Carla/source/native-plugins/zynaddsubfx/DSP/FFTwrapper.h

/*
  ZynAddSubFX - a software synthesizer

  FFTwrapper.h  -  A wrapper for Fast Fourier Transforms
  Copyright (C) 2002-2005 Nasca Octavian Paul
  Author: Nasca Octavian Paul

  This program 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.
*/

#ifndef FFT_WRAPPER_H
#define FFT_WRAPPER_H
#include <fftw3.h>
#include <complex>
#include "../globals.h"

namespace zyncarla {

/**A wrapper for the FFTW library (Fast Fourier Transforms)*/
class FFTwrapper
{
    public:
        /**Constructor
         * @param fftsize The size of samples to be fed to fftw*/
        FFTwrapper(int fftsize_);
        /**Destructor*/
        ~FFTwrapper();
        /**Convert Samples to Frequencies using Fourier Transform
         * @param smps Pointer to Samples to be converted; has length fftsize_
         * @param freqs Structure FFTFREQS which stores the frequencies*/
        void smps2freqs(const float *smps, fft_t *freqs);
        void freqs2smps(const fft_t *freqs, float *smps);
    private:
        int fftsize;
        fftw_real    *time;
        fftw_complex *fft;
        fftw_plan     planfftw, planfftw_inv;
};

/*
 * The "std::polar" template has no clear definition for the range of
 * the input parameters, and some C++ standard library implementations
 * don't accept negative amplitude among others. Define our own
 * FFTpolar template, which works like we expect it to.
 */
template<class _Tp>
std::complex<_Tp>
FFTpolar(const _Tp& __rho, const _Tp& __theta = _Tp(0))
{
        _Tp __x = __rho * cos(__theta);
        if (std::isnan(__x))
                __x = 0;
        _Tp __y = __rho * sin(__theta);
        if (std::isnan(__y))
                __y = 0;
        return std::complex<_Tp>(__x, __y);
}

void FFT_cleanup();

}

#endif