- Qt 5.5
- Qt Multimedia
- Spectrum Example
- FFTReal.h Example File
- Qt 5.5.1 Reference Documentation

# FFTReal.h Example File

spectrum/3rdparty/fftreal/FFTReal.h

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

            FFTReal.h
            Copyright (c) 2005 Laurent de Soras

    --- Legal stuff ---

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

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

    #if ! defined (FFTReal_HEADER_INCLUDED)
    #define 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"

    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 ();

            FORCEINLINE const long *
                                                    get_br_ptr () const;
            FORCEINLINE const DataType      *
                                                    get_trigo_ptr (int level) const;
            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

    #include        "FFTReal.hpp"

    #endif  // FFTReal_HEADER_INCLUDED

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