.NET CORE下读取IP纯真库

用以前放在牛腩公用类库里的IPSearch就行了，编译没有错误，不过直接用发现中文乱码，一通乱改才发现问题，看最后的ReadString方法 ，

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
namespace Niunan.WebAssign.Util
{
///

/// 提供从纯真IP数据库搜索IP信息的方法；
/// 感谢LumaQQ提供纯真IP数据库格式文档；
/// ----HeDaode 2007-12-28 四川教育学院
///

internal class IPSearch
{
FileStream ipFile;
long ip;
string ipfilePath;

///

/// 构造函数
///

///纯真IP数据库路径
public IPSearch(string ipfilePath)
{
this.ipfilePath = ipfilePath;
}

///

/// 地理位置,包括国家和地区
///

public struct IPLocation
{
public string country, area;
}
///

/// 获取指定IP所在地理位置
///

///要查询的IP地址
///
public IPLocation GetIPLocation(string strIP)
{
ip = IPToLong(strIP);
ipFile = new FileStream(ipfilePath, FileMode.Open, FileAccess.Read);
long[] ipArray = BlockToArray(ReadIPBlock());
long offset = SearchIP(ipArray, 0, ipArray.Length - 1) * 7 + 4;
ipFile.Position += offset;//跳过起始IP
ipFile.Position = ReadLongX(3) + 4;//跳过结束IP

IPLocation loc = new IPLocation();
int flag = ipFile.ReadByte();//读取标志
if (flag == 1)//表示国家和地区被转向
{
ipFile.Position = ReadLongX(3);
flag = ipFile.ReadByte();//再读标志
}
long countryOffset = ipFile.Position;
loc.country = ReadString(flag);

if (flag == 2)
{
ipFile.Position = countryOffset + 3;
}
flag = ipFile.ReadByte();
loc.area = ReadString(flag);

ipFile.Close();
ipFile = null;
return loc;
}
///

/// 将字符串形式的IP转换位long
///

///
///
public long IPToLong(string strIP)
{
byte[] ip_bytes = new byte[8];
string[] strArr = strIP.Split(new char[] { '.' });
for (int i = 0; i < 4; i++)
{
ip_bytes[i] = byte.Parse(strArr[3 - i]);
}
return BitConverter.ToInt64(ip_bytes, 0);
}
///

/// 将索引区字节块中的起始IP转换成Long数组
///

///
long[] BlockToArray(byte[] ipBlock)
{
long[] ipArray = new long[ipBlock.Length / 7];
int ipIndex = 0;
byte[] temp = new byte[8];
for (int i = 0; i < ipBlock.Length; i += 7)
{
Array.Copy(ipBlock, i, temp, 0, 4);
ipArray[ipIndex] = BitConverter.ToInt64(temp, 0);
ipIndex++;
}
return ipArray;
}
///

/// 从IP数组中搜索指定IP并返回其索引
///

///IP数组
///指定搜索的起始位置
///指定搜索的结束位置
///
int SearchIP(long[] ipArray, int start, int end)
{
int middle = (start + end) / 2;
if (middle == start)
return middle;
else if (ip < ipArray[middle])
return SearchIP(ipArray, start, middle);
else
return SearchIP(ipArray, middle, end);
}
///

/// 读取IP文件中索引区块
///

///
byte[] ReadIPBlock()
{
long startPosition = ReadLongX(4);
long endPosition = ReadLongX(4);
long count = (endPosition - startPosition) / 7 + 1;//总记录数
ipFile.Position = startPosition;
byte[] ipBlock = new byte[count * 7];
ipFile.Read(ipBlock, 0, ipBlock.Length);
ipFile.Position = startPosition;
return ipBlock;
}
///

/// 从IP文件中读取指定字节并转换位long
///

///需要转换的字节数，主意不要超过8字节
///
long ReadLongX(int bytesCount)
{
byte[] _bytes = new byte[8];
ipFile.Read(_bytes, 0, bytesCount);
return BitConverter.ToInt64(_bytes, 0);
}
///

/// 从IP文件中读取字符串
///

///转向标志
///
string ReadString(int flag)
{
if (flag == 1 || flag == 2)//转向标志
ipFile.Position = ReadLongX(3);
else
ipFile.Position -= 1;

List list = new List();
byte b = (byte)ipFile.ReadByte();
while (b > 0)
{
list.Add(b);
b = (byte)ipFile.ReadByte();
}

return Encoding.GetEncoding("GB2312").GetString(list.ToArray());//.net core下用这个，要不然会出中文乱码
//return Encoding.Default.GetString(list.ToArray()); //.netframework下用这个
}
}
}