1 /* 2 * reserved comment block 3 * DO NOT REMOVE OR ALTER! 4 */ 5 /* 6 * Licensed to the Apache Software Foundation (ASF) under one or more 7 * contributor license agreements. See the NOTICE file distributed with 8 * this work for additional information regarding copyright ownership. 9 * The ASF licenses this file to You under the Apache License, Version 2.0 10 * (the "License"); you may not use this file except in compliance with 11 * the License. You may obtain a copy of the License at 12 * 13 * http://www.apache.org/licenses/LICENSE-2.0 14 * 15 * Unless required by applicable law or agreed to in writing, software 16 * distributed under the License is distributed on an "AS IS" BASIS, 17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 18 * See the License for the specific language governing permissions and 19 * limitations under the License. 20 */ 21 22 package com.sun.org.apache.bcel.internal.generic; 23 24 import java.io.*; 25 26 /** 27 * GOTO - Branch always (to relative offset, not absolute address) 28 * 29 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> 30 */ 31 public class GOTO extends GotoInstruction implements VariableLengthInstruction { 32 /** 33 * Empty constructor needed for the Class.newInstance() statement in 34 * Instruction.readInstruction(). Not to be used otherwise. 35 */ 36 GOTO() {} 37 38 public GOTO(InstructionHandle target) { 39 super(com.sun.org.apache.bcel.internal.Constants.GOTO, target); 40 } 41 42 /** 43 * Dump instruction as byte code to stream out. 44 * @param out Output stream 45 */ 46 public void dump(DataOutputStream out) throws IOException { 47 index = getTargetOffset(); 48 if(opcode == com.sun.org.apache.bcel.internal.Constants.GOTO) 49 super.dump(out); 50 else { // GOTO_W 51 index = getTargetOffset(); 52 out.writeByte(opcode); 53 out.writeInt(index); 54 } 55 } 56 57 /** Called in pass 2 of InstructionList.setPositions() in order to update 58 * the branch target, that may shift due to variable length instructions. 59 */ 60 protected int updatePosition(int offset, int max_offset) { 61 int i = getTargetOffset(); // Depending on old position value 62 63 position += offset; // Position may be shifted by preceding expansions 64 65 if(Math.abs(i) >= (32767 - max_offset)) { // to large for short (estimate) 66 opcode = com.sun.org.apache.bcel.internal.Constants.GOTO_W; 67 length = 5; 68 return 2; // 5 - 3 69 } 70 71 return 0; 72 } 73 74 /** 75 * Call corresponding visitor method(s). The order is: 76 * Call visitor methods of implemented interfaces first, then 77 * call methods according to the class hierarchy in descending order, 78 * i.e., the most specific visitXXX() call comes last. 79 * 80 * @param v Visitor object 81 */ 82 public void accept(Visitor v) { 83 v.visitVariableLengthInstruction(this); 84 v.visitUnconditionalBranch(this); 85 v.visitBranchInstruction(this); 86 v.visitGotoInstruction(this); 87 v.visitGOTO(this); 88 } 89 }