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 java.util.Arrays; 020 021import org.apache.commons.compress.harmony.unpack200.bytecode.ByteCode; 022import org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager; 023 024public class TableSwitchForm extends SwitchForm { 025 026 public TableSwitchForm(final int opcode, final String name) { 027 super(opcode, name); 028 } 029 030 /* 031 * (non-Javadoc) 032 * 033 * @see org.apache.commons.compress.harmony.unpack200.bytecode.forms.SwitchForm#setByteCodeOperands(org.apache.commons. 034 * compress.harmony.unpack200.bytecode.ByteCode, org.apache.commons.compress.harmony.unpack200.bytecode.OperandManager, int) 035 */ 036 @Override 037 public void setByteCodeOperands(final ByteCode byteCode, final OperandManager operandManager, final int codeLength) { 038 final int caseCount = operandManager.nextCaseCount(); 039 final int defaultPc = operandManager.nextLabel(); 040 int caseValue = -1; 041 caseValue = operandManager.nextCaseValues(); 042 043 final int[] casePcs = new int[caseCount]; 044 Arrays.setAll(casePcs, i -> operandManager.nextLabel()); 045 046 final int[] labelsArray = new int[caseCount + 1]; 047 labelsArray[0] = defaultPc; 048 System.arraycopy(casePcs, 0, labelsArray, 1, caseCount + 1 - 1); 049 byteCode.setByteCodeTargets(labelsArray); 050 051 final int lowValue = caseValue; 052 final int highValue = lowValue + caseCount - 1; 053 // All this gets dumped into the rewrite bytes of the 054 // poor bytecode. 055 056 // Unlike most byte codes, the TableSwitch is a 057 // variable-sized bytecode. Because of this, the 058 // rewrite array has to be defined here individually 059 // for each bytecode, rather than in the ByteCodeForm 060 // class. 061 062 // First, there's the bytecode. Then there are 0-3 063 // bytes of padding so that the first (default) 064 // label is on a 4-byte offset. 065 final int padLength = 3 - codeLength % 4; 066 final int rewriteSize = 1 + padLength + 4 // defaultbytes 067 + 4 // lowbyte 068 + 4 // highbyte 069 + 4 * casePcs.length; 070 071 final int[] newRewrite = new int[rewriteSize]; 072 int rewriteIndex = 0; 073 074 // Fill in what we can now 075 // opcode 076 newRewrite[rewriteIndex++] = byteCode.getOpcode(); 077 078 // padding 079 for (int index = 0; index < padLength; index++) { 080 newRewrite[rewriteIndex++] = 0; 081 } 082 083 // defaultbyte 084 // This gets overwritten by fixUpByteCodeTargets 085 newRewrite[rewriteIndex++] = -1; 086 newRewrite[rewriteIndex++] = -1; 087 newRewrite[rewriteIndex++] = -1; 088 newRewrite[rewriteIndex++] = -1; 089 090 // lowbyte 091 final int lowbyteIndex = rewriteIndex; 092 setRewrite4Bytes(lowValue, lowbyteIndex, newRewrite); 093 rewriteIndex += 4; 094 095 // highbyte 096 final int highbyteIndex = rewriteIndex; 097 setRewrite4Bytes(highValue, highbyteIndex, newRewrite); 098 rewriteIndex += 4; 099 100 // jump offsets 101 // The case_pcs will get overwritten by fixUpByteCodeTargets 102 for (int index = 0; index < caseCount; index++) { 103 // offset 104 newRewrite[rewriteIndex++] = -1; 105 newRewrite[rewriteIndex++] = -1; 106 newRewrite[rewriteIndex++] = -1; 107 newRewrite[rewriteIndex++] = -1; 108 } 109 byteCode.setRewrite(newRewrite); 110 } 111}