A FIFO class for handling audio samples. More...

#include <AsyncAudioFifo.h>

Inheritance diagram for Async::AudioFifo:

Public Member Functions
	AudioFifo (unsigned fifo_size)
	Constuctor.

virtual	~AudioFifo (void)
	Destructor.

void	setSize (unsigned new_size)
	Set the size of the FIFO.

bool	empty (void) const
	Check if the FIFO is empty.

bool	full (void) const
	Check if the FIFO is full.

unsigned	samplesInFifo (bool ignore_prebuf=false) const
	Find out how many samples there are in the FIFO.

void	setOverwrite (bool overwrite)
	Set the overwrite mode.

bool	overwrite (void) const
	Check the overwrite mode.

void	clear (void)
	Clear all samples from the FIFO.

void	setPrebufSamples (unsigned prebuf_samples)
	Set the number of samples that must be in the fifo before any samples are written out from it.

void	enableBuffering (bool enable)
	Enable/disable the fifo buffer.

bool	bufferingEnabled (void) const
	Check if buffering is enabled or disabled.

virtual int	writeSamples (const float *samples, int count)
	Write samples into the FIFO.

virtual void	flushSamples (void)
	Tell the FIFO to flush the previously written samples.

virtual void	resumeOutput (void)
	Resume audio output to the connected sink.

Public Member Functions inherited from Async::AudioSink
	AudioSink (void)
	Default constuctor.

virtual	~AudioSink (void)
	Destructor.

bool	registerSource (AudioSource *source)
	Register an audio source to provide samples to this sink.

void	unregisterSource (void)
	Unregister the previously registered audio source.

bool	isRegistered (void) const
	Check if an audio source has been registered.

AudioSource *	source (void) const
	Get the registered audio source.

Public Member Functions inherited from Async::AudioSource
	AudioSource (void)
	Default constuctor.

virtual	~AudioSource (void)
	Destructor.

bool	registerSink (AudioSink *sink, bool managed=false)
	Register an audio sink to provide samples to.

void	unregisterSink (void)
	Unregister the previously registered audio sink.

bool	isRegistered (void) const
	Check if an audio sink has been registered.

AudioSink *	sink (void) const
	Get the registered audio sink.

bool	sinkManaged (void) const
	Check if the sink is managed or not.

void	handleAllSamplesFlushed (void)
	The registered sink has flushed all samples.

Protected Member Functions
virtual void	allSamplesFlushed (void)
	The registered sink has flushed all samples.

Protected Member Functions inherited from Async::AudioSink
void	sourceResumeOutput (void)
	Tell the source that we are ready to accept more samples.

void	sourceAllSamplesFlushed (void)
	Tell the source that all samples have been flushed.

bool	setHandler (AudioSink *handler)
	Setup another sink to handle the incoming audio.

void	clearHandler (void)
	Clear a handler that was previously setup with setHandler.

AudioSink *	handler (void) const

Protected Member Functions inherited from Async::AudioSource
int	sinkWriteSamples (const float *samples, int len)

void	sinkFlushSamples (void)

bool	setHandler (AudioSource *handler)
	Setup another source to handle the outgoing audio.

AudioSource *	handler (void) const

void	clearHandler (void)
	Clear a handler that was previously setup with setHandler.

Detailed Description

A FIFO class for handling audio samples.

Author: Tobias Blomberg / SM0SVX

Date: 2007-10-06

This class implements a FIFO for handling audio samples. The FIFO also have some additional features. Output can be started or stopped and it can be instructed to buffer some samples before starting to output audio. Samples can be automatically output using the normal audio pipe infrastructure or samples could be read on demand using the readSamples method.

Definition at line 119 of file AsyncAudioFifo.h.

Constructor & Destructor Documentation

◆ AudioFifo()

Async::AudioFifo::AudioFifo ( unsigned fifo_size )

explicit

Constuctor.

Parameters

fifo_size This is the size of the fifo expressed in number of samples.

◆ ~AudioFifo()

virtual Async::AudioFifo::~AudioFifo ( void )

virtual

Destructor.

Member Function Documentation

◆ allSamplesFlushed()

virtual void Async::AudioFifo::allSamplesFlushed ( void )

protectedvirtual

The registered sink has flushed all samples.

This function will be called when all samples have been flushed in the registered sink. This function is normally only called from a connected sink object.

Reimplemented from Async::AudioSource.

◆ bufferingEnabled()

bool Async::AudioFifo::bufferingEnabled ( void ) const

inline

Check if buffering is enabled or disabled.

Returns: Returns true if buffering is enabled or else false

Definition at line 227 of file AsyncAudioFifo.h.

