Fast Fourier transform — FFT — source code

//   fft.h - declaration of class
//   of fast Fourier transform - FFT
//
//   The code is property of LIBROW
//   You can use it on your own
//   When utilizing credit LIBROW site

#ifndef _FFT_H_
#define _FFT_H_

#include "complex.h"

class CFFT
{
public:
   //   FORWARD FOURIER TRANSFORM
   //     Input  - input data
   //     Output - transform result
   //     N      - length of both input data and result
   static bool Forward(const complex *const Input, complex *const Output,
      const unsigned int N);

   //   FORWARD FOURIER TRANSFORM, INPLACE VERSION
   //     Data - both input data and output
   //     N    - length of both input data and result
   static bool Forward(complex *const Data, const unsigned int N);

   //   INVERSE FOURIER TRANSFORM
   //     Input  - input data
   //     Output - transform result
   //     N      - length of both input data and result
   //     Scale  - if to scale result
   static bool Inverse(const complex *const Input, complex *const Output,
      const unsigned int N, const bool Scale = true);

   //   INVERSE FOURIER TRANSFORM, INPLACE VERSION
   //     Data  - both input data and output
   //     N     - length of both input data and result
   //     Scale - if to scale result
   static bool Inverse(complex *const Data, const unsigned int N,
      const bool Scale = true);

protected:
   //   Rearrange function and its inplace version
   static void Rearrange(const complex *const Input, complex *const Output,
      const unsigned int N);
   static void Rearrange(complex *const Data, const unsigned int N);

   //   FFT implementation
   static void Perform(complex *const Data, const unsigned int N,
      const bool Inverse = false);

   //   Scaling of inverse FFT result
   static void Scale(complex *const Data, const unsigned int N);
};

#endif