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2ba45a60 DM |
1 | /* |
2 | * This file is part of FFmpeg. | |
3 | * | |
4 | * FFmpeg is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU Lesser General Public | |
6 | * License as published by the Free Software Foundation; either | |
7 | * version 2.1 of the License, or (at your option) any later version. | |
8 | * | |
9 | * FFmpeg is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * Lesser General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public | |
15 | * License along with FFmpeg; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | ||
19 | #include <stdint.h> | |
20 | #include <string.h> | |
21 | ||
22 | #include "atomic.h" | |
23 | #include "buffer_internal.h" | |
24 | #include "common.h" | |
25 | #include "mem.h" | |
26 | ||
27 | AVBufferRef *av_buffer_create(uint8_t *data, int size, | |
28 | void (*free)(void *opaque, uint8_t *data), | |
29 | void *opaque, int flags) | |
30 | { | |
31 | AVBufferRef *ref = NULL; | |
32 | AVBuffer *buf = NULL; | |
33 | ||
34 | buf = av_mallocz(sizeof(*buf)); | |
35 | if (!buf) | |
36 | return NULL; | |
37 | ||
38 | buf->data = data; | |
39 | buf->size = size; | |
40 | buf->free = free ? free : av_buffer_default_free; | |
41 | buf->opaque = opaque; | |
42 | buf->refcount = 1; | |
43 | ||
44 | if (flags & AV_BUFFER_FLAG_READONLY) | |
45 | buf->flags |= BUFFER_FLAG_READONLY; | |
46 | ||
47 | ref = av_mallocz(sizeof(*ref)); | |
48 | if (!ref) { | |
49 | av_freep(&buf); | |
50 | return NULL; | |
51 | } | |
52 | ||
53 | ref->buffer = buf; | |
54 | ref->data = data; | |
55 | ref->size = size; | |
56 | ||
57 | return ref; | |
58 | } | |
59 | ||
60 | void av_buffer_default_free(void *opaque, uint8_t *data) | |
61 | { | |
62 | av_free(data); | |
63 | } | |
64 | ||
65 | AVBufferRef *av_buffer_alloc(int size) | |
66 | { | |
67 | AVBufferRef *ret = NULL; | |
68 | uint8_t *data = NULL; | |
69 | ||
70 | data = av_malloc(size); | |
71 | if (!data) | |
72 | return NULL; | |
73 | ||
74 | ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0); | |
75 | if (!ret) | |
76 | av_freep(&data); | |
77 | ||
78 | return ret; | |
79 | } | |
80 | ||
81 | AVBufferRef *av_buffer_allocz(int size) | |
82 | { | |
83 | AVBufferRef *ret = av_buffer_alloc(size); | |
84 | if (!ret) | |
85 | return NULL; | |
86 | ||
87 | memset(ret->data, 0, size); | |
88 | return ret; | |
89 | } | |
90 | ||
91 | AVBufferRef *av_buffer_ref(AVBufferRef *buf) | |
92 | { | |
93 | AVBufferRef *ret = av_mallocz(sizeof(*ret)); | |
94 | ||
95 | if (!ret) | |
96 | return NULL; | |
97 | ||
98 | *ret = *buf; | |
99 | ||
100 | avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 1); | |
101 | ||
102 | return ret; | |
103 | } | |
104 | ||
105 | void av_buffer_unref(AVBufferRef **buf) | |
106 | { | |
107 | AVBuffer *b; | |
108 | ||
109 | if (!buf || !*buf) | |
110 | return; | |
111 | b = (*buf)->buffer; | |
112 | av_freep(buf); | |
113 | ||
114 | if (!avpriv_atomic_int_add_and_fetch(&b->refcount, -1)) { | |
115 | b->free(b->opaque, b->data); | |
116 | av_freep(&b); | |
117 | } | |
118 | } | |
119 | ||
120 | int av_buffer_is_writable(const AVBufferRef *buf) | |
121 | { | |
122 | if (buf->buffer->flags & AV_BUFFER_FLAG_READONLY) | |
123 | return 0; | |
124 | ||
125 | return avpriv_atomic_int_get(&buf->buffer->refcount) == 1; | |
126 | } | |
127 | ||
128 | void *av_buffer_get_opaque(const AVBufferRef *buf) | |
129 | { | |
130 | return buf->buffer->opaque; | |
