RegisterParam.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;

import com.jswiff.io.InputBitStream;
import com.jswiff.io.OutputBitStream;
import com.jswiff.swfrecords.actions.Action;

import java.io.IOException;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;

/**
 * This class is used by <code>DefineFunction2</code> to specify the
 * function's parameters. These can be either variables or registers.
 */
public final class RegisterParam implements Serializable {
	private short register;

	private String paramName;

	/**
	 * Creates a new RegisterParam instance. If you use 0 as register number,
	 * the parameter can be referenced as a variable within the function (this
	 * variable's name is contained in <code>paramName</code>). If the
	 * register number is greater than 0, the parameter is copied into the
	 * corresponding register.
	 * 
	 * @param register
	 *            register number
	 * @param paramName
	 *            variable name
	 */
	public RegisterParam(short register, String paramName) {
		this.register = register;
		this.paramName = paramName;
	}

	/**
	 * Reads an instance from a bit stream.
	 * 
	 * @param stream
	 *            source bit stream
	 * 
	 * @throws IOException
	 *             if an I/O error has occured
	 */
	public RegisterParam(InputBitStream stream) throws IOException {
		register = stream.readUI8();
		paramName = stream.readString();
	}

	/**
	 * Returns the parameter (i.e. the variable's) name
	 * 
	 * @return variable name
	 */
	public String getParamName() {
		return paramName;
	}

	/**
	 * Returns the register number.
	 * 
	 * @return register number
	 */
	public short getRegister() {
		return register;
	}

	/**
	 * Returns the size of this action record in bytes.
	 * 
	 * @return size of this record
	 * 
	 * @see Action#getSize()
	 */
	public int getSize() {
		// null-terminated unicode + 1 byte
		int size = 2;
		try {
			size += paramName.getBytes("UTF-8").length;
		} catch (UnsupportedEncodingException e) {
			// UTF-8 should always be available
		}
		return size;
	}

	/**
	 * Writes the instance to a bit stream.
	 * 
	 * @param stream
	 *            the target bit stream
	 * 
	 * @throws IOException
	 *             if an I/O error has occured
	 */
	public void write(OutputBitStream stream) throws IOException {
		stream.writeUI8(register);
		stream.writeString(paramName);
	}

	@Override
	public String toString() {
		return register +" "+paramName;
	}
}