content: package org.apache.lucene.analysis.fa;
  
  /**
   * 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.
   */
  
  import static org.apache.lucene.analysis.util.StemmerUtil.*;
  
  /**
   * Normalizer for Persian.
   * <p>
   * Normalization is done in-place for efficiency, operating on a termbuffer.
   * <p>
   * Normalization is defined as:
   * <ul>
   * <li>Normalization of various heh + hamza forms and heh goal to heh.
   * <li>Normalization of farsi yeh and yeh barree to arabic yeh
   * <li>Normalization of persian keheh to arabic kaf
   * </ul>
   * 
   */
  public class PersianNormalizer {
    public static final char YEH = '\u064A';
  
    public static final char FARSI_YEH = '\u06CC';
  
    public static final char YEH_BARREE = '\u06D2';
  
    public static final char KEHEH = '\u06A9';
  
    public static final char KAF = '\u0643';
  
    public static final char HAMZA_ABOVE = '\u0654';
  
    public static final char HEH_YEH = '\u06C0';
  
    public static final char HEH_GOAL = '\u06C1';
  
    public static final char HEH = '\u0647';
  
    /**
     * Normalize an input buffer of Persian text
     * 
     * @param s input buffer
     * @param len length of input buffer
     * @return length of input buffer after normalization
     */
    public int normalize(char s[], int len) {
  
      for (int i = 0; i < len; i++) {
        switch (s[i]) {
        case FARSI_YEH:
        case YEH_BARREE:
          s[i] = YEH;
          break;
        case KEHEH:
          s[i] = KAF;
          break;
        case HEH_YEH:
        case HEH_GOAL:
          s[i] = HEH;
          break;
        case HAMZA_ABOVE: // necessary for HEH + HAMZA
          len = delete(s, i, len);
          i--;
          break;
        default:
          break;
        }
      }
  
      return len;
    }
  }
  