敏感字过滤算法

<span style="font-size:24px;">原文地址 ：http://www.unitymanual.com/thread-40474-1-1.html</span>

using System;using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
 
public abstract class WordFilter
{
        /// <summary>
        /// 敏感字数组
        /// </summary>
        public static string[] s_filters = null;
 
        /// <summary>
        /// 初始化s_filters之后调用filter函数
        /// </summary>
        /// <param name="content">欲过滤的内容</param>
        /// <param name="result_str">执行过滤之后的内容</param>
        /// <param name="filter_deep">检测深度，即s_filters数组中的每个词中的插入几个字以内会被过滤掉，例：检测深度为2，s_filters中有个词是中国，那么“中国”、“中*国”，“中**国”都会被过滤掉（*是任意字）。</param>
        /// <param name="check_only">是否只检测而不执行过滤操作</param>
        /// <param name="bTrim">过滤之前是否要去掉头尾的空字符</param>
        /// <param name="replace_str">将检测到的敏感字替换成的字符</param>
        /// <returns></returns>
        public static bool filter(string content, out string result_str, int filter_deep = 1, bool check_only = false, bool bTrim = false, string replace_str = "*")
        {
                string result = content;
                if (bTrim)
                {
                        result = result.Trim();
                }
                result_str = result;
 
                if (s_filters == null)
                {
                        return false;
                }
 
                bool check = false;
                foreach (string str in s_filters)
                {
                        string s = str.Replace(replace_str, "");
                        if (s.Length == 0)
                        {
                                continue;
                        }
 
                        bool bFiltered = true;
                        while (bFiltered)
                        {
                                int result_index_start = -1;
                                int result_index_end = -1;
                                int idx = 0;
                                while (idx < s.Length)
                                {
                                        string one_s = s.Substring(idx, 1);
                                        if (one_s == replace_str)
                                        {
                                                continue;
                                        }
                                        if (result_index_end + 1 >= result.Length)
                                        {
                                                bFiltered = false;
                                                break;
                                        }
                                        int new_index = result.IndexOf(one_s, result_index_end + 1, StringComparison.OrdinalIgnoreCase);
                                        if (new_index == -1)
                                        {
                                                bFiltered = false;
                                                break;
                                        }
                                        if (idx > 0 && new_index - result_index_end > filter_deep + 1)
                                        {
                                                bFiltered = false;
                                                break;
                                        }
                                        result_index_end = new_index;
 
                                        if (result_index_start == -1)
                                        {
                                                result_index_start = new_index;
                                        }
                                        idx++;
                                }
 
                                if (bFiltered)
                                {
                                        if (check_only)
                                        {
                                                return true;
                                        }
                                        check = true;
                                        string result_left = result.Substring(0, result_index_start);
                                        for (int i = result_index_start; i <= result_index_end; i++)
                                        {
                                                result_left += replace_str;
                                        }
                                        string result_right = result.Substring(result_index_end + 1);
                                        result = result_left + result_right;
                                }
                        }
                }
                result_str = result;
                return check;
        }
}