[转载]IP to Integer

2010-02-09 08:55 AnyKoro 阅读(399) 评论(0) 编辑收藏举报

有时候我们要判断某个IP是否在某个段内，如何实现呢？一个简单办法就是把IP转换成Integer，然后判断整数是否在某个范围内就可以实现这个判断。

转换的算法如下：

比如我们要转换的IP为： 058.062.042.000

First Octet: 058
Second Octet: 062
Third Octet: 042
Fourth Octet: 000

计算公式如下：
(first octet * 256³) + (second octet * 256²) + (third octet * 256) + (fourth octet)
= (first octet * 16777216) + (second octet * 65536) + (third octet * 256) + (fourth octet)
= (058 * 16777216) + (062 * 65536) + (042 * 256) + (000)
= 977152512

网上有现成的服务，比如下面这个地址：

http://www.aboutmyip.com/AboutMyXApp/IP2Integer.jsp

SQL Server 的一个例子如下：

CREATE
 FUNCTION
 dbo.ipStringToInt 

( 

    @ip CHAR
(15) 

) 

RETURNS
 INT
 

AS
 

BEGIN
 

    DECLARE
 @rv INT
, 

        @o1 INT
, 

        @o2 INT
, 

        @o3 INT
, 

        @o4 INT
, 

        @base INT
 

 

    SELECT
 

        @o1 = CONVERT
(INT
, PARSENAME(@ip, 4)), 

        @o2 = CONVERT
(INT
, PARSENAME(@ip, 3)), 

        @o3 = CONVERT
(INT
, PARSENAME(@ip, 2)), 

        @o4 = CONVERT
(INT
, PARSENAME(@ip, 1)) 

 

    IF
 (@o1 BETWEEN
 0 AND
 255) 

        AND
 (@o2 BETWEEN
 0 AND
 255) 

        AND
 (@o3 BETWEEN
 0 AND
 255) 

        AND
 (@o4 BETWEEN
 0 AND
 255) 

    BEGIN
      

        SELECT
 @base = CASE
 

            WHEN
 @o1 < 128 THEN
 

                (@o1 * 16777216) 

            ELSE
 

                -(256 - @o1) * 16777216 

            END
 

     

        SET
 @rv = @base +  

            (@o2 * 65536) +  

            (@o3 * 256) + 

            (@o4) 

    END
 

    ELSE
 

        SET
 @rv = -1 

    RETURN
 @rv 

END


go

调用范例：

select
 dbo.ipStringToInt('058.062.042.000
')

整数转换如下：

CREATE
 FUNCTION
 dbo.ipIntToString 

( 

    @ip INT
 

) 

RETURNS
 CHAR
(15) 

AS
 

BEGIN
 

    DECLARE
 @o1 INT
, 

        @o2 INT
, 

        @o3 INT
, 

        @o4 INT
 

 

    IF
 ABS(@ip) > 2147483647 

        RETURN
 '255.255.255.255
' 

 

    SET
 @o1 = @ip / 16777216 

 

    IF
 @o1 = 0 

        SELECT
 @o1 = 255, @ip = @ip + 16777216 

 

    ELSE
 IF
 @o1 < 0 

    BEGIN
 

        IF
 @ip % 16777216 = 0 

            SET
 @o1 = @o1 + 256 

        ELSE
 

        BEGIN
 

            SET
 @o1 = @o1 + 255 

            IF
 @o1 = 128 

                SET
 @ip = @ip + 2147483648 

            ELSE
 

                SET
 @ip = @ip + (16777216 * (256 - @o1)) 

        END
 

    END
 

    ELSE
 

    BEGIN
 

        SET
 @ip = @ip - (16777216 * @o1) 

    END
 

 

    SET
 @ip = @ip % 16777216 

    SET
 @o2 = @ip / 65536 

    SET
 @ip = @ip % 65536 

    SET
 @o3 = @ip / 256 

    SET
 @ip = @ip % 256 

    SET
 @o4 = @ip 

 

    RETURN
 

        CONVERT
(VARCHAR
(4), @o1) + '.
' + 

        CONVERT
(VARCHAR
(4), @o2) + '.
' + 

        CONVERT
(VARCHAR
(4), @o3) + '.
' + 

        CONVERT
(VARCHAR
(4), @o4) 

END


go

调用范例：

select
 dbo.ipIntToString(977152512)

C# 的例子如下：

using
 System;

using
 System.Net;



namespace
 ConsoleApplication1

{

    class
 Program

    {

        static
 long
 ToInt(string
 addr)

        {

            return
 BitConverter.ToInt32(IPAddress.Parse(addr).GetAddressBytes(), 0); 

        }



        static
 string
 ToAddr(long
 address)

        {

            return
 IPAddress.Parse(address.ToString()).ToString();

            // This also works: 


            // return new IPAddress((uint) IPAddress.HostToNetworkOrder( 


            //    (int) address)).ToString(); 


        }



        static
 void
 Main(string
[] args)

        {

            Console.WriteLine(ToInt("64.233.187.99
"));

            Console.WriteLine(ToAddr(1089059683)); 



            Console.ReadLine();

        }

    }

}