FIRFilter.h

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//
// Last changed  : $Date$
// File revision : $Revision$
//
// $Id$
//
//
// License :
//
//  SoundTouch audio processing library
//  Copyright (c) Olli Parviainen
//
//  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
//

#ifndef FIRFilter_H
#define FIRFilter_H

#include "STTypes.h"

class FIRFilter 
{
protected:
    // Number of FIR filter taps
    uint length;    
    // Number of FIR filter taps divided by 8
    uint lengthDiv8;

    // Result divider factor in 2^k format
    uint resultDivFactor;

    // Result divider value.
    soundtouch::SAMPLETYPE resultDivider;

    // Memory for filter coefficients
    soundtouch::SAMPLETYPE *filterCoeffs;

    virtual uint evaluateFilterStereo(soundtouch::SAMPLETYPE *dest, 
                                      const soundtouch::SAMPLETYPE *src, 
                                      uint numSamples) const;
    virtual uint evaluateFilterMono(soundtouch::SAMPLETYPE *dest, 
                                    const soundtouch::SAMPLETYPE *src, 
                                    uint numSamples) const;

public:
    FIRFilter();
    virtual ~FIRFilter();

    void * operator new(size_t s);

    static FIRFilter *newInstance();

    uint evaluate(soundtouch::SAMPLETYPE *dest, 
                  const soundtouch::SAMPLETYPE *src, 
                  uint numSamples, 
                  uint numChannels) const;

    uint getLength() const;

    virtual void setCoefficients(const soundtouch::SAMPLETYPE *coeffs, 
                                 uint newLength, 
                                 uint uResultDivFactor);
};


// Optional subclasses that implement CPU-specific optimizations:

#ifdef ALLOW_SSE2

    class FIRFilterSSE2 : public FIRFilter
    {
    protected:
        float *filterCoeffsUnalign;
        float *filterCoeffsAlign;

        virtual uint evaluateFilterStereo(float *dest, const float *src, uint numSamples) const;
    public:
        FIRFilterSSE2();
        ~FIRFilterSSE2();

        virtual void setCoefficients(const float *coeffs, uint newLength, uint uResultDivFactor);
    };

#endif // ALLOW_SSE2

#ifdef ALLOW_MMX

    class FIRFilterMMX : public FIRFilter
    {
    protected:
        short *filterCoeffsUnalign;
        short *filterCoeffsAlign;

        virtual uint evaluateFilterStereo(short *dest, const short *src, uint numSamples) const;
    public:
        FIRFilterMMX();
        ~FIRFilterMMX();

        virtual void setCoefficients(const short *coeffs, uint newLength, uint uResultDivFactor);
    };

#endif // ALLOW_MMX

#endif  // FIRFilter_H