BaseMemoryWriteTracker.java

/*
  BaseMemoryWriteTracker.java

  (c) 2012-2015 Edward Swartz

  All rights reserved. This program and the accompanying materials
  are made available under the terms of the Eclipse Public License v1.0
  which accompanies this distribution, and is available at
  http://www.eclipse.org/legal/epl-v10.html
 */
package v9t9.common.memory;

import java.util.BitSet;


/**
 * Track a series of changes to a memory domain
 * @author ejs
 *
 */
public abstract class BaseMemoryWriteTracker {
	protected final IMemoryDomain domain;
	private final int granularityShift;
	private BitSet trackedMemory = new BitSet();
	private IMemoryWriteListener memoryWriteListener;
	
	/**
	 * Track changes to memory, allowing future changes at a granularity of 'granularityShift'
	 * @param domain
	 * @param granularityShift
	 */
	public BaseMemoryWriteTracker(IMemoryDomain domain, int granularityShift) {
		this.domain = domain;
		this.granularityShift = granularityShift;
	}
	
	public synchronized void addMemoryRange(int addr, int size) {
		addr >>>= granularityShift;
		if (granularityShift > 0)
			size = (size + ~(~0 >>> (32 - granularityShift)) - 1) >>> granularityShift;
			
		while (size > 0) {
			if (!trackedMemory.get(addr)) {
				trackedMemory.set(addr);
				recordChange(addr, 1, domain.flatReadByte(addr));
			}
			size--;
			addr++;
		}
	}
	
	public synchronized void removeMemoryRange(int addr, int size) {
		addr >>>= granularityShift;
		if (granularityShift > 0)
			size = (size + ~(~0 >>> (32 - granularityShift)) - 1) >>> granularityShift;
		trackedMemory.set(addr, addr + size, false);
	}
	
	public synchronized void addMemoryListener() {
		if (memoryWriteListener == null) {
			memoryWriteListener = new IMemoryWriteListener() {
	
				public void changed(IMemoryEntry entry, int addr, int size, final int value) {
					synchronized (BaseMemoryWriteTracker.this) {
						int xaddr = addr >>> granularityShift;
						if (trackedMemory.get(xaddr)) {
							recordChange(addr, size, value);
						}
					}
				}
				
			};
			
			clearChanges();
			domain.addWriteListener(memoryWriteListener);
		}
	}
	
	abstract protected void recordChange(int addr, int size, int val);

	abstract public void clearChanges();
	
	public synchronized void removeMemoryListener() {
		if (memoryWriteListener != null) {
			domain.removeWriteListener(memoryWriteListener);
			memoryWriteListener = null;
		}
	}
}