| using Lucene.Net.Analysis.Util; |
| |
| namespace Lucene.Net.Analysis.Hu |
| { |
| /* |
| * 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 Hungarian. |
| /// <para> |
| /// This stemmer implements the "UniNE" algorithm in: |
| /// <c>Light Stemming Approaches for the French, Portuguese, German and Hungarian Languages</c> |
| /// Jacques Savoy |
| /// </para> |
| /// </summary> |
| public class HungarianLightStemmer |
| { |
| public virtual int Stem(char[] s, int len) |
| { |
| for (int i = 0; i < len; i++) |
| { |
| switch (s[i]) |
| { |
| case 'á': |
| s[i] = 'a'; |
| break; |
| case 'ë': |
| case 'é': |
| s[i] = 'e'; |
| break; |
| case 'í': |
| s[i] = 'i'; |
| break; |
| case 'ó': |
| case 'ő': |
| case 'õ': |
| case 'ö': |
| s[i] = 'o'; |
| break; |
| case 'ú': |
| case 'ű': |
| case 'ũ': |
| case 'û': |
| case 'ü': |
| s[i] = 'u'; |
| break; |
| } |
| } |
| |
| len = RemoveCase(s, len); |
| len = RemovePossessive(s, len); |
| len = RemovePlural(s, len); |
| return Normalize(s, len); |
| } |
| |
| private int RemoveCase(char[] s, int len) |
| { |
| if (len > 6 && StemmerUtil.EndsWith(s, len, "kent")) |
| { |
| return len - 4; |
| } |
| |
| if (len > 5) |
| { |
| if (StemmerUtil.EndsWith(s, len, "nak") || StemmerUtil.EndsWith(s, len, "nek") || StemmerUtil.EndsWith(s, len, "val") || StemmerUtil.EndsWith(s, len, "vel") || StemmerUtil.EndsWith(s, len, "ert") || StemmerUtil.EndsWith(s, len, "rol") || StemmerUtil.EndsWith(s, len, "ban") || StemmerUtil.EndsWith(s, len, "ben") || StemmerUtil.EndsWith(s, len, "bol") || StemmerUtil.EndsWith(s, len, "nal") || StemmerUtil.EndsWith(s, len, "nel") || StemmerUtil.EndsWith(s, len, "hoz") || StemmerUtil.EndsWith(s, len, "hez") || StemmerUtil.EndsWith(s, len, "tol")) |
| { |
| return len - 3; |
| } |
| |
| if (StemmerUtil.EndsWith(s, len, "al") || StemmerUtil.EndsWith(s, len, "el")) |
| { |
| if (!IsVowel(s[len - 3]) && s[len - 3] == s[len - 4]) |
| { |
| return len - 3; |
| } |
| } |
| } |
| |
| if (len > 4) |
| { |
| if (StemmerUtil.EndsWith(s, len, "at") || StemmerUtil.EndsWith(s, len, "et") || StemmerUtil.EndsWith(s, len, "ot") || StemmerUtil.EndsWith(s, len, "va") || StemmerUtil.EndsWith(s, len, "ve") || StemmerUtil.EndsWith(s, len, "ra") || StemmerUtil.EndsWith(s, len, "re") || StemmerUtil.EndsWith(s, len, "ba") || StemmerUtil.EndsWith(s, len, "be") || StemmerUtil.EndsWith(s, len, "ul") || StemmerUtil.EndsWith(s, len, "ig")) |
| { |
| return len - 2; |
| } |
| |
| if ((StemmerUtil.EndsWith(s, len, "on") || StemmerUtil.EndsWith(s, len, "en")) && !IsVowel(s[len - 3])) |
| { |
| return len - 2; |
| } |
| |
| switch (s[len - 1]) |
| { |
| case 't': |
| case 'n': |
| return len - 1; |
| case 'a': |
| case 'e': |
| if (s[len - 2] == s[len - 3] && !IsVowel(s[len - 2])) |
