cyf
412 lines
13 KiB
C#
412 lines
13 KiB
C#
using System;
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using System.IO;
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using System.Text;
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using System.Web;
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namespace Zhaizj.Framework.Utils
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{
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/// <summary>
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/// 从IP数据库中读取IP与实际地址
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/// </summary>
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public class IPQuery : IDisposable
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{
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/// <summary>
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/// 地理位置结构体
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/// </summary>
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public struct Location
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{
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public string Region;
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public string City;
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}
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#region 成员变量
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private string m_ipFileAdrress; //IPQWR.dat文件地址
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private string IPFILEADDR = AppDomain.CurrentDomain.BaseDirectory + "IPQuery.Dat"; //默认IP查询数据库文件地址
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private FileStream m_fs;
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private Int32 m_indexOffsetFirst; //第一个索引绝对偏移地址
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private Int32 m_indexOffsetLast; //最后一个索引绝对偏移地址
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private const int INDEX_SIZE = 7; //一个索引占用的字节数
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private const byte REDIRECT_MODE_1 = 0x01; //重定向模式1
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private const byte REDIRECT_MODE_2 = 0x02; //重定向模式2
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#endregion
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#region 构造函数
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/// <summary>
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/// IP地址查询对象的构造函数
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/// </summary>
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/// <param name="ipFileAddress">IP数据库文件地址</param>
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public IPQuery(string ipFileAddress)
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{
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this.m_ipFileAdrress = ipFileAddress;
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try
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{
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m_fs = new FileStream(m_ipFileAdrress, FileMode.Open);
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//m_fs = new FileStream(m_ipFileAdrress, FileMode.Open, FileAccess.Read);
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}
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catch (FileNotFoundException e)
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{
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throw e;
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}
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finally
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{
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Initialize();
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}
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}
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/// <summary>
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/// IP地址查询对象的构造函数
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/// </summary>
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public IPQuery()
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{
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//获取项目根目录后寻找文件位置
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this.m_ipFileAdrress = IPFILEADDR;
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try
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{
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m_fs = new FileStream(m_ipFileAdrress, FileMode.Open, FileAccess.Read);
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}
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catch (FileNotFoundException e)
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{
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throw e;
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}
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finally
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{
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Initialize();
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}
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}
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#endregion
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#region IDisposable 成员
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/// <summary>
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/// 释放非托管资源
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/// </summary>
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public void Dispose()
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{
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m_fs.Dispose();
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m_fs.Close();//关闭文件流
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}
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#endregion
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/// <summary>
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/// 根据IP查找IP段所在的地理位置
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/// </summary>
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/// <param name="ip">IP地址数组</param>
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/// <returns>地理位置</returns>
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public Location GetIPLocation(byte[] ip)
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{
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if (!ValidateIP(ip))
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{
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throw new ArgumentException("IP数组有误");
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}
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Int32 offset = FindIpRecdOffset(ip);
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Location location = ReadLocation(offset);
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return location;
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}
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/// <summary>
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/// 根据IP查找IP段所在的地理位置
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/// </summary>
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/// <param name="ip">IP地址数组</param>
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/// <returns>地理位置</returns>
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public Location GetIPLocation(string ip)
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{
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byte[] bIp = new byte[4];
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int i = 0;
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foreach (string secIp in ip.Split(new char[] { '.' }))
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{
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bIp[i++] = (byte)(Convert.ToInt16(secIp));
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}
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if (!ValidateIP(bIp))
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{
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throw new ArgumentException("IP数组有误");
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}
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Int32 offset = FindIpRecdOffset(bIp);
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Location location = ReadLocation(offset);
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return location;
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}
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#region 私有成员方法
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/// <summary>
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/// 初始化类数据
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/// </summary>
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private void Initialize()
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{
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this.ReadIndexOffset();
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}
