Lucene.Net  3.0.3
Lucene.Net is a port of the Lucene search engine library, written in C# and targeted at .NET runtime users.
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CharStream.cs
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2  * Licensed to the Apache Software Foundation (ASF) under one or more
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9  * http://www.apache.org/licenses/LICENSE-2.0
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17 
18 namespace Lucene.Net.Analysis
19 {
20 
21  /// <summary> CharStream adds <see cref="CorrectOffset" />
22  /// functionality over <see cref="System.IO.TextReader" />. All Tokenizers accept a
23  /// CharStream instead of <see cref="System.IO.TextReader" /> as input, which enables
24  /// arbitrary character based filtering before tokenization.
25  /// The <see cref="CorrectOffset" /> method fixed offsets to account for
26  /// removal or insertion of characters, so that the offsets
27  /// reported in the tokens match the character offsets of the
28  /// original Reader.
29  /// </summary>
30  public abstract class CharStream : System.IO.StreamReader
31  {
32  protected CharStream(System.IO.StreamReader reader) : base(reader.BaseStream)
33  {
34  }
35 
36  /// <summary> Called by CharFilter(s) and Tokenizer to correct token offset.
37  ///
38  /// </summary>
39  /// <param name="currentOff">offset as seen in the output
40  /// </param>
41  /// <returns> corrected offset based on the input
42  /// </returns>
43  public abstract int CorrectOffset(int currentOff);
44  }
45 }