122 lines
2.7 KiB
C++
122 lines
2.7 KiB
C++
/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
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/*
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QM DSP Library
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Centre for Digital Music, Queen Mary, University of London.
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This file 2005-2006 Christian Landone.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version. See the file
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COPYING included with this distribution for more information.
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*/
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#include "FiltFilt.h"
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//////////////////////////////////////////////////////////////////////
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// Construction/Destruction
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//////////////////////////////////////////////////////////////////////
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FiltFilt::FiltFilt(Filter::Parameters parameters) :
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m_filter(parameters)
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{
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m_ord = m_filter.getOrder();
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}
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FiltFilt::~FiltFilt()
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{
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}
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void FiltFilt::process(double *src, double *dst, unsigned int length)
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{
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unsigned int i;
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if (length == 0) return;
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if (length < 2) {
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for( i = 0; i < length; i++ ) {
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dst[i] = src [i];
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}
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return;
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}
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unsigned int nFilt = m_ord + 1;
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unsigned int nFact = 3 * ( nFilt - 1);
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unsigned int nExt = length + 2 * nFact;
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double *filtScratchIn = new double[ nExt ];
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double *filtScratchOut = new double[ nExt ];
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for( i = 0; i< nExt; i++ )
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{
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filtScratchIn[ i ] = 0.0;
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filtScratchOut[ i ] = 0.0;
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}
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// Edge transients reflection
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double sample0 = 2 * src[ 0 ];
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double sampleN = 2 * src[ length - 1 ];
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unsigned int index = 0;
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for( i = nFact; i > 0; i-- )
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{
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filtScratchIn[ index++ ] = sample0 - src[ i ];
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}
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index = 0;
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for( i = 0; i < nFact && i + 2 < length; i++ )
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{
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filtScratchIn[ (nExt - nFact) + index++ ] = sampleN - src[ (length - 2) - i ];
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}
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for(; i < nFact; i++ )
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{
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filtScratchIn[ (nExt - nFact) + index++ ] = 0;
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}
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index = 0;
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for( i = 0; i < length; i++ )
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{
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filtScratchIn[ i + nFact ] = src[ i ];
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}
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////////////////////////////////
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// Do 0Ph filtering
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m_filter.process( filtScratchIn, filtScratchOut, nExt);
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// reverse the series for FILTFILT
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for ( i = 0; i < nExt; i++)
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{
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filtScratchIn[ i ] = filtScratchOut[ nExt - i - 1];
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}
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// do FILTER again
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m_filter.process( filtScratchIn, filtScratchOut, nExt);
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// reverse the series back
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for ( i = 0; i < nExt; i++)
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{
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filtScratchIn[ i ] = filtScratchOut[ nExt - i - 1 ];
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}
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for ( i = 0;i < nExt; i++)
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{
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filtScratchOut[ i ] = filtScratchIn[ i ];
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}
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index = 0;
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for( i = 0; i < length; i++ )
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{
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dst[ index++ ] = filtScratchOut[ i + nFact ];
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}
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delete [] filtScratchIn;
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delete [] filtScratchOut;
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}
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void FiltFilt::reset()
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{
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}
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