mem: Fix usage of memalign() on DJGPP.

[ffmpeg] / libavutil / buffer.h

diff --git a/libavutil/buffer.h b/libavutil/buffer.h
index 843dfbe24a6dd848614395038680c69816e498ff..e33775aee3b04924c2001453050ede161d10d34f 100644 (file)
--- a/libavutil/buffer.h
+++ b/libavutil/buffer.h
@@ -1,18 +1,18 @@
 /*
- * This file is part of Libav.
+ * This file is part of FFmpeg.
  *
- * Libav is free software; you can redistribute it and/or
+ * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
- * Libav is distributed in the hope that it will be useful,
+ * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
- * License along with Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
@@ -49,7 +49,7 @@
  * Use av_buffer_unref() to free a reference (this will automatically free the
  * data once all the references are freed).
  *
- * The convention throughout this API and the rest of Libav is such that the
+ * The convention throughout this API and the rest of FFmpeg is such that the
  * buffer is considered writable if there exists only one reference to it (and
  * it has not been marked as read-only). The av_buffer_is_writable() function is
  * provided to check whether this is true and av_buffer_make_writable() will
@@ -190,6 +190,76 @@ int av_buffer_make_writable(AVBufferRef **buf);
  */
 int av_buffer_realloc(AVBufferRef **buf, int size);
 
+/**
+ * @}
+ */
+
+/**
+ * @defgroup lavu_bufferpool AVBufferPool
+ * @ingroup lavu_data
+ *
+ * @{
+ * AVBufferPool is an API for a lock-free thread-safe pool of AVBuffers.
+ *
+ * Frequently allocating and freeing large buffers may be slow. AVBufferPool is
+ * meant to solve this in cases when the caller needs a set of buffers of the
+ * same size (the most obvious use case being buffers for raw video or audio
+ * frames).
+ *
+ * At the beginning, the user must call av_buffer_pool_init() to create the
+ * buffer pool. Then whenever a buffer is needed, call av_buffer_pool_get() to
+ * get a reference to a new buffer, similar to av_buffer_alloc(). This new
+ * reference works in all aspects the same way as the one created by
+ * av_buffer_alloc(). However, when the last reference to this buffer is
+ * unreferenced, it is returned to the pool instead of being freed and will be
+ * reused for subsequent av_buffer_pool_get() calls.
+ *
+ * When the caller is done with the pool and no longer needs to allocate any new
+ * buffers, av_buffer_pool_uninit() must be called to mark the pool as freeable.
+ * Once all the buffers are released, it will automatically be freed.
+ *
+ * Allocating and releasing buffers with this API is thread-safe as long as
+ * either the default alloc callback is used, or the user-supplied one is
+ * thread-safe.
+ */
+
+/**
+ * The buffer pool. This structure is opaque and not meant to be accessed
+ * directly. It is allocated with av_buffer_pool_init() and freed with
+ * av_buffer_pool_uninit().
+ */
+typedef struct AVBufferPool AVBufferPool;
+
+/**
+ * Allocate and initialize a buffer pool.
+ *
+ * @param size size of each buffer in this pool
+ * @param alloc a function that will be used to allocate new buffers when the
+ * pool is empty. May be NULL, then the default allocator will be used
+ * (av_buffer_alloc()).
+ * @return newly created buffer pool on success, NULL on error.
+ */
+AVBufferPool *av_buffer_pool_init(int size, AVBufferRef* (*alloc)(int size));
+
+/**
+ * Mark the pool as being available for freeing. It will actually be freed only
+ * once all the allocated buffers associated with the pool are released. Thus it
+ * is safe to call this function while some of the allocated buffers are still
+ * in use.
+ *
+ * @param pool pointer to the pool to be freed. It will be set to NULL.
+ * @see av_buffer_pool_can_uninit()
+ */
+void av_buffer_pool_uninit(AVBufferPool **pool);
+
+/**
+ * Allocate a new AVBuffer, reusing an old buffer from the pool when available.
+ * This function may be called simultaneously from multiple threads.
+ *
+ * @return a reference to the new buffer on success, NULL on error.
+ */
+AVBufferRef *av_buffer_pool_get(AVBufferPool *pool);
+
 /**
  * @}
  */