buffer: add support for pools using caller data in allocation
[libav.git] / libavutil / buffer.c
1 /*
2 * This file is part of Libav.
3 *
4 * Libav 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 * Libav 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 Libav; 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 #include "thread.h"
27
28 AVBufferRef *av_buffer_create(uint8_t *data, int size,
29 void (*free)(void *opaque, uint8_t *data),
30 void *opaque, int flags)
31 {
32 AVBufferRef *ref = NULL;
33 AVBuffer *buf = NULL;
34
35 buf = av_mallocz(sizeof(*buf));
36 if (!buf)
37 return NULL;
38
39 buf->data = data;
40 buf->size = size;
41 buf->free = free ? free : av_buffer_default_free;
42 buf->opaque = opaque;
43 buf->refcount = 1;
44
45 if (flags & AV_BUFFER_FLAG_READONLY)
46 buf->flags |= BUFFER_FLAG_READONLY;
47
48 ref = av_mallocz(sizeof(*ref));
49 if (!ref) {
50 av_freep(&buf);
51 return NULL;
52 }
53
54 ref->buffer = buf;
55 ref->data = data;
56 ref->size = size;
57
58 return ref;
59 }
60
61 void av_buffer_default_free(void *opaque, uint8_t *data)
62 {
63 av_free(data);
64 }
65
66 AVBufferRef *av_buffer_alloc(int size)
67 {
68 AVBufferRef *ret = NULL;
69 uint8_t *data = NULL;
70
71 data = av_malloc(size);
72 if (!data)
73 return NULL;
74
75 ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
76 if (!ret)
77 av_freep(&data);
78
79 return ret;
80 }
81
82 AVBufferRef *av_buffer_allocz(int size)
83 {
84 AVBufferRef *ret = av_buffer_alloc(size);
85 if (!ret)
86 return NULL;
87
88 memset(ret->data, 0, size);
89 return ret;
90 }
91
92 AVBufferRef *av_buffer_ref(AVBufferRef *buf)
93 {
94 AVBufferRef *ret = av_mallocz(sizeof(*ret));
95
96 if (!ret)
97 return NULL;
98
99 *ret = *buf;
100
101 avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 1);
102
103 return ret;
104 }
105
106 void av_buffer_unref(AVBufferRef **buf)
107 {
108 AVBuffer *b;
109
110 if (!buf || !*buf)
111 return;
112 b = (*buf)->buffer;
113 av_freep(buf);
114
115 if (!avpriv_atomic_int_add_and_fetch(&b->refcount, -1)) {
116 b->free(b->opaque, b->data);
117 av_freep(&b);
118 }
119 }
120
121 int av_buffer_is_writable(const AVBufferRef *buf)
122 {
123 if (buf->buffer->flags & AV_BUFFER_FLAG_READONLY)
124 return 0;
125
126 return avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 0) == 1;
127 }
128
129 int av_buffer_make_writable(AVBufferRef **pbuf)
130 {
131 AVBufferRef *newbuf, *buf = *pbuf;
132
133 if (av_buffer_is_writable(buf))
134 return 0;
135
136 newbuf = av_buffer_alloc(buf->size);
137 if (!newbuf)
138 return AVERROR(ENOMEM);
139
140 memcpy(newbuf->data, buf->data, buf->size);
141 av_buffer_unref(pbuf);
142 *pbuf = newbuf;
143
144 return 0;
145 }
146
147 int av_buffer_realloc(AVBufferRef **pbuf, int size)
148 {
149 AVBufferRef *buf = *pbuf;
150 uint8_t *tmp;
151
152 if (!buf) {
153 /* allocate a new buffer with av_realloc(), so it will be reallocatable
154 * later */
155 uint8_t *data = av_realloc(NULL, size);
156 if (!data)
157 return AVERROR(ENOMEM);
158
159 buf = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
160 if (!buf) {
161 av_freep(&data);
162 return AVERROR(ENOMEM);
163 }
164
165 buf->buffer->flags |= BUFFER_FLAG_REALLOCATABLE;
166 *pbuf = buf;
167
168 return 0;
169 } else if (buf->size == size)
170 return 0;
171
172 if (!(buf->buffer->flags & BUFFER_FLAG_REALLOCATABLE) ||
173 !av_buffer_is_writable(buf)) {
174 /* cannot realloc, allocate a new reallocable buffer and copy data */
175 AVBufferRef *new = NULL;
176
177 av_buffer_realloc(&new, size);
178 if (!new)
179 return AVERROR(ENOMEM);
