c@120: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
c@120: /*
c@120:     Constant-Q library
c@120:     Copyright (c) 2013-2014 Queen Mary, University of London
c@120: 
c@120:     Permission is hereby granted, free of charge, to any person
c@120:     obtaining a copy of this software and associated documentation
c@120:     files (the "Software"), to deal in the Software without
c@120:     restriction, including without limitation the rights to use, copy,
c@120:     modify, merge, publish, distribute, sublicense, and/or sell copies
c@120:     of the Software, and to permit persons to whom the Software is
c@120:     furnished to do so, subject to the following conditions:
c@120: 
c@120:     The above copyright notice and this permission notice shall be
c@120:     included in all copies or substantial portions of the Software.
c@120: 
c@120:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
c@120:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
c@120:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
c@120:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
c@120:     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
c@120:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
c@120:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
c@120: 
c@120:     Except as contained in this notice, the names of the Centre for
c@120:     Digital Music; Queen Mary, University of London; and Chris Cannam
c@120:     shall not be used in advertising or otherwise to promote the sale,
c@120:     use or other dealings in this Software without prior written
c@120:     authorization.
c@120: */
c@120: 
c@120: #ifndef FFT_H
c@120: #define FFT_H
c@120: 
c@120: class FFT  
c@120: {
c@120: public:
c@120:     /**
c@120:      * Construct an FFT object to carry out complex-to-complex
c@120:      * transforms of size nsamples. nsamples does not have to be a
c@120:      * power of two.
c@120:      */
c@120:     FFT(int nsamples);
c@120:     ~FFT();
c@120: 
c@120:     /**
c@120:      * Carry out a forward or inverse transform (depending on the
c@120:      * value of inverse) of size nsamples, where nsamples is the value
c@120:      * provided to the constructor above.
c@120:      *
c@120:      * realIn and (where present) imagIn should contain nsamples each,
c@120:      * and realOut and imagOut should point to enough space to receive
c@120:      * nsamples each.
c@120:      *
c@120:      * imagIn may be NULL if the signal is real, but the other
c@120:      * pointers must be valid.
c@120:      *
c@120:      * The inverse transform is scaled by 1/nsamples.
c@120:      */
c@120:     void process(bool inverse,
c@120:                  const double *realIn, const double *imagIn,
c@120:                  double *realOut, double *imagOut);
c@120:     
c@120: private:
c@120:     class D;
c@120:     D *m_d;
c@120: };
c@120: 
c@120: class FFTReal
c@120: {
c@120: public:
c@120:     /**
c@120:      * Construct an FFT object to carry out real-to-complex transforms
c@120:      * of size nsamples. nsamples does not have to be a power of two,
c@120:      * but it does have to be even. (Use the complex-complex FFT above
c@120:      * if you need an odd FFT size. This constructor will throw
c@120:      * std::invalid_argument if nsamples is odd.)
c@120:      */
c@120:     FFTReal(int nsamples);
c@120:     ~FFTReal();
c@120: 
c@120:     /**
c@120:      * Carry out a forward real-to-complex transform of size nsamples,
c@120:      * where nsamples is the value provided to the constructor above.
c@120:      *
c@120:      * realIn, realOut, and imagOut must point to (enough space for)
c@120:      * nsamples values. For consistency with the FFT class above, and
c@120:      * compatibility with existing code, the conjugate half of the
c@120:      * output is returned even though it is redundant.
c@120:      */
c@120:     void forward(const double *realIn,
c@120:                  double *realOut, double *imagOut);
c@120: 
c@120:     /**
c@120:      * Carry out a forward real-to-complex transform of size nsamples,
c@120:      * where nsamples is the value provided to the constructor
c@120:      * above. Return only the magnitudes of the complex output values.
c@120:      *
c@120:      * realIn and magOut must point to (enough space for) nsamples
c@120:      * values. For consistency with the FFT class above, and
c@120:      * compatibility with existing code, the conjugate half of the
c@120:      * output is returned even though it is redundant.
c@120:      */
c@120:     void forwardMagnitude(const double *realIn, double *magOut);
c@120: 
c@120:     /**
c@120:      * Carry out an inverse real transform (i.e. complex-to-real) of
c@120:      * size nsamples, where nsamples is the value provided to the
c@120:      * constructor above.
c@120:      *
c@120:      * realIn and imagIn should point to at least nsamples/2+1 values;
c@120:      * if more are provided, only the first nsamples/2+1 values of
c@120:      * each will be used (the conjugate half will always be deduced
c@120:      * from the first nsamples/2+1 rather than being read from the
c@120:      * input data).  realOut should point to enough space to receive
c@120:      * nsamples values.
c@120:      *
c@120:      * The inverse transform is scaled by 1/nsamples.
c@120:      */
c@120:     void inverse(const double *realIn, const double *imagIn,
c@120:                  double *realOut);
c@120: 
c@120: private:
c@120:     class D;
c@120:     D *m_d;
c@120: };    
c@120: 
c@120: #endif