001/*
002 * Copyright (c) 2012-2017 Institut National des Sciences Appliquées de Lyon (INSA-Lyon)
003 *
004 * All rights reserved. This program and the accompanying materials
005 * are made available under the terms of the Eclipse Public License v1.0
006 * which accompanies this distribution, and is available at
007 * http://www.eclipse.org/legal/epl-v10.html
008 */
009
010package org.eclipse.golo.compiler.parser;
011
012import java.io.IOException;
013
014/**
015 * JavaCharStream extension allowing to track token offsets.
016 */
017public class JavaOffsetCharStream extends JavaCharStream {
018
019  private int beginOffset;
020
021  private int currentOffset;
022
023  public JavaOffsetCharStream(final JavaCharStream delegate) {
024    super(delegate.inputStream);
025  }
026
027  @Override
028  public char BeginToken() throws IOException {
029    /*
030     * JavaCC use a pre fetch buffer and may not call readChar causing our
031     * offset not to be updated
032     */
033    if (inBuf > 0) {
034      currentOffset++;
035    }
036    char c = super.BeginToken();
037    beginOffset = currentOffset;
038    return c;
039  }
040
041  @Override
042  public char readChar() throws IOException {
043    char c = super.readChar();
044    currentOffset++;
045    return c;
046  }
047
048  @Override
049  public void backup(int amount) {
050    super.backup(amount);
051    currentOffset -= amount;
052  }
053
054  public int getBeginOffset() {
055    return beginOffset;
056  }
057
058  public int getCurrentOffset() {
059    return currentOffset;
060  }
061}