1 | /*
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2 | * Copyright (C) 2009-2012 by Matthias Ringwald
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3 | *
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4 | * Redistribution and use in source and binary forms, with or without
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5 | * modification, are permitted provided that the following conditions
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6 | * are met:
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7 | *
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the copyright holders nor the names of
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14 | * contributors may be used to endorse or promote products derived
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15 | * from this software without specific prior written permission.
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16 | * 4. Any redistribution, use, or modification is done solely for
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17 | * personal benefit and not for any commercial purpose or for
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18 | * monetary gain.
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19 | *
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20 | * THIS SOFTWARE IS PROVIDED BY MATTHIAS RINGWALD AND CONTRIBUTORS
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21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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22 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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23 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
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24 | * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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25 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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26 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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27 | * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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28 | * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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29 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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30 | * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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31 | * SUCH DAMAGE.
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32 | *
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33 | * Please inquire about commercial licensing options at btstack@ringwald.ch
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34 | *
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35 | */
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36 |
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37 | /*
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38 | * memory_pool.c
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39 | *
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40 | * Fixed-size block allocation
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41 | *
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42 | * Free blocks are kept in singly linked list
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43 | *
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44 | */
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45 |
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46 | #include <btstack/memory_pool.h>
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47 | #include <stddef.h>
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48 |
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49 | typedef struct node {
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50 | struct node * next;
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51 | } node_t;
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52 |
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53 | void memory_pool_create(memory_pool_t *pool, void * storage, int count, int block_size){
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54 | node_t *free_blocks = (node_t*) pool;
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55 | char *mem_ptr = (char *) storage;
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56 | int i;
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57 |
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58 | // create singly linked list of all available blocks
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59 | free_blocks->next = NULL;
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60 | for (i = 0 ; i < count ; i++){
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61 | memory_pool_free(pool, mem_ptr);
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62 | mem_ptr += block_size;
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63 | }
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64 | }
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65 |
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66 | void * memory_pool_get(memory_pool_t *pool){
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67 | node_t *free_blocks = (node_t*) pool;
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68 | node_t *node;
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69 |
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70 | if (!free_blocks->next) return NULL;
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71 |
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72 | // remove first
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73 | node = free_blocks->next;
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74 | free_blocks->next = node->next;
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75 |
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76 | return (void*) node;
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77 | }
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78 |
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79 | void memory_pool_free(memory_pool_t *pool, void * block){
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80 | node_t *free_blocks = (node_t*) pool;
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81 | node_t *node = (node_t*) block;
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82 | // add block as node to list
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83 | node->next = free_blocks->next;
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84 | free_blocks->next = node;
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85 | }
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