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/// <summary>
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/// 指定字节序列编码成Int32类型数据
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/// </summary>
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/// <param name="buf">字节数组</param>
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/// <param name="start">要编码序列在数组中的起始位置</param>
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/// <param name="count">要编码序列的长度大小</param>
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/// <returns>编码出的Int32类型值</returns>
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private Int32 EncodeToInt32(byte[] buf, int start, int count)
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{
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//检查边界条件
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if (count > 4 ||
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count < 1 ||
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start < 0 ||
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start > buf.GetLength(0) - 1)
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{
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throw new ArgumentOutOfRangeException();
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}
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else
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{
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//编码Little-Endian字节序列
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Int32 offset = 0;
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for (int i = 0; i < count; i++)
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{
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offset |= (buf[start + i] << (i * 8));
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}
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return offset;
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}
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}
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/// <summary>
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/// 从IP数据库文件中读取索引绝对偏移地址
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/// </summary>
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private void ReadIndexOffset()
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{
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//读取文件头数据
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byte[] head = new byte[8];
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m_fs.Seek(0, SeekOrigin.Begin);
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m_fs.Read(head, 0, 8);
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//解析第一个索引绝对偏移
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m_indexOffsetFirst = EncodeToInt32(head, 0, 4);
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//解析第一个索引绝对偏移
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m_indexOffsetLast = EncodeToInt32(head, 4, 4);
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}
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/// <summary>
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/// 检验IP的合法性，IP数组元素必须为4且字段值在[0,255]内
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/// </summary>
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/// <param name="ip">IP数组，有且只有4个元素</param>
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/// <returns>IP合法返回true，否则返回false</returns>
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private bool ValidateIP(byte[] ip)
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{
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if (ip.GetLength(0) != 4)
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{
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return false;
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//throw new ArgumentException("ip数组元素必须为4");
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}
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else
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{
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for (int i = 0; i < 4; i++)
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{
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if (ip[i] > 255 || ip[i] < 0)
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{
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return false;
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//throw new ArgumentException("IP字段值非法，必须在[0,255]内。");
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}
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}
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}
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return true;
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}
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/// <summary>
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/// 按照字典排序法，比较两个IP的大小
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/// </summary>
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/// <param name="ip1">第一个IP</param>
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/// <param name="ip2">第二个IP</param>
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/// <returns>0代表相等；1代表ip1大于ip2；2代表ip1小于ip2</returns>
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private int CompareIP(byte[] ip1, byte[] ip2)
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{
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for (int i = 0; i < 4; i++)
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{
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if (ip1[i] < ip2[i])
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{
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return -1;
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}
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else if (ip1[i] > ip2[i])
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{
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return 1;
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}
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}
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return 0;
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}
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/// <summary>
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/// 使用二分搜索法，在索引中检索到IP记录的绝对偏移
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/// </summary>
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/// <returns>IP记录的绝对偏移地址</returns>
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private Int32 FindIpRecdOffset(byte[] ip)
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{
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Int32 first = m_indexOffsetFirst;
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Int32 last = m_indexOffsetLast;
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byte[] indexBuf = new byte[INDEX_SIZE];
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while (last - first >= INDEX_SIZE)
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{
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Int32 mid = first + (last - first) / 2 / INDEX_SIZE * INDEX_SIZE;
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m_fs.Seek(mid, SeekOrigin.Begin);
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m_fs.Read(indexBuf, 0, INDEX_SIZE);
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if (mid == first)
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{
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break;
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}
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//复制索引中的IP至临时ip数组中
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byte[] midIp = new byte[4];
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for (int i = 0; i < 4; i++)
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{
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//索引中的ip顺序是从低字段到高字段，转换成从高到底
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midIp[i] = indexBuf[3 - i];
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}
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if (CompareIP(ip, midIp) < 0)
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{
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last = mid;
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}
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else if (CompareIP(ip, midIp) > 0)
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{
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first = mid;
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}
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else
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{
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break;
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}
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}
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//获取IP地理位置记录的绝对偏移记录
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Int32 offset = EncodeToInt32(indexBuf, 4, INDEX_SIZE - 4);
