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Java > Open Source Codes > proguard > classfile > attribute > preverification > StackMapTableAttribute


1 /*
2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
3  * of Java bytecode.
4  *
5  * Copyright (c) 2002-2007 Eric Lafortune (eric@graphics.cornell.edu)
6  *
7  * This library is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License as published by the Free
9  * Software Foundation; either version 2 of the License, or (at your option)
10  * any later version.
11  *
12  * This library is distributed in the hope that it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
15  * for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public License
18  * along with this library; if not, write to the Free Software Foundation,
19  * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21 package proguard.classfile.attribute.preverification;
22
23 import proguard.classfile.*;
24 import proguard.classfile.attribute.*;
25 import proguard.classfile.attribute.preverification.visitor.StackMapFrameVisitor;
26 import proguard.classfile.attribute.visitor.AttributeVisitor;
27
28 /**
29  * This Attribute represents a stack map table attribute.
30  *
31  * @author Eric Lafortune
32  */
33 public class StackMapTableAttribute extends Attribute
34 {
35     public int u2stackMapFramesCount;
36     public StackMapFrame[] stackMapFrames;
37
38
39     /**
40      * Creates an uninitialized StackMapTableAttribute.
41      */
42     public StackMapTableAttribute()
43     {
44     }
45
46
47     /**
48      * Creates a StackMapTableAttribute with the given stack map frames.
49      */
50     public StackMapTableAttribute(StackMapFrame[] stackMapFrames)
51     {
52         this(stackMapFrames.length, stackMapFrames);
53     }
54
55
56     /**
57      * Creates a StackMapTableAttribute with the given stack map frames.
58      */
59     public StackMapTableAttribute(int stackMapFramesCount,
60                                   StackMapFrame[] stackMapFrames)
61     {
62         this.u2stackMapFramesCount = stackMapFramesCount;
63         this.stackMapFrames = stackMapFrames;
64     }
65
66
67     // Implementations for Attribute.
68
69     public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, AttributeVisitor attributeVisitor)
70     {
71         attributeVisitor.visitStackMapTableAttribute(clazz, method, codeAttribute, this);
72     }
73
74
75     /**
76      * Applies the given stack map frame visitor to all stack map frames.
77      */
78     public void stackMapFramesAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, StackMapFrameVisitor stackMapFrameVisitor)
79     {
80         int offset = 0;
81
82         for (int index = 0; index < u2stackMapFramesCount; index++)
83         {
84             StackMapFrame stackMapFrame = stackMapFrames[index];
85
86             // Note that the byte code offset is computed differently for the
87 // first stack map frame.
88 offset += stackMapFrame.getOffsetDelta() + (index == 0 ? 0 : 1);
89
90             stackMapFrame.accept(clazz, method, codeAttribute, offset, stackMapFrameVisitor);
91         }
92     }
93 }
94
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