131 | } | |
132 | ||
133 | int av_buffer_get_ref_count(const AVBufferRef *buf) | |
134 | { | |
135 | return buf->buffer->refcount; | |
136 | } | |
137 | ||
138 | int av_buffer_make_writable(AVBufferRef **pbuf) | |
139 | { | |
140 | AVBufferRef *newbuf, *buf = *pbuf; | |
141 | ||
142 | if (av_buffer_is_writable(buf)) | |
143 | return 0; | |
144 | ||
145 | newbuf = av_buffer_alloc(buf->size); | |
146 | if (!newbuf) | |
147 | return AVERROR(ENOMEM); | |
148 | ||
149 | memcpy(newbuf->data, buf->data, buf->size); | |
150 | av_buffer_unref(pbuf); | |
151 | *pbuf = newbuf; | |
152 | ||
153 | return 0; | |
154 | } | |
155 | ||
156 | int av_buffer_realloc(AVBufferRef **pbuf, int size) | |
157 | { | |
158 | AVBufferRef *buf = *pbuf; | |
159 | uint8_t *tmp; | |
160 | ||
161 | if (!buf) { | |
162 | /* allocate a new buffer with av_realloc(), so it will be reallocatable | |
163 | * later */ | |
164 | uint8_t *data = av_realloc(NULL, size); | |
165 | if (!data) | |
166 | return AVERROR(ENOMEM); | |
167 | ||
168 | buf = av_buffer_create(data, size, av_buffer_default_free, NULL, 0); | |
169 | if (!buf) { | |
170 | av_freep(&data); | |
171 | return AVERROR(ENOMEM); | |
172 | } | |
173 | ||
174 | buf->buffer->flags |= BUFFER_FLAG_REALLOCATABLE; | |
175 | *pbuf = buf; | |
176 | ||
177 | return 0; | |
178 | } else if (buf->size == size) | |
179 | return 0; | |
180 | ||
181 | if (!(buf->buffer->flags & BUFFER_FLAG_REALLOCATABLE) || | |
182 | !av_buffer_is_writable(buf)) { | |
183 | /* cannot realloc, allocate a new reallocable buffer and copy data */ | |
184 | AVBufferRef *new = NULL; | |
185 | ||
186 | av_buffer_realloc(&new, size); | |
187 | if (!new) | |
188 | return AVERROR(ENOMEM); | |
189 | ||
190 | memcpy(new->data, buf->data, FFMIN(size, buf->size)); | |
191 | ||
192 | av_buffer_unref(pbuf); | |
193 | *pbuf = new; | |
194 | return 0; | |
195 | } | |
196 | ||
197 | tmp = av_realloc(buf->buffer->data, size); | |
198 | if (!tmp) | |
199 | return AVERROR(ENOMEM); | |
200 | ||
201 | buf->buffer->data = buf->data = tmp; | |
202 | buf->buffer->size = buf->size = size; | |
203 | return 0; | |
204 | } | |
205 | ||
206 | AVBufferPool *av_buffer_pool_init(int size, AVBufferRef* (*alloc)(int size)) | |
207 | { | |
208 | AVBufferPool *pool = av_mallocz(sizeof(*pool)); | |
209 | if (!pool) | |
210 | return NULL; | |
211 | ||
212 | pool->size = size; | |
213 | pool->alloc = alloc ? alloc : av_buffer_alloc; | |
214 | ||
215 | avpriv_atomic_int_set(&pool->refcount, 1); | |
216 | ||
217 | return pool; | |
218 | } | |
219 | ||
220 | /* | |
221 | * This function gets called when the pool has been uninited and | |
222 | * all the buffers returned to it. | |
223 | */ | |
224 | static void buffer_pool_free(AVBufferPool *pool) | |
225 | { | |
226 | while (pool->pool) { | |
227 | BufferPoolEntry *buf = pool->pool; | |
228 | pool->pool = buf->next; | |
229 | ||
230 | buf->free(buf->opaque, buf->data); | |
231 | av_freep(&buf); | |
232 | } | |
233 | av_freep(&pool); | |
234 | } | |
235 | ||
236 | void av_buffer_pool_uninit(AVBufferPool **ppool) | |
237 | { | |
238 | AVBufferPool *pool; | |
239 | ||
240 | if (!ppool || !*ppool) | |
241 | return; | |
242 | pool = *ppool; | |
243 | *ppool = NULL; | |
244 | ||
245 | if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1)) | |
246 | buffer_pool_free(pool); | |
247 | } | |
248 | ||
249 | /* remove the whole buffer list from the pool and return it */ | |
