/*
<This Java Class is part of the jMusic API version 1.5, March 2004.>
Copyright (C) 2000 Andrew Sorensen & Andrew Brown
This program 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 any
later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
package jm.audio.synth;
import java.io.IOException;
import java.util.Vector;
import java.lang.Float;
import jm.audio.AudioObject;
import jm.audio.AOException;
import jm.music.data.Note;
/**
* The <bl>Delay</bl> Audio Object is a simple delay line.
* It calculates the delay time in samples (so the time will depend
* on the current sample rate). It only passes on the delayed data
* so an add Audio Object needs to be used in the chain to mix the
* delayed signal with the original if that is required for an echo effect.
* @author Andrew Brown
* @version 1.0,Sun Feb 25 18:42:45 2001
*/
public final class Delay extends AudioObject{
//----------------------------------------------
// Attributes
//----------------------------------------------
/**
* A place to keep the previous sample values
*/
Vector storedSamples = new Vector();
// Vector <Float> storedSamples = new Vector<Float>(); // solves java generics warnings but breaks 1.3 compatability
/**
* The number of samples long the delay line is
*/
int sampleDelay = 0;
/**
* The number of samples processed so far
*/
int sampleCounter = 0;
//----------------------------------------------
// Constructors
//----------------------------------------------
/**
* The Delay constructor takes the object previous
* to it in the chain, and the delay length in samples.
* @param sampleDelay the lenght of the delay in samples
* @param ao the single AudioObject taken as input.
*/
public Delay(AudioObject ao, int sampleDelay){
super(ao, "[Delay]");
this.sampleDelay = sampleDelay;
}
//----------------------------------------------
// Public Methods
//----------------------------------------------
//----------------------------------------------
// Protected Methods
//----------------------------------------------
/**
* The nextWork method for <bl>Delay<bl> will store
* the sample and send out the delayed one instead.
*/
public int work(float[] buffer)throws AOException{
int returned = this.previous[0].nextWork(buffer);
if (sampleCounter >= sampleDelay) {
for(int i=0;i<returned;i++){
// keep the current sample from the chain
storedSamples.addElement(new Float(buffer[i]));
// replace it with a stored sample
Float tempFloat = (Float)storedSamples.elementAt(storedSamples.size()-1);
buffer[i] = tempFloat.floatValue();
// remove the used stored sample
storedSamples.removeElementAt(storedSamples.size()-1);
}
} else { // early on pad with silence
for(int i=0;i<returned;i++){
// keep the current sample from the chain
storedSamples.addElement(new Float(buffer[i]));
// send out a zero value
buffer[i] = (float)0.0;
}
}
sampleCounter ++;
return returned;
}
}