2 * This file is part of Libav.
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.
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.
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
23 #include "buffer_internal.h"
27 AVBufferRef *av_buffer_create(uint8_t *data, int size,
28 void (*free)(void *opaque, uint8_t *data),
29 void *opaque, int flags)
31 AVBufferRef *ref = NULL;
34 buf = av_mallocz(sizeof(*buf));
40 buf->free = free ? free : av_buffer_default_free;
44 if (flags & AV_BUFFER_FLAG_READONLY)
45 buf->flags |= BUFFER_FLAG_READONLY;
47 ref = av_mallocz(sizeof(*ref));
60 void av_buffer_default_free(void *opaque, uint8_t *data)
65 AVBufferRef *av_buffer_alloc(int size)
67 AVBufferRef *ret = NULL;
70 data = av_malloc(size);
74 ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
81 AVBufferRef *av_buffer_allocz(int size)
83 AVBufferRef *ret = av_buffer_alloc(size);
87 memset(ret->data, 0, size);
91 AVBufferRef *av_buffer_ref(AVBufferRef *buf)
93 AVBufferRef *ret = av_mallocz(sizeof(*ret));
100 avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 1);
105 void av_buffer_unref(AVBufferRef **buf)
114 if (!avpriv_atomic_int_add_and_fetch(&b->refcount, -1)) {
115 b->free(b->opaque, b->data);
120 int av_buffer_is_writable(const AVBufferRef *buf)
122 if (buf->buffer->flags & AV_BUFFER_FLAG_READONLY)
125 return avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 0) == 1;
128 int av_buffer_make_writable(AVBufferRef **pbuf)
130 AVBufferRef *newbuf, *buf = *pbuf;
132 if (av_buffer_is_writable(buf))
135 newbuf = av_buffer_alloc(buf->size);
137 return AVERROR(ENOMEM);
139 memcpy(newbuf->data, buf->data, buf->size);
140 av_buffer_unref(pbuf);
146 int av_buffer_realloc(AVBufferRef **pbuf, int size)
148 AVBufferRef *buf = *pbuf;
152 /* allocate a new buffer with av_realloc(), so it will be reallocatable
154 uint8_t *data = av_realloc(NULL, size);
156 return AVERROR(ENOMEM);
158 buf = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);
161 return AVERROR(ENOMEM);
164 buf->buffer->flags |= BUFFER_FLAG_REALLOCATABLE;
168 } else if (buf->size == size)
171 if (!(buf->buffer->flags & BUFFER_FLAG_REALLOCATABLE) ||
172 !av_buffer_is_writable(buf)) {
173 /* cannot realloc, allocate a new reallocable buffer and copy data */
174 AVBufferRef *new = NULL;
176 av_buffer_realloc(&new, size);
178 return AVERROR(ENOMEM);
180 memcpy(new->data, buf->data, FFMIN(size, buf->size));
182 av_buffer_unref(pbuf);
187 tmp = av_realloc(buf->buffer->data, size);
189 return AVERROR(ENOMEM);
191 buf->buffer->data = buf->data = tmp;
192 buf->buffer->size = buf->size = size;
196 AVBufferPool *av_buffer_pool_init(int size, AVBufferRef* (*alloc)(int size))
198 AVBufferPool *pool = av_mallocz(sizeof(*pool));
203 pool->alloc = alloc ? alloc : av_buffer_alloc;
205 avpriv_atomic_int_set(&pool->refcount, 1);
211 * This function gets called when the pool has been uninited and
212 * all the buffers returned to it.
214 static void buffer_pool_free(AVBufferPool *pool)
217 BufferPoolEntry *buf = pool->pool;
218 pool->pool = buf->next;
220 buf->free(buf->opaque, buf->data);
226 void av_buffer_pool_uninit(AVBufferPool **ppool)
230 if (!ppool || !*ppool)
235 if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
236 buffer_pool_free(pool);
239 /* remove the whole buffer list from the pool and return it */
240 static BufferPoolEntry *get_pool(AVBufferPool *pool)
242 BufferPoolEntry *cur = NULL, *last = NULL;
245 FFSWAP(BufferPoolEntry*, cur, last);
246 cur = avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, last, NULL);
249 } while (cur != last);
254 static void add_to_pool(BufferPoolEntry *buf)
257 BufferPoolEntry *cur, *end = buf;
266 while ((cur = avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, NULL, buf))) {
267 /* pool is not empty, retrieve it and append it to our list */
268 cur = get_pool(pool);
275 static void pool_release_buffer(void *opaque, uint8_t *data)
277 BufferPoolEntry *buf = opaque;
278 AVBufferPool *pool = buf->pool;
280 if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))
281 buffer_pool_free(pool);
284 /* allocate a new buffer and override its free() callback so that
285 * it is returned to the pool on free */
286 static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool)
288 BufferPoolEntry *buf;
291 ret = pool->alloc(pool->size);
295 buf = av_mallocz(sizeof(*buf));
297 av_buffer_unref(&ret);
301 buf->data = ret->buffer->data;
302 buf->opaque = ret->buffer->opaque;
303 buf->free = ret->buffer->free;
306 ret->buffer->opaque = buf;
307 ret->buffer->free = pool_release_buffer;
309 avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);
314 AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)
317 BufferPoolEntry *buf;
319 /* check whether the pool is empty */
320 buf = get_pool(pool);
322 return pool_alloc_buffer(pool);
324 /* keep the first entry, return the rest of the list to the pool */
325 add_to_pool(buf->next);
328 ret = av_buffer_create(buf->data, pool->size, pool_release_buffer,
334 avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);