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return offset;
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}
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/// <summary>
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/// 从一条IP信息记录中读取出地理位置数据
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/// </summary>
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/// <param name="offset">IP信息绝对偏移地址</param>
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/// <returns>IP所在的地理位置</returns>
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private Location ReadLocation(Int32 offset)
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{
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if (offset < 8 || offset >= m_indexOffsetFirst)
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{
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throw new ArgumentOutOfRangeException("offset", "offset值不在IP信息记录范围内");
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}
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m_fs.Seek(offset + 4, SeekOrigin.Begin);
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Location location = new Location { Region = "", City = "" };
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byte mode = (byte)(m_fs.ReadByte());
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if (mode == REDIRECT_MODE_1)
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{
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byte[] offsetBuf = new byte[3];
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m_fs.Read(offsetBuf, 0, 3);
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Int32 contentOffset = EncodeToInt32(offsetBuf, 0, 3);
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m_fs.Seek(contentOffset, SeekOrigin.Begin);
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mode = (byte)(m_fs.ReadByte());
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if (mode == REDIRECT_MODE_2)
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{
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m_fs.Read(offsetBuf, 0, 3);
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Int32 regionOffset = EncodeToInt32(offsetBuf, 0, 3);
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location.Region = ReadString(regionOffset);
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Int32 cityOffset = contentOffset + 4;
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m_fs.Seek(cityOffset, SeekOrigin.Begin);
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mode = (byte)(m_fs.ReadByte());
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//第三种情况的结构
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if (mode == REDIRECT_MODE_1 || mode == REDIRECT_MODE_2)
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{
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m_fs.Seek(cityOffset + 1, SeekOrigin.Begin);
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m_fs.Read(offsetBuf, 0, 3);
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cityOffset = EncodeToInt32(offsetBuf, 0, 3);
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location.City = ReadString(cityOffset);
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}
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//第二种情况的结构
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else
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{
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m_fs.Seek(cityOffset, SeekOrigin.Begin);
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location.City = ReadString(cityOffset);
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}
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}
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//第一种情况的结构
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else
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{
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//读取区域和城市字符串
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Int32 endOffset;
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location.Region = ReadString(contentOffset, out endOffset);
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location.City = ReadString(endOffset);
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}
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}
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//第四种情况
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else if (mode == REDIRECT_MODE_2)
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{
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Int32 regionOffset = offset + 5;
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byte[] offsetBuf = new byte[3];
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m_fs.Seek(regionOffset, SeekOrigin.Begin);
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m_fs.Read(offsetBuf, 0, 3);
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regionOffset = EncodeToInt32(offsetBuf, 0, 3);
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location.Region = ReadString(regionOffset);
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Int32 cityOffset = offset + 8;
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location.City = ReadString(cityOffset);
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}
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//第零种情况
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else
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{
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Int32 endOffset;
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location.Region = ReadString(offset + 4, out endOffset);
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location.City = ReadString(endOffset);
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}
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return location;
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}
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/// <summary>
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/// 从指定位置读取一个字符串
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/// </summary>
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/// <param name="offset">字符串首的绝对偏移地址</param>
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/// <returns>读取出的字符串</returns>
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private string ReadString(Int32 offset)
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{
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m_fs.Seek(offset, SeekOrigin.Begin);
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byte[] regionBuf = new byte[1024];
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byte bt = (byte)(m_fs.ReadByte());
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int i = 0;
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while (bt != 0)
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{
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regionBuf[i++] = bt;
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bt = (byte)(m_fs.ReadByte());
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}
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return Encoding.Default.GetString(regionBuf, 0, i);
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}
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/// <summary>
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/// 从指定位置读取一个字符串
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/// </summary>
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/// <param name="offset">字符串首的绝对偏移地址</param>
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/// <param name="endOffset">输出字符串尾部的绝对偏移地址</param>
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/// <returns>读取的字符串</returns>
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private string ReadString(Int32 offset, out Int32 endOffset)
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{
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m_fs.Seek(offset, SeekOrigin.Begin);
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byte[] regionBuf = new byte[1024];
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byte bt = (byte)(m_fs.ReadByte());
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int i = 0;
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while (bt != 0)
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{
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regionBuf[i++] = bt;
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bt = (byte)(m_fs.ReadByte());
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}
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endOffset = offset + i;
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return Encoding.Default.GetString(regionBuf, 0, i);
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}
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#endregion
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}
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}
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