/* ContinueBlock Copyright (C) 1998-2002 Jochen Hoenicke.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2, 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 Lesser General Public License
 * along with this program; see the file COPYING.LESSER.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id: ContinueBlock.java,v 3.5.4.1 2002/05/28 17:34:08 hoenicke Exp $
 */

package alterrs.jode.flow;

import alterrs.jode.decompiler.TabbedPrintWriter;

/**
 *
 */
public class ContinueBlock extends StructuredBlock {
	LoopBlock continuesBlock;
	String continueLabel;

	public ContinueBlock(LoopBlock continuesBlock, boolean needsLabel) {
		this.continuesBlock = continuesBlock;
		if (needsLabel)
			continueLabel = continuesBlock.getLabel();
		else
			continueLabel = null;
	}

	public void checkConsistent() {
		super.checkConsistent();
		StructuredBlock sb = outer;
		while (sb != continuesBlock) {
			if (sb == null)
				throw new RuntimeException("Inconsistency");
			sb = sb.outer;
		}
	}

	/**
	 * Tells if this block is empty and only changes control flow.
	 */
	public boolean isEmpty() {
		return true;
	}

	/**
	 * Returns the block where the control will normally flow to, when this
	 * block is finished (not ignoring the jump after this block).
	 */
	public StructuredBlock getNextBlock() {
		/* This continues to continuesBlock. */
		return continuesBlock;
	}

	/**
	 * Returns the flow block where the control will normally flow to, when this
	 * block is finished (not ignoring the jump after this block).
	 * 
	 * @return null, if the control flows into a non empty structured block or
	 *         if this is the outermost block.
	 */
	public FlowBlock getNextFlowBlock() {
		return null;
	}

	/**
	 * This is called after the analysis is completely done. It will remove all
	 * PUSH/stack_i expressions, (if the bytecode is correct).
	 * 
	 * @param stack
	 *            the stackmap at begin of the block
	 * @return null if the bytecode isn't correct and stack mapping didn't
	 *         worked, otherwise the stack after the block has executed.
	 */
	public VariableStack mapStackToLocal(VariableStack stack) {
		continuesBlock.mergeContinueStack(stack);
		return null;
	}

	public void dumpInstruction(TabbedPrintWriter writer)
			throws java.io.IOException {
		writer.println("continue"
				+ (continueLabel == null ? "" : " " + continueLabel) + ";");
	}

	public boolean needsBraces() {
		return false;
	}

	public boolean jumpMayBeChanged() {
		return true;
	}
}
