1 package org.apache.bcel.verifier.statics;
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.generic.Type;
58 import org.apache.bcel.verifier.exc.*;
59 import java.util.Hashtable;
60
61 /***
62 * A utility class holding the information about
63 * the name and the type of a local variable in
64 * a given slot (== index). This information
65 * often changes in course of byte code offsets.
66 *
67 * @version $Id: LocalVariableInfo.java,v 1.2 2002/06/13 09:32:50 enver Exp $
68 * @author <A HREF="http://www.inf.fu-berlin.de/~ehaase"/>Enver Haase</A>
69 */
70 public class LocalVariableInfo{
71
72 /*** The types database. KEY: String representing the offset integer. */
73 private Hashtable types = new Hashtable();
74 /*** The names database. KEY: String representing the offset integer. */
75 private Hashtable names = new Hashtable();
76
77 /***
78 * Adds a name of a local variable and a certain slot to our 'names'
79 * (Hashtable) database.
80 */
81 private void setName(int offset, String name){
82 names.put( ((Integer.toString(offset))), name);
83 }
84 /***
85 * Adds a type of a local variable and a certain slot to our 'types'
86 * (Hashtable) database.
87 */
88 private void setType(int offset, Type t){
89 types.put( ((Integer.toString(offset))), t);
90 }
91
92 /***
93 * Returns the type of the local variable that uses this local
94 * variable slot at the given bytecode offset.
95 * Care for legal bytecode offsets yourself, otherwise the return value
96 * might be wrong.
97 * May return 'null' if nothing is known about the type of this local
98 * variable slot at the given bytecode offset.
99 */
100 public Type getType(int offset){
101 return (Type) types.get(Integer.toString(offset));
102 }
103 /***
104 * Returns the name of the local variable that uses this local
105 * variable slot at the given bytecode offset.
106 * Care for legal bytecode offsets yourself, otherwise the return value
107 * might be wrong.
108 * May return 'null' if nothing is known about the type of this local
109 * variable slot at the given bytecode offset.
110 */
111 public String getName(int offset){
112 return (String) (names.get(Integer.toString(offset)));
113 }
114 /***
115 * Adds some information about this local variable (slot).
116 * @throws LocalVariableInfoInconsistentException if the new information conflicts
117 * with already gathered information.
118 */
119 public void add(String name, int startpc, int length, Type t) throws LocalVariableInfoInconsistentException{
120 for (int i=startpc; i<=startpc+length; i++){ // incl/incl-notation!
121 add(i,name,t);
122 }
123 }
124
125 /***
126 * Adds information about name and type for a given offset.
127 * @throws LocalVariableInfoInconsistentException if the new information conflicts
128 * with already gathered information.
129 */
130 private void add(int offset, String name, Type t) throws LocalVariableInfoInconsistentException{
131 if (getName(offset) != null){
132 if (! getName(offset).equals(name)){
133 throw new LocalVariableInfoInconsistentException("At bytecode offset '"+offset+"' a local variable has two different names: '"+getName(offset)+"' and '"+name+"'.");
134 }
135 }
136 if (getType(offset) != null){
137 if (! getType(offset).equals(t)){
138 throw new LocalVariableInfoInconsistentException("At bytecode offset '"+offset+"' a local variable has two different types: '"+getType(offset)+"' and '"+t+"'.");
139 }
140 }
141 setName(offset, name);
142 setType(offset, t);
143 }
144 }
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