| using Lucene.Net.Analysis.Util; |
| |
| namespace Lucene.Net.Analysis.Ru |
| { |
| /* |
| * 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. |
| */ |
| |
| /// <summary> |
| /// Light Stemmer for Russian. |
| /// <para> |
| /// This stemmer implements the following algorithm: |
| /// <c>Indexing and Searching Strategies for the Russian Language.</c> |
| /// Ljiljana Dolamic and Jacques Savoy. |
| /// </para> |
| /// </summary> |
| public class RussianLightStemmer |
| { |
| public virtual int Stem(char[] s, int len) |
| { |
| len = RemoveCase(s, len); |
| return Normalize(s, len); |
| } |
| |
| private int Normalize(char[] s, int len) |
| { |
| if (len > 3) |
| { |
| switch (s[len - 1]) |
| { |
| case 'ь': |
| case 'и': |
| return len - 1; |
| case 'н': |
| if (s[len - 2] == 'н') |
| { |
| return len - 1; |
| } |
| break; |
| } |
| } |
| return len; |
| } |
| |
| private int RemoveCase(char[] s, int len) |
| { |
| if (len > 6 && (StemmerUtil.EndsWith(s, len, "иями") || StemmerUtil.EndsWith(s, len, "оями"))) |
| { |
| return len - 4; |
| } |
| |
| if (len > 5 && (StemmerUtil.EndsWith(s, len, "иям") || StemmerUtil.EndsWith(s, len, "иях") || StemmerUtil.EndsWith(s, len, "оях") || StemmerUtil.EndsWith(s, len, "ями") || StemmerUtil.EndsWith(s, len, "оям") || StemmerUtil.EndsWith(s, len, "оьв") || StemmerUtil.EndsWith(s, len, "ами") || StemmerUtil.EndsWith(s, len, "его") || StemmerUtil.EndsWith(s, len, "ему") || StemmerUtil.EndsWith(s, len, "ери") || StemmerUtil.EndsWith(s, len, "ими") || StemmerUtil.EndsWith(s, len, "ого") || StemmerUtil.EndsWith(s, len, "ому") || StemmerUtil.EndsWith(s, len, "ыми") || StemmerUtil.EndsWith(s, len, "оев"))) |
| { |
| return len - 3; |
| } |
| |
| if (len > 4 && (StemmerUtil.EndsWith(s, len, "ая") || StemmerUtil.EndsWith(s, len, "яя") || StemmerUtil.EndsWith(s, len, "ях") || StemmerUtil.EndsWith(s, len, "юю") || StemmerUtil.EndsWith(s, len, "ах") || StemmerUtil.EndsWith(s, len, "ею") || StemmerUtil.EndsWith(s, len, "их") || StemmerUtil.EndsWith(s, len, "ия") || StemmerUtil.EndsWith(s, len, "ию") || StemmerUtil.EndsWith(s, len, "ьв") || StemmerUtil.EndsWith(s, len, "ою") || StemmerUtil.EndsWith(s, len, "ую") || StemmerUtil.EndsWith(s, len, "ям") || StemmerUtil.EndsWith(s, len, "ых") || StemmerUtil.EndsWith(s, len, "ея") || StemmerUtil.EndsWith(s, len, "ам") || StemmerUtil.EndsWith(s, len, "ем") || StemmerUtil.EndsWith(s, len, "ей") || StemmerUtil.EndsWith(s, len, "ём") || StemmerUtil.EndsWith(s, len, "ев") || StemmerUtil.EndsWith(s, len, "ий") || StemmerUtil.EndsWith(s, len, "им") || StemmerUtil.EndsWith(s, len, "ое") || StemmerUtil.EndsWith(s, len, "ой") || StemmerUtil.EndsWith(s, len, "ом") || StemmerUtil.EndsWith(s, len, "ов") || StemmerUtil.EndsWith(s, len, "ые") || StemmerUtil.EndsWith(s, len, "ый") || StemmerUtil.EndsWith(s, len, "ым") || StemmerUtil.EndsWith(s, len, "ми"))) |
| { |
| return len - 2; |
| } |
| |
| if (len > 3) |
| { |
| switch (s[len - 1]) |
| { |
| case 'а': |
| case 'е': |
| case 'и': |
| case 'о': |
| case 'у': |
| case 'й': |
| case 'ы': |
| case 'я': |
| case 'ь': |
| return len - 1; |
| } |
| } |
| |
| return len; |
| } |
| } |
| } |
