NGramTokenFilter.h

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// Copyright (c) 2009-2014 Alan Wright. All rights reserved.
// Distributable under the terms of either the Apache License (Version 2.0)
// or the GNU Lesser General Public License.
 
#ifndef NGRAMTOKENFILTER_H
#define NGRAMTOKENFILTER_H
 
#include "TokenFilter.h"
 
namespace Lucene {
 
class LPPAPI NGramTokenFilter : public TokenFilter {
public:
    static const bool DEFAULT_PRESERVE_ORIGINAL;
 
public:
    NGramTokenFilter(const TokenStreamPtr& input, int32_t gramSize);
    NGramTokenFilter(const TokenStreamPtr& input, int32_t minGram, int32_t maxGram);
    NGramTokenFilter(const TokenStreamPtr& input, int32_t minGram, int32_t maxGram, bool preserveOriginal);
 
    virtual ~NGramTokenFilter();
 
    LUCENE_CLASS(NGramTokenFilter);
 
protected:
    int32_t minGram;
    int32_t maxGram;
    bool preserveOriginal;
 
    CharArray curTermBuffer;
    int32_t curTermLength;
    int32_t curGramSize;
    int32_t curPos;
    int32_t curPosIncr;
    AttributeSourceStatePtr state;
 
    TermAttributePtr termAtt;
    PositionIncrementAttributePtr posIncrAtt;
 
protected:
    void init(int32_t minGram, int32_t maxGram, bool preserveOriginal);
 
public:
    virtual bool incrementToken();
    virtual void reset();
    virtual void end();
};
 
}
 
#endif