| { |
| return len - 2; |
| } |
| break; |
| } |
| } |
| |
| return len; |
| } |
| |
| private int RemovePossessive(char[] s, int len) |
| { |
| if (len > 6) |
| { |
| if (!IsVowel(s[len - 5]) && (StemmerUtil.EndsWith(s, len, "atok") || StemmerUtil.EndsWith(s, len, "otok") || StemmerUtil.EndsWith(s, len, "etek"))) |
| { |
| return len - 4; |
| } |
| |
| if (StemmerUtil.EndsWith(s, len, "itek") || StemmerUtil.EndsWith(s, len, "itok")) |
| { |
| return len - 4; |
| } |
| } |
| |
| if (len > 5) |
| { |
| if (!IsVowel(s[len - 4]) && (StemmerUtil.EndsWith(s, len, "unk") || StemmerUtil.EndsWith(s, len, "tok") || StemmerUtil.EndsWith(s, len, "tek"))) |
| { |
| return len - 3; |
| } |
| |
| if (IsVowel(s[len - 4]) && StemmerUtil.EndsWith(s, len, "juk")) |
| { |
| return len - 3; |
| } |
| |
| if (StemmerUtil.EndsWith(s, len, "ink")) |
| { |
| return len - 3; |
| } |
| } |
| |
| if (len > 4) |
| { |
| if (!IsVowel(s[len - 3]) && (StemmerUtil.EndsWith(s, len, "am") || StemmerUtil.EndsWith(s, len, "em") || StemmerUtil.EndsWith(s, len, "om") || StemmerUtil.EndsWith(s, len, "ad") || StemmerUtil.EndsWith(s, len, "ed") || StemmerUtil.EndsWith(s, len, "od") || StemmerUtil.EndsWith(s, len, "uk"))) |
| { |
| return len - 2; |
| } |
| |
| if (IsVowel(s[len - 3]) && (StemmerUtil.EndsWith(s, len, "nk") || StemmerUtil.EndsWith(s, len, "ja") || StemmerUtil.EndsWith(s, len, "je"))) |
| { |
| return len - 2; |
| } |
| |
| if (StemmerUtil.EndsWith(s, len, "im") || StemmerUtil.EndsWith(s, len, "id") || StemmerUtil.EndsWith(s, len, "ik")) |
| { |
| return len - 2; |
| } |
| } |
| |
| if (len > 3) |
| { |
| switch (s[len - 1]) |
| { |
| case 'a': |
| case 'e': |
| if (!IsVowel(s[len - 2])) |
| { |
| return len - 1; |
| } |
| break; |
| case 'm': |
| case 'd': |
| if (IsVowel(s[len - 2])) |
| { |
| return len - 1; |
| } |
| break; |
| case 'i': |
| return len - 1; |
| } |
| } |
| |
| return len; |
| } |
| |
| private int RemovePlural(char[] s, int len) |
| { |
| if (len > 3 && s[len - 1] == 'k') |
| { |
| switch (s[len - 2]) |
| { |
| case 'a': |
| case 'o': |
| case 'e': // intentional fallthru |
| if (len > 4) |
| { |
| return len - 2; |
| } |
| return len - 1;// LUCENENET NOTE: Cannot fall through, so need to return the same value as default |
| default: |
| return len - 1; |
| } |
| } |
| return len; |
| } |
| |
| private int Normalize(char[] s, int len) |
| { |
| if (len > 3) |
| { |
| switch (s[len - 1]) |
| { |
| case 'a': |
| case 'e': |
| case 'i': |
| case 'o': |
| return len - 1; |
| } |
| } |
| return len; |
| } |
| |
| private bool IsVowel(char ch) |
| { |
| switch (ch) |
| { |
| case 'a': |
| case 'e': |
| case 'i': |
| case 'o': |
| case 'u': |
| case 'y': |
| return true; |
| default: |
| return false; |
| } |
| } |
| } |
| } |
