MoreZeroFrame.java revision 9f606f95f03a75961498803e24bee6799a7c0885 
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.CodeAttribute;
25import proguard.classfile.attribute.preverification.visitor.*;
26
27/**
28 * This StackMapFrame represents an "append frame".
29 *
30 * @author Eric Lafortune
31 */
32public class MoreZeroFrame extends StackMapFrame
33{
34    public int                additionalVariablesCount;
35    public VerificationType[] additionalVariables;
36
37
38    /**
39     * Creates an uninitialized MoreZeroFrame.
40     */
41    public MoreZeroFrame()
42    {
43    }
44
45
46    /**
47     * Creates a MoreZeroFrame with the given tag.
48     */
49    public MoreZeroFrame(int tag)
50    {
51        additionalVariablesCount = tag + 1 - MORE_ZERO_FRAME;
52    }
53
54
55    /**
56     * Creates a MoreZeroFrame with the given additional variables.
57     */
58    public MoreZeroFrame(VerificationType[] additionalVariables)
59    {
60        this(additionalVariables.length, additionalVariables);
61    }
62
63
64    /**
65     * Creates a MoreZeroFrame with the given additional variables.
66     */
67    public MoreZeroFrame(int                additionalVariablesCount,
68                         VerificationType[] additionalVariables)
69    {
70        this.additionalVariablesCount = additionalVariablesCount;
71        this.additionalVariables      = additionalVariables;
72    }
73
74
75    /**
76     * Applies the given verification type visitor to all variables.
77     */
78    public void additionalVariablesAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, VerificationTypeVisitor verificationTypeVisitor)
79    {
80        for (int index = 0; index < additionalVariablesCount; index++)
81        {
82            additionalVariables[index].accept(clazz, method, codeAttribute, offset, verificationTypeVisitor);
83        }
84    }
85
86
87    // Implementations for StackMapFrame.
88
89    public int getTag()
90    {
91        return MORE_ZERO_FRAME + additionalVariablesCount - 1;
92    }
93
94
95    public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, StackMapFrameVisitor stackMapFrameVisitor)
96    {
97        stackMapFrameVisitor.visitMoreZeroFrame(clazz, method, codeAttribute, offset, this);
98    }
99
100
101    // Implementations for Object.
102
103    public boolean equals(Object object)
104    {
105        if (!super.equals(object))
106        {
107            return false;
108        }
109
110        MoreZeroFrame other = (MoreZeroFrame)object;
111
112        if (this.u2offsetDelta            != other.u2offsetDelta ||
113            this.additionalVariablesCount != other.additionalVariablesCount)
114        {
115            return false;
116        }
117
118        for (int index = 0; index < additionalVariablesCount; index++)
119        {
120            VerificationType thisType  = this.additionalVariables[index];
121            VerificationType otherType = other.additionalVariables[index];
122
123            if (!thisType.equals(otherType))
124            {
125                return false;
126            }
127        }
128
129        return true;
130    }
131
132
133    public int hashCode()
134    {
135        int hashCode = super.hashCode();
136
137        for (int index = 0; index < additionalVariablesCount; index++)
138        {
139            hashCode ^= additionalVariables[index].hashCode();
140        }
141
142        return hashCode;
143    }
144
145
146    public String toString()
147    {
148        StringBuffer buffer = new StringBuffer(super.toString()).append("Var: ...");
149
150        for (int index = 0; index < additionalVariablesCount; index++)
151        {
152            buffer = buffer.append('[')
153                           .append(additionalVariables[index].toString())
154                           .append(']');
155        }
156
157        buffer.append(", Stack: (empty)");
158
159        return buffer.toString();
160    }
161}
162