content: package org.apache.lucene.analysis.fi;
  
  /**
   * 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.
   */
  
  /* 
   * This algorithm is updated based on code located at:
   * http://members.unine.ch/jacques.savoy/clef/
   * 
   * Full copyright for that code follows:
   */
  
  /*
   * Copyright (c) 2005, Jacques Savoy
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without 
   * modification, are permitted provided that the following conditions are met:
   *
   * Redistributions of source code must retain the above copyright notice, this 
   * list of conditions and the following disclaimer. Redistributions in binary 
   * form must reproduce the above copyright notice, this list of conditions and
   * the following disclaimer in the documentation and/or other materials 
   * provided with the distribution. Neither the name of the author nor the names 
   * of its contributors may be used to endorse or promote products derived from 
   * this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  import static org.apache.lucene.analysis.util.StemmerUtil.*;
  
  /**
   * Light Stemmer for Finnish.
   * <p>
   * This stemmer implements the algorithm described in:
   * <i>Report on CLEF-2003 Monolingual Tracks</i>
   * Jacques Savoy
   */
  public class FinnishLightStemmer {
    
    public int stem(char s[], int len) {
      if (len < 4)
        return len;
      
      for (int i = 0; i < len; i++)
        switch(s[i]) {
          case 'ä':
          case 'å': s[i] = 'a'; break;
          case 'ö': s[i] = 'o'; break;
        }
      
      len = step1(s, len);
      len = step2(s, len);
      len = step3(s, len);
      len = norm1(s, len);
      len = norm2(s, len);
      return len;
    }
    
    private int step1(char s[], int len) {
      if (len > 8) {
        if (endsWith(s, len, "kin"))
          return step1(s, len-3);
        if (endsWith(s, len, "ko"))
          return step1(s, len-2);
      }
      
      if (len > 11) {
        if (endsWith(s, len, "dellinen"))
          return len-8;
        if (endsWith(s, len, "dellisuus"))
          return len-9;
      }
      return len;
    }
    
    private int step2(char s[], int len) {
      if (len > 5) {
        if (endsWith(s, len, "lla")
            || endsWith(s, len, "tse")
            || endsWith(s, len, "sti"))
          return len-3;
        
        if (endsWith(s, len, "ni"))
          return len-2;
        
        if (endsWith(s, len, "aa"))
          return len-1; // aa -> a
      }
      
      return len;
    }
    
    private int step3(char s[], int len) {
      if (len > 8) {
        if (endsWith(s, len, "nnen")) {
          s[len-4] = 's';
          return len-3;
        }
        
        if (endsWith(s, len, "ntena")) {
          s[len-5] = 's';
          return len-4;
        }
        
        if (endsWith(s, len, "tten"))
          return len-4;
        
        if (endsWith(s, len, "eiden"))
          return len-5;
      }
      
      if (len > 6) {
        if (endsWith(s, len, "neen")
            || endsWith(s, len, "niin")
            || endsWith(s, len, "seen")
            || endsWith(s, len, "teen")
            || endsWith(s, len, "inen"))
            return len-4;
        
        if (s[len-3] == 'h' && isVowel(s[len-2]) && s[len-1] == 'n')
          return len-3;
        
        if (endsWith(s, len, "den")) {
          s[len-3] = 's';
          return len-2;
        }
        
        if (endsWith(s, len, "ksen")) {
          s[len-4] = 's';
          return len-3;
        }
        
        if (endsWith(s, len, "ssa")
            || endsWith(s, len, "sta")
            || endsWith(s, len, "lla")
            || endsWith(s, len, "lta")
            || endsWith(s, len, "tta")
            || endsWith(s, len, "ksi")
            || endsWith(s, len, "lle"))
          return len-3; 
      }
      
      if (len > 5) {
        if (endsWith(s, len, "na")
            || endsWith(s, len, "ne"))
          return len-2;
        
        if (endsWith(s, len, "nei"))
          return len-3;
      }
      
      if (len > 4) {
        if (endsWith(s, len, "ja")
            || endsWith(s, len, "ta"))
          return len-2;
        
        if (s[len-1] == 'a')
          return len-1;
        
        if (s[len-1] == 'n' && isVowel(s[len-2]))
          return len-2;
        
        if (s[len-1] == 'n')
          return len-1;
      }
      
      return len;
    }
    
    private int norm1(char s[], int len) {
      if (len > 5 && endsWith(s, len, "hde")) {
          s[len-3] = 'k';
          s[len-2] = 's';
          s[len-1] = 'i';
      }
      
      if (len > 4) {
        if (endsWith(s, len, "ei") || endsWith(s, len, "at"))
          return len-2;
      }
      
      if (len > 3)
        switch(s[len-1]) {
          case 't':
          case 's':
          case 'j':
          case 'e':
          case 'a':
          case 'i': return len-1;
        }
      
      return len;
    }
    
    private int norm2(char s[], int len) {
      if (len > 8) {
        if (s[len-1] == 'e' 
            || s[len-1] == 'o' 
            || s[len-1] == 'u')
          len--;
      }
      
      if (len > 4) {
        if (s[len-1] == 'i')
          len--;
        
        if (len > 4) {
          char ch = s[0];
          for (int i = 1; i < len; i++) {
            if (s[i] == ch &&
                (ch == 'k' || ch == 'p' || ch == 't'))
              len = delete(s, i--, len);
            else
              ch = s[i];
          }
        }
      }
      
      return len;
    }
    
    private boolean isVowel(char ch) {
      switch(ch) {
        case 'a':
        case 'e':
        case 'i':
        case 'o':
        case 'u':
        case 'y': return true;
        default: return false;
      }
    }
  }
  