diff options
Diffstat (limited to 'src/loris/FourierTransform.h')
| -rw-r--r-- | src/loris/FourierTransform.h | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/src/loris/FourierTransform.h b/src/loris/FourierTransform.h new file mode 100644 index 0000000..34867ee --- /dev/null +++ b/src/loris/FourierTransform.h @@ -0,0 +1,223 @@ +#ifndef INCLUDE_FOURIERTRANSFORM_H +#define INCLUDE_FOURIERTRANSFORM_H +/* + * This is the Loris C++ Class Library, implementing analysis, + * manipulation, and synthesis of digitized sounds using the Reassigned + * Bandwidth-Enhanced Additive Sound Model. + * + * Loris is Copyright (c) 1999-2010 by Kelly Fitz and Lippold Haken + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * + * FourierTransform.h + * + * Definition of class Loris::FourierTransform, providing a simplified + * uniform interface to the FFTW library (www.fftw.org), version 2.1.3 + * or newer (including version 3), or to the General Purpose FFT package + * by Takuya OOURA, http://momonga.t.u-tokyo.ac.jp/~ooura/fft.html if + * FFTW is unavailable. + * + * Kelly Fitz, 2 Jun 2006 + * loris@cerlsoundgroup.org + * + * http://www.cerlsoundgroup.org/Loris/ + * + */ +#include <complex> +#include <vector> + +// begin namespace +namespace Loris { + +// insulating implementation class, defined in FourierTransform.C +class FTimpl; + +// --------------------------------------------------------------------------- +// class FourierTransform +// +//! FourierTransform provides a simplified interface to the FFTW library +//! (www.fftw.org). Loris uses the FFTW library to perform efficient +//! Fourier transforms of arbitrary length. Clients store and access +//! the in-place transform data as a sequence of std::complex< double >. +//! Samples are stored in the FourierTransform instance using subscript +//! or iterator access, the transform is computed by the transform member, +//! and the transformed samples replace the input samples, and are +//! accessed by subscript or iterator. FourierTransform computes a complex +//! transform, so it can be used to invert a transform of real samples +//! as well. Uses the standard library complex class, which implements +//! arithmetic operations. +//! +//! Supports FFTW versions 2 and 3. +//! Does not make use of FFTW "wisdom" to speed up transform computation. +//! +//! If FFTW is unavailable, uses instead the General Purpose FFT package +//! by Takuya OOURA, http://momonga.t.u-tokyo.ac.jp/~ooura/fft.html defined +//! in fftsg.c for power-of-two transforms, and a very slow direct DFT +//! implementation for non-PO2 transforms. +// +class FourierTransform +{ +// -- public interface -- +public: + + //! An unsigned integral type large enough + //! to represent the length of any transform. + typedef std::vector< std::complex< double > >::size_type size_type; + + //! The type of a non-const iterator of (complex) transform samples. + typedef std::vector< std::complex< double > >::iterator iterator; + + //! The type of a const iterator of (complex) transform samples. + typedef std::vector< std::complex< double > >::const_iterator const_iterator; + +// --- lifecycle --- + + //! Initialize a new FourierTransform of the specified size. + //! + //! \param len is the length of the transform in samples (the + //! number of samples in the transform) + //! \throw RuntimeError if the necessary buffers cannot be + //! allocated, or there is an error configuring FFTW. + FourierTransform( size_type len ); + + //! Initialize a new FourierTransform that is a copy of another, + //! having the same size and the same buffer contents. + //! + //! \param rhs is the instance to copy + //! \throw RuntimeError if the necessary buffers cannot be + //! allocated, or there is an error configuring FFTW. + FourierTransform( const FourierTransform & rhs ); + + //! Free the resources associated with this FourierTransform. + ~FourierTransform( void ); + +// --- operators --- + + //! Make this FourierTransform a copy of another, having + //! the same size and buffer contents. + //! + //! \param rhs is the instance to copy + //! \return a refernce to this instance + //! \throw RuntimeError if the necessary buffers cannot be + //! allocated, or there is an error configuring FFTW. + FourierTransform & operator= ( const FourierTransform & rhs ); + + +// --- access/mutation --- + + //! Access (read/write) a transform sample by index. + //! Use this member to fill the transform buffer before + //! computing the transform, and to access the samples + //! after computing the transform. (inlined for speed) + //! + //! \param index is the index or rank of the complex + //! transform sample to access. Zero is the first + //! position in the buffer. + //! \return non-const reference to the std::complex< double > + //! at the specified position in the buffer. + std::complex< double > & operator[] ( size_type index ) + { + return _buffer[ index ]; + } + + //! Access (read-only) a transform sample by index. + //! Use this member to fill the transform buffer before + //! computing the transform, and to access the samples + //! after computing the transform. (inlined for speed) + //! + //! \param index is the index or rank of the complex + //! transform sample to access. Zero is the first + //! position in the buffer. + //! \return const reference to the std::complex< double > + //! at the specified position in the buffer. + const std::complex< double > & operator[] ( size_type index ) const + { + return _buffer[ index ]; + } + + //! Return an iterator refering to the beginning of the sequence of + //! complex samples in the transform buffer. + //! + //! \return a non-const iterator refering to the first position + //! in the transform buffer. + iterator begin( void ) + { + return _buffer.begin(); + } + + //! Return an iterator refering to the end of the sequence of + //! complex samples in the transform buffer. + //! + //! \return a non-const iterator refering to one past the last + //! position in the transform buffer. + iterator end( void ) + { + return _buffer.end(); + } + + //! Return a const iterator refering to the beginning of the sequence of + //! complex samples in the transform buffer. + //! + //! \return a const iterator refering to the first position + //! in the transform buffer. + const_iterator begin( void ) const + { + return _buffer.begin(); + } + + //! Return a const iterator refering to the end of the sequence of + //! complex samples in the transform buffer. + //! + //! \return a const iterator refering to one past the last + //! position in the transform buffer. + const_iterator end( void ) const + { + return _buffer.end(); + } + +// --- operations --- + + //! Compute the Fourier transform of the samples stored in the + //! transform buffer. The samples stored in the transform buffer + //! (accessed by index or by iterator) are replaced by the + //! transformed samples, in-place. + void transform( void ); + +// --- inquiry --- + + //! Return the length of the transform (in samples). + //! + //! \return the length of the transform in samples. + size_type size( void ) const ; + +// -- instance variables -- +private: + + //! buffer containing the complex transform input before + //! computing the transform, and the complex transform output + //! after computing the transform + std::vector< std::complex< double > > _buffer; + + // insulating implementation instance (defined in + // FourierTransform.C), conceals interface to FFTW + FTimpl * _impl; + +}; // end of class FourierTransform + + +} // end of namespace Loris + +#endif /* ndef INCLUDE_FOURIERTRANSFORM_H */ |