/* This file is part of the db4o object database http://www.db4o.com

Copyright (C) 2004 - 2011  Versant Corporation http://www.versant.com

db4o is free software; you can redistribute it and/or modify it under
the terms of version 3 of the GNU General Public License as published
by the Free Software Foundation.

db4o is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with this program.  If not, see http://www.gnu.org/licenses/. */
package EDU.purdue.cs.bloat.tree;

import EDU.purdue.cs.bloat.editor.*;

/**
 * ArrayRefExpr represents an expression that references an element in an array.
 */
public class ArrayRefExpr extends MemRefExpr {
	Expr array;

	Expr index;

	Type elementType;

	/**
	 * Constructor.
	 * 
	 * @param array
	 *            The array whose element we are indexing.
	 * @param index
	 *            The index into the array.
	 * @param elementType
	 *            The type of elements in array.
	 * @param type
	 *            The type of this expression.
	 */
	public ArrayRefExpr(final Expr array, final Expr index,
			final Type elementType, final Type type) {
		super(type);
		this.array = array;
		this.index = index;
		this.elementType = elementType;

		array.setParent(this);
		index.setParent(this);
	}

	public Expr array() {
		return array;
	}

	public Expr index() {
		return index;
	}

	public Type elementType() {
		return elementType;
	}

	public void visitForceChildren(final TreeVisitor visitor) {
		if (visitor.reverse()) {
			index.visit(visitor);
			array.visit(visitor);
		} else {
			array.visit(visitor);
			index.visit(visitor);
		}
	}

	public void visit(final TreeVisitor visitor) {
		visitor.visitArrayRefExpr(this);
	}

	public int exprHashCode() {
		return 4 + array.exprHashCode() ^ index.exprHashCode();
	}

	public boolean equalsExpr(final Expr other) {
		return (other != null) && (other instanceof ArrayRefExpr)
				&& ((ArrayRefExpr) other).array.equalsExpr(array)
				&& ((ArrayRefExpr) other).index.equalsExpr(index);
	}

	public Object clone() {
		return copyInto(new ArrayRefExpr((Expr) array.clone(), (Expr) index
				.clone(), elementType, type));
	}
}