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123 lines
3.6 KiB
123 lines
3.6 KiB
/*
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Copyright (C) 2000 Jeff Tranter
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tranter@pobox.com
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2001 Matthias Kretz
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kretz@kde.org
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public License
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along with this library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA.
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*/
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#include "artsmodulessynth.h"
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#include "stdsynthmodule.h"
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#include <math.h>
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#include <cstring>
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using namespace Arts;
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// This delays the input signal for an amount of time. The time
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// specification can be any number greater or equal zero.
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// The delay is constant during the calculation, that means it
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// can't be modified. This saves computing time as no interpolation is
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// done, and is useful for recursive structures. Actually it can be
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// modified, but without interpolation it won't sound too good. See
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// the description for Synth_DELAY.
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class Synth_CDELAY_impl : virtual public Synth_CDELAY_skel,
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virtual public StdSynthModule
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{
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protected:
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unsigned long _buffersize;
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unsigned long _bitmask;
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float *_buffer; // holds the data to be delayed (variable size)
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float _delaytime;
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unsigned int _readpos;
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unsigned int _writepos;
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public:
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Synth_CDELAY_impl() : _buffersize( 0 ), _bitmask( 0 ), _buffer( 0 ), _delaytime( 0 ), _readpos( 0 ), _writepos( 0 )
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{
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}
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~Synth_CDELAY_impl()
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{
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delete[] _buffer;
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}
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float time() { return _delaytime; }
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void time(float newTime)
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{
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_delaytime = newTime;
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double n = ceil( log( double(_delaytime * samplingRateFloat )) / log( 2. ) );
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unsigned long newbuffersize = (unsigned long)( pow( 2, n ) );
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unsigned long newbitmask = newbuffersize - 1;
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if( newbuffersize != _buffersize )
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{
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float *newbuffer = new float[newbuffersize];
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if( newbuffersize > _buffersize ) {
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for( unsigned long i = 0; i < _buffersize; i++ ) {
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newbuffer[i] = _buffer[_writepos];
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_writepos++;
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_writepos &= newbitmask;
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}
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for( unsigned long i = _buffersize; i < newbuffersize; i++ )
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newbuffer[i] = 0;
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} else {
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_writepos -= newbuffersize;
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_writepos &= newbitmask;
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for( unsigned long i = 0; i < newbuffersize; i++ ) {
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newbuffer[i] = _buffer[_writepos];
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_writepos++;
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_writepos &= newbitmask;
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}
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}
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_buffer = newbuffer;
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_buffersize = newbuffersize;
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_bitmask = newbitmask;
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}
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_readpos = (unsigned long)rint( _writepos - _delaytime * samplingRateFloat ) & _bitmask;
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time_changed( _delaytime );
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}
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void streamInit()
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{
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// initialize buffer to all zeroes
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if( _buffer )
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for( unsigned long i = 0; i < _buffersize; i++ )
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_buffer[i] = 0.0;
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}
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void calculateBlock(unsigned long samples)
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{
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if( ! _buffer ) {
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memcpy( outvalue, invalue, sizeof( float ) * samples );
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return;
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}
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for( unsigned long i = 0; i < samples; i++ ) {
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_buffer[_writepos] = invalue[i];
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outvalue[i] = _buffer[_readpos];
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_readpos++;
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_readpos &= _bitmask;
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_writepos++;
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_writepos &= _bitmask;
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}
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}
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};
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REGISTER_IMPLEMENTATION(Synth_CDELAY_impl);
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