/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
using System;
namespace Lucene.Net.Analysis
{
/// Subclasses of CharFilter can be chained to filter CharStream.
/// They can be used as {@link java.io.Reader} with additional offset
/// correction. {@link Tokenizer}s will automatically use {@link #CorrectOffset}
/// if a CharFilter/CharStream subclass is used.
///
///
/// $Id$
///
///
public abstract class CharFilter:CharStream
{
private long currentPosition = -1;
protected internal CharStream input;
protected internal CharFilter(CharStream in_Renamed) : base(in_Renamed)
{
input = in_Renamed;
}
/// Subclass may want to override to correct the current offset.
///
///
/// current offset
///
/// corrected offset
///
public /*protected internal*/ virtual int Correct(int currentOff)
{
return currentOff;
}
/// Chains the corrected offset through the input
/// CharFilter.
///
public override int CorrectOffset(int currentOff)
{
return input.CorrectOffset(Correct(currentOff));
}
public override void Close()
{
input.Close();
}
public override int Read(System.Char[] cbuf, int off, int len)
{
return input.Read(cbuf, off, len);
}
public bool MarkSupported()
{
return input.BaseStream.CanSeek;
}
public void Mark(int readAheadLimit)
{
currentPosition = input.BaseStream.Position;
input.BaseStream.Position = readAheadLimit;
}
public void Reset()
{
input.BaseStream.Position = currentPosition;
}
}
}