/*
* 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.
*/
using System;
using System.IO;
using System.Collections;
using Lucene.Net.Analysis;
using Lucene.Net.Analysis.Tokenattributes;
using Lucene.Net.Util;
namespace Lucene.Net.Analysis.AR
{
/**
* Normalizer for Arabic.
*
* Normalization is done in-place for efficiency, operating on a termbuffer.
*
* Normalization is defined as:
*
* - Normalization of hamza with alef seat to a bare alef.
* - Normalization of teh marbuta to heh
* - Normalization of dotless yeh (alef maksura) to yeh.
* - Removal of Arabic diacritics (the harakat)
* - Removal of tatweel (stretching character).
*
*
*/
public class ArabicNormalizer
{
public const char ALEF = '\u0627';
public const char ALEF_MADDA = '\u0622';
public const char ALEF_HAMZA_ABOVE = '\u0623';
public const char ALEF_HAMZA_BELOW = '\u0625';
public const char YEH = '\u064A';
public const char DOTLESS_YEH = '\u0649';
public const char TEH_MARBUTA = '\u0629';
public const char HEH = '\u0647';
public const char TATWEEL = '\u0640';
public const char FATHATAN = '\u064B';
public const char DAMMATAN = '\u064C';
public const char KASRATAN = '\u064D';
public const char FATHA = '\u064E';
public const char DAMMA = '\u064F';
public const char KASRA = '\u0650';
public const char SHADDA = '\u0651';
public const char SUKUN = '\u0652';
/**
* Normalize an input buffer of Arabic text
*
* input buffer
* length of input buffer
* length of input buffer after normalization
*/
public int Normalize(char[] s, int len)
{
for (int i = 0; i < len; i++)
{
switch (s[i])
{
case ALEF_MADDA:
case ALEF_HAMZA_ABOVE:
case ALEF_HAMZA_BELOW:
s[i] = ALEF;
break;
case DOTLESS_YEH:
s[i] = YEH;
break;
case TEH_MARBUTA:
s[i] = HEH;
break;
case TATWEEL:
case KASRATAN:
case DAMMATAN:
case FATHATAN:
case FATHA:
case DAMMA:
case KASRA:
case SHADDA:
case SUKUN:
len = Delete(s, i, len);
i--;
break;
default:
break;
}
}
return len;
}
/**
* Delete a character in-place
*
* Input Buffer
* Position of character to delete
* length of input buffer
* length of input buffer after deletion
*/
protected int Delete(char[] s, int pos, int len)
{
if (pos < len)
Array.Copy(s, pos + 1, s, pos, len - pos - 1);
return len - 1;
}
}
}