1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2013 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.CodeAttribute;
25import proguard.classfile.attribute.preverification.visitor.StackMapFrameVisitor;
26
27/**
28 * This StackMapFrame represents an "chop frame".
29 *
30 * @author Eric Lafortune
31 */
32public class LessZeroFrame extends StackMapFrame
33{
34    public int choppedVariablesCount;
35
36
37    /**
38     * Creates an uninitialized LessZeroFrame.
39     */
40    public LessZeroFrame()
41    {
42    }
43
44
45    /**
46     * Creates a LessZeroFrame with the given tag.
47     */
48    public LessZeroFrame(int tag)
49    {
50        choppedVariablesCount = LESS_ZERO_FRAME + 3 - tag;
51    }
52
53
54    /**
55     * Creates a LessZeroFrame with the given number of chopped variables.
56     */
57    public LessZeroFrame(byte choppedVariablesCount)
58    {
59        this.choppedVariablesCount = (int)choppedVariablesCount;
60    }
61
62
63    // Implementations for StackMapFrame.
64
65    public int getTag()
66    {
67        return LESS_ZERO_FRAME + 3 - choppedVariablesCount;
68    }
69
70
71    public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, StackMapFrameVisitor stackMapFrameVisitor)
72    {
73        stackMapFrameVisitor.visitLessZeroFrame(clazz, method, codeAttribute, offset, this);
74    }
75
76
77    // Implementations for Object.
78
79    public boolean equals(Object object)
80    {
81        if (!super.equals(object))
82        {
83            return false;
84        }
85
86        LessZeroFrame other = (LessZeroFrame)object;
87
88        return this.u2offsetDelta == other.u2offsetDelta &&
89               this.choppedVariablesCount != other.choppedVariablesCount;
90    }
91
92
93    public int hashCode()
94    {
95        return super.hashCode() ^ choppedVariablesCount;
96    }
97
98
99    public String toString()
100    {
101        return super.toString()+"Var: (chopped "+choppedVariablesCount+"), Stack: (empty)";
102    }
103}
104