[270] | 1 | /*
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| 2 | ** pool.c - memory pool
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| 3 | **
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| 4 | ** See Copyright Notice in mruby.h
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| 5 | */
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| 6 |
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| 7 | #include <string.h>
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[331] | 8 | #include <mruby.h>
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[270] | 9 |
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| 10 | /* configuration section */
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| 11 | /* allocated memory address should be multiple of POOL_ALIGNMENT */
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| 12 | /* or undef it if alignment does not matter */
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| 13 | #ifndef POOL_ALIGNMENT
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[331] | 14 | #if INTPTR_MAX == INT64_MAX
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| 15 | #define POOL_ALIGNMENT 8
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| 16 | #else
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[270] | 17 | #define POOL_ALIGNMENT 4
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| 18 | #endif
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[331] | 19 | #endif
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[270] | 20 | /* page size of memory pool */
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| 21 | #ifndef POOL_PAGE_SIZE
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| 22 | #define POOL_PAGE_SIZE 16000
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| 23 | #endif
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| 24 | /* end of configuration section */
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| 25 |
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[439] | 26 | /* Disable MSVC warning "C4200: nonstandard extension used: zero-sized array
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| 27 | * in struct/union" when in C++ mode */
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| 28 | #ifdef _MSC_VER
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| 29 | #pragma warning(push)
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| 30 | #pragma warning(disable : 4200)
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| 31 | #endif
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| 32 |
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[270] | 33 | struct mrb_pool_page {
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| 34 | struct mrb_pool_page *next;
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| 35 | size_t offset;
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| 36 | size_t len;
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| 37 | void *last;
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| 38 | char page[];
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| 39 | };
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| 40 |
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[439] | 41 | #ifdef _MSC_VER
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| 42 | #pragma warning(pop)
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| 43 | #endif
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| 44 |
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[270] | 45 | struct mrb_pool {
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| 46 | mrb_state *mrb;
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| 47 | struct mrb_pool_page *pages;
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| 48 | };
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| 49 |
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| 50 | #undef TEST_POOL
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| 51 | #ifdef TEST_POOL
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| 52 |
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| 53 | #define mrb_malloc_simple(m,s) malloc(s)
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| 54 | #define mrb_free(m,p) free(p)
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| 55 | #endif
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| 56 |
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| 57 | #ifdef POOL_ALIGNMENT
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| 58 | # define ALIGN_PADDING(x) ((SIZE_MAX - (x) + 1) & (POOL_ALIGNMENT - 1))
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| 59 | #else
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| 60 | # define ALIGN_PADDING(x) (0)
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| 61 | #endif
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| 62 |
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| 63 | MRB_API mrb_pool*
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| 64 | mrb_pool_open(mrb_state *mrb)
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| 65 | {
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| 66 | mrb_pool *pool = (mrb_pool *)mrb_malloc_simple(mrb, sizeof(mrb_pool));
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| 67 |
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| 68 | if (pool) {
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| 69 | pool->mrb = mrb;
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| 70 | pool->pages = NULL;
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| 71 | }
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| 72 |
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| 73 | return pool;
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| 74 | }
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| 75 |
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| 76 | MRB_API void
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| 77 | mrb_pool_close(mrb_pool *pool)
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| 78 | {
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| 79 | struct mrb_pool_page *page, *tmp;
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| 80 |
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| 81 | if (!pool) return;
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| 82 | page = pool->pages;
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| 83 | while (page) {
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| 84 | tmp = page;
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| 85 | page = page->next;
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| 86 | mrb_free(pool->mrb, tmp);
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| 87 | }
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| 88 | mrb_free(pool->mrb, pool);
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| 89 | }
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| 90 |
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| 91 | static struct mrb_pool_page*
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| 92 | page_alloc(mrb_pool *pool, size_t len)
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| 93 | {
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| 94 | struct mrb_pool_page *page;
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| 95 |
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| 96 | if (len < POOL_PAGE_SIZE)
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| 97 | len = POOL_PAGE_SIZE;
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| 98 | page = (struct mrb_pool_page *)mrb_malloc_simple(pool->mrb, sizeof(struct mrb_pool_page)+len);
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| 99 | if (page) {
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| 100 | page->offset = 0;
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| 101 | page->len = len;
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| 102 | }
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| 103 |
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| 104 | return page;
