001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.compress.harmony.unpack200.bytecode.forms; 018 019import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode; 020import org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute; 021import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager; 022 023/** 024 * This class implements the byte code form for those bytecodes which have label references (and only label references). 025 */ 026public class LabelForm extends ByteCodeForm { 027 028 protected boolean widened; 029 030 public LabelForm(final int opcode, final String name, final int[] rewrite) { 031 super(opcode, name, rewrite); 032 } 033 034 public LabelForm(final int opcode, final String name, final int[] rewrite, final boolean widened) { 035 this(opcode, name, rewrite); 036 this.widened = widened; 037 } 038 039 /* 040 * (non-Javadoc) 041 * 042 * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#fixUpByteCodeTarget(org.apache.commons. 043 * compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute) 044 */ 045 @Override 046 public void fixUpByteCodeTargets(final ByteCode byteCode, final CodeAttribute codeAttribute) { 047 // LabelForms need to fix up the target of label operations 048 final int originalTarget = byteCode.getByteCodeTargets()[0]; 049 final int sourceIndex = byteCode.getByteCodeIndex(); 050 final int absoluteInstructionTargetIndex = sourceIndex + originalTarget; 051 final int targetValue = codeAttribute.byteCodeOffsets.get(absoluteInstructionTargetIndex).intValue(); 052 final int sourceValue = codeAttribute.byteCodeOffsets.get(sourceIndex).intValue(); 053 // The operand is the difference between the source instruction 054 // and the destination instruction. 055 byteCode.setOperandSigned2Bytes(targetValue - sourceValue, 0); 056 if (widened) { 057 byteCode.setNestedPositions(new int[][] { { 0, 4 } }); 058 } else { 059 byteCode.setNestedPositions(new int[][] { { 0, 2 } }); 060 } 061 } 062 063 /* 064 * (non-Javadoc) 065 * 066 * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#setByteCodeOperands(org.apache.commons. 067 * compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.OperandTable, 068 * org.apache.commons.compress.harmony.unpack200.SegmentConstantPool) 069 */ 070 @Override 071 public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager, final int codeLength) { 072 byteCode.setByteCodeTargets(new int[] { operandManager.nextLabel() }); 073 // The byte code operands actually get set later - 074 // once we have all the bytecodes - in fixUpByteCodeTarget(). 075 } 076}