gecko-dev/gc/boehm/leaksoup/FileTable.java
2005-12-31 16:02:07 +00:00

97 lines
3.3 KiB
Java
Executable File

/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* 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. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* 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.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Patrick C. Beard <beard@netscape.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
import java.io.*;
import java.util.*;
/**
* Provides a way to map from byte offsets into a file to line numbers.
*/
public class FileTable {
private static class Line {
int mOffset;
int mLength;
Line(int offset, int length) {
mOffset = offset;
mLength = length;
}
}
private Line[] mLines;
public FileTable(String path) throws IOException {
Vector lines = new Vector();
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(path)));
int offset = 0;
for (String line = reader.readLine(); line != null; line = reader.readLine()) {
// always add 1 for the line feed.
int length = 1 + line.length();
lines.addElement(new Line(offset, length));
offset += length;
}
reader.close();
int size = lines.size();
mLines = new Line[size];
lines.copyInto(mLines);
}
public int getLine(int offset) {
// use binary search to find the line which spans this offset.
int length = mLines.length;
int minIndex = 0, maxIndex = length - 1;
int index = maxIndex / 2;
while (minIndex <= maxIndex) {
Line line = mLines[index];
if (offset < line.mOffset) {
maxIndex = (index - 1);
index = (minIndex + maxIndex) / 2;
} else {
if (offset < (line.mOffset + line.mLength)) {
return index;
}
minIndex = (index + 1);
index = (minIndex + maxIndex) / 2;
}
}
// this case shouldn't happen, but provides a helpful value to detect errors.
return -1;
}
}