250 | static BufferPoolEntry *get_pool(AVBufferPool *pool) | |
251 | { | |
252 | BufferPoolEntry *cur = *(void * volatile *)&pool->pool, *last = NULL; | |
253 | ||
254 | while (cur != last) { | |
255 | last = cur; | |
256 | cur = avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, last, NULL); | |
257 | if (!cur) | |
258 | return NULL; | |
259 | } | |
260 | ||
261 | return cur; | |
262 | } | |
263 | ||
264 | static void add_to_pool(BufferPoolEntry *buf) | |
265 | { | |
266 | AVBufferPool *pool; | |
267 | BufferPoolEntry *cur, *end = buf; | |
268 | ||
269 | if (!buf) | |
270 | return; | |
271 | pool = buf->pool; | |
272 | ||
273 | while (end->next) | |
274 | end = end->next; | |
275 | ||
276 | while (avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, NULL, buf)) { | |
277 | /* pool is not empty, retrieve it and append it to our list */ | |
278 | cur = get_pool(pool); | |
279 | end->next = cur; | |
280 | while (end->next) | |
281 | end = end->next; | |
282 | } | |
283 | } | |
284 | ||
285 | static void pool_release_buffer(void *opaque, uint8_t *data) | |
286 | { | |
287 | BufferPoolEntry *buf = opaque; | |
288 | AVBufferPool *pool = buf->pool; | |
289 | ||
290 | if(CONFIG_MEMORY_POISONING) | |
291 | memset(buf->data, FF_MEMORY_POISON, pool->size); | |
292 | ||
293 | add_to_pool(buf); | |
294 | if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1)) | |
295 | buffer_pool_free(pool); | |
296 | } | |
297 | ||
298 | /* allocate a new buffer and override its free() callback so that | |
299 | * it is returned to the pool on free */ | |
300 | static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool) | |
301 | { | |
302 | BufferPoolEntry *buf; | |
303 | AVBufferRef *ret; | |
304 | ||
305 | ret = pool->alloc(pool->size); | |
306 | if (!ret) | |
307 | return NULL; | |
308 | ||
309 | buf = av_mallocz(sizeof(*buf)); | |
310 | if (!buf) { | |
311 | av_buffer_unref(&ret); | |
312 | return NULL; | |
313 | } | |
314 | ||
315 | buf->data = ret->buffer->data; | |
316 | buf->opaque = ret->buffer->opaque; | |
317 | buf->free = ret->buffer->free; | |
318 | buf->pool = pool; | |
319 | ||
320 | ret->buffer->opaque = buf; | |
321 | ret->buffer->free = pool_release_buffer; | |
322 | ||
323 | avpriv_atomic_int_add_and_fetch(&pool->refcount, 1); | |
324 | avpriv_atomic_int_add_and_fetch(&pool->nb_allocated, 1); | |
325 | ||
326 | return ret; | |
327 | } | |
328 | ||
329 | AVBufferRef *av_buffer_pool_get(AVBufferPool *pool) | |
330 | { | |
331 | AVBufferRef *ret; | |
332 | BufferPoolEntry *buf; | |
333 | ||
334 | /* check whether the pool is empty */ | |
335 | buf = get_pool(pool); | |
336 | if (!buf && pool->refcount <= pool->nb_allocated) { | |
337 | av_log(NULL, AV_LOG_DEBUG, "Pool race dectected, spining to avoid overallocation and eventual OOM\n"); | |
338 | while (!buf && avpriv_atomic_int_get(&pool->refcount) <= avpriv_atomic_int_get(&pool->nb_allocated)) | |
339 | buf = get_pool(pool); | |
340 | } | |
341 | ||
342 | if (!buf) | |
343 | return pool_alloc_buffer(pool); | |
344 | ||
345 | /* keep the first entry, return the rest of the list to the pool */ | |
346 | add_to_pool(buf->next); | |
347 | buf->next = NULL; | |
348 | ||
349 | ret = av_buffer_create(buf->data, pool->size, pool_release_buffer, | |
350 | buf, 0); | |
351 | if (!ret) { | |
352 | add_to_pool(buf); | |
353 | return NULL; | |
354 | } | |
355 | avpriv_atomic_int_add_and_fetch(&pool->refcount, 1); | |
356 | ||
357 | return ret; | |
358 | } |