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/*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* Copyright 2009-2011 Jörg Hermann Müller
*
* This file is part of AudaSpace.
*
* Audaspace 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.
*
* AudaSpace 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 Audaspace; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* ***** END GPL LICENSE BLOCK *****
*/
/** \file audaspace/FX/AUD_BaseIIRFilterReader.h
* \ingroup audfx
*/
#ifndef __AUD_BASEIIRFILTERREADER_H__
#define __AUD_BASEIIRFILTERREADER_H__
#include "AUD_EffectReader.h"
#include "AUD_Buffer.h"
/**
* This class is a base class for infinite impulse response filters.
*/
class AUD_BaseIIRFilterReader : public AUD_EffectReader
{
private:
/**
* Specs.
*/
AUD_Specs m_specs;
/**
* Length of input samples needed.
*/
int m_xlen;
/**
* Length of output samples needed.
*/
int m_ylen;
/**
* The last in samples array.
*/
sample_t* m_x;
/**
* The last out samples array.
*/
sample_t* m_y;
/**
* Position of the current input sample in the input array.
*/
int m_xpos;
/**
* Position of the current output sample in the output array.
*/
int m_ypos;
/**
* Current channel.
*/
int m_channel;
// hide copy constructor and operator=
AUD_BaseIIRFilterReader(const AUD_BaseIIRFilterReader&);
AUD_BaseIIRFilterReader& operator=(const AUD_BaseIIRFilterReader&);
protected:
/**
* Creates a new base IIR filter reader.
* \param reader The reader to read from.
* \param in The count of past input samples needed.
* \param out The count of past output samples needed.
*/
AUD_BaseIIRFilterReader(boost::shared_ptr<AUD_IReader> reader, int in, int out);
void setLengths(int in, int out);
public:
/**
* Retrieves the last input samples.
* \param pos The position, valid are 0 (current) or negative values.
* \return The sample value.
*/
inline sample_t x(int pos)
{
return m_x[(m_xpos + pos + m_xlen) % m_xlen * m_specs.channels + m_channel];
}
/**
* Retrieves the last output samples.
* \param pos The position, valid are negative values.
* \return The sample value.
*/
inline sample_t y(int pos)
{
return m_y[(m_ypos + pos + m_ylen) % m_ylen * m_specs.channels + m_channel];
}
virtual ~AUD_BaseIIRFilterReader();
virtual void read(int& length, bool& eos, sample_t* buffer);
/**
* Runs the filtering function.
* \return The current output sample value.
*/
virtual sample_t filter()=0;
/**
* Notifies the filter about a sample rate change.
* \param rate The new sample rate.
*/
virtual void sampleRateChanged(AUD_SampleRate rate);
};
#endif //__AUD_BASEIIRFILTERREADER_H__
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