Chris@366: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@366: /*
Chris@366:     Constant-Q library
Chris@366:     Copyright (c) 2013-2014 Queen Mary, University of London
Chris@366: 
Chris@366:     Permission is hereby granted, free of charge, to any person
Chris@366:     obtaining a copy of this software and associated documentation
Chris@366:     files (the "Software"), to deal in the Software without
Chris@366:     restriction, including without limitation the rights to use, copy,
Chris@366:     modify, merge, publish, distribute, sublicense, and/or sell copies
Chris@366:     of the Software, and to permit persons to whom the Software is
Chris@366:     furnished to do so, subject to the following conditions:
Chris@366: 
Chris@366:     The above copyright notice and this permission notice shall be
Chris@366:     included in all copies or substantial portions of the Software.
Chris@366: 
Chris@366:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@366:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@366:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
Chris@366:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
Chris@366:     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@366:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@366:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@366: 
Chris@366:     Except as contained in this notice, the names of the Centre for
Chris@366:     Digital Music; Queen Mary, University of London; and Chris Cannam
Chris@366:     shall not be used in advertising or otherwise to promote the sale,
Chris@366:     use or other dealings in this Software without prior written
Chris@366:     authorization.
Chris@366: */
Chris@366: 
Chris@366: #ifndef FFT_H
Chris@366: #define FFT_H
Chris@366: 
Chris@366: class FFT  
Chris@366: {
Chris@366: public:
Chris@366:     /**
Chris@366:      * Construct an FFT object to carry out complex-to-complex
Chris@366:      * transforms of size nsamples. nsamples does not have to be a
Chris@366:      * power of two.
Chris@366:      */
Chris@366:     FFT(int nsamples);
Chris@366:     ~FFT();
Chris@366: 
Chris@366:     /**
Chris@366:      * Carry out a forward or inverse transform (depending on the
Chris@366:      * value of inverse) of size nsamples, where nsamples is the value
Chris@366:      * provided to the constructor above.
Chris@366:      *
Chris@366:      * realIn and (where present) imagIn should contain nsamples each,
Chris@366:      * and realOut and imagOut should point to enough space to receive
Chris@366:      * nsamples each.
Chris@366:      *
Chris@366:      * imagIn may be NULL if the signal is real, but the other
Chris@366:      * pointers must be valid.
Chris@366:      *
Chris@366:      * The inverse transform is scaled by 1/nsamples.
Chris@366:      */
Chris@366:     void process(bool inverse,
Chris@366:                  const double *realIn, const double *imagIn,
Chris@366:                  double *realOut, double *imagOut);
Chris@366:     
Chris@366: private:
Chris@366:     class D;
Chris@366:     D *m_d;
Chris@366: };
Chris@366: 
Chris@366: class FFTReal
Chris@366: {
Chris@366: public:
Chris@366:     /**
Chris@366:      * Construct an FFT object to carry out real-to-complex transforms
Chris@366:      * of size nsamples. nsamples does not have to be a power of two,
Chris@366:      * but it does have to be even. (Use the complex-complex FFT above
Chris@366:      * if you need an odd FFT size. This constructor will throw
Chris@366:      * std::invalid_argument if nsamples is odd.)
Chris@366:      */
Chris@366:     FFTReal(int nsamples);
Chris@366:     ~FFTReal();
Chris@366: 
Chris@366:     /**
Chris@366:      * Carry out a forward real-to-complex transform of size nsamples,
Chris@366:      * where nsamples is the value provided to the constructor above.
Chris@366:      *
Chris@366:      * realIn, realOut, and imagOut must point to (enough space for)
Chris@366:      * nsamples values. For consistency with the FFT class above, and
Chris@366:      * compatibility with existing code, the conjugate half of the
Chris@366:      * output is returned even though it is redundant.
Chris@366:      */
Chris@366:     void forward(const double *realIn,
Chris@366:                  double *realOut, double *imagOut);
Chris@366: 
Chris@366:     /**
Chris@366:      * Carry out a forward real-to-complex transform of size nsamples,
Chris@366:      * where nsamples is the value provided to the constructor
Chris@366:      * above. Return only the magnitudes of the complex output values.
Chris@366:      *
Chris@366:      * realIn and magOut must point to (enough space for) nsamples
Chris@366:      * values. For consistency with the FFT class above, and
Chris@366:      * compatibility with existing code, the conjugate half of the
Chris@366:      * output is returned even though it is redundant.
Chris@366:      */
Chris@366:     void forwardMagnitude(const double *realIn, double *magOut);
Chris@366: 
Chris@366:     /**
Chris@366:      * Carry out an inverse real transform (i.e. complex-to-real) of
Chris@366:      * size nsamples, where nsamples is the value provided to the
Chris@366:      * constructor above.
Chris@366:      *
Chris@366:      * realIn and imagIn should point to at least nsamples/2+1 values;
Chris@366:      * if more are provided, only the first nsamples/2+1 values of
Chris@366:      * each will be used (the conjugate half will always be deduced
Chris@366:      * from the first nsamples/2+1 rather than being read from the
Chris@366:      * input data).  realOut should point to enough space to receive
Chris@366:      * nsamples values.
Chris@366:      *
Chris@366:      * The inverse transform is scaled by 1/nsamples.
Chris@366:      */
Chris@366:     void inverse(const double *realIn, const double *imagIn,
Chris@366:                  double *realOut);
Chris@366: 
Chris@366: private:
Chris@366:     class D;
Chris@366:     D *m_d;
Chris@366: };    
Chris@366: 
Chris@366: #endif