--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/searchengine/oss/loc/analysis/inc/public/ngram.h	Fri Oct 15 12:09:28 2010 +0530
@@ -0,0 +1,153 @@
+/*
+* Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description: 
+*
+*/
+#ifndef NGRAM_H_
+#define NGRAM_H_
+
+#include "tinyanalysis.h"
+#include "tinyunicode.h"
+#include "clutil.h"
+
+namespace analysis {
+
+	/**
+	 * Returns true, if the character is non-cjk letter
+	 */
+    int IsNonCjk(int c);
+    
+    /**
+     * TinyCjkTokenizer. Contains tiny analysis classes, that are 
+     * used to turn Chinese, Korean and Japanese into 1-grams, while
+     * using letter analyzer for other kinds of text (western, cyrillic,
+     * etc.)   
+     * 
+     * @tparam I the iterator, that is used to read characters
+     */
+    template<typename I>
+    struct TinyCjkTokenizer {
+    
+    	/** Deals with cjk */
+        tiny::NGramTokenizer<I> cjk_;
+    	/** Letter tokenizer for space separated language */
+        tiny::CustomTokenizer<I> noncjk_; 
+    	/** Combines cjk with noncjk */
+        tiny::PairTokenizer<I> pair_;
+        /** Moves forward, if tokenization fails */
+        tiny::RelaxedTokenizer<I> t_;
+        
+        /** 
+         * Constructs the tiny cjk tokenizer with given ngram size
+         *
+         * @param ngramsize cjk text is treated with n-gram analyzer of this size   
+         */
+        TinyCjkTokenizer(int ngramsize) 
+        : cjk_(ngramsize, &unicode::IsCjk),
+          noncjk_(&IsNonCjk),
+          pair_(cjk_, noncjk_),
+          t_(pair_) {}          
+        
+        /**
+         * Consumes a token from given iterator. Returns n-grams
+         * for cjk text, letter tokenized words for non-cjk text. 
+         * Always returns something unless EOS has been reached.
+         */
+        inline tiny::Token<I> consume(I& i) {
+            return t_.consume(i);
+        }
+    };
+
+    
+    /**
+     * Constructs n-grams of Chinese, Korean and Japanese text. Uses
+     * letter tokenization for other kinds of texts. 
+     */
+	class CjkNGramTokenizer : public lucene::analysis::Tokenizer {
+	
+		public: 
+	
+			/** Reads from buffer */
+			typedef tiny::cl::ReaderBuffer<512>::iterator buffer_iterator;
+
+			/** Turns utf16 to unicode */
+	        typedef tiny::Utf16Iterator<buffer_iterator> iterator;
+
+		public:
+	
+			CjkNGramTokenizer( lucene::util::Reader* reader, int gramSize );
+			
+			virtual bool next( lucene::analysis::Token* token );			
+	
+		private:
+
+			/** The tokenizer */
+            TinyCjkTokenizer<iterator> t_;
+
+            /** Buffer */
+			tiny::cl::ReaderBuffer<512> in_;
+
+			/** Reads utf16 from buffer and transforms it to unicode*/
+			iterator i_; 
+			
+	};
+	
+	/**
+	 * The great difference of this class compared to CJK ngram, 
+	 * that it decomposes Hangul syllables into Hangul Jamu letters.
+	 * 
+	 * This analyzer appeared to have bad performance in testing. 
+	 */
+	class JamuNGramTokenizer : public lucene::analysis::Tokenizer {
+   
+       public:
+    
+           typedef tiny::cl::ReaderBuffer<512>::iterator buffer_iterator;
+
+           typedef tiny::Utf16Iterator<buffer_iterator> utf16_iterator;
+            
+           typedef tiny::JamuIterator<utf16_iterator> iterator;
+            
+       public:
+    
+           JamuNGramTokenizer( lucene::util::Reader* reader, int gramSize );
+            
+           virtual bool next( lucene::analysis::Token* token );            
+    
+       private:
+            
+           TinyCjkTokenizer<iterator> t_;
+       
+           tiny::cl::ReaderBuffer<512> in_;
+            
+           iterator i_; 
+           
+    };
+	
+	// Analyzers using the tokenizers
+	//   * Provided mainly for testing
+	//
+	
+	/** CjkNGramTokenizer plus lowercase filter */
+    typedef TemplateAnalyzer1A1F<CjkNGramTokenizer, int, lucene::analysis::LowerCaseFilter> 
+        CjkNGramAnalyzer;
+    
+	/** JamuNGramTokenizer plus lowercase filter */
+    typedef TemplateAnalyzer1A1F<JamuNGramTokenizer, int, lucene::analysis::LowerCaseFilter> 
+        JamuNGramAnalyzer;
+
+}
+
+
+#endif /* NGRAM_H_ */