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/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2017 Eric Lafortune @ GuardSquare
*
* 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.attribute.*;
import proguard.classfile.attribute.visitor.AttributeVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import java.util.Arrays;
/**
* This AttributeVisitor trims the line number table attributes that it visits.
*
* @author Eric Lafortune
*/
public class LineNumberTableAttributeTrimmer
extends SimplifiedVisitor
implements AttributeVisitor
{
// Implementations for AttributeVisitor.
public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
public void visitLineNumberTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LineNumberTableAttribute lineNumberTableAttribute)
{
LineNumberInfo[] lineNumberTable = lineNumberTableAttribute.lineNumberTable;
int lineNumberTableLength = lineNumberTableAttribute.u2lineNumberTableLength;
// Overwrite all empty line number entries.
int newIndex = 0;
for (int index = 0; index < lineNumberTableLength; index++)
{
LineNumberInfo lineNumberInfo = lineNumberTable[index];
int startPC = lineNumberInfo.u2startPC;
int lineNumber = lineNumberInfo.u2lineNumber;
// The offset must lie inside the code.
// The offset must be smaller than the next one.
// The line number should be different from the previous one.
if (startPC < codeAttribute.u4codeLength &&
(index == lineNumberTableLength - 1 ||
startPC < lineNumberTable[index + 1].u2startPC) &&
(index == 0 ||
lineNumber != lineNumberTable[index - 1].u2lineNumber))
{
lineNumberTable[newIndex++] = lineNumberInfo;
}
}
// Clear the unused array entries.
Arrays.fill(lineNumberTable, newIndex, lineNumberTableAttribute.u2lineNumberTableLength, null);
lineNumberTableAttribute.u2lineNumberTableLength = newIndex;
}
}
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