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1 package org.apache.bcel.generic; 2 3 /* ==================================================================== 4 * The Apache Software License, Version 1.1 5 * 6 * Copyright (c) 2001 The Apache Software Foundation. All rights 7 * reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. The end-user documentation included with the redistribution, 22 * if any, must include the following acknowledgment: 23 * "This product includes software developed by the 24 * Apache Software Foundation (http://www.apache.org/)." 25 * Alternately, this acknowledgment may appear in the software itself, 26 * if and wherever such third-party acknowledgments normally appear. 27 * 28 * 4. The names "Apache" and "Apache Software Foundation" and 29 * "Apache BCEL" must not be used to endorse or promote products 30 * derived from this software without prior written permission. For 31 * written permission, please contact apache@apache.org. 32 * 33 * 5. Products derived from this software may not be called "Apache", 34 * "Apache BCEL", nor may "Apache" appear in their name, without 35 * prior written permission of the Apache Software Foundation. 36 * 37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 48 * SUCH DAMAGE. 49 * ==================================================================== 50 * 51 * This software consists of voluntary contributions made by many 52 * individuals on behalf of the Apache Software Foundation. For more 53 * information on the Apache Software Foundation, please see 54 * <http://www.apache.org/>;. 55 */ 56 57 import org.apache.bcel.Constants; 58 import org.apache.bcel.classfile.*; 59 60 /*** 61 * This class represents a local variable within a method. It contains its 62 * scope, name and type. The generated LocalVariable object can be obtained 63 * with getLocalVariable which needs the instruction list and the constant 64 * pool as parameters. 65 * 66 * @version $Id: LocalVariableGen.java,v 1.3 2002/07/11 19:39:04 mdahm Exp $ 67 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> 68 * @see LocalVariable 69 * @see MethodGen 70 */ 71 public class LocalVariableGen 72 implements InstructionTargeter, NamedAndTyped, Cloneable, 73 java.io.Serializable 74 { 75 private int index; 76 private String name; 77 private Type type; 78 private InstructionHandle start, end; 79 80 /*** 81 * Generate a local variable that with index `index'. Note that double and long 82 * variables need two indexs. Index indices have to be provided by the user. 83 * 84 * @param index index of local variable 85 * @param name its name 86 * @param type its type 87 * @param start from where the instruction is valid (null means from the start) 88 * @param end until where the instruction is valid (null means to the end) 89 */ 90 public LocalVariableGen(int index, String name, Type type, 91 InstructionHandle start, InstructionHandle end) { 92 if((index < 0) || (index > Constants.MAX_SHORT)) 93 throw new ClassGenException("Invalid index index: " + index); 94 95 this.name = name; 96 this.type = type; 97 this.index = index; 98 setStart(start); 99 setEnd(end); 100 } 101 102 /*** 103 * Get LocalVariable object. 104 * 105 * This relies on that the instruction list has already been dumped to byte code or 106 * or that the `setPositions' methods has been called for the instruction list. 107 * 108 * Note that for local variables whose scope end at the last 109 * instruction of the method's code, the JVM specification is ambiguous: 110 * both a start_pc+length ending at the last instruction and 111 * start_pc+length ending at first index beyond the end of the code are 112 * valid. 113 * 114 * @param il instruction list (byte code) which this variable belongs to 115 * @param cp constant pool 116 */ 117 public LocalVariable getLocalVariable(ConstantPoolGen cp) { 118 int start_pc = start.getPosition(); 119 int length = end.getPosition() - start_pc; 120 121 if(length > 0) 122 length += end.getInstruction().getLength(); 123 124 int name_index = cp.addUtf8(name); 125 int signature_index = cp.addUtf8(type.getSignature()); 126 127 return new LocalVariable(start_pc, length, name_index, 128 signature_index, index, cp.getConstantPool()); 129 } 130 131 public void setIndex(int index) { this.index = index; } 132 public int getIndex() { return index; } 133 public void setName(String name) { this.name = name; } 134 public String getName() { return name; } 135 public void setType(Type type) { this.type = type; } 136 public Type getType() { return type; } 137 138 public InstructionHandle getStart() { return start; } 139 public InstructionHandle getEnd() { return end; } 140 141 public void setStart(InstructionHandle start) { 142 BranchInstruction.notifyTarget(this.start, start, this); 143 this.start = start; 144 } 145 146 public void setEnd(InstructionHandle end) { 147 BranchInstruction.notifyTarget(this.end, end, this); 148 this.end = end; 149 } 150 151 /*** 152 * @param old_ih old target, either start or end 153 * @param new_ih new target 154 */ 155 public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) { 156 boolean targeted = false; 157 158 if(start == old_ih) { 159 targeted = true; 160 setStart(new_ih); 161 } 162 163 if(end == old_ih) { 164 targeted = true; 165 setEnd(new_ih); 166 } 167 168 if(!targeted) 169 throw new ClassGenException("Not targeting " + old_ih + ", but {" + start + ", " + 170 end + "}"); 171 } 172 173 /*** 174 * @return true, if ih is target of this variable 175 */ 176 public boolean containsTarget(InstructionHandle ih) { 177 return (start == ih) || (end == ih); 178 } 179 180 /*** 181 * We consider to local variables to be equal, if the use the same index and 182 * are valid in the same range. 183 */ 184 public boolean equals(Object o) { 185 if(!(o instanceof LocalVariableGen)) 186 return false; 187 188 LocalVariableGen l = (LocalVariableGen)o; 189 return (l.index == index) && (l.start == start) && (l.end == end); 190 } 191 192 public String toString() { 193 return "LocalVariableGen(" + name + ", " + type + ", " + start + ", " + end + ")"; 194 } 195 196 public Object clone() { 197 try { 198 return super.clone(); 199 } catch(CloneNotSupportedException e) { 200 System.err.println(e); 201 return null; 202 } 203 } 204 }

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