| /* |
| * ProGuard -- shrinking, optimization, obfuscation, and preverification |
| * of Java bytecode. |
| * |
| * Copyright (c) 2002-2009 Eric Lafortune (eric@graphics.cornell.edu) |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the Free |
| * Software Foundation; either version 2 of the License, or (at your option) |
| * any later version. |
| * |
| * This program is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| * more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| package proguard.classfile.editor; |
| |
| import proguard.classfile.*; |
| import proguard.classfile.constant.Constant; |
| import proguard.classfile.util.SimplifiedVisitor; |
| import proguard.classfile.visitor.ClassVisitor; |
| |
| import java.util.Arrays; |
| |
| /** |
| * This ClassVisitor sorts the constant pool entries of the program classes |
| * that it visits. The sorting order is based on the types of the constant pool |
| * entries in the first place, and on their contents in the second place. |
| * |
| * @author Eric Lafortune |
| */ |
| public class ConstantPoolSorter |
| extends SimplifiedVisitor |
| implements ClassVisitor |
| { |
| private int[] constantIndexMap = new int[ClassConstants.TYPICAL_CONSTANT_POOL_SIZE]; |
| private ComparableConstant[] comparableConstantPool = new ComparableConstant[ClassConstants.TYPICAL_CONSTANT_POOL_SIZE]; |
| private Constant[] newConstantPool = new Constant[ClassConstants.TYPICAL_CONSTANT_POOL_SIZE]; |
| |
| private final ConstantPoolRemapper constantPoolRemapper = new ConstantPoolRemapper(); |
| |
| |
| // Implementations for ClassVisitor. |
| |
| public void visitProgramClass(ProgramClass programClass) |
| { |
| int constantPoolCount = programClass.u2constantPoolCount; |
| |
| // Sort the constant pool and set up an index map. |
| if (constantIndexMap.length < constantPoolCount) |
| { |
| constantIndexMap = new int[constantPoolCount]; |
| comparableConstantPool = new ComparableConstant[constantPoolCount]; |
| newConstantPool = new Constant[constantPoolCount]; |
| } |
| |
| // Initialize an array whose elements can be compared. |
| int sortLength = 0; |
| for (int oldIndex = 1; oldIndex < constantPoolCount; oldIndex++) |
| { |
| Constant constant = programClass.constantPool[oldIndex]; |
| if (constant != null) |
| { |
| comparableConstantPool[sortLength++] = |
| new ComparableConstant(programClass, oldIndex, constant); |
| } |
| } |
| |
| // Sort the array. |
| Arrays.sort(comparableConstantPool, 0, sortLength); |
| |
| // Save the sorted elements. |
| int newLength = 1; |
| int newIndex = 1; |
| ComparableConstant previousComparableConstant = null; |
| for (int sortIndex = 0; sortIndex < sortLength; sortIndex++) |
| { |
| ComparableConstant comparableConstant = comparableConstantPool[sortIndex]; |
| |
| // Isn't this a duplicate of the previous constant? |
| if (!comparableConstant.equals(previousComparableConstant)) |
| { |
| // Remember the index of the new entry. |
| newIndex = newLength; |
| |
| // Copy the sorted constant pool entry over to the constant pool. |
| Constant constant = comparableConstant.getConstant(); |
| |
| newConstantPool[newLength++] = constant; |
| |
| // Long entries take up two slots, the second of which is null. |
| int tag = constant.getTag(); |
| if (tag == ClassConstants.CONSTANT_Long || |
| tag == ClassConstants.CONSTANT_Double) |
| { |
| newConstantPool[newLength++] = null; |
| } |
| |
| previousComparableConstant = comparableConstant; |
| } |
| |
| // Fill out the map array. |
| constantIndexMap[comparableConstant.getIndex()] = newIndex; |
| } |
| |
| // Copy the new constant pool over. |
| System.arraycopy(newConstantPool, 0, programClass.constantPool, 0, newLength); |
| |
| // Clear any remaining entries. |
| for (int index = newLength; index < constantPoolCount; index++) |
| { |
| programClass.constantPool[index] = null; |
| } |
| |
| programClass.u2constantPoolCount = newLength; |
| |
| // Remap all constant pool references. |
| constantPoolRemapper.setConstantIndexMap(constantIndexMap); |
| constantPoolRemapper.visitProgramClass(programClass); |
| } |
| } |