1, void *key2, void *user_context);
131 /****f* silcutil/SilcHashTableAPI/SilcHashDestructor
135 * typedef void (*SilcHashDestructor)(void *key, void *context,
136 * void *user_context);
140 * A destructor callback that the library will call to destroy the
141 * `key' and `context'. The appliation provides the function when
142 * allocating a new hash table. The `user_context' is application
143 * specific context and is delivered to the callback.
146 typedef void (*SilcHashDestructor)(void *key, void *context,
149 /****f* silcutil/SilcHashTableAPI/SilcHashForeach
153 * typedef void (*SilcHashForeach)(void *key, void *context,
154 * void *user_context);
158 * Foreach function. This is called when traversing the entrys in the
159 * hash table using silc_hash_table_foreach. The `user_context' is
160 * application specific context and is delivered to the callback.
163 typedef void (*SilcHashForeach)(void *key, void *context, void *user_context);
165 /* Simple hash table interface */
167 /****f* silcutil/SilcHashTableAPI/silc_hash_table_alloc
171 * SilcHashTable silc_hash_table_alloc(SilcUInt32 table_size,
172 * SilcHashFunction hash,
173 * void *hash_user_context,
174 * SilcHashCompare compare,
175 * void *compare_user_context,
176 * SilcHashDestructor destructor,
177 * void *destructor_user_context,
182 * Allocates new hash table and returns it. If the `table_size' is not
183 * zero then the hash table size is the size provided. If zero then the
184 * default size will be used. Note that if the `table_size' is provided
185 * it should be a prime. The `hash', `compare' and `destructor' are
186 * the hash function, the key comparison function and key and context
187 * destructor function, respectively. The `hash' is mandatory, the others
191 SilcHashTable silc_hash_table_alloc(SilcUInt32 table_size,
192 SilcHashFunction hash,
193 void *hash_user_context,
194 SilcHashCompare compare,
195 void *compare_user_context,
196 SilcHashDestructor destructor,
197 void *destructor_user_context,
200 /****f* silcutil/SilcHashTableAPI/silc_hash_table_free
204 * void silc_hash_table_free(SilcHashTable ht);
208 * Frees the hash table. The destructor function provided in the
209 * silc_hash_table_alloc will be called for all keys in the hash table.
212 void silc_hash_table_free(SilcHashTable ht);
214 /****f* silcutil/SilcHashTableAPI/silc_hash_table_size
218 * SilcUInt32 silc_hash_table_size(SilcHashTable ht);
222 * Returns the size of the hash table. This is the true size of the
226 SilcUInt32 silc_hash_table_size(SilcHashTable ht);
228 /****f* silcutil/SilcHashTableAPI/silc_hash_table_count
232 * SilcUInt32 silc_hash_table_count(SilcHashTable ht);
236 * Returns the number of the entires in the hash table. If there is more
237 * entries in the table thatn the size of the hash table calling the
238 * silc_hash_table_rehash is recommended.
241 SilcUInt32 silc_hash_table_count(SilcHashTable ht);
243 /****f* silcutil/SilcHashTableAPI/silc_hash_table_add
247 * void silc_hash_table_add(SilcHashTable ht, void *key, void *context);
251 * Adds new entry to the hash table. The `key' is hashed using the
252 * hash function and the both `key' and `context' will be saved to the
253 * hash table. This function quarantees that the entry is always added
254 * to the hash table reliably (it is collision resistant).
257 void silc_hash_table_add(SilcHashTable ht, void *key, void *context);
259 /****f* silcutil/SilcHashTableAPI/silc_hash_table_replace
263 * void silc_hash_table_replace(SilcHashTable ht, void *key, void *context);
267 * Same as silc_hash_table_add but if the `key' already exists in the
268 * hash table the old key and the old context will be replaced with the
269 * `key' and the `context. The destructor function will be called for the
270 * replaced key and context.
