0,0 → 1,177 |
/* |
* Copyright (C) 2006 Jakub Jermar |
* All rights reserved. |
* |
* Redistribution and use in source and binary forms, with or without |
* modification, are permitted provided that the following conditions |
* are met: |
* |
* - Redistributions of source code must retain the above copyright |
* notice, this list of conditions and the following disclaimer. |
* - Redistributions in binary form must reproduce the above copyright |
* notice, this list of conditions and the following disclaimer in the |
* documentation and/or other materials provided with the distribution. |
* - The name of the author may not be used to endorse or promote products |
* derived from this software without specific prior written permission. |
* |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
*/ |
|
/* |
* This is an implementation of generic chained hash table. |
*/ |
|
#include <adt/hash_table.h> |
#include <adt/list.h> |
#include <typedefs.h> |
#include <arch/types.h> |
#include <debug.h> |
#include <mm/heap.h> |
#include <memstr.h> |
|
/** Create chained hash table. |
* |
* @param h Hash table structure. Will be initialized by this call. |
* @param m Number of slots in the hash table. |
* @param max_keys Maximal number of keys needed to identify an item. |
* @param op Hash table operations structure. |
*/ |
void hash_table_create(hash_table_t *h, count_t m, count_t max_keys, hash_table_operations_t *op) |
{ |
ASSERT(h); |
ASSERT(op && op->hash && op->compare); |
ASSERT(max_keys > 0); |
|
h->entry = malloc(m * sizeof(link_t *)); |
if (!h->entry) { |
panic("cannot allocate memory for hash table\n"); |
} |
memsetb((__address) h->entry, m * sizeof(link_t *), 0); |
|
h->entries = m; |
h->max_keys = max_keys; |
h->op = op; |
} |
|
/** Insert item into hash table. |
* |
* @param h Hash table. |
* @param hey Array of all keys necessary to compute hash index. |
* @param item Item to be inserted into the hash table. |
* |
* @return true on success, false if the keys were already present in the hash table. |
*/ |
bool hash_table_insert(hash_table_t *h, __native key[], link_t *item) |
{ |
index_t chain; |
|
ASSERT(item); |
ASSERT(h && h->op && h->op->hash && h->op->compare); |
|
chain = h->op->hash(key); |
ASSERT(chain < h->entries); |
|
if (hash_table_find(h, key)) { |
/* |
* The hash table is not redundant. |
* Signal failure on return. |
*/ |
return false; |
} |
|
list_append(item, &h->entry[chain]); |
return true; |
} |
|
/** Search hash table for an item matching keys. |
* |
* @param h Hash table. |
* @param key Array of all keys needed to compute hash index. |
* |
* @return Matching item on success, NULL if there is no such item. |
*/ |
link_t *hash_table_find(hash_table_t *h, __native key[]) |
{ |
link_t *cur; |
index_t chain; |
|
ASSERT(h && h->op && h->op->hash && h->op->compare); |
|
chain = h->op->hash(key); |
ASSERT(chain < h->entries); |
|
/* |
* The hash table is not redundant. |
* Check if the keys are not in place already. |
*/ |
for (cur = h->entry[chain].next; cur != &h->entry[chain]; cur = cur->next) { |
if (h->op->compare(key, h->max_keys, cur)) { |
/* |
* The entry is there. |
*/ |
return cur; |
} |
} |
|
return NULL; |
} |
|
/** Remove all matching items from hash table. |
* |
* For each removed item, h->remove_callback() is called. |
* |
* @param h Hash table. |
* @param key Array of keys that will be compared against items of the hash table. |
* @param keys Number of keys in the 'key' array. |
*/ |
void hash_table_remove(hash_table_t *h, __native key[], count_t keys) |
{ |
index_t chain; |
link_t *cur; |
|
ASSERT(h && h->op && h->op->hash && h->op->compare && h->op->remove_callback); |
ASSERT(keys <= h->max_keys); |
|
if (keys == h->max_keys) { |
|
/* |
* All keys are known, hash_table_find() can be used to find the entry. |
*/ |
|
cur = hash_table_find(h, key); |
if (cur) { |
list_remove(cur); |
h->op->remove_callback(cur); |
} |
return; |
} |
|
/* |
* Fewer keys were passed. |
* Any partially matching entries are to be removed. |
*/ |
for (chain = 0; chain < h->entries; chain++) { |
for (cur = h->entry[chain].next; cur != &h->entry[chain]; cur = cur->next) { |
if (h->op->compare(key, keys, cur)) { |
link_t *hlp; |
|
hlp = cur; |
cur = cur->prev; |
|
list_remove(hlp); |
h->op->remove_callback(hlp); |
|
continue; |
} |
} |
} |
} |