◆ clear()

void Async::AudioFifo::clear ( void )

Clear all samples from the FIFO.

This will immediately reset the FIFO and discard all samples. The source will be told that all samples have been flushed.

◆ empty()

bool Async::AudioFifo::empty ( void ) const

inline

Check if the FIFO is empty.

Returns: Returns true if the FIFO is empty or else false

Definition at line 148 of file AsyncAudioFifo.h.

◆ enableBuffering()

void Async::AudioFifo::enableBuffering ( bool enable )

Enable/disable the fifo buffer.

Parameters

enable Set to true to enable buffering or else false

Use this method to turn buffering on and off. When buffering is off, no incoming samples will be stored in the fifo. If there are samples in the fifo at the time when buffering is disabled they will be sent out in the normal way. Don't disable buffering when pre-buffering is used. This will get you into trouble.

◆ flushSamples()

virtual void Async::AudioFifo::flushSamples ( void )

virtual

Tell the FIFO to flush the previously written samples.

This function is used to tell the FIFO to flush previously written samples. This function is normally only called from a connected source object.

Reimplemented from Async::AudioSink.

◆ full()

bool Async::AudioFifo::full ( void ) const

inline

Check if the FIFO is full.

Returns: Returns true if the FIFO is full or else false

This function is used to check if the FIFO is full or not. The FIFO can only reach the buffer full condition if overwrite is false. The overwrite mode is set by the setOverwrite function.

Definition at line 158 of file AsyncAudioFifo.h.

◆ overwrite()

bool Async::AudioFifo::overwrite ( void ) const

inline

Check the overwrite mode.

Returns: Returns true if overwrite is enabled or else false

The FIFO can operate in overwrite or normal mode. When in normal mode, it will not be possible to add any more samples to the FIFO when it is full. Samples has to be removed first. When overwrite is set, newly added samples will overwrite the oldest samples in the buffer so the FIFO will never get full but instead samples are lost. Use this function the check the current overwrite mode. Use the setOverwrite function to set the overwrite mode.

Definition at line 193 of file AsyncAudioFifo.h.

Referenced by setOverwrite().

◆ resumeOutput()

virtual void Async::AudioFifo::resumeOutput ( void )

virtual

Resume audio output to the connected sink.

This function will be called when the registered audio sink is ready to accept more samples. This function is normally only called from a connected sink object.

Reimplemented from Async::AudioSource.

◆ samplesInFifo()

unsigned Async::AudioFifo::samplesInFifo ( bool ignore_prebuf = false ) const

Find out how many samples there are in the FIFO.

Parameters

ignore_prebuf Set to true to not report pre-buffered samples.

Returns: Returns the number of samples in the FIFO

◆ setOverwrite()

void Async::AudioFifo::setOverwrite ( bool overwrite )

inline

Set the overwrite mode.

Parameters

overwrite Set to true to overwrite or else false

The FIFO can operate in overwrite or normal mode. When in normal mode, it will not be possible to add any more samples to the FIFO when it is full. Samples has to be removed first. When overwrite is set, newly added samples will overwrite the oldest samples in the buffer so the FIFO will never get full but instead samples are lost. Use this function to set the overwrite mode.

Definition at line 179 of file AsyncAudioFifo.h.

References overwrite().

◆ setPrebufSamples()

void Async::AudioFifo::setPrebufSamples ( unsigned prebuf_samples )

Set the number of samples that must be in the fifo before any samples are written out from it.

Parameters

prebuf_samples The number of samples

◆ setSize()

void Async::AudioFifo::setSize ( unsigned new_size )

Set the size of the FIFO.

Parameters

new_size This is the size of the fifo expressed in number of samples.

Use this function to set the size of the FIFO. In doing this, the FIFO will also be cleared.

◆ writeSamples()

virtual int Async::AudioFifo::writeSamples	(	const float *	samples,
		int	count )

virtual

Write samples into the FIFO.

Parameters

samples	The buffer containing the samples
count	The number of samples in the buffer

Returns: Returns the number of samples that has been taken care of

This function is used to write audio into the FIFO. If it returns 0, no more samples should be written until the resumeOutput function in the source have been called. This function is normally only called from a connected source object.

Reimplemented from Async::AudioSink.

The documentation for this class was generated from the following file:

AsyncAudioFifo.h

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ AudioFifo()

◆ ~AudioFifo()

Member Function Documentation

◆ allSamplesFlushed()

◆ bufferingEnabled()

◆ clear()

◆ empty()

◆ enableBuffering()

◆ flushSamples()

◆ full()

◆ overwrite()

◆ resumeOutput()

◆ samplesInFifo()

◆ setOverwrite()

◆ setPrebufSamples()

◆ setSize()

◆ writeSamples()