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207 lines
5.6 KiB
207 lines
5.6 KiB
/* CaseBlock Copyright (C) 1998-2002 Jochen Hoenicke.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; see the file COPYING.LESSER. If not, write to
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* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id$
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*/
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package jode.flow;
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import jode.expr.ConstOperator;
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import jode.type.Type;
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/**
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* This block represents a case instruction. A case instruction is a
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* part of a switch construction and may have a subpart or not (for
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* multiple case directly after each other.
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*
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* @author Jochen Hoenicke */
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public class CaseBlock extends StructuredBlock {
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/**
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* The inner block that jumps to the subroutine, or null
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* if this is a value only.
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*/
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StructuredBlock subBlock;
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/**
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* The value of this case.
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*/
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int value;
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/**
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* True, if this is the default case
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*/
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boolean isDefault = false;
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/**
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* True, if the previous case falls through to this case
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*/
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boolean isFallThrough = false;
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/**
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* True, if this is the last case in a switch
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*/
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boolean isLastBlock = false;
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public CaseBlock(int value) {
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this.value = value;
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subBlock = null;
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}
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public CaseBlock(int value, Jump dest) {
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this.value = value;
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subBlock = new EmptyBlock(dest);
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subBlock.outer = this;
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}
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public void checkConsistent() {
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if (!(outer instanceof SwitchBlock))
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throw new jode.AssertError("Inconsistency");
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super.checkConsistent();
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}
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/**
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* Replaces the given sub block with a new block.
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* @param oldBlock the old sub block.
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* @param newBlock the new sub block.
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* @return false, if oldBlock wasn't a direct sub block.
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*/
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public boolean replaceSubBlock(StructuredBlock oldBlock,
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StructuredBlock newBlock) {
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if (subBlock == oldBlock)
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subBlock = newBlock;
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else
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return false;
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return true;
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}
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/**
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* Tells if we want braces around this case. We only need braces
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* if there is a declaration on the first level (list of
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* sequential blocks).
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*/
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protected boolean wantBraces() {
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StructuredBlock block = subBlock;
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if (block == null)
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return false;
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for (;;) {
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if (block.declare != null && !block.declare.isEmpty()) {
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/* A declaration; we need braces. */
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return true;
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}
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if (!(block instanceof SequentialBlock)) {
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/* This was the last block on the first level.
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* Finally check if that is an declaring InstructionBlock.
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*/
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if (block instanceof InstructionBlock
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&& ((InstructionBlock)block).isDeclaration)
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return true;
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/* If we get here, we need no braces.
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*/
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return false;
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}
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StructuredBlock[] subBlocks = block.getSubBlocks();
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if (subBlocks[0] instanceof InstructionBlock
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&& ((InstructionBlock)subBlocks[0]).isDeclaration) {
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/* An instruction block declares on the same level as
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* the surrounding SequentialBlock.
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*/
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return true;
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}
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/* continue with the second sub block. */
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block = subBlocks[1];
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}
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}
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/**
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* Returns all sub block of this structured block.
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*/
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public StructuredBlock[] getSubBlocks() {
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return (subBlock != null)
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? new StructuredBlock[] { subBlock }
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: new StructuredBlock[0];
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}
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public void dumpInstruction(jode.decompiler.TabbedPrintWriter writer)
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throws java.io.IOException
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{
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if (isDefault) {
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/* If this is the default case and does nothing, we can
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* skip this.
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* We have to make sure, that nothing flows into the default
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* block though. XXX remove if sure.
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*/
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if (isLastBlock
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&& subBlock instanceof EmptyBlock
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&& subBlock.jump == null)
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return;
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if (subBlock instanceof BreakBlock
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&& ((BreakBlock) subBlock).breaksBlock == this) {
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/* make sure that the previous block is correctly breaked */
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if (isFallThrough) {
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writer.tab();
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subBlock.dumpSource(writer);
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writer.untab();
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}
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return;
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}
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if (isFallThrough) {
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writer.tab();
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writer.println("/* fall through */");
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writer.untab();
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}
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writer.print("default:");
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} else {
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if (isFallThrough) {
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writer.tab();
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writer.println("/* fall through */");
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writer.untab();
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}
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ConstOperator constOp = new ConstOperator(new Integer(value));
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Type type = ((SwitchBlock)outer).getInstruction().getType();
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constOp.setType(type);
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constOp.makeInitializer(type);
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writer.print("case " + constOp.toString() + ":");
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}
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if (subBlock != null) {
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boolean needBraces = wantBraces();
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if (needBraces)
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writer.openBrace();
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else
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writer.println();
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if (subBlock != null) {
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writer.tab();
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subBlock.dumpSource(writer);
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writer.untab();
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}
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if (needBraces)
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writer.closeBrace();
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} else
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writer.println();
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}
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/**
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* Determines if there is a sub block, that flows through to the end
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* of this block. If this returns true, you know that jump is null.
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* @return true, if the jump may be safely changed.
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*/
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public boolean jumpMayBeChanged() {
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return subBlock.jump != null || subBlock.jumpMayBeChanged();
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}
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}
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