1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.compress.harmony.unpack200.bytecode.forms; 18 19 import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode; 20 import org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute; 21 import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager; 22 23 /** 24 * This class implements the byte code form for those bytecodes which have label references (and only label references). 25 */ 26 public class LabelForm extends ByteCodeForm { 27 28 protected boolean widened; 29 30 public LabelForm(final int opcode, final String name, final int[] rewrite) { 31 super(opcode, name, rewrite); 32 } 33 34 public LabelForm(final int opcode, final String name, final int[] rewrite, final boolean widened) { 35 this(opcode, name, rewrite); 36 this.widened = widened; 37 } 38 39 /* 40 * (non-Javadoc) 41 * 42 * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#fixUpByteCodeTarget(org.apache.commons. 43 * compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.CodeAttribute) 44 */ 45 @Override 46 public void fixUpByteCodeTargets(final ByteCode byteCode, final CodeAttribute codeAttribute) { 47 // LabelForms need to fix up the target of label operations 48 final int originalTarget = byteCode.getByteCodeTargets()[0]; 49 final int sourceIndex = byteCode.getByteCodeIndex(); 50 final int absoluteInstructionTargetIndex = sourceIndex + originalTarget; 51 final int targetValue = codeAttribute.byteCodeOffsets.get(absoluteInstructionTargetIndex).intValue(); 52 final int sourceValue = codeAttribute.byteCodeOffsets.get(sourceIndex).intValue(); 53 // The operand is the difference between the source instruction 54 // and the destination instruction. 55 byteCode.setOperandSigned2Bytes(targetValue - sourceValue, 0); 56 if (widened) { 57 byteCode.setNestedPositions(new int[][] { { 0, 4 } }); 58 } else { 59 byteCode.setNestedPositions(new int[][] { { 0, 2 } }); 60 } 61 } 62 63 /* 64 * (non-Javadoc) 65 * 66 * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm#setByteCodeOperands(org.apache.commons. 67 * compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.OperandTable, 68 * org.apache.commons.compress.harmony.unpack200.SegmentConstantPool) 69 */ 70 @Override 71 public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager, final int codeLength) { 72 byteCode.setByteCodeTargets(new int[] { operandManager.nextLabel() }); 73 // The byte code operands actually get set later - 74 // once we have all the bytecodes - in fixUpByteCodeTarget(). 75 } 76 }