package org.eclipse.team.internal.ccvs.core.util;

/*
 * (c) Copyright IBM Corp. 2000, 2002.
 * All Rights Reserved.
 */
 
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.SubProgressMonitor;

/**
 * Provides an infinite progress monitor by subdividing by half repeatedly.
 * 
 * The ticks parameter represents the number of ticks shown in the progress dialog.
 * However, the number of ticks that can actually be worked is n*ticks/2 where
 * 2^n = ticks. What this means is that if you provide a ticks of 32 (2^5) than
 * the maximum number of ticks is 5*32/2 = 80.
 * 
 */
public class InfiniteSubProgressMonitor extends SubProgressMonitor {

	int totalWork;
	int halfWay;
	int currentIncrement;
	int nextProgress;
	int worked;
		
	/**
	 * Constructor for InfiniteSubProgressMonitor.
	 * @param monitor
	 * @param ticks
	 */
	public InfiniteSubProgressMonitor(IProgressMonitor monitor, int ticks) {
		this(monitor, ticks, 0);
	}

	/**
	 * Constructor for InfiniteSubProgressMonitor.
	 * @param monitor
	 * @param ticks
	 * @param style
	 */
	public InfiniteSubProgressMonitor(IProgressMonitor monitor, int ticks, int style) {
		super(monitor, ticks, style);
	}
	
	public void beginTask(String name, int totalWork) {
		super.beginTask(name, totalWork);
		this.totalWork = totalWork;
		this.halfWay = totalWork / 2;
		this.currentIncrement = 1;
		this.nextProgress = currentIncrement;
		this.worked = 0;
	}
	
	public void worked(int work) {
		if (worked >= totalWork) return;
		if (--nextProgress <= 0) {
			super.worked(1);
			worked++;
			if (worked >= halfWay) {
				// we have passed the current halfway point, so double the
				// increment and reset the halfway point.
				currentIncrement *= 2;
				halfWay += (totalWork - halfWay) / 2;				
			}
			// reset the progress counter to another full increment
			nextProgress = currentIncrement;
		}			
	}

}