scouter.javassist.bytecode.LineNumberAttribute Maven / Gradle / Ivy
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package scouter.javassist.bytecode;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.Map;
import scouter.javassist.bytecode.AttributeInfo;
import scouter.javassist.bytecode.ByteArray;
import scouter.javassist.bytecode.ConstPool;
/**
* LineNumberTable_attribute.
*/
public class LineNumberAttribute extends AttributeInfo {
/**
* The name of this attribute "LineNumberTable".
*/
public static final String tag = "LineNumberTable";
LineNumberAttribute(ConstPool cp, int n, DataInputStream in)
throws IOException
{
super(cp, n, in);
}
private LineNumberAttribute(ConstPool cp, byte[] i) {
super(cp, tag, i);
}
/**
* Returns line_number_table_length.
* This represents the number of entries in the table.
*/
public int tableLength() {
return ByteArray.readU16bit(info, 0);
}
/**
* Returns line_number_table[i].start_pc.
* This represents the index into the code array at which the code
* for a new line in the original source file begins.
*
* @param i the i-th entry.
*/
public int startPc(int i) {
return ByteArray.readU16bit(info, i * 4 + 2);
}
/**
* Returns line_number_table[i].line_number.
* This represents the corresponding line number in the original
* source file.
*
* @param i the i-th entry.
*/
public int lineNumber(int i) {
return ByteArray.readU16bit(info, i * 4 + 4);
}
/**
* Returns the line number corresponding to the specified bytecode.
*
* @param pc the index into the code array.
*/
public int toLineNumber(int pc) {
int n = tableLength();
int i = 0;
for (; i < n; ++i)
if (pc < startPc(i))
if (i == 0)
return lineNumber(0);
else
break;
return lineNumber(i - 1);
}
/**
* Returns the index into the code array at which the code for
* the specified line begins.
*
* @param line the line number.
* @return -1 if the specified line is not found.
*/
public int toStartPc(int line) {
int n = tableLength();
for (int i = 0; i < n; ++i)
if (line == lineNumber(i))
return startPc(i);
return -1;
}
/**
* Used as a return type of toNearPc().
*/
static public class Pc {
/**
* The index into the code array.
*/
public int index;
/**
* The line number.
*/
public int line;
}
/**
* Returns the index into the code array at which the code for
* the specified line (or the nearest line after the specified one)
* begins.
*
* @param line the line number.
* @return a pair of the index and the line number of the
* bytecode at that index.
*/
public Pc toNearPc(int line) {
int n = tableLength();
int nearPc = 0;
int distance = 0;
if (n > 0) {
distance = lineNumber(0) - line;
nearPc = startPc(0);
}
for (int i = 1; i < n; ++i) {
int d = lineNumber(i) - line;
if ((d < 0 && d > distance)
|| (d >= 0 && (d < distance || distance < 0))) {
distance = d;
nearPc = startPc(i);
}
}
Pc res = new Pc();
res.index = nearPc;
res.line = line + distance;
return res;
}
/**
* Makes a copy.
*
* @param newCp the constant pool table used by the new copy.
* @param classnames should be null.
*/
public AttributeInfo copy(ConstPool newCp, Map classnames) {
byte[] src = info;
int num = src.length;
byte[] dest = new byte[num];
for (int i = 0; i < num; ++i)
dest[i] = src[i];
LineNumberAttribute attr = new LineNumberAttribute(newCp, dest);
return attr;
}
/**
* Adjusts start_pc if bytecode is inserted in a method body.
*/
void shiftPc(int where, int gapLength, boolean exclusive) {
int n = tableLength();
for (int i = 0; i < n; ++i) {
int pos = i * 4 + 2;
int pc = ByteArray.readU16bit(info, pos);
if (pc > where || (exclusive && pc == where))
ByteArray.write16bit(pc + gapLength, info, pos);
}
}
}