container_fifo.h File Reference

#include <stddef.h>

Go to the source code of this file.

Typedefs
typedef struct AVContainerFifo	AVContainerFifo
	AVContainerFifo is a FIFO for "containers" - dynamically allocated reusable structs (e.g.

Enumerations
enum	AVContainerFifoFlags { AV_CONTAINER_FIFO_FLAG_REF = (1 << 0) , AV_CONTAINER_FIFO_FLAG_USER = (1 << 16) }

Functions
AVContainerFifo *	av_container_fifo_alloc (void *opaque, void *(*container_alloc)(void *opaque), void(*container_reset)(void *opaque, void *obj), void(*container_free)(void *opaque, void *obj), int(*fifo_transfer)(void *opaque, void *dst, void *src, unsigned flags), unsigned flags)
	Allocate a new AVContainerFifo for the container type defined by provided callbacks.
AVContainerFifo *	av_container_fifo_alloc_avframe (unsigned flags)
	Allocate an AVContainerFifo instance for AVFrames.
void	av_container_fifo_free (AVContainerFifo **cf)
	Free a AVContainerFifo and everything in it.
int	av_container_fifo_write (AVContainerFifo *cf, void *obj, unsigned flags)
	Write the contents of obj to the FIFO.
int	av_container_fifo_read (AVContainerFifo *cf, void *obj, unsigned flags)
	Read the next available object from the FIFO into obj.
int	av_container_fifo_peek (AVContainerFifo *cf, void **pobj, size_t offset)
	Access objects stored in the FIFO without retrieving them.
void	av_container_fifo_drain (AVContainerFifo *cf, size_t nb_elems)
	Discard the specified number of elements from the FIFO.
size_t	av_container_fifo_can_read (const AVContainerFifo *cf)

Typedef Documentation

AVContainerFifo

typedef struct AVContainerFifo AVContainerFifo

AVContainerFifo is a FIFO for "containers" - dynamically allocated reusable structs (e.g.

AVFrame or AVPacket). AVContainerFifo uses an internal pool of such containers to avoid allocating and freeing them repeatedly.

Definition at line 29 of file container_fifo.h.

Enumeration Type Documentation

AVContainerFifoFlags

enum AVContainerFifoFlags

Enumerator
AV_CONTAINER_FIFO_FLAG_REF	Signal to av_container_fifo_write() that it should make a new reference to data in src rather than consume its contents. Note you must handle this flag manually in your own fifo_transfer() callback
AV_CONTAINER_FIFO_FLAG_USER	This and all higher bits in flags may be set to any value by the caller and are guaranteed to be passed through to the fifo_transfer() callback and not be interpreted by AVContainerFifo code.

Definition at line 31 of file container_fifo.h.

Function Documentation

av_container_fifo_alloc()

AVContainerFifo * av_container_fifo_alloc	(	void *	opaque,
		void *(*	container_alloc )(void *opaque),
		void(*	container_reset )(void *opaque, void *obj),
		void(*	container_free )(void *opaque, void *obj),
		int(*	fifo_transfer )(void *opaque, void *dst, void *src, unsigned flags),
		unsigned	flags )

Allocate a new AVContainerFifo for the container type defined by provided callbacks.

Parameters

opaque	user data that will be passed to the callbacks provided to this function
container_alloc	allocate a new container instance and return a pointer to it, or NULL on failure
container_reset	reset the provided container instance to a clean state
container_free	free the provided container instance
fifo_transfer	Transfer the contents of container src to dst.
flags	currently unused

Returns

newly allocated AVContainerFifo, or NULL on failure

av_container_fifo_alloc_avframe()

AVContainerFifo * av_container_fifo_alloc_avframe

(

unsigned

flags

)

Allocate an AVContainerFifo instance for AVFrames.

Parameters

flags

currently unused

av_container_fifo_free()

void av_container_fifo_free

(

AVContainerFifo **

cf

)

Free a AVContainerFifo and everything in it.

av_container_fifo_write()

int av_container_fifo_write	(	AVContainerFifo *	cf,
		void *	obj,
		unsigned	flags )

Write the contents of obj to the FIFO.

The fifo_transfer() callback previously provided to av_container_fifo_alloc() will be called with obj as src in order to perform the actual transfer.

av_container_fifo_read()

int av_container_fifo_read	(	AVContainerFifo *	cf,
		void *	obj,
		unsigned	flags )

Read the next available object from the FIFO into obj.

The fifo_read() callback previously provided to av_container_fifo_alloc() will be called with obj as dst in order to perform the actual transfer.

av_container_fifo_peek()

int av_container_fifo_peek	(	AVContainerFifo *	cf,
		void **	pobj,
		size_t	offset )

Access objects stored in the FIFO without retrieving them.

The fifo_transfer() callback will NOT be invoked and the FIFO state will not be modified.

Parameters

pobj	Pointer to the object stored in the FIFO will be written here on success. The object remains owned by the FIFO and the caller may only access it as long as the FIFO is not modified.
offset	Position of the object to retrieve - 0 is the next item that would be read, 1 the one after, etc. Must be smaller than av_container_fifo_can_read().

Return values

0	success, a pointer was written into pobj
AVERROR(EINVAL)	invalid offset value

av_container_fifo_drain()

void av_container_fifo_drain	(	AVContainerFifo *	cf,
		size_t	nb_elems )

Discard the specified number of elements from the FIFO.

Parameters

nb_elems

number of elements to discard, MUST NOT be larger than av_fifo_can_read(f)

av_container_fifo_can_read()

size_t av_container_fifo_can_read

(

const AVContainerFifo *

cf

)

Returns

number of objects available for reading