1 /* 2 * ProGuard -- shrinking, optimization, obfuscation, and preverification 3 * of Java bytecode. 4 * 5 * Copyright (c) 2002-2009 Eric Lafortune (eric@graphics.cornell.edu) 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the Free 9 * Software Foundation; either version 2 of the License, or (at your option) 10 * any later version. 11 * 12 * This program is distributed in the hope that it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 15 * more details. 16 * 17 * You should have received a copy of the GNU General Public License along 18 * with this program; if not, write to the Free Software Foundation, Inc., 19 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 package proguard.classfile.instruction; 22 23 import proguard.classfile.*; 24 import proguard.classfile.attribute.CodeAttribute; 25 import proguard.classfile.instruction.visitor.InstructionVisitor; 26 27 /** 28 * This Instruction represents a simple instruction without variable arguments 29 * or constant pool references. 30 * 31 * @author Eric Lafortune 32 */ 33 public class TableSwitchInstruction extends SwitchInstruction 34 { 35 public int lowCase; 36 public int highCase; 37 38 39 /** 40 * Creates an uninitialized TableSwitchInstruction. 41 */ TableSwitchInstruction()42 public TableSwitchInstruction() {} 43 44 45 /** 46 * Creates a new TableSwitchInstruction with the given arguments. 47 */ TableSwitchInstruction(byte opcode, int defaultOffset, int lowCase, int highCase, int[] jumpOffsets)48 public TableSwitchInstruction(byte opcode, 49 int defaultOffset, 50 int lowCase, 51 int highCase, 52 int[] jumpOffsets) 53 { 54 this.opcode = opcode; 55 this.defaultOffset = defaultOffset; 56 this.lowCase = lowCase; 57 this.highCase = highCase; 58 this.jumpOffsets = jumpOffsets; 59 } 60 61 62 /** 63 * Copies the given instruction into this instruction. 64 * @param tableSwitchInstruction the instruction to be copied. 65 * @return this instruction. 66 */ copy(TableSwitchInstruction tableSwitchInstruction)67 public TableSwitchInstruction copy(TableSwitchInstruction tableSwitchInstruction) 68 { 69 this.opcode = tableSwitchInstruction.opcode; 70 this.defaultOffset = tableSwitchInstruction.defaultOffset; 71 this.lowCase = tableSwitchInstruction.lowCase; 72 this.highCase = tableSwitchInstruction.highCase; 73 this.jumpOffsets = tableSwitchInstruction.jumpOffsets; 74 75 return this; 76 } 77 78 79 // Implementations for Instruction. 80 shrink()81 public Instruction shrink() 82 { 83 // There aren't any ways to shrink this instruction. 84 return this; 85 } 86 readInfo(byte[] code, int offset)87 protected void readInfo(byte[] code, int offset) 88 { 89 // Skip up to three padding bytes. 90 offset += -offset & 3; 91 92 // Read the three 32-bit arguments. 93 defaultOffset = readInt(code, offset); offset += 4; 94 lowCase = readInt(code, offset); offset += 4; 95 highCase = readInt(code, offset); offset += 4; 96 97 // Read the jump offsets. 98 jumpOffsets = new int[highCase - lowCase + 1]; 99 100 for (int index = 0; index < jumpOffsets.length; index++) 101 { 102 jumpOffsets[index] = readInt(code, offset); offset += 4; 103 } 104 } 105 106 writeInfo(byte[] code, int offset)107 protected void writeInfo(byte[] code, int offset) 108 { 109 // Write up to three padding bytes. 110 while ((offset & 3) != 0) 111 { 112 writeByte(code, offset++, 0); 113 } 114 115 // Write the three 32-bit arguments. 116 writeInt(code, offset, defaultOffset); offset += 4; 117 writeInt(code, offset, lowCase); offset += 4; 118 writeInt(code, offset, highCase); offset += 4; 119 120 // Write the jump offsets. 121 int length = highCase - lowCase + 1; 122 for (int index = 0; index < length; index++) 123 { 124 writeInt(code, offset, jumpOffsets[index]); offset += 4; 125 } 126 } 127 128 length(int offset)129 public int length(int offset) 130 { 131 return 1 + (-(offset+1) & 3) + 12 + (highCase - lowCase + 1) * 4; 132 } 133 134 accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, InstructionVisitor instructionVisitor)135 public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, InstructionVisitor instructionVisitor) 136 { 137 instructionVisitor.visitTableSwitchInstruction(clazz, method, codeAttribute, offset, this); 138 } 139 } 140