unit ffm.buffer;

{$i ffmpeg.inc}

interface

/// *
// * This file is part of ffm.
// *
// * 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.
// *
// * 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 FFmpeg; if not, write to the Free Software
// * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
// */
//
/// **
// * @file
// * @ingroup lavu_buffer
// * refcounted data buffer API
// */
//
// #ifndef AVUTIL_BUFFER_H
// #define AVUTIL_BUFFER_H
//
// #include <stdint.h>
//
/// **
// * @defgroup lavu_buffer AVBuffer
// * @ingroup lavu_data
// *
// * @{
// * AVBuffer is an API for reference-counted data buffers.
// *
// * There are two core objects in this API -- AVBuffer and AVBufferRef. AVBuffer
// * represents the data buffer itself; it is opaque and not meant to be accessed
// * by the caller directly, but only through AVBufferRef. However, the caller may
// * e.g. compare two AVBuffer pointers to check whether two different references
// * are describing the same data buffer. AVBufferRef represents a single
// * reference to an AVBuffer and it is the object that may be manipulated by the
// * caller directly.
// *
// * There are two functions provided for creating a new AVBuffer with a single
// * reference -- av_buffer_alloc() to just allocate a new buffer, and
// * av_buffer_create() to wrap an existing array in an AVBuffer. From an existing
// * reference, additional references may be created with av_buffer_ref().
// * 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 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
// * automatically create a new writable buffer when necessary.
// * Of course nothing prevents the calling code from violating this convention,
// * however that is safe only when all the existing references are under its
// * control.
// *
// * @note Referencing and unreferencing the buffers is thread-safe and thus
// * may be done from multiple threads simultaneously without any need for
// * additional locking.
// *
// * @note Two different references to the same buffer can point to different
// * parts of the buffer (i.e. their AVBufferRef.data will not be equal).
// */
//
/// **
// * A reference counted buffer type. It is opaque and is meant to be used through
// * references (AVBufferRef).
// */
Type
  pAVBuffer = Pointer;

  (*
    * A reference to a data buffer.
    *
    * The size of this struct is not a part of the public ABI and it is not meant
    * to be allocated directly.
  *)
  pAVBufferRef = ^TAVBufferRef;
  ppAVBufferRef = ^pAVBufferRef;

  TAVBufferRef = {packed} record
    buffer: pAVBuffer;
    (*
      * The data buffer. It is considered writable if and only if
      * this is the only reference to the buffer, in which case
      * av_buffer_is_writable() returns 1.
    *)
    data: pByte;
    (*
      * Size of data in bytes.
    *)
    size: Integer;
  end;

  /// **
  // * Allocate an AVBuffer of the given size using av_malloc().
  // *
  // * @return an AVBufferRef of given size or NULL when out of memory
  // */
  // AVBufferRef *av_buffer_alloc(int size);
  //
  /// **
  // * Same as av_buffer_alloc(), except the returned buffer will be initialized
  // * to zero.
  // */
  // AVBufferRef *av_buffer_allocz(int size);
  //
  /// **
  // * Always treat the buffer as read-only, even when it has only one
  // * reference.
  // */
  // #define AV_BUFFER_FLAG_READONLY (1 << 0)
  //
  /// **
  // * Create an AVBuffer from an existing array.
  // *
  // * If this function is successful, data is owned by the AVBuffer. The caller may
  // * only access data through the returned AVBufferRef and references derived from
  // * it.
  // * If this function fails, data is left untouched.
  // * @param data   data array
  // * @param size   size of data in bytes
  // * @param free   a callback for freeing this buffer's data
  // * @param opaque parameter to be got for processing or passed to free
  // * @param flags  a combination of AV_BUFFER_FLAG_*
  // *
  // * @return an AVBufferRef referring to data on success, NULL on failure.
  // */
  // AVBufferRef *av_buffer_create(uint8_t *data, int size,
  // void (*free)(void *opaque, uint8_t *data),
  // void *opaque, int flags);
  //
  /// **
  // * Default free callback, which calls av_free() on the buffer data.
  // * This function is meant to be passed to av_buffer_create(), not called
  // * directly.
  // */
  // void av_buffer_default_free(void *opaque, uint8_t *data);
  //
  /// **
  // * Create a new reference to an AVBuffer.
  // *
  // * @return a new AVBufferRef referring to the same AVBuffer as buf or NULL on
  // * failure.
  // */
  // AVBufferRef *av_buffer_ref(AVBufferRef *buf);
  //
  /// **
  // * Free a given reference and automatically free the buffer if there are no more
  // * references to it.
  // *
  // * @param buf the reference to be freed. The pointer is set to NULL on return.
  // */
  // void av_buffer_unref(AVBufferRef **buf);
  //
  /// **
  // * @return 1 if the caller may write to the data referred to by buf (which is
  // * true if and only if buf is the only reference to the underlying AVBuffer).
  // * Return 0 otherwise.
  // * A positive answer is valid until av_buffer_ref() is called on buf.
  // */
  // int av_buffer_is_writable(const AVBufferRef *buf);
  //
  /// **
  // * @return the opaque parameter set by av_buffer_create.
  // */
  // void *av_buffer_get_opaque(const AVBufferRef *buf);
  //
  // int av_buffer_get_ref_count(const AVBufferRef *buf);
  //
  /// **
  // * Create a writable reference from a given buffer reference, avoiding data copy
  // * if possible.
  // *
  // * @param buf buffer reference to make writable. On success, buf is either left
  // *            untouched, or it is unreferenced and a new writable AVBufferRef is
  // *            written in its place. On failure, buf is left untouched.
  // * @return 0 on success, a negative AVERROR on failure.
  // */
  // int av_buffer_make_writable(AVBufferRef **buf);
  //
  /// **
  // * Reallocate a given buffer.
  // *
  // * @param buf  a buffer reference to reallocate. On success, buf will be
  // *             unreferenced and a new reference with the required size will be
  // *             written in its place. On failure buf will be left untouched. *buf
  // *             may be NULL, then a new buffer is allocated.
  // * @param size required new buffer size.
  // * @return 0 on success, a negative AVERROR on failure.
  // *
  // * @note the buffer is actually reallocated with av_realloc() only if it was
  // * initially allocated through av_buffer_realloc(NULL) and there is only one
  // * reference to it (i.e. the one passed to this function). In all other cases
  // * a new buffer is allocated and the data is copied.
  // */
  // 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);
  //
  /// **
  // * @}
  // */

implementation

end.