/*

*   File:       ProcessFloatSamples.h

*

*   Contains:   This file provides the interface to a simple filter that implements a lowpass filter with with a 400 Hz cutoff.  

*               Good references for the implementation of filters include:

*                -Discrete-Time Signal Processing, Schafer

*                -Introduction to Signal Processing, Orfanidis

*                -Understanding Digital Signal Processing, Lyons

*   

*   Version:    1.0

*

*   Created:    11-23-2004

*

*   � Copyright 2004-2013 Apple Computer, Inc. All rights reserved.

*

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#include <IOKit/IOTypes.h>

// _ParamStruct - coefficients for filter

__BEGIN_DECLS

typedef struct _ParamStruct 

{

    float       b0;

    float       b1;

    float       b2;

    float       a1;

    float       a2;

} ParamStruct, *ParamStructPtr;

// _StateStruct - state variables for filter

typedef struct _StateStruct 

{

    float       xstate1l;

    float       xstate2l;

    float       ystate1l;

    float       ystate2l;

    float       xstate1r;

    float       xstate2r;

    float       ystate1r;

    float       ystate2r;

} StateStruct, *StateStructPtr;

void processSamples (float * dataBuffer, UInt32 numSampleFrames, UInt32 numChannels, ParamStructPtr inParamStructPtr, StateStructPtr inStateStructPtr);

void resetProcessingState (StateStructPtr inStateStructPtr);

void setProcessingParameters (ParamStructPtr inParamStructPtr, UInt32 inSampleRate, UInt32 inNumChannels);

__END_DECLS