InterfaceSorter.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.editor;
22
23import proguard.classfile.*;
24import proguard.classfile.util.SimplifiedVisitor;
25import proguard.classfile.visitor.ClassVisitor;
26
27import java.util.Arrays;
28
29/**
30 * This ClassVisitor sorts the interfaces of the program classes that it visits.
31 *
32 * @author Eric Lafortune
33 */
34public class InterfaceSorter
35extends      SimplifiedVisitor
36implements   ClassVisitor
37{
38    // Implementations for ClassVisitor.
39
40    public void visitProgramClass(ProgramClass programClass)
41    {
42        int[] interfaces      = programClass.u2interfaces;
43        int   interfacesCount = programClass.u2interfacesCount;
44
45        // Sort the interfaces.
46        Arrays.sort(interfaces, 0, interfacesCount);
47
48        // Remove any duplicate entries.
49        int newInterfacesCount     = 0;
50        int previousInterfaceIndex = 0;
51        for (int index = 0; index < interfacesCount; index++)
52        {
53            int interfaceIndex = interfaces[index];
54
55            // Isn't this a duplicate of the previous interface?
56            if (interfaceIndex != previousInterfaceIndex)
57            {
58                interfaces[newInterfacesCount++] = interfaceIndex;
59
60                // Remember the interface.
61                previousInterfaceIndex = interfaceIndex;
62            }
63        }
64
65        programClass.u2interfacesCount = newInterfacesCount;
66    }
67}
68