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annotate src/tools.c @ 644:c9f8c7e6f57e
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| author | Thinker K.F. Li <thinker@branda.to> |
|---|---|
| date | Wed, 28 Jul 2010 08:36:58 +0800 |
| parents | 530bb7728546 |
| children | 586e50f82c1f |
| rev | line source |
|---|---|
| 12 | 1 #include <stdlib.h> |
|
186
530bb7728546
Move header files to $(top_srcdir)/include/ and prefixed with 'mb_'.
Thinker K.F. Li <thinker@branda.to>
parents:
185
diff
changeset
|
2 #include "mb_tools.h" |
| 12 | 3 |
| 4 | |
| 5 /*! \brief Small fixed size data elements management. | |
| 6 * | |
| 7 * It is used to management a large number of data elements | |
| 8 * they with the same memory size, a fixed size. It allocate | |
| 9 * a large block for a lot of elements a time for more efficiency | |
| 10 * utilization of memory. | |
| 11 * | |
| 12 * Elements with the size and in a large number usually be accessed | |
| 13 * very close in time. Allocate a large block for elements also | |
| 14 * increase cache hit rate. | |
| 15 * | |
| 16 * Blocks are keep track as a linking list. They are freed when | |
| 17 * the elmpool_t is freed. It costs overhead of size of a element | |
| 18 * for each block. We use memory of first element of blocks to | |
| 19 * be next pointer of linking list. So, it can not be used by user | |
| 20 * code. | |
| 21 */ | |
| 22 struct _elmpool { | |
| 23 int elm_sz; | |
| 24 int inc_num; | |
| 25 void *frees; | |
| 26 void *blks; /* list of allocated blocks. */ | |
| 27 }; | |
| 28 | |
| 29 /*! \brief Create a new data elements pool. | |
| 30 * | |
| 31 * elmpool_t provide a pool of fixed size elements to gain better | |
| 32 * utilization of memory. It try to allocate bigger memory blocks | |
| 33 * for multiple elements. | |
| 34 * | |
| 35 * \param elm_sz size of elements. | |
| 36 * \param inc_num is number of elments to allocate every time. (>= 16) | |
| 37 * \return A elmpool or NULL for error. | |
| 38 */ | |
| 39 elmpool_t *elmpool_new(int elm_sz, int inc_num) { | |
| 40 int _elm_sz; | |
| 41 elmpool_t *pool; | |
| 42 | |
| 43 if(inc_num < 16) | |
| 44 return NULL; | |
| 45 | |
| 46 if(elm_sz >= sizeof(void *)) | |
| 47 _elm_sz = elm_sz; | |
| 48 else | |
| 49 _elm_sz = sizeof(void *); | |
| 50 | |
| 51 pool = (elmpool_t *)malloc(sizeof(elmpool_t)); | |
| 52 if(pool == NULL) | |
| 53 return NULL; | |
| 54 | |
| 55 pool->elm_sz = _elm_sz; | |
| 56 if(inc_num == 0) | |
| 57 inc_num = 256; | |
| 58 pool->inc_num = inc_num; | |
| 59 pool->frees = NULL; | |
| 60 pool->blks = NULL; | |
| 61 | |
| 62 return pool; | |
| 63 } | |
| 64 | |
| 65 void *elmpool_elm_alloc(elmpool_t *pool) { | |
| 66 void *blk, *elm; | |
| 67 int elm_sz, inc_num; | |
| 68 int i; | |
| 69 | |
| 70 if(pool->frees == NULL) { | |
| 71 inc_num = pool->inc_num; | |
| 72 elm_sz = pool->elm_sz; | |
| 73 blk = malloc(elm_sz * inc_num); | |
| 74 if(blk == NULL) | |
| 75 return NULL; | |
| 76 | |
| 77 *(void **)blk = pool->blks; | |
| 78 pool->blks = blk; | |
| 79 | |
| 80 blk = blk + elm_sz; | |
| 81 pool->frees = blk; | |
| 82 for(i = 2; i < inc_num; i++) { | |
| 83 *(void **)blk = blk + elm_sz; | |
| 84 blk = *(void **)blk; | |
| 85 } | |
| 86 *(void **)blk = NULL; | |
| 87 } | |
| 88 | |
| 89 elm = pool->frees; | |
| 90 pool->frees = *(void **)elm; | |
| 91 | |
| 92 return elm; | |
| 93 } | |
| 94 | |
| 95 void elmpool_elm_free(elmpool_t *pool, void *elm) { | |
| 96 *(void **)elm = pool->frees; | |
| 97 pool->frees = elm; | |
| 98 } | |
| 99 | |
| 100 void elmpool_free(elmpool_t *pool) { | |
| 101 void *blk, *next_blk; | |
| 102 | |
| 103 blk = pool->blks; | |
| 104 while(blk) { | |
| 105 next_blk = *(void **)blk; | |
| 106 free(blk); | |
| 107 blk = next_blk; | |
| 108 } | |
| 109 } | |
| 110 | |
| 111 #ifdef UNITTEST | |
| 112 | |
| 113 #include <CUnit/Basic.h> | |
| 114 | |
| 115 void test_elmpool(void) { | |
| 116 elmpool_t *pool; | |
| 117 void *elm; | |
| 118 int i; | |
| 119 | |
| 120 pool = elmpool_new(64, 16); | |
| 121 for(i = 0; i < 15; i++) { | |
| 122 elm = elmpool_elm_alloc(pool); | |
| 123 CU_ASSERT(elm != NULL); | |
| 124 } | |
| 125 CU_ASSERT(pool->frees == NULL); | |
| 126 | |
| 127 for(i = 0; i < 15; i++) { | |
| 128 elm = elmpool_elm_alloc(pool); | |
| 129 CU_ASSERT(elm != NULL); | |
| 130 } | |
| 131 CU_ASSERT(pool->frees == NULL); | |
| 132 | |
| 133 elmpool_elm_free(pool, elm); | |
| 134 CU_ASSERT(pool->frees == elm); | |
| 135 | |
| 136 elm = elmpool_elm_alloc(pool); | |
| 137 CU_ASSERT(elm != NULL); | |
| 138 CU_ASSERT(pool->frees == NULL); | |
| 139 | |
| 140 elmpool_free(pool); | |
| 141 } | |
| 142 | |
| 143 CU_pSuite get_tools_suite(void) { | |
| 144 CU_pSuite suite; | |
| 145 | |
| 146 suite = CU_add_suite("Suite_tools", NULL, NULL); | |
| 147 CU_ADD_TEST(suite, test_elmpool); | |
| 148 | |
| 149 return suite; | |
| 150 } | |
| 151 | |
| 152 #endif /* UNITTEST */ |