annotate src/samer/units/OverlapAndAdd.java @ 8:5e3cbbf173aa tip

Reorganise some more

/*
 *	Copyright (c) 2000, Samer Abdallah, King's College London.
 *	All rights reserved.
 *
 *	This software is provided AS iS and WITHOUT ANY WARRANTY;
 *	without even the implied warranty of MERCHANTABILITY or
 *	FITNESS FOR A PARTICULAR PURPOSE.
 */

package samer.units;

import samer.maths.*;
import samer.core.*;
import samer.core.types.*;
import samer.tools.*;
import samer.functions.*;
import javax.sound.sampled.*;

/**
 * Overlap and add input vectors into a buffer. At each iteration,
 * the buffer is shifted by <hop> and the new data is added in.
 */

public class OverlapAndAdd extends NamedTask
{
	VVector			vec;	// input
	VVector			out;
	int				N, hop; // frame size, hop size
	double[]			x, y; // input and output arrays
	double[]			H; 	// array containing window, eg Hanning

	/** Create overlap and add buffer for input vector with given hop size */
	
	public OverlapAndAdd(VVector input, int hop) throws Exception
	{
		super("overlap");
		vec = input; N = vec.size();
		out = new VVector("output",N);
		H=new double[N];
		x=vec.array();
		y=out.array();
		this.hop=hop;
	}

	/** Sets windowing array to samples from the given function.
	 *  The domain [0,1) is mapped on to the array indices 0:N-1 
	 */ 
	
	public void setWindow(Function fn) {
		for (int i=0; i<N; i++) H[i] = (double)i/N;
		fn.apply(H);
	}

	public VVector input() { return vec; }
	public VVector output() { return out; }
	public void setHop(int hop) { this.hop=hop; }

	public void dispose() { out.dispose(); }
	public void run() throws Exception
	{
		// shift everything in buffer along
		System.arraycopy(y,hop,y,0,N-hop);

		// addin new stuff
		int i=0;
		for (; i<N-hop; i++) y[i]+=H[i]*x[i];
		for (; i<N; i++) y[i]=H[i]*x[i];

		out.changed();
	}
}