mirror of https://git.videolan.org/git/ffmpeg.git
243 lines
8.3 KiB
C
243 lines
8.3 KiB
C
/*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* 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_fifo
|
|
* A generic FIFO API
|
|
*/
|
|
|
|
#ifndef AVUTIL_FIFO_H
|
|
#define AVUTIL_FIFO_H
|
|
|
|
#include <stddef.h>
|
|
|
|
/**
|
|
* @defgroup lavu_fifo AVFifo
|
|
* @ingroup lavu_data
|
|
*
|
|
* @{
|
|
* A generic FIFO API
|
|
*/
|
|
|
|
typedef struct AVFifo AVFifo;
|
|
|
|
/**
|
|
* Callback for writing or reading from a FIFO, passed to (and invoked from) the
|
|
* av_fifo_*_cb() functions. It may be invoked multiple times from a single
|
|
* av_fifo_*_cb() call and may process less data than the maximum size indicated
|
|
* by nb_elems.
|
|
*
|
|
* @param opaque the opaque pointer provided to the av_fifo_*_cb() function
|
|
* @param buf the buffer for reading or writing the data, depending on which
|
|
* av_fifo_*_cb function is called
|
|
* @param nb_elems On entry contains the maximum number of elements that can be
|
|
* read from / written into buf. On success, the callback should
|
|
* update it to contain the number of elements actually written.
|
|
*
|
|
* @return 0 on success, a negative error code on failure (will be returned from
|
|
* the invoking av_fifo_*_cb() function)
|
|
*/
|
|
typedef int AVFifoCB(void *opaque, void *buf, size_t *nb_elems);
|
|
|
|
/**
|
|
* Automatically resize the FIFO on writes, so that the data fits. This
|
|
* automatic resizing happens up to a limit that can be modified with
|
|
* av_fifo_auto_grow_limit().
|
|
*/
|
|
#define AV_FIFO_FLAG_AUTO_GROW (1 << 0)
|
|
|
|
/**
|
|
* Allocate and initialize an AVFifo with a given element size.
|
|
*
|
|
* @param elems initial number of elements that can be stored in the FIFO
|
|
* @param elem_size Size in bytes of a single element. Further operations on
|
|
* the returned FIFO will implicitly use this element size.
|
|
* @param flags a combination of AV_FIFO_FLAG_*
|
|
*
|
|
* @return newly-allocated AVFifo on success, a negative error code on failure
|
|
*/
|
|
AVFifo *av_fifo_alloc2(size_t elems, size_t elem_size,
|
|
unsigned int flags);
|
|
|
|
/**
|
|
* @return Element size for FIFO operations. This element size is set at
|
|
* FIFO allocation and remains constant during its lifetime
|
|
*/
|
|
size_t av_fifo_elem_size(const AVFifo *f);
|
|
|
|
/**
|
|
* Set the maximum size (in elements) to which the FIFO can be resized
|
|
* automatically. Has no effect unless AV_FIFO_FLAG_AUTO_GROW is used.
|
|
*/
|
|
void av_fifo_auto_grow_limit(AVFifo *f, size_t max_elems);
|
|
|
|
/**
|
|
* @return number of elements available for reading from the given FIFO.
|
|
*/
|
|
size_t av_fifo_can_read(const AVFifo *f);
|
|
|
|
/**
|
|
* @return Number of elements that can be written into the given FIFO without
|
|
* growing it.
|
|
*
|
|
* In other words, this number of elements or less is guaranteed to fit
|
|
* into the FIFO. More data may be written when the
|
|
* AV_FIFO_FLAG_AUTO_GROW flag was specified at FIFO creation, but this
|
|
* may involve memory allocation, which can fail.
|
|
*/
|
|
size_t av_fifo_can_write(const AVFifo *f);
|
|
|
|
/**
|
|
* Enlarge an AVFifo.
|
|
*
|
|
* On success, the FIFO will be large enough to hold exactly
|
|
* inc + av_fifo_can_read() + av_fifo_can_write()
|
|
* elements. In case of failure, the old FIFO is kept unchanged.
|
|
*
|
|
* @param f AVFifo to resize
|
|
* @param inc number of elements to allocate for, in addition to the current
|
|
* allocated size
|
|
* @return a non-negative number on success, a negative error code on failure
|
|
*/
|
|
int av_fifo_grow2(AVFifo *f, size_t inc);
|
|
|
|
/**
|
|
* Write data into a FIFO.
|
|
*
|
|
* In case nb_elems > av_fifo_can_write(f) and the AV_FIFO_FLAG_AUTO_GROW flag
|
|
* was not specified at FIFO creation, nothing is written and an error
|
|
* is returned.
|
|
*
|
|
* Calling function is guaranteed to succeed if nb_elems <= av_fifo_can_write(f).
