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/**************************************************************************
*
* Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/**
* @file
* General purpose hash table implementation.
*
* Just uses the cso_hash for now, but it might be better switch to a linear
* probing hash table implementation at some point -- as it is said they have
* better lookup and cache performance and it appears to be possible to write
* a lock-free implementation of such hash tables .
*
* @author José Fonseca <jrfonseca@tungstengraphics.com>
*/
#include "pipe/p_compiler.h"
#include "pipe/p_debug.h"
#include "pipe/p_util.h"
#include "cso_cache/cso_hash.h"
#include "u_hash_table.h"
struct hash_table
{
struct cso_hash *cso;
/** Hash function */
unsigned (*hash)(void *key);
/** Compare two keys */
int (*compare)(void *key1, void *key2);
/* TODO: key, value destructors? */
};
struct hash_table_item
{
void *key;
void *value;
};
struct hash_table *
hash_table_create(unsigned (*hash)(void *key),
int (*compare)(void *key1, void *key2))
{
struct hash_table *ht;
ht = MALLOC_STRUCT(hash_table);
if(!ht)
return NULL;
ht->cso = cso_hash_create();
if(!ht->cso) {
FREE(ht);
return NULL;
}
ht->hash = hash;
ht->compare = compare;
return ht;
}
static struct hash_table_item *
hash_table_find_item(struct hash_table *ht,
void *key,
unsigned key_hash)
{
struct cso_hash_iter iter;
struct hash_table_item *item;
iter = cso_hash_find(ht->cso, key_hash);
while (!cso_hash_iter_is_null(iter)) {
item = (struct hash_table_item *)cso_hash_iter_data(iter);
if (!ht->compare(item->key, key))
return item;
iter = cso_hash_iter_next(iter);
}
return NULL;
}
enum pipe_error
hash_table_set(struct hash_table *ht,
void *key,
void *value)
{
unsigned key_hash;
struct hash_table_item *item;
assert(ht);
key_hash = ht->hash(key);
item = hash_table_find_item(ht, key, key_hash);
if(item) {
/* TODO: key/value destruction? */
item->value = value;
return PIPE_OK;
}
item = MALLOC_STRUCT(hash_table_item);
if(!item)
return PIPE_ERROR_OUT_OF_MEMORY;
item->key = key;
item->value = value;
cso_hash_insert(ht->cso, key_hash, item);
/* FIXME: there is no OOM propagation in cso_hash */
if(0) {
FREE(item);
return PIPE_ERROR_OUT_OF_MEMORY;
}
return PIPE_OK;
}
void *
hash_table_get(struct hash_table *ht,
void *key)
{
unsigned key_hash;
struct hash_table_item *item;
assert(ht);
key_hash = ht->hash(key);
item = hash_table_find_item(ht, key, key_hash);
if(!item)
return NULL;
return item->value;
}
void
hash_table_remove(struct hash_table *ht,
void *key)
{
unsigned key_hash;
struct hash_table_item *item;
assert(ht);
key_hash = ht->hash(key);
item = hash_table_find_item(ht, key, key_hash);
if(!item)
return;
/* FIXME: cso_hash_take takes the first element of the collision list
* indiscriminately, so we can not take the item down. */
item->value = NULL;
}
void
hash_table_destroy(struct hash_table *ht)
{
assert(ht);
cso_hash_delete(ht->cso);
FREE(ht);
}
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