- package com.sun.org.apache.bcel.internal.generic;
-
- /* ====================================================================
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 2001 The Apache Software Foundation. All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. The end-user documentation included with the redistribution,
- * if any, must include the following acknowledgment:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowledgment may appear in the software itself,
- * if and wherever such third-party acknowledgments normally appear.
- *
- * 4. The names "Apache" and "Apache Software Foundation" and
- * "Apache BCEL" must not be used to endorse or promote products
- * derived from this software without prior written permission. For
- * written permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache",
- * "Apache BCEL", nor may "Apache" appear in their name, without
- * prior written permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- */
- import java.io.*;
- import com.sun.org.apache.bcel.internal.util.ByteSequence;
-
- /**
- * Select - Abstract super class for LOOKUPSWITCH and TABLESWITCH instructions.
- *
- * @version $Id: Select.java,v 1.1.1.1 2001/10/29 20:00:27 jvanzyl Exp $
- * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
- * @see LOOKUPSWITCH
- * @see TABLESWITCH
- * @see InstructionList
- */
- public abstract class Select extends BranchInstruction
- implements VariableLengthInstruction, StackProducer
- {
- protected int[] match; // matches, i.e., case 1: ...
- protected int[] indices; // target offsets
- protected InstructionHandle[] targets; // target objects in instruction list
- protected int fixed_length; // fixed length defined by subclasses
- protected int match_length; // number of cases
- protected int padding = 0; // number of pad bytes for alignment
-
- /**
- * Empty constructor needed for the Class.newInstance() statement in
- * Instruction.readInstruction(). Not to be used otherwise.
- */
- Select() {}
-
- /**
- * (Match, target) pairs for switch.
- * `Match' and `targets' must have the same length of course.
- *
- * @param match array of matching values
- * @param targets instruction targets
- * @param target default instruction target
- */
- Select(short opcode, int[] match, InstructionHandle[] targets,
- InstructionHandle target) {
- super(opcode, target);
-
- this.targets = targets;
- for(int i=0; i < targets.length; i++)
- notifyTarget(null, targets[i], this);
-
- this.match = match;
-
- if((match_length = match.length) != targets.length)
- throw new ClassGenException("Match and target array have not the same length");
-
- indices = new int[match_length];
- }
-
- /**
- * Since this is a variable length instruction, it may shift the following
- * instructions which then need to update their position.
- *
- * Called by InstructionList.setPositions when setting the position for every
- * instruction. In the presence of variable length instructions `setPositions'
- * performs multiple passes over the instruction list to calculate the
- * correct (byte) positions and offsets by calling this function.
- *
- * @param offset additional offset caused by preceding (variable length) instructions
- * @param max_offset the maximum offset that may be caused by these instructions
- * @return additional offset caused by possible change of this instruction's length
- */
- protected int updatePosition(int offset, int max_offset) {
- position += offset; // Additional offset caused by preceding SWITCHs, GOTOs, etc.
-
- short old_length = length;
-
- /* Alignment on 4-byte-boundary, + 1, because of tag byte.
- */
- padding = (4 - ((position + 1) % 4)) % 4;
- length = (short)(fixed_length + padding); // Update length
-
- return length - old_length;
- }
-
- /**
- * Dump instruction as byte code to stream out.
- * @param out Output stream
- */
- public void dump(DataOutputStream out) throws IOException {
- out.writeByte(opcode);
-
- for(int i=0; i < padding; i++) // Padding bytes
- out.writeByte(0);
-
- index = getTargetOffset(); // Write default target offset
- out.writeInt(index);
- }
-
- /**
- * Read needed data (e.g. index) from file.
- */
- protected void initFromFile(ByteSequence bytes, boolean wide) throws IOException
- {
- padding = (4 - (bytes.getIndex() % 4)) % 4; // Compute number of pad bytes
-
- for(int i=0; i < padding; i++) {
- byte b;
- if((b=bytes.readByte()) != 0)
- throw new ClassGenException("Padding byte != 0: " + b);
- }
-
- // Default branch target common for both cases (TABLESWITCH, LOOKUPSWITCH)
- index = bytes.readInt();
- }
-
- /**
- * @return mnemonic for instruction
- */
- public String toString(boolean verbose) {
- StringBuffer buf = new StringBuffer(super.toString(verbose));
-
- if(verbose) {
- for(int i=0; i < match_length; i++) {
- String s = "null";
-
- if(targets[i] != null)
- s = targets[i].getInstruction().toString();
-
- buf.append("(" + match[i] + ", " + s + " = {" + indices[i] + "})");
- }
- }
- else
- buf.append(" ...");
-
- return buf.toString();
- }
-
- /**
- * Set branch target for `i'th case
- */
- public void setTarget(int i, InstructionHandle target) {
- notifyTarget(targets[i], target, this);
- targets[i] = target;
- }
-
- /**
- * @param old_ih old target
- * @param new_ih new target
- */
- public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) {
- boolean targeted = false;
-
- if(target == old_ih) {
- targeted = true;
- setTarget(new_ih);
- }
-
- for(int i=0; i < targets.length; i++) {
- if(targets[i] == old_ih) {
- targeted = true;
- setTarget(i, new_ih);
- }
- }
-
- if(!targeted)
- throw new ClassGenException("Not targeting " + old_ih);
- }
-
- /**
- * @return true, if ih is target of this instruction
- */
- public boolean containsTarget(InstructionHandle ih) {
- if(target == ih)
- return true;
-
- for(int i=0; i < targets.length; i++)
- if(targets[i] == ih)
- return true;
-
- return false;
- }
-
- /**
- * Inform targets that they're not targeted anymore.
- */
- void dispose() {
- super.dispose();
-
- for(int i=0; i < targets.length; i++)
- targets[i].removeTargeter(this);
- }
-
- /**
- * @return array of match indices
- */
- public int[] getMatchs() { return match; }
-
- /**
- * @return array of match target offsets
- */
- public int[] getIndices() { return indices; }
-
- /**
- * @return array of match targets
- */
- public InstructionHandle[] getTargets() { return targets; }
- }