BaseInterpolator Struct Reference

Base class for resampling algorithms using a buffer of float values. More...

#include <ResampleStreamT.h>

Inheritance diagram for BaseInterpolator:

Public Member Functions
void	addValue (float value)
	Adds a new value to the buffer, discarding the oldest.
bool	begin ()
	Constructor. Initializes the buffer with four zeros.
bool	getValue (float &newValue)
	Gets the next interpolated value.
	operator bool () const
	Returns true if there are more values to read.
void	setStepSize (float step)
	Sets the step size for interpolation.
float	valueExt (float *y, float xf)

Protected Member Functions
virtual float	value (float *y, float xf)=0
	Interpolation function to be implemented by derived classes.
virtual int	vectorSize ()=0

Protected Attributes
float	step = 0
float	step_size = 1.0f
	Step size for resampling, default is 1.0.
SingleBuffer< float >	values
	Buffer holding the last 4 values for interpolation.

Detailed Description

Base class for resampling algorithms using a buffer of float values.

Call getValue() to get the next interpolated value until it returns false. Then provide a new value with addValue() to continue.

Derived classes must implement the value() and vectorSize() methods for interpolation. The calculation depends on n values. For example, a linear interpolation only needs the last two values, while a cubic B-spline interpolation requires the last four values. The buffer is always filled with the required number of values, so the derived class can assume that it has access to all required values for interpolation.

The buffer is initilaized with 0 values and it is re-initialized when setStepSize() is called with a different size.

Member Function Documentation

addValue()

void addValue ( float  value )

inline

Adds a new value to the buffer, discarding the oldest.

Parameters

value

The new sample value to add.

begin()

bool begin ( )

inline

Constructor. Initializes the buffer with four zeros.

getValue()

bool getValue ( float &  newValue )

inline

Gets the next interpolated value.

Parameters

newValue

Reference to store the interpolated value.

Returns

True if a value was produced, false if more input is needed.

operator bool()

operator bool ( ) const

inline

Returns true if there are more values to read.

setStepSize()

void setStepSize ( float  step )

inline

Sets the step size for interpolation.

Parameters

step	The new step size.

value()

virtual float value ( float *  y, float  xf  )

protectedpure virtual

Interpolation function to be implemented by derived classes.

Parameters

y	Pointer to the buffer of 4 values.
xf	The fractional index for interpolation.

Returns

Interpolated value.

Implemented in LinearInterpolator, BSplineInterpolator, LagrangeInterpolator, HermiteInterpolator, and ParabolicInterpolator.

valueExt()

float valueExt ( float *  y, float  xf  )

inline

vectorSize()

virtual int vectorSize ( )

protectedpure virtual

Implemented in LinearInterpolator, BSplineInterpolator, LagrangeInterpolator, HermiteInterpolator, and ParabolicInterpolator.

Member Data Documentation

step

float step = 0

protected

step_size

float step_size = 1.0f

protected

Step size for resampling, default is 1.0.

values

SingleBuffer<float> values

protected

Buffer holding the last 4 values for interpolation.

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

• src/AudioTools/CoreAudio/ResampleStreamT.h