[Abora-cvs] abora-ash/src/org/abora/ash/space Region.java,NONE,1.1 IntegerRegion.java,NONE,1.1

[<dg...@us...>]

Update of /cvsroot/abora/abora-ash/src/org/abora/ash/space
In directory sc8-pr-cvs1:/tmp/cvs-serv3306/src/org/abora/ash/space

Added Files:
	Region.java IntegerRegion.java 
Log Message:
-Add start of Ash subproject, which is currently the beginnings of a port of the dolphin-demo smalltalk server code

--- NEW FILE: Region.java ---
/*
 * Abora-Ash
 * Part of the Abora hypermedia project: http://www.abora.org
 * Copyright 2003 David G Jones
 */

package org.abora.ash.space;

import org.abora.ash.engine.AboraObject;

/**
 */
public abstract class Region extends AboraObject {

}

--- NEW FILE: IntegerRegion.java ---
/*
 * Abora-Ash
 * Part of the Abora hypermedia project: http://www.abora.org
 * Copyright 2003 David G Jones
 */

package org.abora.ash.space;


/**
 */
public class IntegerRegion extends Region {
	private final int startPosition;
	private final int extent;
	private static final IntegerRegion EMPTY_REGION = new IntegerRegion(0, 0);

	private IntegerRegion(int startPosition, int extent) {
		this.startPosition = startPosition;
		this.extent = extent;
	}
	public static IntegerRegion startExtent(int startPosition, int extent) {
		return new IntegerRegion(startPosition, extent);
	}
	public static IntegerRegion startEnd(int startPosition, int endPosition) {
		return new IntegerRegion(startPosition, endPosition - startPosition + 1);
	}
	public static IntegerRegion empty() {
		return EMPTY_REGION;
	}

	public boolean equals(Object o) {
		if (!(o instanceof IntegerRegion))
			return false;
		IntegerRegion r = (IntegerRegion) o;
		return r.getStartPosition() == getStartPosition() && r.getExtent() == getExtent();
	}
	public int getExtent() {
		return extent;
	}

	public int getStartPosition() {
		return startPosition;
	}
	public int getBeyondPosition() {
		return getStartPosition() + getExtent();
	}
	public String asString() {
		return "IntegerRegion[" + getStartPosition() + ", " + getEndPosition() + "]";
	}
	//	do: operation
	//		^self startPosition to: self endPosition do: [:position | operation value: position]!
	public int getEndPosition() {
		return getStartPosition() + getExtent() - 1;
	}
	public int hashCode() {
		return getStartPosition() << 1 | getExtent();
	}
	public boolean includes(int position) {
		final int relativePosition = relativePosition(position);
		return relativePosition >= 0 && relativePosition < getExtent();
	}
	/**
	 * Answer a region with positions the receiver and anotherRegion have in common.
	 */
	public IntegerRegion intersection(IntegerRegion anotherRegion) {
		if (intersects(anotherRegion)) {
			int newStart = Math.max(getStartPosition(), anotherRegion.getStartPosition());
			int newEnd = Math.min(getEndPosition(), anotherRegion.getEndPosition());
			return IntegerRegion.startEnd(newStart, newEnd);
		} else {
			return IntegerRegion.empty();
		}
	}
	/*
	 * Answer whether any position of the receiver can be found in anotherRegion.
	 */
	public boolean intersects(IntegerRegion anotherRegion) {
		return getStartPosition() <= anotherRegion.getEndPosition()
			&& getEndPosition() >= anotherRegion.getStartPosition();
	}
	public boolean isEmpty() {
		return getExtent() <= 0;
	}
	public int relativePosition(int position) {
		return position - getStartPosition();
	}
}