1 /*
2 * Copyright (C) 2014 BlueKitchen GmbH
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the copyright holders nor the names of
14 * contributors may be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * 4. Any redistribution, use, or modification is done solely for
17 * personal benefit and not for any commercial purpose or for
18 * monetary gain.
19 *
20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN
24 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * Please inquire about commercial licensing options at
34 * [email protected]
35 *
36 */
37
38 #define BTSTACK_FILE__ "btstack_memory_pool.c"
39
40 /*
41 * btstack_memory_pool.c
42 *
43 * Fixed-size block allocation
44 *
45 * Free blocks are kept in singly linked list
46 *
47 */
48
49 #include "btstack_memory_pool.h"
50
51 #include <stddef.h>
52 #include "btstack_debug.h"
53
54 typedef struct node {
55 struct node * next;
56 } node_t;
57
btstack_memory_pool_create(btstack_memory_pool_t * pool,void * storage,int count,int block_size)58 void btstack_memory_pool_create(btstack_memory_pool_t *pool, void * storage, int count, int block_size){
59 node_t *free_blocks = (node_t*) pool;
60 char *mem_ptr = (char *) storage;
61 int i;
62
63 // create singly linked list of all available blocks
64 free_blocks->next = NULL;
65 for (i = 0 ; i < count ; i++){
66 btstack_memory_pool_free(pool, mem_ptr);
67 mem_ptr += block_size;
68 }
69 }
70
btstack_memory_pool_get(btstack_memory_pool_t * pool)71 void * btstack_memory_pool_get(btstack_memory_pool_t *pool){
72 node_t *free_blocks = (node_t*) pool;
73
74 if (!free_blocks->next) return NULL;
75
76 // remove first
77 node_t *node = free_blocks->next;
78 free_blocks->next = node->next;
79
80 return (void*) node;
81 }
82
btstack_memory_pool_free(btstack_memory_pool_t * pool,void * block)83 void btstack_memory_pool_free(btstack_memory_pool_t *pool, void * block){
84 node_t *free_blocks = (node_t*) pool;
85 node_t *node = (node_t*) block;
86
87 // assert that node is not already in list
88 node_t * it;
89 for (it = free_blocks->next; it != NULL; it = it->next){
90 btstack_assert(it != node);
91 }
92
93 // add block as node to list
94 node->next = free_blocks->next;
95 free_blocks->next = node;
96 }
97