An accent and case insensitive analyzer for lucene.net 4.8

AccentFoldingAnalyzer.cs

using Lucene.Net.Analysis;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using Lucene.Net.Analysis.Util;
using Lucene.Net.Util;
using Lucene.Net.Analysis.Standard;
using Lucene.Net.Analysis.Core;

namespace Map.Lucene
{
    public class AccentFoldingAnalyzer : Analyzer
    {

        private readonly LuceneVersion luceneVersion;

        public AccentFoldingAnalyzer(): this(LuceneVersion.LUCENE_48)
        {
        }

        public AccentFoldingAnalyzer(LuceneVersion luceneVersion): base()
        {
            this.luceneVersion = luceneVersion;
        }

        protected override TokenStreamComponents CreateComponents(string fieldName, TextReader reader)
        {
            Tokenizer source = new StandardTokenizer(luceneVersion, reader);
            TokenStream result = new StandardFilter(luceneVersion, source);
            result = new LowerCaseFilter(luceneVersion, result);
            result = new AccentFoldingFilter(result);
            return new TokenStreamComponents(source, result);
        }
    }
}

AccentFoldingFilter.cs

using Lucene.Net.Analysis.TokenAttributes;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Lucene.Net.Search;
using Lucene.Net.Analysis;

namespace Map.Lucene
{
    public sealed class AccentFoldingFilter : TokenFilter
    {
        private ICharTermAttribute termAttribute;

        public AccentFoldingFilter(TokenStream input) : base(input)
        {
            termAttribute = this.GetAttribute<ICharTermAttribute>();
        }

        public override bool IncrementToken()
        {
            if (this.m_input.IncrementToken())
            {
                string buffer = termAttribute.ToString().RemoveDiacritics();
                termAttribute.SetEmpty().Append(buffer);
                return true;
            }
            return false;
        }
    }
}

RemoveDiacritics.cs

        public static string RemoveDiacritics(this string text)
        {
            var normalizedString = text.Normalize(NormalizationForm.FormD);
            var stringBuilder = new StringBuilder();

            foreach (var c in normalizedString)
            {
                var unicodeCategory = CharUnicodeInfo.GetUnicodeCategory(c);
                if (unicodeCategory != UnicodeCategory.NonSpacingMark)
                {
                    stringBuilder.Append(c);
                }
            }

            return stringBuilder.ToString().Normalize(NormalizationForm.FormC);
        }