过滤脏字算法

net过滤脏字的代码，一般用于处理论坛等言论的敏感词过滤，我主要用到了代码内的TrieFilter工具类，其他工具类若有需求可以自行研究

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;

namespace FilterTest
{
    /// 

    /// http://www.cnblogs.com/xingd/archive/2008/02/01/1061800.html上的方法
    /// 

    public class BadWordsFilter
    {
        private HashSet hash = new HashSet（）;
        private byte[] fastCheck = new byte[char.MaxValue];
        private byte[] fastLength = new byte[char.MaxValue];
        private BitArray charCheck = new BitArray（char.MaxValue）;
        private BitArray endCheck = new BitArray（char.MaxValue）;
        private int maxWordLength = 0;
        private int minWordLength = int.MaxValue;

        public BadWordsFilter（）
        {
        }

        public void AddKey（string word）
        {
            maxWordLength = Math.Max（maxWordLength word.Length）;
            minWordLength = Math.Min（minWordLength word.Length）;

            for （int i = 0; i < 7 && i < word.Length; i++）
            {
                fastCheck[word[i]] |= （byte）（1 << i）;
            }

            for （int i = 7; i < word.Length; i++）
            {
                fastCheck[word[i]] |= 0x80;
            }

            if （word.Length == 1）
            {
                charCheck[word[0]] = true;
            }
            else
            {
                fastLength[word[0]] |= （byte）（1 << （Math.Min（7 word.Length - 2）））;
                endCheck[word[word.Length - 1]] = true;
                hash.Add（word）;
            }
        }

        public string Filter（string text string mask）
        {
            throw new NotImplementedException（）;
        }

        public bool HasBadWord（string text）
        {
            int index = 0;

            while （index < text.Length）
            {
                int count = 1;

                if （index > 0 || （fastCheck[text[index]] & 1） == 0）
                {
                    while （index < text.Length - 1 && （fastCheck[text[++index]] & 1） == 0） ;
                }

                char begin = text[index];

                if （minWordLength == 1 && charCheck[begin]）
                {
                    return true;
                }

                for （int j = 1; j <= Math.Min（maxWordLength text.Length - index - 1）; j++）
                {
                    char current = text[index + j];

                    if （（fastCheck[current] & 1） == 0）
                    {
                        ++count;
                    }

                    if （（fastCheck[current] & （1 << Math.Min（j 7））） == 0）
                    {
                        break;
                    }

                    if （j + 1 >= minWordLength）
                    {
                        if （（fastLength[begin] & （1 << Math.Min（j - 1 7））） > 0 && endCheck[current]）
                        {
                            string sub = text.Substring（index j + 1）;

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2017-09-12 10:14  FilterTest\
     目录           0  2017-09-12 10:14  FilterTest\Backup\
     目录           0  2017-09-12 10:14  FilterTest\Backup\FilterTest\
     文件       65391  2011-08-25 22:53  FilterTest\Backup\FilterTest\BadWord.txt
     文件        3341  2011-09-01 13:51  FilterTest\Backup\FilterTest\BadWordsFilter.cs
     文件        3031  2011-08-25 23:15  FilterTest\Backup\FilterTest\CodeTimer.cs
     文件        2916  2011-09-01 13:43  FilterTest\Backup\FilterTest\FilterTest.csproj
     文件         168  2011-09-01 13:43  FilterTest\Backup\FilterTest\FilterTest.csproj.user
     文件        3002  2011-09-01 13:43  FilterTest\Backup\FilterTest\HashFilter.cs
     文件        2938  2011-09-01 13:50  FilterTest\Backup\FilterTest\Program.cs
     目录           0  2017-09-12 10:14  FilterTest\Backup\FilterTest\Properties\
     文件        1376  2011-09-01 13:33  FilterTest\Backup\FilterTest\Properties\AssemblyInfo.cs
     文件        1285  2011-08-29 07:34  FilterTest\Backup\FilterTest\Talk.txt
     文件        5634  2011-09-01 13:46  FilterTest\Backup\FilterTest\TrieFilter.cs
     文件         920  2011-09-01 13:33  FilterTest\Backup\FilterTest.sln
     目录           0  2017-09-12 10:15  FilterTest\FilterTest\
     文件        3341  2011-09-01 13:51  FilterTest\FilterTest\BadWordsFilter.cs
     文件        3031  2011-08-25 23:15  FilterTest\FilterTest\CodeTimer.cs
     文件        4405  2017-04-11 14:38  FilterTest\FilterTest\FilterTest.csproj
     文件         498  2017-04-11 14:38  FilterTest\FilterTest\FilterTest.csproj.user
     文件        3002  2011-09-01 13:43  FilterTest\FilterTest\HashFilter.cs
     文件        4608  2017-04-12 18:31  FilterTest\FilterTest\Program.cs
     目录           0  2017-09-12 10:14  FilterTest\FilterTest\Properties\
     文件        1376  2011-09-01 13:33  FilterTest\FilterTest\Properties\AssemblyInfo.cs
     文件        1285  2011-08-29 07:34  FilterTest\FilterTest\Talk.txt
     文件        5688  2017-04-11 14:38  FilterTest\FilterTest\TrieFilter.cs
     文件         161  2017-04-11 14:38  FilterTest\FilterTest\app.config
     目录           0  2017-09-12 10:14  FilterTest\FilterTest\bin\
     目录           0  2017-09-12 10:14  FilterTest\FilterTest\bin\Debug\
     文件     1607406  2017-04-12 11:15  FilterTest\FilterTest\bin\Debug\BadWord.txt
     文件       14848  2017-04-12 18:33  FilterTest\FilterTest\bin\Debug\FilterTest.exe
............此处省略20个文件信息