/*****************************************************************************

        FFTReal.h
        By Laurent de Soras

--- Legal stuff ---

This program is free software. It comes without any warranty, to
the extent permitted by applicable law. You can redistribute it
and/or modify it under the terms of the Do What The Fuck You Want
To Public License, Version 2, as published by Sam Hocevar. See
http://sam.zoy.org/wtfpl/COPYING for more details.

*Tab=3***********************************************************************/

#if !defined(ffft_FFTReal_HEADER_INCLUDED)
#  define ffft_FFTReal_HEADER_INCLUDED

#  if defined(_MSC_VER)
#    pragma once
#    pragma warning(4 : 4250) // "Inherits via dominance."
#  endif

/*\\\ INCLUDE FILES \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/

#  include "def.h"
#  include "DynArray.h"
#  include "OscSinCos.h"

namespace ffft
{

template<class DT>
class FFTReal
{

  /*\\\ PUBLIC \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/

public:
  enum
  {
    MAX_BIT_DEPTH = 30
  }; // So length can be represented as long int

  typedef DT DataType;

  explicit FFTReal(long length);
  virtual ~FFTReal() {}

  long get_length() const;
  void do_fft(DataType f[], const DataType x[]) const;
  void do_ifft(const DataType f[], DataType x[]) const;
  void rescale(DataType x[]) const;
  DataType *use_buffer() const;

  /*\\\ PROTECTED \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/

protected:
  /*\\\ PRIVATE \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/

private:
  // Over this bit depth, we use direct calculation for sin/cos
  enum
  {
    TRIGO_BD_LIMIT = 12
  };

  typedef OscSinCos<DataType> OscType;

  void init_br_lut();
  void init_trigo_lut();
  void init_trigo_osc();

  ffft_FORCEINLINE const long *get_br_ptr() const;
  ffft_FORCEINLINE const DataType *get_trigo_ptr(int level) const;
  ffft_FORCEINLINE long get_trigo_level_index(int level) const;

  inline void compute_fft_general(DataType f[], const DataType x[]) const;
  inline void compute_direct_pass_1_2(DataType df[], const DataType x[]) const;
  inline void compute_direct_pass_3(DataType df[], const DataType sf[]) const;
  inline void compute_direct_pass_n(DataType df[], const DataType sf[],
                                    int pass) const;
  inline void compute_direct_pass_n_lut(DataType df[], const DataType sf[],
                                        int pass) const;
  inline void compute_direct_pass_n_osc(DataType df[], const DataType sf[],
                                        int pass) const;

  inline void compute_ifft_general(const DataType f[], DataType x[]) const;
  inline void compute_inverse_pass_n(DataType df[], const DataType sf[],
                                     int pass) const;
  inline void compute_inverse_pass_n_osc(DataType df[], const DataType sf[],
                                         int pass) const;
  inline void compute_inverse_pass_n_lut(DataType df[], const DataType sf[],
                                         int pass) const;
  inline void compute_inverse_pass_3(DataType df[], const DataType sf[]) const;
  inline void compute_inverse_pass_1_2(DataType x[], const DataType sf[]) const;

  const long _length;
  const int _nbr_bits;
  DynArray<long> _br_lut;
  DynArray<DataType> _trigo_lut;
  mutable DynArray<DataType> _buffer;
  mutable DynArray<OscType> _trigo_osc;

  /*\\\ FORBIDDEN MEMBER FUNCTIONS \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/

private:
  FFTReal();
  FFTReal(const FFTReal &other);
  FFTReal &operator=(const FFTReal &other);
  bool operator==(const FFTReal &other);
  bool operator!=(const FFTReal &other);

}; // class FFTReal

} // namespace ffft

#  include "FFTReal.hpp"

#endif // ffft_FFTReal_HEADER_INCLUDED

/*\\\ EOF \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/