|
|
*
|
|
* @param f the FIFO buffer
|
|
* @param buf Data to be written. nb_elems * av_fifo_elem_size(f) bytes will be
|
|
* read from buf on success.
|
|
* @param nb_elems number of elements to write into FIFO
|
|
*
|
|
* @return a non-negative number on success, a negative error code on failure
|
|
*/
|
|
int av_fifo_write(AVFifo *f, const void *buf, size_t nb_elems);
|
|
|
|
/**
|
|
* Write data from a user-provided callback into a FIFO.
|
|
*
|
|
* @param f the FIFO buffer
|
|
* @param read_cb Callback supplying the data to the FIFO. May be called
|
|
* multiple times.
|
|
* @param opaque opaque user data to be provided to read_cb
|
|
* @param nb_elems Should point to the maximum number of elements that can be
|
|
* written. Will be updated to contain the number of elements
|
|
* actually written.
|
|
*
|
|
* @return non-negative number on success, a negative error code on failure
|
|
*/
|
|
int av_fifo_write_from_cb(AVFifo *f, AVFifoCB read_cb,
|
|
void *opaque, size_t *nb_elems);
|
|
|
|
/**
|
|
* Read data from a FIFO.
|
|
*
|
|
* In case nb_elems > av_fifo_can_read(f), nothing is read and an error
|
|
* is returned.
|
|
*
|
|
* @param f the FIFO buffer
|
|
* @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes
|
|
* will be written into buf on success.
|
|
* @param nb_elems number of elements to read from FIFO
|
|
*
|
|
* @return a non-negative number on success, a negative error code on failure
|
|
*/
|
|
int av_fifo_read(AVFifo *f, void *buf, size_t nb_elems);
|
|
|
|
/**
|
|
* Feed data from a FIFO into a user-provided callback.
|
|
*
|
|
* @param f the FIFO buffer
|
|
* @param write_cb Callback the data will be supplied to. May be called
|
|
* multiple times.
|
|
* @param opaque opaque user data to be provided to write_cb
|
|
* @param nb_elems Should point to the maximum number of elements that can be
|
|
* read. Will be updated to contain the total number of elements
|
|
* actually sent to the callback.
|
|
*
|
|
* @return non-negative number on success, a negative error code on failure
|
|
*/
|
|
int av_fifo_read_to_cb(AVFifo *f, AVFifoCB write_cb,
|
|
void *opaque, size_t *nb_elems);
|
|
|
|
/**
|
|
* Read data from a FIFO without modifying FIFO state.
|
|
*
|
|
* Returns an error if an attempt is made to peek to nonexistent elements
|
|
* (i.e. if offset + nb_elems is larger than av_fifo_can_read(f)).
|
|
*
|
|
* @param f the FIFO buffer
|
|
* @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes
|
|
* will be written into buf.
|
|
* @param nb_elems number of elements to read from FIFO
|
|
* @param offset number of initial elements to skip.
|
|
*
|
|
* @return a non-negative number on success, a negative error code on failure
|
|
*/
|
|
int av_fifo_peek(const AVFifo *f, void *buf, size_t nb_elems, size_t offset);
|
|
|
|
/**
|
|
* Feed data from a FIFO into a user-provided callback.
|
|
*
|
|
* @param f the FIFO buffer
|
|
* @param write_cb Callback the data will be supplied to. May be called
|
|
* multiple times.
|
|
* @param opaque opaque user data to be provided to write_cb
|
|
* @param nb_elems Should point to the maximum number of elements that can be
|
|
* read. Will be updated to contain the total number of elements
|
|
* actually sent to the callback.
|
|
* @param offset number of initial elements to skip; offset + *nb_elems must not
|
|
* be larger than av_fifo_can_read(f).
|
|
*
|
|
* @return a non-negative number on success, a negative error code on failure
|
|
*/
|
|
int av_fifo_peek_to_cb(const AVFifo *f, AVFifoCB write_cb, void *opaque,
|
|
size_t *nb_elems, size_t offset);
|
|
|
|
/**
|
|
* Discard the specified amount of data from an AVFifo.
|
|
* @param size number of elements to discard, MUST NOT be larger than
|
|
* av_fifo_can_read(f)
|
|
*/
|
|
void av_fifo_drain2(AVFifo *f, size_t size);
|
|
|
|
/*
|
|
* Empty the AVFifo.
|
|
* @param f AVFifo to reset
|
|
*/
|
|
void av_fifo_reset2(AVFifo *f);
|
|
|
|
/**
|
|
* Free an AVFifo and reset pointer to NULL.
|
|
* @param f Pointer to an AVFifo to free. *f == NULL is allowed.
|
|
*/
|
|
void av_fifo_freep2(AVFifo **f);
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
#endif /* AVUTIL_FIFO_H */
|