273 void silc_hash_table_replace(SilcHashTable ht, void *key, void *context);
275 /****f* silcutil/SilcHashTableAPI/silc_hash_table_del
279 * bool silc_hash_table_del(SilcHashTable ht, void *key);
283 * Removes the entry from the hash table by the provided `key'. This will
284 * call the destructor funtion for the found entry. Return TRUE if the
285 * entry was removed successfully and FALSE otherwise.
288 bool silc_hash_table_del(SilcHashTable ht, void *key);
290 /****f* silcutil/SilcHashTableAPI/silc_hash_table_del_by_context
294 * bool silc_hash_table_del_by_context(SilcHashTable ht, void *key,
299 * Same as silc_hash_table_del but verifies that the context associated
300 * with the `key' matches the `context'. This is handy to use with hash
301 * tables that may have duplicate keys. In that case the `context' may
302 * be used to check whether the correct entry is being deleted.
305 bool silc_hash_table_del_by_context(SilcHashTable ht, void *key,
308 /****f* silcutil/SilcHashTableAPI/silc_hash_table_find
312 * bool silc_hash_table_find(SilcHashTable ht, void *key,
313 * void **ret_key, void **ret_context);
317 * Finds the entry in the hash table by the provided `key' as fast as
318 * possible. Return TRUE if the entry was found and FALSE otherwise.
319 * The found entry is returned to the `ret_key' and `ret_context',
320 * respectively. If the `ret_key and `ret_context' are NULL then this
321 * maybe used only to check whether given key exists in the table.
324 bool silc_hash_table_find(SilcHashTable ht, void *key,
325 void **ret_key, void **ret_context);
327 /****f* silcutil/SilcHashTableAPI/silc_hash_table_find_foreach
331 * void silc_hash_table_find_foreach(SilcHashTable ht, void *key,
332 * SilcHashForeach foreach,
333 * void *user_context);
337 * As the hash table is collision resistant it is possible to save duplicate
338 * keys to the hash table. This function can be used to find all keys
339 * and contexts from the hash table that are found using the `key'. The
340 * `foreach' is called for every found key.
344 * The hash table will not be rehashed during the traversing of the table,
345 * even if the table was marked as auto rehashable. The caller also must
346 * not call silc_hash_table_rehash while traversing the table.
349 void silc_hash_table_find_foreach(SilcHashTable ht, void *key,
350 SilcHashForeach foreach, void *user_context);
352 /****f* silcutil/SilcHashTableAPI/silc_hash_table_foreach
356 * void silc_hash_table_foreach(SilcHashTable ht, SilcHashForeach foreach,
357 * void *user_context);
361 * Traverse all entrys in the hash table and call the `foreach' for
362 * every entry with the `user_context' context.
366 * The hash table will not be rehashed during the traversing of the table,
367 * even if the table was marked as auto rehashable. The caller also must
368 * not call silc_hash_table_rehash while traversing the table.
371 void silc_hash_table_foreach(SilcHashTable ht, SilcHashForeach foreach,
374 /****f* silcutil/SilcHashTableAPI/silc_hash_table_rehash
378 * void silc_hash_table_rehash(SilcHashTable ht, SilcUInt32 new_size);
382 * Rehashs the hash table. The size of the new hash table is provided
383 * as `new_size'. If the `new_size' is zero then this routine will make
384 * the new table of a suitable size. Note that this operation may be
388 void silc_hash_table_rehash(SilcHashTable ht, SilcUInt32 new_size);
390 /****f* silcutil/SilcHashTableAPI/silc_hash_table_list
394 * void silc_hash_table_list(SilcHashTable ht, SilcHashTableList *htl);
398 * Prepares the `htl' SilcHashTableList sent as argument to be used in the
399 * hash table traversing with the silc_hash_table_get. After the hash
400 * table traversing is completed the silc_hash_table_list_reset must be
405 * The hash table will not be rehashed during the traversing of the list,
406 * even if the table was marked as auto rehashable. The caller also must
407 * not call silc_hash_table_rehash while traversing the list.
