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Java > Open Source Codes > com > sun > org > apache > bcel > internal > classfile > StackMap


1 package com.sun.org.apache.bcel.internal.classfile;
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 com.sun.org.apache.bcel.internal.Constants;
58 import java.io.*;
59
60 /**
61  * This class represents a stack map attribute used for
62  * preverification of Java classes for the <a
63  * HREF="http://java.sun.com/j2me/"> Java 2 Micro Edition</a>
64  * (J2ME). This attribute is used by the <a
65  * HREF="http://java.sun.com/products/cldc/">KVM</a> and contained
66  * within the Code attribute of a method. See CLDC specification
67  * &#247;5.3.1.2
68  *
69  * @version $Id: StackMap.java,v 1.1.1.1 2001/10/29 20:00:03 jvanzyl Exp $
70  * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
71  * @see Code
72  * @see StackMapEntry
73  * @see StackMapType
74  */
75 public final class StackMap extends Attribute implements Node {
76   private int map_length;
77   private StackMapEntry[] map; // Table of stack map entries
78
79   /*
80    * @param name_index Index of name
81    * @param length Content length in bytes
82    * @param map Table of stack map entries
83    * @param constant_pool Array of constants
84    */
85   public StackMap(int name_index, int length, StackMapEntry[] map,
86           ConstantPool constant_pool)
87   {
88     super(Constants.ATTR_STACK_MAP, name_index, length, constant_pool);
89
90     setStackMap(map);
91   }
92    
93   /**
94    * Construct object from file stream.
95    * @param name_index Index of name
96    * @param length Content length in bytes
97    * @param file Input stream
98    * @throw IOException
99    * @param constant_pool Array of constants
100    */
101   StackMap(int name_index, int length, DataInputStream file,
102        ConstantPool constant_pool) throws IOException
103   {
104     this(name_index, length, (StackMapEntry[])null, constant_pool);
105
106     map_length = file.readUnsignedShort();
107     map = new StackMapEntry[map_length];
108
109     for(int i=0; i < map_length; i++)
110       map[i] = new StackMapEntry(file, constant_pool);
111   }
112
113   /**
114    * Dump line number table attribute to file stream in binary format.
115    *
116    * @param file Output file stream
117    * @throw IOException
118    */
119   public final void dump(DataOutputStream file) throws IOException
120   {
121     super.dump(file);
122     file.writeShort(map_length);
123     for(int i=0; i < map_length; i++)
124       map[i].dump(file);
125   }
126    
127   /**
128    * @return Array of stack map entries
129    */
130   public final StackMapEntry[] getStackMap() { return map; }
131
132   /**
133    * @param map Array of stack map entries
134    */
135   public final void setStackMap(StackMapEntry[] map) {
136     this.map = map;
137
138     map_length = (map == null)? 0 : map.length;
139   }
140
141   /**
142    * @return String representation.
143    */
144   public final String JavaDoc toString() {
145     StringBuffer JavaDoc buf = new StringBuffer JavaDoc("StackMap(");
146
147     for(int i=0; i < map_length; i++) {
148       buf.append(map[i].toString());
149
150       if(i < map_length - 1)
151     buf.append(", ");
152     }
153
154     buf.append(')');
155     
156     return buf.toString();
157   }
158
159   /**
160    * @return deep copy of this attribute
161    */
162   public Attribute copy(ConstantPool constant_pool) {
163     StackMap c = (StackMap)clone();
164
165     c.map = new StackMapEntry[map_length];
166     for(int i=0; i < map_length; i++)
167       c.map[i] = map[i].copy();
168
169     c.constant_pool = constant_pool;
170     return c;
171   }
172
173   /**
174    * Called by objects that are traversing the nodes of the tree implicitely
175    * defined by the contents of a Java class. I.e., the hierarchy of methods,
176    * fields, attributes, etc. spawns a tree of objects.
177    *
178    * @param v Visitor object
179    */
180    public void accept(Visitor v) {
181      v.visitStackMap(this);
182    }
183
184   public final int getMapLength() { return map_length; }
185 }
186
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