giuliomoro@148: /*
giuliomoro@148:  * IirFilter.h
giuliomoro@148:  *
giuliomoro@148:  *  Created on: 17 Sep 2015
giuliomoro@148:  *      Author: giulio
giuliomoro@148:  */
giuliomoro@148: 
giuliomoro@148: #ifndef IIRFILTER_H_
giuliomoro@148: #define IIRFILTER_H_
giuliomoro@148: 
giuliomoro@148: #define IIR_FILTER_STAGE_COEFFICIENTS (5)
giuliomoro@148: #define IIR_FILTER_STAGE_STATES (IIR_FILTER_STAGE_COEFFICIENTS - 1)
giuliomoro@148: 
giuliomoro@148: class IirFilterStage{ //TODO : to save (some) memory we should only store the coefficients pointers here,
giuliomoro@148: 						//so that IirFilter can share them among multiple stages if needbe)
giuliomoro@148: private:
giuliomoro@148: 	double coefficients[IIR_FILTER_STAGE_COEFFICIENTS]; // these are b0,b1,b2,a1,a2
giuliomoro@148: 	double states[IIR_FILTER_STAGE_STATES]; // these are xprev, xprevprev, yprev, yprevprev
giuliomoro@148: public:
giuliomoro@148: 	IirFilterStage();
giuliomoro@148: 	void setCoefficients(double* newCoefficients);
giuliomoro@148: 	void setStates(double* newStates);
giuliomoro@148: 	double process(double in);
giuliomoro@148: 	void process(double* inout, int length);
giuliomoro@148: 	void process(double* in, double* out, int length);
giuliomoro@148: };
giuliomoro@148: 
giuliomoro@148: class IirFilter{
giuliomoro@148: private:
giuliomoro@148: 	struct IirFilterStage** stages;
giuliomoro@148: 	int numberOfStages;
giuliomoro@148: 	void dealloc();
giuliomoro@148: public:
giuliomoro@148: 	IirFilter();
giuliomoro@148: 	IirFilter(int newNumberOfStages);
giuliomoro@148: 	IirFilter(int newNumberOfStages, double *newCoefficients);
giuliomoro@148: 	void setCoefficients(double* newCoefficients);
giuliomoro@148: 	void setStates(double* newStates);
giuliomoro@148: 	void setNumberOfStages(int newNumberOfStages);
giuliomoro@148: 	double process(double in);
giuliomoro@148: 	void process(double* inout, int length);
giuliomoro@148: 	void process(double* in, double* out, int length);
giuliomoro@148: };
giuliomoro@148: 
giuliomoro@148: #endif /* IIRFILTER_H_ */