lucene/analysis/common/src/java/org/apache/lucene/analysis/hi/HindiStemmer.java

/*
 * 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.
 */
package org.apache.lucene.analysis.hi;

import static org.apache.lucene.analysis.util.StemmerUtil.*;

/**
 * Light Stemmer for Hindi.
 *
 * <p>Implements the algorithm specified in: <i>A Lightweight Stemmer for Hindi</i> Ananthakrishnan
 * Ramanathan and Durgesh D Rao.
 * http://computing.open.ac.uk/Sites/EACLSouthAsia/Papers/p6-Ramanathan.pdf
 */
public class HindiStemmer {
  public int stem(char buffer[], int len) {
    // 5
    if ((len > 6)
        && (endsWith(buffer, len, "ाएंगी")
            || endsWith(buffer, len, "ाएंगे")
            || endsWith(buffer, len, "ाऊंगी")
            || endsWith(buffer, len, "ाऊंगा")
            || endsWith(buffer, len, "ाइयाँ")
            || endsWith(buffer, len, "ाइयों")
            || endsWith(buffer, len, "ाइयां"))) return len - 5;

    // 4
    if ((len > 5)
        && (endsWith(buffer, len, "ाएगी")
            || endsWith(buffer, len, "ाएगा")
            || endsWith(buffer, len, "ाओगी")
            || endsWith(buffer, len, "ाओगे")
            || endsWith(buffer, len, "एंगी")
            || endsWith(buffer, len, "ेंगी")
            || endsWith(buffer, len, "एंगे")
            || endsWith(buffer, len, "ेंगे")
            || endsWith(buffer, len, "ूंगी")
            || endsWith(buffer, len, "ूंगा")
            || endsWith(buffer, len, "ातीं")
            || endsWith(buffer, len, "नाओं")
            || endsWith(buffer, len, "नाएं")
            || endsWith(buffer, len, "ताओं")
            || endsWith(buffer, len, "ताएं")
            || endsWith(buffer, len, "ियाँ")
            || endsWith(buffer, len, "ियों")
            || endsWith(buffer, len, "ियां"))) return len - 4;

    // 3
    if ((len > 4)
        && (endsWith(buffer, len, "ाकर")
            || endsWith(buffer, len, "ाइए")
            || endsWith(buffer, len, "ाईं")
            || endsWith(buffer, len, "ाया")
            || endsWith(buffer, len, "ेगी")
            || endsWith(buffer, len, "ेगा")
            || endsWith(buffer, len, "ोगी")
            || endsWith(buffer, len, "ोगे")
            || endsWith(buffer, len, "ाने")
            || endsWith(buffer, len, "ाना")
            || endsWith(buffer, len, "ाते")
            || endsWith(buffer, len, "ाती")
            || endsWith(buffer, len, "ाता")
            || endsWith(buffer, len, "तीं")
            || endsWith(buffer, len, "ाओं")
            || endsWith(buffer, len, "ाएं")
            || endsWith(buffer, len, "ुओं")
            || endsWith(buffer, len, "ुएं")
            || endsWith(buffer, len, "ुआं"))) return len - 3;

    // 2
    if ((len > 3)
        && (endsWith(buffer, len, "कर")
            || endsWith(buffer, len, "ाओ")
            || endsWith(buffer, len, "िए")
            || endsWith(buffer, len, "ाई")
            || endsWith(buffer, len, "ाए")
            || endsWith(buffer, len, "ने")
            || endsWith(buffer, len, "नी")
            || endsWith(buffer, len, "ना")
            || endsWith(buffer, len, "ते")
            || endsWith(buffer, len, "ीं")
            || endsWith(buffer, len, "ती")
            || endsWith(buffer, len, "ता")
            || endsWith(buffer, len, "ाँ")
            || endsWith(buffer, len, "ां")
            || endsWith(buffer, len, "ों")
            || endsWith(buffer, len, "ें"))) return len - 2;

    // 1
    if ((len > 2)
        && (endsWith(buffer, len, "ो")
            || endsWith(buffer, len, "े")
            || endsWith(buffer, len, "ू")
            || endsWith(buffer, len, "ु")
            || endsWith(buffer, len, "ी")
            || endsWith(buffer, len, "ि")
            || endsWith(buffer, len, "ा"))) return len - 1;
    return len;
  }
}