#ifndef __HANSIS_FFT_H
#define __HANSIS_FFT_H

#ifndef CMPLX_DEFINED
#define CMPLX_DEFINED
typedef struct {
        double x,y;
} cmplx;
#endif

class FFTer
{
public:
	FFTer( int l, int mod=0 );
	~FFTer();

#if 0
	Vector<Complex> operator*( const Vector<Complex>& fd );
	Vector<Complex> operator*( const Vector<double>& fd );
	Vector<Complex> operator*( const Vector<short>& fd );

	friend Vector<Complex> operator*( const Vector<Complex>& fd, 
					  const FFTer& fft );
	friend Vector<Complex> operator*( const Vector<double>& fd, 
					  const FFTer& fft );
	friend Vector<Complex> operator*( const Vector<short>& fd, 
					  const FFTer& fft );
	friend Vector<Complex> operator/( const Vector<Complex>& fd, 
					  const FFTer& fft );
#endif

protected:
	int len, M;
	int mode;
	double *real_a, *imag_a;


public:	
	// Dumm-DFT: Hilfsfunktionen und -tabellen
	cmplx *Dm;
#if 0
	Vector<Complex> dft( const Vector<Complex>, int invers ) const;
	Vector<Complex> dft( const Vector<double>, int invers ) const;
	Vector<Complex> dft( const Vector<short>, int invers ) const;
	void dft_init();
	void dft_remove();
#endif

	// Split-Radix FFT mit Hilfstabellen (Base 2) und -funktionen
	void fftsr_init();
	void fftsr_remove();
	void fftsr_bitrevers(double *x, double *y) const;
	double *CT1, *CT3, *ST1, *ST3;
	int *itab;

	// a) normale Transformation (komplex)
	cmplx* fftsr( const cmplx* ) const;
	void fftsr_helper( int, int, int, double *, double *, 
			   double *, double *, double *, double *, 
			   double *, double *) const;
	void fftsr_main( double *, double *) const;
	// b) inverse Split-Radix (auch komplex)
	cmplx* ifftsr( const cmplx* ) const;
	void ifftsr_main( double *, double *) const;
	void ifftsr_helper( int, int, double *, double *, 
			    double *, double *, double *, double *, 
			    double *, double *) const;
	// c) reele Transformation (Input=Vector<double>)
	cmplx* rfftsr( const double* ) const;
	cmplx* rfftsr( const short* ) const;
	cmplx* rfftsr_wrapper( double *) const;
	void rfftsr_bitrevers(double *x) const;
	void rfftsr_main( double *) const;
	void rfftsr_helper( int, int, double *, double *, double *,
			    double *) const;
};

#endif