If.java

/*
 * JSwiff is an open source Java API for Macromedia Flash file generation
 * and manipulation
 *
 * Copyright (C) 2004-2005 Ralf Terdic (contact@jswiff.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package com.jswiff.swfrecords.actions;

import com.jswiff.io.InputBitStream;
import com.jswiff.io.OutputBitStream;

import java.io.IOException;

/**
 * <p>
 * Evaluates a condition to determine the next action in an SWF file. If the
 * condition is true, the execution continues at the action with the specified
 * label.
 * </p>
 * 
 * <p>
 * Performed stack operations:<br>
 * <code>pop cond</code> (the condition - must evaluate to 0 or 1, or as of
 * SWF 5 to <code>false</code> or <code>true</code>)
 * </p>
 * 
 * <p>
 * ActionScript equivalent: <code>if</code> statement
 * </p>
 * 
 * @see ActionBlock
 * @since SWF 4
 */
public final class If extends Branch {
	private short branchOffset;

	private String branchLabel;
	
//	private int branchType;

	/**
	 * Creates a new If action.<br>
	 * The <code>branchLabel</code> parameter specifies the target of the jump
	 * in case the condition is fulfilled. This label must be identical to the
	 * one assigned to the action record the execution is supposed to continue
	 * at. Assign <code>ActionBlock.LABEL_END</code> in order to jump to the
	 * end of the action block.
	 * 
	 * @param branchLabel
	 *            label of the action the execution is supposed to continue at
	 */
	public If(String branchLabel) {
		code = ActionConstants.IF;
		this.branchLabel = branchLabel;
	}

	/*
	 * Reads an If action from a bit stream.
	 */
	If(InputBitStream stream) throws IOException {
		code = ActionConstants.IF;
		branchOffset = stream.readSI16();
	}

	/**
	 * Returns the label of the action the execution is supposed to continue at,
	 * if the condition is fulfilled.
	 * 
	 * @return branch label
	 */
	public String getBranchLabel() {
		return branchLabel;
	}

	/**
	 * Returns the branch offset.
	 * 
	 * @return branch offset
	 */
	public short getBranchOffset() {
		return branchOffset;
	}

	/**
	 * Returns the size of this action record in bytes.
	 * 
	 * @return size of this record
	 * 
	 * @see Action#getSize()
	 */
	public int getSize() {
		return 5; // 1 (code) + 2 (data length) + 2 (branch offset)
	}

	/**
	 * Returns a short description of this action.
	 * 
	 * @return <code>"If", branchLabel</code>
	 */
	public String toString() {
		return "If branchLabel: " + branchLabel;
	}

	protected void writeData(OutputBitStream dataStream, OutputBitStream mainStream) throws IOException {
		dataStream.writeSI16(branchOffset);
	}

	public void setBranchLabel(String branchLabel) {
		this.branchLabel = branchLabel;
	}

	void setBranchOffset(short branchOffset) {
		this.branchOffset = branchOffset;
	}

//	public int getBranchType() {
//		return branchType;
//	}

//	public void setBranchType(int branchType) {
//		this.branchType = branchType;
//	}

	
}