/*----------------------------------------------------------------------------------------------*/
/*! \file fft.h
//
// FILENAME: fft.h
//
// DESCRIPTION: Defines the FFT class.
//
// DEVELOPERS: Gregory W. Heckler (2003-2009)
//
// LICENSE TERMS: Copyright (c) Gregory W. Heckler 2009
//
// This file is part of the GPS Software Defined Radio (GPS-SDR)
//
// The GPS-SDR is free software; you can redistribute it and/or modify it under the terms of the
// GNU General Public License as published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version. The GPS-SDR is distributed in the hope that
// it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// Note:  Comments within this file follow a syntax that is compatible with
//        DOXYGEN and are utilized for automated document extraction
//
// Reference:
*/
/*----------------------------------------------------------------------------------------------*/

#ifndef FFT_H_
#define FFT_H_

#include "gps_sdr_defines.h"
#include "gps_sdr_signal_processing.h"

#define MAX_RANKS (16)

/*! @ingroup CLASSES
	@brief /xyzzy */
class FFT
{

	private:

		MIX *W;						//!< Twiddle lookup array for FFT
		MIX *iW;					//!< Twiddle lookup array for iFFT
		int32 *BRX;					//!< Re-order temp array
		int32 *BR;					//!< Re-order index array

		int32 N;					//!< Length (should be 2^N!!!)
		int32 M;					//!< Log2(N) (number of ranks)
		int32 R[16];				//!< Programmable rank scaling

		void initW();				//!< Initialize twiddles
		void initBR();				//!< Initialize re-order array
		void doShuffle(CPX *_x);	//!< Do bit-reverse shuffling

	public:

		FFT();								//!< Initialize FFT
		FFT(int32 _N);						//!< Initialize FFT for 2^N
		FFT(int32 _N, int32 _R[MAX_RANKS]);			//!< Initialize FFT for 2^N, with ranks
		~FFT();								//!< Destructor
		void doFFT(CPX *_x, bool _shuf);	//!< Forward FFT, decimate in time
		void doiFFT(CPX *_x, bool _shuf);	//!< Inverse FFT, decimate in time
		void doFFTdf(CPX *_x, bool _shuf);	//!< Forward FFT, decimate in frequency
		void doiFFTdf(CPX *_x, bool _shuf);	//!< Inverse FFT, decimate in frequency

};

#endif /*FFT_H_*/