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/*
Copyright (C) 2000 Jeff Tranter
tranter@pobox.com
2001 Matthias Kretz
kretz@kde.org
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
#include "artsmodulessynth.h"
#include "stdsynthmodule.h"
#include <math.h>
#include <cstring>
using namespace Arts;
// This delays the input signal for an amount of time. The time
// specification can be any number greater or equal zero.
// The delay is constant during the calculation, that means it
// can't be modified. This saves computing time as no interpolation is
// done, and is useful for recursive structures. Actually it can be
// modified, but without interpolation it won't sound too good. See
// the description for Synth_DELAY.
class Synth_CDELAY_impl : virtual public Synth_CDELAY_skel,
virtual public StdSynthModule
{
protected:
unsigned long _buffersize;
unsigned long _bitmask;
float *_buffer; // holds the data to be delayed (variable size)
float _delaytime;
unsigned int _readpos;
unsigned int _writepos;
public:
Synth_CDELAY_impl() : _buffersize( 0 ), _bitmask( 0 ), _buffer( 0 ), _delaytime( 0 ), _readpos( 0 ), _writepos( 0 )
{
}
~Synth_CDELAY_impl()
{
delete[] _buffer;
}
float time() { return _delaytime; }
void time(float newTime)
{
_delaytime = newTime;
double n = ceil( log( double(_delaytime * samplingRateFloat )) / log( 2. ) );
unsigned long newbuffersize = (unsigned long)( pow( 2, n ) );
unsigned long newbitmask = newbuffersize - 1;
if( newbuffersize != _buffersize )
{
float *newbuffer = new float[newbuffersize];
if( newbuffersize > _buffersize ) {
for( unsigned long i = 0; i < _buffersize; i++ ) {
newbuffer[i] = _buffer[_writepos];
_writepos++;
_writepos &= newbitmask;
}
for( unsigned long i = _buffersize; i < newbuffersize; i++ )
newbuffer[i] = 0;
} else {
_writepos -= newbuffersize;
_writepos &= newbitmask;
for( unsigned long i = 0; i < newbuffersize; i++ ) {
newbuffer[i] = _buffer[_writepos];
_writepos++;
_writepos &= newbitmask;
}
}
_buffer = newbuffer;
_buffersize = newbuffersize;
_bitmask = newbitmask;
}
_readpos = (unsigned long)rint( _writepos - _delaytime * samplingRateFloat ) & _bitmask;
time_changed( _delaytime );
}
void streamInit()
{
// initialize buffer to all zeroes
if( _buffer )
for( unsigned long i = 0; i < _buffersize; i++ )
_buffer[i] = 0.0;
}
void calculateBlock(unsigned long samples)
{
if( ! _buffer ) {
memcpy( outvalue, invalue, sizeof( float ) * samples );
return;
}
for( unsigned long i = 0; i < samples; i++ ) {
_buffer[_writepos] = invalue[i];
outvalue[i] = _buffer[_readpos];
_readpos++;
_readpos &= _bitmask;
_writepos++;
_writepos &= _bitmask;
}
}
};
// vim:sw=4:ts=4
REGISTER_IMPLEMENTATION(Synth_CDELAY_impl);
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