410 void silc_hash_table_list(SilcHashTable ht, SilcHashTableList *htl);
412 /****f* silcutil/SilcHashTableAPI/silc_hash_table_list_reset
416 * void silc_hash_table_list_reset(SilcHashTableList *htl);
420 * Resets the `htl' SilcHashTableList. This must be called after the
421 * hash table traversing is completed.
424 void silc_hash_table_list_reset(SilcHashTableList *htl);
426 /****f* silcutil/SilcHashTableAPI/silc_hash_table_get
430 * bool silc_hash_table_get(SilcHashTableList *htl, void **key,
435 * Returns always the next entry in the hash table into the `key' and
436 * `context' and TRUE. If this returns FALSE then there are no anymore
440 bool silc_hash_table_get(SilcHashTableList *htl, void **key, void **context);
443 /* Extended hash table interface (same as above but with specific
444 hash and comparison functions). */
446 /****f* silcutil/SilcHashTableAPI/silc_hash_table_add_ext
450 * void silc_hash_table_add_ext(SilcHashTable ht, void *key, void *context,
451 * SilcHashFunction hash,
452 * void *hash_user_context);
456 * Adds new entry to the hash table. The `key' is hashed using the
457 * hash function and the both `key' and `context' will be saved to the
458 * hash table. This function quarantees that the entry is always added
459 * to the hash table reliably (it is collision resistant).
461 * The `hash' and `hash_user_context' are application specified hash
462 * function. If not provided the hash table's default is used.
465 void silc_hash_table_add_ext(SilcHashTable ht, void *key, void *context,
466 SilcHashFunction hash, void *hash_user_context);
468 /****f* silcutil/SilcHashTableAPI/silc_hash_table_replace_ext
472 * void silc_hash_table_replace_ext(SilcHashTable ht, void *key,
474 * SilcHashFunction hash,
475 * void *hash_user_context);
479 * Same as silc_hash_table_add_ext but if the `key' already exists in the
480 * hash table the old key and the old context will be replaced with the
481 * `key' and the `context. The destructor function will be called for the
482 * replaced key and context.
484 * The `hash' and `hash_user_context' are application specified hash
485 * function. If not provided the hash table's default is used.
488 void silc_hash_table_replace_ext(SilcHashTable ht, void *key, void *context,
489 SilcHashFunction hash,
490 void *hash_user_context);
492 /****f* silcutil/SilcHashTableAPI/silc_hash_table_del_ext
496 * bool silc_hash_table_del_ext(SilcHashTable ht, void *key,
497 * SilcHashFunction hash,
498 * void *hash_user_context,
499 * SilcHashCompare compare,
500 * void *compare_user_context,
501 * SilcHashDestructor destructor,
502 * void *destructor_user_context);
506 * Removes the entry from the hash table by the provided `key'. This will
507 * call the destructor funtion for the found entry. Return TRUE if the
508 * entry was removed successfully and FALSE otherwise.
510 * The `hash' and `hash_user_context' are application specified hash
511 * function. If not provided the hash table's default is used.
512 * The `compare' and `compare_user_context' are application specified
513 * comparing function. If not provided the hash table's default is used.
514 * The `destructor' and `destructor_user_context' are application
515 * specific destructor function.
518 bool silc_hash_table_del_ext(SilcHashTable ht, void *key,
519 SilcHashFunction hash,
520 void *hash_user_context,
521 SilcHashCompare compare,
522 void *compare_user_context,
523 SilcHashDestructor destructor,
524 void *destructor_user_context);
526 /****f* silcutil/SilcHashTableAPI/silc_hash_table_del_by_context_ext
530 * bool silc_hash_table_del_by_context_ext(SilcHashTable ht, void *key,
532 * SilcHashFunction hash,
533 * void *hash_user_context,
534 * SilcHashCompare compare,
535 * void *compare_user_context,
536 * SilcHashDestructor destructor,
537 * void *destructor_user_context);
541 * Same as silc_hash_table_del but verifies that the context associated
542 * with the `key' matches the `context'. This is handy to use with hash
543 * tables that may have duplicate keys. In that case the `context' may
544 * be used to check whether the correct entry is being deleted.
