StackMapTableAttribute.java revision db267bc191f906f55eaef21a27110cce2ec57fdf 
1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2009 Eric Lafortune (eric@graphics.cornell.edu)
6 *
7 * This program 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 program 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 General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21package proguard.classfile.attribute.preverification;
22
23import proguard.classfile.*;
24import proguard.classfile.attribute.*;
25import proguard.classfile.attribute.preverification.visitor.StackMapFrameVisitor;
26import proguard.classfile.attribute.visitor.AttributeVisitor;
27
28/**
29 * This Attribute represents a stack map table attribute.
30 *
31 * @author Eric Lafortune
32 */
33public 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