/*
 * Copyright  2000-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); 
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License. 
 *
 */
package org.apache.bcel.classfile;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import org.apache.bcel.Constants;

/**
 * This class represents a stack map attribute used for preverification of Java
 * classes for the <a href="http://java.sun.com/j2me/"> Java 2 Micro Edition</a>
 * (J2ME). This attribute is used by the <a
 * href="http://java.sun.com/products/cldc/">KVM</a> and contained within the
 * Code attribute of a method. See CLDC specification 5.3.1.2
 * 
 * @version $Id: StackMap.java 386056 2006-03-15 11:31:56Z tcurdt $
 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 * @see Code
 * @see StackMapEntry
 * @see StackMapType
 */
public final class StackMap extends Attribute implements Node {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private int map_length;
	private StackMapEntry[] map; // Table of stack map entries

	/*
	 * @param name_index Index of name
	 * 
	 * @param length Content length in bytes
	 * 
	 * @param map Table of stack map entries
	 * 
	 * @param constant_pool Array of constants
	 */
	public StackMap(int name_index, int length, StackMapEntry[] map,
			ConstantPool constant_pool) {
		super(Constants.ATTR_STACK_MAP, name_index, length, constant_pool);
		setStackMap(map);
	}

	/**
	 * Construct object from file stream.
	 * 
	 * @param name_index
	 *            Index of name
	 * @param length
	 *            Content length in bytes
	 * @param file
	 *            Input stream
	 * @param constant_pool
	 *            Array of constants
	 * @throws IOException
	 */
	StackMap(int name_index, int length, DataInputStream file,
			ConstantPool constant_pool) throws IOException {
		this(name_index, length, (StackMapEntry[]) null, constant_pool);
		map_length = file.readUnsignedShort();
		map = new StackMapEntry[map_length];
		for (int i = 0; i < map_length; i++) {
			map[i] = new StackMapEntry(file, constant_pool);
		}
	}

	/**
	 * Dump line number table attribute to file stream in binary format.
	 * 
	 * @param file
	 *            Output file stream
	 * @throws IOException
	 */
	@Override
	public final void dump(DataOutputStream file) throws IOException {
		super.dump(file);
		file.writeShort(map_length);
		for (int i = 0; i < map_length; i++) {
			map[i].dump(file);
		}
	}

	/**
	 * @return Array of stack map entries
	 */
	public final StackMapEntry[] getStackMap() {
		return map;
	}

	/**
	 * @param map
	 *            Array of stack map entries
	 */
	public final void setStackMap(StackMapEntry[] map) {
		this.map = map;
		map_length = (map == null) ? 0 : map.length;
	}

	/**
	 * @return String representation.
	 */
	@Override
	public final String toString() {
		StringBuffer buf = new StringBuffer("StackMap(");
		for (int i = 0; i < map_length; i++) {
			buf.append(map[i].toString());
			if (i < map_length - 1) {
				buf.append(", ");
			}
		}
		buf.append(')');
		return buf.toString();
	}

	/**
	 * @return deep copy of this attribute
	 */
	@Override
	public Attribute copy(ConstantPool _constant_pool) {
		StackMap c = (StackMap) clone();
		c.map = new StackMapEntry[map_length];
		for (int i = 0; i < map_length; i++) {
			c.map[i] = map[i].copy();
		}
		c.constant_pool = _constant_pool;
		return c;
	}

	/**
	 * Called by objects that are traversing the nodes of the tree implicitely
	 * defined by the contents of a Java class. I.e., the hierarchy of methods,
	 * fields, attributes, etc. spawns a tree of objects.
	 * 
	 * @param v
	 *            Visitor object
	 */
	@Override
	public void accept(Visitor v) {
		v.visitStackMap(this);
	}

	public final int getMapLength() {
		return map_length;
	}
}
