TransformationReader< T > Class Template Reference

ConverterStream Helper class which implements the readBytes with the help of write. More...

#include <AudioIO.h>

Public Member Functions
int	available ()
void	begin (T *transform, Stream *source)
	setup of the TransformationReader class
void	end ()
size_t	getTotalBytesRead () const
size_t	readBytes (uint8_t *data, size_t len)
void	resizeResultQueue (int size)
	Defines the queue size for result.
void	setEofOnZeroReads (bool flag)
void	setMaxReadSize (int size)
void	setResultQueueFactor (int factor)
	Defines the queue size dependent on the read size.
void	setZeroReadDelay (uint32_t delay_ms)

Protected Member Functions
void	fillResultQueue (size_t len)
void	resizeReadBuffer (int size)
	Defines the read buffer size for individual reads.
void	restoreOutput (Print *out)
	restores the original output in the converter class
void	setupBuffers (size_t len)
Print *	setupOutput ()

Protected Attributes
bool	active = false
Vector< uint8_t >	buffer {0}
bool	eof_on_zero_reads = true
bool	is_eof = false
float	last_byte_factor = 0.0f
int	last_setup_buffer_size = 0
int	max_read_size = DEFAULT_BUFFER_SIZE
Stream *	p_stream = nullptr
T *	p_transform = nullptr
QueueStream< uint8_t >	result_queue {result_queue_buffer}
RingBuffer< uint8_t >	result_queue_buffer {0}
int	result_queue_factor = 5
size_t	total_bytes_read = 0
uint32_t	zero_read_delay_ms = 5

Detailed Description

template<class T>
class audio_tools::TransformationReader< T >

ConverterStream Helper class which implements the readBytes with the help of write.

Author

Phil Schatzmann

Copyright

GPLv3

Template Parameters

T	class name of the original transformer stream

Member Function Documentation

available()

template<class T >

int available ( )

inline

Fills the internal queue up to at least DEFAULT_BUFFER_SIZE bytes (if possible) and reports the currently available queue size limited by max_read_size.

begin()

template<class T >

void begin ( T *  transform, Stream *  source  )

inline

setup of the TransformationReader class

Parameters

transform	The original transformer stream
source	The data source of the data to be converted the requested converted bytes

end()

template<class T >

void end ( )

inline

fillResultQueue()

template<class T >

void fillResultQueue ( size_t  len )

inlineprotected

Fills the result queue until at least len bytes are available or no more input data arrives.

getTotalBytesRead()

template<class T >

size_t getTotalBytesRead ( ) const

inline

readBytes()

template<class T >

size_t readBytes ( uint8_t *  data, size_t  len  )

inline

resizeReadBuffer()

template<class T >

void resizeReadBuffer ( int  size )

inlineprotected

Defines the read buffer size for individual reads.

resizeResultQueue()

template<class T >

void resizeResultQueue ( int  size )

inline

Defines the queue size for result.

restoreOutput()

template<class T >

void restoreOutput ( Print *  out )

inlineprotected

restores the original output in the converter class

Parameters

out

setEofOnZeroReads()

template<class T >

void setEofOnZeroReads ( bool  flag )

inline

Defines how a run of MAX_ZERO_READ_COUNT consecutive empty reads from the source is interpreted:

• true (default): the source is treated as finished (e.g. end of file) and is_eof latches permanently - matches the historical behavior for decoders/encoders reading a finite stream.
• false: the source is treated as a live/continuous producer that is just momentarily empty (a buffer underflow). is_eof is never set, so the next call simply tries again once more data has arrived.

setMaxReadSize()

template<class T >

void setMaxReadSize ( int  size )

inline

setResultQueueFactor()

template<class T >

void setResultQueueFactor ( int  factor )

inline

Defines the queue size dependent on the read size.

setupBuffers()

template<class T >

void setupBuffers ( size_t  len )

inlineprotected

setupOutput()

template<class T >

Print * setupOutput ( )

inlineprotected

Makes sure that the data is written to the array

Parameters

data

Returns

original output of the converter class

setZeroReadDelay()

template<class T >

void setZeroReadDelay ( uint32_t  delay_ms )

inline

Defines how long fillResultQueue() blocks in delay() after each empty read from the source, before retrying (up to MAX_ZERO_READ_COUNT times). Default is 5ms, matching historical behavior. For a live producer read from the same thread/task that also has to keep some other time-critical consumer fed (e.g. an I2S output pump driven from the same loop()), blocking here for up to MAX_ZERO_READ_COUNT * this value on every transient underflow can itself starve that consumer - set this to 0 in that case so a momentarily-empty source just returns immediately with whatever's available instead of stalling the caller.

Member Data Documentation

active

template<class T >

bool active = false

protected

buffer

template<class T >

Vector<uint8_t> buffer {0}

protected

eof_on_zero_reads

template<class T >

bool eof_on_zero_reads = true

protected

is_eof

template<class T >

bool is_eof = false

protected

last_byte_factor

template<class T >

float last_byte_factor = 0.0f

protected

last_setup_buffer_size

template<class T >

int last_setup_buffer_size = 0

protected

max_read_size

template<class T >

int max_read_size = DEFAULT_BUFFER_SIZE

protected

p_stream

template<class T >

Stream* p_stream = nullptr

protected

p_transform

template<class T >

T* p_transform = nullptr

protected

result_queue

template<class T >

QueueStream<uint8_t> result_queue {result_queue_buffer}

protected

result_queue_buffer

template<class T >

RingBuffer<uint8_t> result_queue_buffer {0}

protected

result_queue_factor

template<class T >

int result_queue_factor = 5

protected

total_bytes_read

template<class T >

size_t total_bytes_read = 0

protected

zero_read_delay_ms

template<class T >

uint32_t zero_read_delay_ms = 5

protected

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

• src/AudioTools/CoreAudio/AudioIO.h