FFTReal.h

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

        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 \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\*/