| /* |
| * reserved comment block |
| * DO NOT REMOVE OR ALTER! |
| */ |
| 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; |
| import com.sun.org.apache.bcel.internal.classfile.Utility; |
| import com.sun.org.apache.bcel.internal.Constants; |
| |
| /** |
| * Abstract super class for instructions dealing with local variables. |
| * |
| * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> |
| */ |
| public abstract class LocalVariableInstruction extends Instruction |
| implements TypedInstruction, IndexedInstruction { |
| protected int n = -1; // index of referenced variable |
| private short c_tag = -1; // compact version, such as ILOAD_0 |
| private short canon_tag = -1; // canonical tag such as ILOAD |
| |
| private final boolean wide() { return n > Constants.MAX_BYTE; } |
| |
| /** |
| * Empty constructor needed for the Class.newInstance() statement in |
| * Instruction.readInstruction(). Not to be used otherwise. |
| * tag and length are defined in readInstruction and initFromFile, respectively. |
| */ |
| LocalVariableInstruction(short canon_tag, short c_tag) { |
| super(); |
| this.canon_tag = canon_tag; |
| this.c_tag = c_tag; |
| } |
| |
| /** |
| * Empty constructor needed for the Class.newInstance() statement in |
| * Instruction.readInstruction(). Also used by IINC()! |
| */ |
| LocalVariableInstruction() { |
| } |
| |
| /** |
| * @param opcode Instruction opcode |
| * @param c_tag Instruction number for compact version, ALOAD_0, e.g. |
| * @param n local variable index (unsigned short) |
| */ |
| protected LocalVariableInstruction(short opcode, short c_tag, int n) { |
| super(opcode, (short)2); |
| |
| this.c_tag = c_tag; |
| canon_tag = opcode; |
| |
| setIndex(n); |
| } |
| |
| /** |
| * Dump instruction as byte code to stream out. |
| * @param out Output stream |
| */ |
| public void dump(DataOutputStream out) throws IOException { |
| if(wide()) // Need WIDE prefix ? |
| out.writeByte(Constants.WIDE); |
| |
| out.writeByte(opcode); |
| |
| if(length > 1) { // Otherwise ILOAD_n, instruction, e.g. |
| if(wide()) |
| out.writeShort(n); |
| else |
| out.writeByte(n); |
| } |
| } |
| |
| /** |
| * Long output format: |
| * |
| * <name of opcode> "["<opcode number>"]" |
| * "("<length of instruction>")" "<"< local variable index>">" |
| * |
| * @param verbose long/short format switch |
| * @return mnemonic for instruction |
| */ |
| public String toString(boolean verbose) { |
| if(((opcode >= Constants.ILOAD_0) && |
| (opcode <= Constants.ALOAD_3)) || |
| ((opcode >= Constants.ISTORE_0) && |
| (opcode <= Constants.ASTORE_3))) |
| return super.toString(verbose); |
| else |
| return super.toString(verbose) + " " + n; |
| } |
| |
| /** |
| * Read needed data (e.g. index) from file. |
| * PRE: (ILOAD <= tag <= ALOAD_3) || (ISTORE <= tag <= ASTORE_3) |
| */ |
| protected void initFromFile(ByteSequence bytes, boolean wide) |
| throws IOException |
| { |
| if(wide) { |
| n = bytes.readUnsignedShort(); |
| length = 4; |
| } else if(((opcode >= Constants.ILOAD) && |
| (opcode <= Constants.ALOAD)) || |
| ((opcode >= Constants.ISTORE) && |
| (opcode <= Constants.ASTORE))) { |
| n = bytes.readUnsignedByte(); |
| length = 2; |
| } else if(opcode <= Constants.ALOAD_3) { // compact load instruction such as ILOAD_2 |
| n = (opcode - Constants.ILOAD_0) % 4; |
| length = 1; |
| } else { // Assert ISTORE_0 <= tag <= ASTORE_3 |
| n = (opcode - Constants.ISTORE_0) % 4; |
| length = 1; |
| } |
| } |
| |
| /** |
| * @return local variable index referred by this instruction. |
| */ |
| public final int getIndex() { return n; } |
| |
| /** |
| * Set the local variable index |
| */ |
| public void setIndex(int n) { |
| if((n < 0) || (n > Constants.MAX_SHORT)) |
| throw new ClassGenException("Illegal value: " + n); |
| |
| this.n = n; |
| |
| if(n >= 0 && n <= 3) { // Use more compact instruction xLOAD_n |
| opcode = (short)(c_tag + n); |
| length = 1; |
| } else { |
| opcode = canon_tag; |
| |
| if(wide()) // Need WIDE prefix ? |
| length = 4; |
| else |
| length = 2; |
| } |
| } |
| |
| /** @return canonical tag for instruction, e.g., ALOAD for ALOAD_0 |
| */ |
| public short getCanonicalTag() { |
| return canon_tag; |
| } |
| |
| /** |
| * Returns the type associated with the instruction - |
| * in case of ALOAD or ASTORE Type.OBJECT is returned. |
| * This is just a bit incorrect, because ALOAD and ASTORE |
| * may work on every ReferenceType (including Type.NULL) and |
| * ASTORE may even work on a ReturnaddressType . |
| * @return type associated with the instruction |
| */ |
| public Type getType(ConstantPoolGen cp) { |
| switch(canon_tag) { |
| case Constants.ILOAD: case Constants.ISTORE: |
| return Type.INT; |
| case Constants.LLOAD: case Constants.LSTORE: |
| return Type.LONG; |
| case Constants.DLOAD: case Constants.DSTORE: |
| return Type.DOUBLE; |
| case Constants.FLOAD: case Constants.FSTORE: |
| return Type.FLOAT; |
| case Constants.ALOAD: case Constants.ASTORE: |
| return Type.OBJECT; |
| |
| default: throw new ClassGenException("Oops: unknown case in switch" + canon_tag); |
| } |
| } |
| } |