Fifos

Thread save fifo buffers for A/V data. More...

Typedefs
typedef struct bg_fifo_s	bg_fifo_t
	Opaque fifo handle.
Enumerations
enum	bg_fifo_state_t {   BG_FIFO_PLAYING,   BG_FIFO_STOPPED,   BG_FIFO_PAUSED }
	Operation states a fifo can have. More...
Functions
bg_fifo_t *	bg_fifo_create (int num_frames, void *(*create_func)(void *), void *data)
	Create a fifo.
void	bg_fifo_destroy (bg_fifo_t *f, void(*destroy_func)(void *, void *), void *data)
	Destroy a fifo.
void *	bg_fifo_lock_read (bg_fifo_t *f, bg_fifo_state_t *state)
	Lock a fifo for reading.
void *	bg_fifo_try_lock_read (bg_fifo_t *f, bg_fifo_state_t *state)
	Lock a fifo for reading (nonblocking).
void	bg_fifo_unlock_read (bg_fifo_t *f)
	Unlock a fifo for reading.
void *	bg_fifo_lock_write (bg_fifo_t *f, bg_fifo_state_t *state)
	Lock a fifo for writing.
void *	bg_fifo_try_lock_write (bg_fifo_t *f, bg_fifo_state_t *state)
	Lock a fifo for writing (nonblocking).
void	bg_fifo_unlock_write (bg_fifo_t *f, int eof)
	Unlock a fifo for writing.
void	bg_fifo_set_state (bg_fifo_t *f, bg_fifo_state_t state)
	Set the state of a fifo.
void	bg_fifo_clear (bg_fifo_t *f)
	Clear a fifo.

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Detailed Description

Thread save fifo buffers for A/V data.

Fifos are used in multithreaded realtime applications to transfer A/V frames from the source to the destination. They have a fixed number of frames.

They also allow save suspension and termination of threads through the state values returned by the bg_fifo_lock_* functions.

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Typedef Documentation

typedef struct bg_fifo_s bg_fifo_t

Opaque fifo handle.

You don't want to know what's inside

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Enumeration Type Documentation

enum bg_fifo_state_t

Operation states a fifo can have.

Enumerator:

BG_FIFO_PLAYING	Normal operation.
BG_FIFO_STOPPED	Playback is stopped, threads should be terminated.
BG_FIFO_PAUSED	Playback is paused, threads should wait until playback is resumed.

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Function Documentation

bg_fifo_t* bg_fifo_create	(	int	num_frames,
		void *(*)(void *)	create_func,
		void *	data
	)

Create a fifo.

Parameters:

	num_frames	Number of frames
	create_func	Function to be called for each created frame
	data	Argument for create_func

Returns:

A newly allocated fifo

void bg_fifo_destroy	(	bg_fifo_t *	f,
		void(*)(void *, void *)	destroy_func,
		void *	data
	)

Destroy a fifo.

Parameters:

	f	A fifo
	destroy_func	Function to be called for each frame to destroy it
	data	Argument for destroy_func

void* bg_fifo_lock_read	(	bg_fifo_t *	f,
		bg_fifo_state_t *	state
	)

Lock a fifo for reading.

Parameters:

	f	A fifo
	state	If non NULL, returns the state of the fifo

Returns:

A frame or NULL

This function blocks until a new frame is available

void* bg_fifo_try_lock_read	(	bg_fifo_t *	f,
		bg_fifo_state_t *	state
	)

Lock a fifo for reading (nonblocking).

Parameters:

	f	A fifo
	state	If non NULL, returns the state of the fifo

Returns:

A frame or NULL

void bg_fifo_unlock_read

(

bg_fifo_t *

f

)

Unlock a fifo for reading.

Parameters:

f

A fifo

void* bg_fifo_lock_write	(	bg_fifo_t *	f,
		bg_fifo_state_t *	state
	)

Lock a fifo for writing.

Parameters:

	f	A fifo
	state	If non NULL, returns the state of the fifo

Returns:

A frame or NULL

This function blocks until a new frame is available

void* bg_fifo_try_lock_write	(	bg_fifo_t *	f,
		bg_fifo_state_t *	state
	)

Lock a fifo for writing (nonblocking).

Parameters:

	f	A fifo
	state	If non NULL, returns the state of the fifo

Returns:

A frame or NULL

void bg_fifo_unlock_write	(	bg_fifo_t *	f,
		int	eof
	)

Unlock a fifo for writing.

Parameters:

	f	A fifo
	eof	Set to 1 if EOF (also means, the last frame is invalid)

void bg_fifo_set_state	(	bg_fifo_t *	f,
		bg_fifo_state_t	state
	)

Set the state of a fifo.

Parameters:

	f	A fifo
	state	The new state

void bg_fifo_clear

(

bg_fifo_t *

f

)

Clear a fifo.

Parameters:

f

A fifo

This flushes the fifo but keeps all buffers. It should only be called, if there are no other threads accessing the fifo