180
181 memcpy(new->data, buf->data, FFMIN(size, buf->size));
182
183 av_buffer_unref(pbuf);
184 *pbuf = new;
185 return 0;
186 }
187
188 tmp = av_realloc(buf->buffer->data, size);
189 if (!tmp)
190 return AVERROR(ENOMEM);
191
192 buf->buffer->data = buf->data = tmp;
193 buf->buffer->size = buf->size = size;
194 return 0;
195 }
196
197 AVBufferPool *av_buffer_pool_init2(int size, void *opaque,
198 AVBufferRef* (*alloc)(void *opaque, int size),
199 void (*pool_free)(void *opaque))
200 {
201 AVBufferPool *pool = av_mallocz(sizeof(*pool));
202 if (!pool)
203 return NULL;
204
205 ff_mutex_init(&pool->mutex, NULL);
206
207 pool->size = size;
208 pool->opaque = opaque;
209 pool->alloc2 = alloc;
210 pool->pool_free = pool_free;
211
212 avpriv_atomic_int_set(&pool->refcount, 1);
213
214 return pool;
215 }
216
217 AVBufferPool *av_buffer_pool_init(int size, AVBufferRef* (*alloc)(int size))
218 {
219 AVBufferPool *pool = av_mallocz(sizeof(*pool));
220 if (!pool)
221 return NULL;
222
223 ff_mutex_init(&pool->mutex, NULL);
224
225 pool->size = size;
226 pool->alloc = alloc ? alloc : av_buffer_alloc;
227
228 avpriv_atomic_int_set(&pool->refcount, 1);
229
230 return pool;
231 }
232
233 /*
234 * This function gets called when the pool has been uninited and
235 * all the buffers returned to it.
236 */
237 static void buffer_pool_free(AVBufferPool *pool)
238 {
239 while (pool->pool) {
240 BufferPoolEntry *buf = pool->pool;
241 pool->pool = buf->next;
242
243 buf->free(buf->opaque, buf->data);
244 av_freep(&buf);
245 }
246 ff_mutex_destroy(&pool->mutex);
247
248 if (pool->pool_free)
249 pool->pool_free(pool->opaque);
250
251 av_freep(&pool);
252 }
253
254 void av_buffer_pool_uninit(AVBufferPool **ppool)
255 {
256 AVBufferPool *pool;
257
258 if (!ppool || !*ppool)
259 return;
260 pool = *ppool;
261 *ppool = NULL;
262
263 if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
264 buffer_pool_free(pool);
265 }
266
267 static void pool_release_buffer(void *opaque, uint8_t *data)
268 {
269 BufferPoolEntry *buf = opaque;
270 AVBufferPool *pool = buf->pool;
271
272 ff_mutex_lock(&pool->mutex);
273 buf->next = pool->pool;
274 pool->pool = buf;
275 ff_mutex_unlock(&pool->mutex);
276
277 if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
278 buffer_pool_free(pool);
279 }
280
281 /* allocate a new buffer and override its free() callback so that
282 * it is returned to the pool on free */
283 static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool)
284 {
285 BufferPoolEntry *buf;
286 AVBufferRef *ret;
287
288 ret = pool->alloc2 ? pool->alloc2(pool->opaque, pool->size) :
289 pool->alloc(pool->size);
290 if (!ret)
291 return NULL;
292
293 buf = av_mallocz(sizeof(*buf));
294 if (!buf) {
295 av_buffer_unref(&ret);
296 return NULL;
297 }
298
299 buf->data = ret->buffer->data;
300 buf->opaque = ret->buffer->opaque;
301 buf->free = ret->buffer->free;
302 buf->pool = pool;
303
304 ret->buffer->opaque = buf;
305 ret->buffer->free = pool_release_buffer;
306
307 return ret;
308 }
309
310 AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)
311 {
312 AVBufferRef *ret;
313 BufferPoolEntry *buf;
314
315 ff_mutex_lock(&pool->mutex);
316 buf = pool->pool;
317 if (buf) {
318 ret = av_buffer_create(buf->data, pool->size, pool_release_buffer,
319 buf, 0);
320 if (ret) {
321 pool->pool = buf->next;
322 buf->next = NULL;
323 }
324 } else {
325 ret = pool_alloc_buffer(pool);
326 }
327 ff_mutex_unlock(&pool->mutex);
328
329 if (ret)
330 avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);
331
332 return ret;
333 }