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| 105 | }
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| 106 |
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| 107 | MRB_API void*
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| 108 | mrb_pool_alloc(mrb_pool *pool, size_t len)
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| 109 | {
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| 110 | struct mrb_pool_page *page;
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| 111 | size_t n;
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| 112 |
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| 113 | if (!pool) return NULL;
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| 114 | len += ALIGN_PADDING(len);
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| 115 | page = pool->pages;
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| 116 | while (page) {
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| 117 | if (page->offset + len <= page->len) {
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| 118 | n = page->offset;
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| 119 | page->offset += len;
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| 120 | page->last = (char*)page->page+n;
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| 121 | return page->last;
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| 122 | }
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| 123 | page = page->next;
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| 124 | }
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| 125 | page = page_alloc(pool, len);
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| 126 | if (!page) return NULL;
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| 127 | page->offset = len;
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| 128 | page->next = pool->pages;
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| 129 | pool->pages = page;
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| 130 |
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| 131 | page->last = (void*)page->page;
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| 132 | return page->last;
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| 133 | }
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| 134 |
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| 135 | MRB_API mrb_bool
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| 136 | mrb_pool_can_realloc(mrb_pool *pool, void *p, size_t len)
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| 137 | {
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| 138 | struct mrb_pool_page *page;
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| 139 |
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| 140 | if (!pool) return FALSE;
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| 141 | len += ALIGN_PADDING(len);
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| 142 | page = pool->pages;
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| 143 | while (page) {
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| 144 | if (page->last == p) {
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| 145 | size_t beg;
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| 146 |
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| 147 | beg = (char*)p - page->page;
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| 148 | if (beg + len > page->len) return FALSE;
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| 149 | return TRUE;
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| 150 | }
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| 151 | page = page->next;
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| 152 | }
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| 153 | return FALSE;
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| 154 | }
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| 155 |
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| 156 | MRB_API void*
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| 157 | mrb_pool_realloc(mrb_pool *pool, void *p, size_t oldlen, size_t newlen)
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| 158 | {
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| 159 | struct mrb_pool_page *page;
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| 160 | void *np;
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| 161 |
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| 162 | if (!pool) return NULL;
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| 163 | oldlen += ALIGN_PADDING(oldlen);
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| 164 | newlen += ALIGN_PADDING(newlen);
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| 165 | page = pool->pages;
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| 166 | while (page) {
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| 167 | if (page->last == p) {
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| 168 | size_t beg;
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| 169 |
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| 170 | beg = (char*)p - page->page;
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| 171 | if (beg + oldlen != page->offset) break;
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| 172 | if (beg + newlen > page->len) {
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| 173 | page->offset = beg;
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| 174 | break;
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| 175 | }
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| 176 | page->offset = beg + newlen;
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| 177 | return p;
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| 178 | }
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| 179 | page = page->next;
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| 180 | }
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| 181 | np = mrb_pool_alloc(pool, newlen);
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| 182 | if (np == NULL) {
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| 183 | return NULL;
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| 184 | }
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| 185 | memcpy(np, p, oldlen);
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| 186 | return np;
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| 187 | }
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| 188 |
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| 189 | #ifdef TEST_POOL
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| 190 | int
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| 191 | main(void)
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| 192 | {
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| 193 | int i, len = 250;
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| 194 | mrb_pool *pool;
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| 195 | void *p;
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| 196 |
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| 197 | pool = mrb_pool_open(NULL);
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| 198 | p = mrb_pool_alloc(pool, len);
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| 199 | for (i=1; i<20; i++) {
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| 200 | printf("%p (len=%d) %ud\n", p, len, mrb_pool_can_realloc(pool, p, len*2));
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| 201 | p = mrb_pool_realloc(pool, p, len, len*2);
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| 202 | len *= 2;
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| 203 | }
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| 204 | mrb_pool_close(pool);
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| 205 | return 0;
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| 206 | }
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| 207 | #endif
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