1   package org.apache.bcel.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  org.apache.bcel.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   * §5.3.1.2
68   *
69   * @version $Id: StackMap.java,v 1.2 2002/03/11 16:16:35 mdahm 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     * @throws 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    * @throws 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 toString() {
145     StringBuffer buf = new StringBuffer("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 }
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