/***************************************************************************/
/* FFT.H                                                                 */
/* Fast-Fourier-Transformation 
/* Author:          Jens Ahrensfeld                                        */
/* Datum :          24.06.1999                                             */
/* letzte Änderung: 09.06.2000                                             */
/***************************************************************************/
/* Tabellen und Funktionen für die FFT                                     */
/***************************************************************************/
#ifndef FFT_H
#define FFT_H

#define	PI			3.1415926535897932384626433832795
typedef struct _sCOMPLEX 
{ 
	double real, imag;
} COMPLEX;


#ifdef __cplusplus
class cfft 
	{
	public:
	cfft(unsigned);
	~cfft();
	void  fft (double*, double*);
	void ifft (double*, double*);
	COMPLEX *pTwiddleTbl;

	protected:
	unsigned m_numPoints, m_numStages;

};
#endif /* __cplusplus */

typedef struct _sFFT 
{
	unsigned m_numPoints, m_numStages;
	COMPLEX *pTwiddleTbl;
} FFT;

typedef struct _sFFT2D 
{
	struct _sFFT *pXfft, *pYfft;
	unsigned m_Nx, m_Ny;
} FFT2D;

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/* DFT functions */
extern void DFT(double *pDataR, double *pDataI, unsigned N);
extern void IDFT(double *pDataR, double *pDataI, unsigned N);

/* FFT functions */
extern void FFTinit(FFT *pFFT, unsigned N);
extern void FFTfree(FFT *pFFT);
extern void  fft (FFT *pFFT, double*, double*);
extern void ifft (FFT *pFFT, double*, double*);
extern void FFTCalcTwiddleTable (COMPLEX *pTwfTbl, unsigned numPoints);

/* 2D FFT functions */
extern void FFT2Dinit(struct _sFFT2D *pFFT, unsigned Nx, unsigned Ny);
extern void FFT2Dfree(struct _sFFT2D *pFFT);
extern void  fft2d(struct _sFFT2D *pFFT, double **ppReal, double **ppImag);
extern void ifft2d(struct _sFFT2D *pFFT, double **ppReal, double **ppImag);

/* Helper functions */
extern void Scale(double *pRealData, double *pImagData , double scaleFactor, unsigned N); 
extern void Modulus(double *pRealData, double *pImagData, unsigned N);
extern void Modulus2(double *pRealData, double *pImagData, double *pModulus, unsigned N);
extern void Hanning (double *pRealData, double *pImagData, unsigned N, unsigned maximum);
extern double hanning_k (unsigned, unsigned);
extern double gauss_k(unsigned, unsigned, unsigned);
extern int BiPower(unsigned int N);


#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* FFT_H */