| using Lucene.Net.Analysis.Util; |
| using System; |
| |
| namespace Lucene.Net.Analysis.No |
| { |
| /* |
| * 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. |
| */ |
| |
| [System.Flags] |
| public enum NorwegianStandard |
| { |
| /// <summary> |
| /// Constant to remove Bokmål-specific endings </summary> |
| BOKMAAL = 1, |
| /// <summary> |
| /// Constant to remove Nynorsk-specific endings </summary> |
| NYNORSK = 2 |
| } |
| |
| /// <summary> |
| /// Light Stemmer for Norwegian. |
| /// <para> |
| /// Parts of this stemmer is adapted from <see cref="Sv.SwedishLightStemFilter"/>, except |
| /// that while the Swedish one has a pre-defined rule set and a corresponding |
| /// corpus to validate against whereas the Norwegian one is hand crafted. |
| /// </para> |
| /// </summary> |
| public class NorwegianLightStemmer |
| { |
| // LUCENENET specific - made flags into their own [Flags] enum named NorwegianStandard and de-nested from this type |
| |
| private readonly bool useBokmaal; |
| private readonly bool useNynorsk; |
| |
| /// <summary> |
| /// Creates a new <see cref="NorwegianLightStemmer"/> </summary> |
| /// <param name="flags"> set to <see cref="NorwegianStandard.BOKMAAL"/>, <see cref="NorwegianStandard.NYNORSK"/>, or both. </param> |
| public NorwegianLightStemmer(NorwegianStandard flags) |
| { |
| if (flags <= 0 || flags > (int)NorwegianStandard.BOKMAAL + NorwegianStandard.NYNORSK) |
| { |
| throw new ArgumentException("invalid flags"); |
| } |
| useBokmaal = (flags & NorwegianStandard.BOKMAAL) != 0; |
| useNynorsk = (flags & NorwegianStandard.NYNORSK) != 0; |
| } |
| |
| public virtual int Stem(char[] s, int len) |
| { |
| // Remove posessive -s (bilens -> bilen) and continue checking |
| if (len > 4 && s[len - 1] == 's') |
| { |
| len--; |
| } |
| |
| // Remove common endings, single-pass |
| if (len > 7 && ((StemmerUtil.EndsWith(s, len, "heter") && useBokmaal) || (StemmerUtil.EndsWith(s, len, "heten") && useBokmaal) || (StemmerUtil.EndsWith(s, len, "heita") && useNynorsk))) // general ending (hemmeleg-heita -> hemmeleg) - general ending (hemmelig-heten -> hemmelig) - general ending (hemmelig-heter -> hemmelig) |
| { |
| return len - 5; |
| } |
| |
| // Remove Nynorsk common endings, single-pass |
| if (len > 8 && useNynorsk && (StemmerUtil.EndsWith(s, len, "heiter") || StemmerUtil.EndsWith(s, len, "leiken") || StemmerUtil.EndsWith(s, len, "leikar"))) // general ending (trygg-leikar -> trygg) - general ending (trygg-leiken -> trygg) - general ending (hemmeleg-heiter -> hemmeleg) |
| { |
| return len - 6; |
| } |
| |
| if (len > 5 && (StemmerUtil.EndsWith(s, len, "dom") || (StemmerUtil.EndsWith(s, len, "het") && useBokmaal))) // general ending (hemmelig-het -> hemmelig) - general ending (kristen-dom -> kristen) |
| { |
| return len - 3; |
| } |
| |
| if (len > 6 && useNynorsk && (StemmerUtil.EndsWith(s, len, "heit") || StemmerUtil.EndsWith(s, len, "semd") || StemmerUtil.EndsWith(s, len, "leik"))) // general ending (trygg-leik -> trygg) - general ending (verk-semd -> verk) - general ending (hemmeleg-heit -> hemmeleg) |
| { |
| return len - 4; |
| } |
| |
| if (len > 7 && (StemmerUtil.EndsWith(s, len, "elser") || StemmerUtil.EndsWith(s, len, "elsen"))) // general ending (føl-elsen -> føl) - general ending (føl-elser -> føl) |
| { |
| return len - 5; |
| } |
| |
| if (len > 6 && ((StemmerUtil.EndsWith(s, len, "ende") && useBokmaal) || (StemmerUtil.EndsWith(s, len, "ande") && useNynorsk) || StemmerUtil.EndsWith(s, len, "else") || (StemmerUtil.EndsWith(s, len, "este") && useBokmaal) || (StemmerUtil.EndsWith(s, len, "aste") && useNynorsk) || (StemmerUtil.EndsWith(s, len, "eren") && useBokmaal) || (StemmerUtil.EndsWith(s, len, "aren") && useNynorsk))) // masc - masc - adj (fin-aste -> fin) - adj (fin-este -> fin) - general ending (føl-else -> føl) - (sov-ande -> sov) - (sov-ende -> sov) |
| { |
| return len - 4; |
| } |
| |
| if (len > 5 && ((StemmerUtil.EndsWith(s, len, "ere") && useBokmaal) || (StemmerUtil.EndsWith(s, len, "are") && useNynorsk) || (StemmerUtil.EndsWith(s, len, "est") && useBokmaal) || (StemmerUtil.EndsWith(s, len, "ast") && useNynorsk) || StemmerUtil.EndsWith(s, len, "ene") || (StemmerUtil.EndsWith(s, len, "ane") && useNynorsk))) // masc pl definite (gut-ane) - masc/fem/neutr pl definite (hus-ene) - adj (fin-ast -> fin) - adj (fin-est -> fin) - adj (fin-are -> fin) - adj (fin-ere -> fin) |
| { |
| return len - 3; |
| } |
| |
| if (len > 4 && (StemmerUtil.EndsWith(s, len, "er") || StemmerUtil.EndsWith(s, len, "en") || StemmerUtil.EndsWith(s, len, "et") || (StemmerUtil.EndsWith(s, len, "ar") && useNynorsk) || (StemmerUtil.EndsWith(s, len, "st") && useBokmaal) || StemmerUtil.EndsWith(s, len, "te"))) // adj (billig-st -> billig) - masc pl indefinite - neutr definite - masc/fem definite - masc/fem indefinite |
| { |
| return len - 2; |
| } |
| |
| if (len > 3) |
| { |
| switch (s[len - 1]) |
| { |
| case 'a': // fem definite |
| case 'e': // to get correct stem for nouns ending in -e (kake -> kak, kaker -> kak) |
| case 'n': |
| return len - 1; |
| } |
| } |
| |
| return len; |
| } |
| } |
| } |
