btstack/src/memory_pool.c
2012-05-07 21:54:09 +00:00

85 lines
2.9 KiB
C

/*
* Copyright (C) 2009-2012 by Matthias Ringwald
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the copyright holders nor the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* 4. Any redistribution, use, or modification is done solely for
* personal benefit and not for any commercial purpose or for
* monetary gain.
*
* THIS SOFTWARE IS PROVIDED BY MATTHIAS RINGWALD AND CONTRIBUTORS
* ``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 MATTHIAS
* RINGWALD OR CONTRIBUTORS 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.
*
* Please inquire about commercial licensing options at btstack@ringwald.ch
*
*/
/*
* memory_pool.c
*
* Fixed-size block allocation
*
* Free blocks are kept in singly linked list
*
*/
#include <btstack/memory_pool.h>
#include <stddef.h>
typedef struct node {
struct node * next;
} node_t;
void memory_pool_create(memory_pool_t *pool, void * storage, int count, int block_size){
node_t *free_blocks = (node_t*) pool;
char *mem_ptr = (char *) storage;
int i;
// create singly linked list of all available blocks
free_blocks->next = NULL;
for (i = 0 ; i < count ; i++){
memory_pool_free(pool, mem_ptr);
mem_ptr += block_size;
}
}
void * memory_pool_get(memory_pool_t *pool){
node_t *free_blocks = (node_t*) pool;
if (!free_blocks->next) return NULL;
// remove first
node_t *node = free_blocks->next;
free_blocks->next = node->next;
return (void*) node;
}
void memory_pool_free(memory_pool_t *pool, void * block){
node_t *free_blocks = (node_t*) pool;
node_t *node = (node_t*) block;
// add block as node to list
node->next = free_blocks->next;
free_blocks->next = node;
}