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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