fftadapter.h

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/*****************************************************************************
 * Copyright 2015 Haye Hinrichsen, Christoph Wick
 *
 * This file is part of Entropy Piano Tuner.
 *
 * Entropy Piano Tuner 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 3 of the License, or (at your
 * option) any later version.
 *
 * Entropy Piano Tuner 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.
 *
 * You should have received a copy of the GNU General Public License along with
 * Entropy Piano Tuner. If not, see http://www.gnu.org/licenses/.
 *****************************************************************************/

//=============================================================================
//                  Adapter for fast Fourier transformations
//=============================================================================

#ifndef FFTADAPTER
#define FFTADAPTER

#include <complex>
#include <vector>
#include <map>
#include <memory>

// Data types to be processed by the FFT software
using FFTRealType      = double;
using FFTComplexType   = std::complex<double>;
using FFTRealVector    = std::vector<FFTRealType>;
using FFTComplexVector = std::vector<FFTComplexType>;

// external used datatypes

using FFTWType      = FFTRealType;
using FFTWVector = std::vector<FFTWType>;
typedef std::map<double,double> FFTPolygon;

struct FFTData {
    FFTWVector fft;         
    int samplingRate = -1;  

    bool isValid() {
        return fft.size() > 0 && samplingRate > 0;
    }

    double getTime() {
        return fft.size() * 2.0 / samplingRate;
    }
};

using FFTDataPointer = std::shared_ptr<FFTData>;


class FFTAdapter
{
public:

    FFTAdapter() {}
    virtual ~FFTAdapter() {}

    virtual void calculateFFT  (const FFTRealVector &in, FFTComplexVector &out) = 0;
    virtual void calculateFFT  (const FFTComplexVector &in, FFTRealVector &out) = 0;

    // Call these functions to speed up FFT with the same size
    virtual void optimize (FFTRealVector &in) = 0;
    virtual void optimize (FFTComplexVector &in) = 0;

};

#endif // FFTADAPTER