/*
* Copyright 2004-2010 Brian S O'Neill
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.cojen.classfile.attribute;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.cojen.classfile.Attribute;
import org.cojen.classfile.ConstantPool;
import org.cojen.classfile.FixedLocation;
import org.cojen.classfile.Location;
/**
* This class corresponds to the LineNumberTable_attribute structure as defined
* in <i>The Java Virtual Machine Specification</i>.
*
* @author Brian S O'Neill
*/
public class LineNumberTableAttr extends Attribute {
private List<Entry> mEntries = new ArrayList<Entry>();
private boolean mClean = false;
public LineNumberTableAttr(ConstantPool cp) {
super(cp, LINE_NUMBER_TABLE);
}
public LineNumberTableAttr(ConstantPool cp, String name) {
super(cp, name);
}
public LineNumberTableAttr(ConstantPool cp, String name, int length, DataInput din)
throws IOException
{
super(cp, name);
int size = din.readUnsignedShort();
for (int i=0; i<size; i++) {
int start_pc = din.readUnsignedShort();
int line_number = din.readUnsignedShort();
try {
addEntry(new FixedLocation(start_pc), line_number);
} catch (IllegalArgumentException e) {
}
}
}
public int getLineNumber(Location start) {
clean();
int index = Collections.binarySearch(mEntries, new Entry(start, 0));
if (index < 0) {
if ((index = -index - 2) < 0) {
return -1;
}
}
return mEntries.get(index).mLineNumber;
}
public void addEntry(Location start, int line_number) throws IllegalArgumentException {
if (line_number < 0 || line_number > 65535) {
throw new IllegalArgumentException("Value for line number out of " +
"valid range: " + line_number);
}
mEntries.add(new Entry(start, line_number));
mClean = false;
}
public int getLength() {
clean();
return 2 + 4 * mEntries.size();
}
public void writeDataTo(DataOutput dout) throws IOException {
int size = mEntries.size();
dout.writeShort(size);
for (int i=0; i<size; i++) {
Entry entry = mEntries.get(i);
int start_pc = entry.mStart.getLocation();
if (start_pc < 0 || start_pc > 65535) {
throw new IllegalStateException
("Value for line number table entry start PC out of " +
"valid range: " + start_pc);
}
dout.writeShort(start_pc);
dout.writeShort(entry.mLineNumber);
}
}
private void clean() {
if (!mClean) {
mClean = true;
// Clean things up by removing multiple mappings of the same
// start_pc to line numbers. Only keep the last one.
// This has to be performed now because the Labels should have
// a pc location, but before they did not. Since entries must be
// sorted ascending by start_pc, use a sorted set.
Set<Entry> reduced = new TreeSet<Entry>();
for (int i = mEntries.size(); --i >= 0; ) {
reduced.add(mEntries.get(i));
}
mEntries = new ArrayList<Entry>(reduced);
}
}
private static class Entry implements Comparable<Entry> {
public final Location mStart;
public final int mLineNumber;
public Entry(Location start, int line_number) {
mStart = start;
mLineNumber = line_number;
}
public int compareTo(Entry other) {
int thisLoc = mStart.getLocation();
int thatLoc = other.mStart.getLocation();
if (thisLoc < thatLoc) {
return -1;
} else if (thisLoc > thatLoc) {
return 1;
} else {
return 0;
}
}
public boolean equals(Object other) {
if (other instanceof Entry) {
return mStart.getLocation() == ((Entry)other).mStart.getLocation();
}
return false;
}
public String toString() {
return "start_pc=" + mStart.getLocation() + " => " +
"line_number=" + mLineNumber;
}
}
}