xref: /external/proguard/src/proguard/classfile/attribute/LineNumberTableAttribute.java

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2013 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.attribute;

import proguard.classfile.*;
import proguard.classfile.attribute.visitor.*;

/**
 * This Attribute represents a line number table attribute.
 *
 * @author Eric Lafortune
 */
public class LineNumberTableAttribute extends Attribute
{
    public int              u2lineNumberTableLength;
    public LineNumberInfo[] lineNumberTable;


    /**
     * Creates an uninitialized LineNumberTableAttribute.
     */
    public LineNumberTableAttribute()
    {
    }


    /**
     * Creates an initialized LineNumberTableAttribute.
     */
    public LineNumberTableAttribute(int              u2attributeNameIndex,
                                    int              u2lineNumberTableLength,
                                    LineNumberInfo[] lineNumberTable)
    {
        super(u2attributeNameIndex);

        this.u2lineNumberTableLength = u2lineNumberTableLength;
        this.lineNumberTable         = lineNumberTable;
    }


    /**
     * Returns the line number corresponding to the given byte code program
     * counter.
     */
    public int getLineNumber(int pc)
    {
        for (int index = u2lineNumberTableLength-1 ; index >= 0 ; index--)
        {
            LineNumberInfo info = lineNumberTable[index];
            if (pc >= info.u2startPC)
            {
                return info.u2lineNumber;
            }
        }

        return u2lineNumberTableLength > 0 ?
            lineNumberTable[0].u2lineNumber :
            0;
    }


    /**
     * Returns the lowest line number, or 0 if there aren't any line numbers.
     */
    public int getLowestLineNumber()
    {
        if (u2lineNumberTableLength == 0)
        {
            return 0;
        }

        int lowestLineNumber = Integer.MAX_VALUE;

        for (int index = 0; index < u2lineNumberTableLength; index++)
        {
            int lineNumber = lineNumberTable[index].u2lineNumber;
            if (lineNumber < lowestLineNumber)
            {
                lowestLineNumber = lineNumber;
            }
        }

        return lowestLineNumber;
    }


    /**
     * Returns the highest line number, or 0 if there aren't any line numbers.
     */
    public int getHighestLineNumber()
    {
        if (u2lineNumberTableLength == 0)
        {
            return 0;
        }

        int highestLineNumber = Integer.MIN_VALUE;

        for (int index = 0; index < u2lineNumberTableLength; index++)
        {
            int lineNumber = lineNumberTable[index].u2lineNumber;
            if (lineNumber > highestLineNumber)
            {
                highestLineNumber = lineNumber;
            }
        }

        return highestLineNumber;
    }


    // Implementations for Attribute.

    public void accept(Clazz clazz, Method method, CodeAttribute codeAttribute, AttributeVisitor attributeVisitor)
    {
        attributeVisitor.visitLineNumberTableAttribute(clazz, method, codeAttribute, this);
    }


    /**
     * Applies the given visitor to all line numbers.
     */
    public void lineNumbersAccept(Clazz clazz, Method method, CodeAttribute codeAttribute, LineNumberInfoVisitor lineNumberInfoVisitor)
    {
        for (int index = 0; index < u2lineNumberTableLength; index++)
        {
            // We don't need double dispatching here, since there is only one
            // type of LineNumberInfo.
            lineNumberInfoVisitor.visitLineNumberInfo(clazz, method, codeAttribute, lineNumberTable[index]);
        }
    }
}