546 * The `hash' and `hash_user_context' are application specified hash
547 * function. If not provided the hash table's default is used.
548 * The `compare' and `compare_user_context' are application specified
549 * comparing function. If not provided the hash table's default is used.
550 * The `destructor' and `destructor_user_context' are application
551 * specific destructor function.
554 bool silc_hash_table_del_by_context_ext(SilcHashTable ht, void *key,
556 SilcHashFunction hash,
557 void *hash_user_context,
558 SilcHashCompare compare,
559 void *compare_user_context,
560 SilcHashDestructor destructor,
561 void *destructor_user_context);
563 /****f* silcutil/SilcHashTableAPI/silc_hash_table_find_ext
567 * bool silc_hash_table_find_ext(SilcHashTable ht, void *key,
568 * void **ret_key, void **ret_context,
569 * SilcHashFunction hash,
570 * void *hash_user_context,
571 * SilcHashCompare compare,
572 * void *compare_user_context);
576 * Finds the entry in the hash table by the provided `key' as fast as
577 * possible. Return TRUE if the entry was found and FALSE otherwise.
578 * The found entry is returned to the `ret_key' and `ret_context',
579 * respectively. If the `ret_key and `ret_context' are NULL then this
580 * maybe used only to check whether given key exists in the table.
582 * The `hash' and `hash_user_context' are application specified hash
583 * function. If not provided the hash table's default is used.
584 * The `compare' and `compare_user_context' are application specified
585 * comparing function. If not provided the hash table's default is used.
588 bool silc_hash_table_find_ext(SilcHashTable ht, void *key,
589 void **ret_key, void **ret_context,
590 SilcHashFunction hash,
591 void *hash_user_context,
592 SilcHashCompare compare,
593 void *compare_user_context);
595 /****f* silcutil/SilcHashTableAPI/silc_hash_table_find_foreach_ext
599 * void silc_hash_table_find_foreach_ext(SilcHashTable ht, void *key,
600 * SilcHashFunction hash,
601 * void *hash_user_context,
602 * SilcHashCompare compare,
603 * void *compare_user_context,
604 * SilcHashForeach foreach,
605 * void *foreach_user_context);
609 * As the hash table is collision resistant it is possible to save duplicate
610 * keys to the hash table. This function can be used to find all keys
611 * and contexts from the hash table that are found using the `key'. The
612 * `foreach' is called for every found key.
614 * The `hash' and `hash_user_context' are application specified hash
615 * function. If not provided the hash table's default is used.
616 * The `compare' and `compare_user_context' are application specified
617 * comparing function. If not provided the hash table's default is used.
621 * The hash table will not be rehashed during the traversing of the table,
622 * even if the table was marked as auto rehashable. The caller also must
623 * not call silc_hash_table_rehash while traversing the table.
626 void silc_hash_table_find_foreach_ext(SilcHashTable ht, void *key,
627 SilcHashFunction hash,
628 void *hash_user_context,
629 SilcHashCompare compare,
630 void *compare_user_context,
631 SilcHashForeach foreach,
632 void *foreach_user_context);
634 /****f* silcutil/SilcHashTableAPI/silc_hash_table_rehash_ext
638 * void silc_hash_table_rehash_ext(SilcHashTable ht, SilcUInt32 new_size,
639 * SilcHashFunction hash,
640 * void *hash_user_context);
644 * Rehashs the hash table. The size of the new hash table is provided
645 * as `new_size'. If the `new_size' is zero then this routine will make
646 * the new table of a suitable size. Note that this operation may be
649 * The `hash' and `hash_user_context' are application specified hash
650 * function. If not provided the hash table's default is used.
653 void silc_hash_table_rehash_ext(SilcHashTable ht, SilcUInt32 new_size,
654 SilcHashFunction hash,
655 void *hash_user_context);