samer@0: /*
samer@0:  *	Copyright (c) 2000, Samer Abdallah, King's College London.
samer@0:  *	All rights reserved.
samer@0:  *
samer@0:  *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
samer@0:  *	without even the implied warranty of MERCHANTABILITY or 
samer@0:  *	FITNESS FOR A PARTICULAR PURPOSE.
samer@0:  */
samer@0: 
samer@0: package samer.units;
samer@0: import  samer.core.*;
samer@0: import  samer.maths.*;
samer@0: import  samer.maths.random.*;
samer@0: 
samer@0: /**
samer@0: 	Periodic generator: generates periodic signal from
samer@0: 	a wave table
samer@0:  */
samer@0: 
samer@0: public class Wavetable implements Generator
samer@0: {
samer@0: 	int		start, end, j;
samer@0: 	Vec		vec;
samer@0: 	double [] pp;
samer@0: 
samer@0: 	public Wavetable(Vec vec) {
samer@0: 		this(vec,0,vec.size());
samer@0: 	}
samer@0: 
samer@0: 	public Wavetable(Vec vec, int start, int end) 
samer@0: 	{ 
samer@0: 		this.vec   = vec;
samer@0: 		this.start = start;
samer@0: 		this.end   = end;
samer@0: 		pp = vec.array();
samer@0: 		j = start;
samer@0: 	}
samer@0: 
samer@0: 	public int  period() { return end-start; }
samer@0: 	public void dispose() {}
samer@0: 	public double next() 
samer@0: 	{ 
samer@0: 		double r=pp[j++]; 
samer@0: 		if (j>=end) j=start; 
samer@0: 		return r; 
samer@0: 	}
samer@0: 
samer@0: 	public void next(double [] x) 
samer@0: 	{ 
samer@0: 		int	remaining=x.length;
samer@0: 		int	iput=0;
samer@0: 
samer@0: 		while (remaining>0) {
samer@0: 			int avail = end-j;
samer@0: 			int block = remaining > avail ? avail : remaining;
samer@0: 
samer@0: 			System.arraycopy( pp, j, x,iput, block);
samer@0: 			j+=block; iput+=block; remaining-=block;
samer@0: 			if (j>=end) j=start;
samer@0: 		}
samer@0: 	}
samer@0: 
samer@0: 	public String toString() { return "wavetable"; }
samer@0: } 
samer@0: 		
samer@0: