http://blog.joycode.com/ghj/tags/287.aspx
前一篇博客 IP to Integer 提供的 SQL 函數是 IP 轉換成 Integer 的方法。 Integer 的最大值爲: 2147483647(2^31 - 1)。按照 IP 轉換成整數的算法,會算出來大於這個值的,所以之前提供的 IP 轉換成 Integer 的方法會算出負值。
下面是 IP to BigInt 的轉換算法, 這時候運算就不會小於零。
CREATE FUNCTION dbo.ipStringToBigInt ( @ip CHAR(15) ) RETURNS bigint AS BEGIN DECLARE @rv bigint, @o1 bigint, @o2 INT, @o3 INT, @o4 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 SET @rv = (@o1 * 16777216) + (@o2 * 65536) + (@o3 * 256) + (@o4) END ELSE SET @rv = -1 RETURN @rv END go CREATE FUNCTION dbo.ipBigIntToString ( @ip bigint ) RETURNS CHAR(15) AS BEGIN DECLARE @o1 INT, @o2 INT, @o3 INT, @o4 INT IF @ip > 4294967295 RETURN '255.255.255.255' IF @ip <= 0 RETURN '0.0.0.0' SET @o1 = @ip / 16777216 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 -- 調用例子 select dbo.ipBigIntToString(3708279131) select dbo.ipStringToBigInt('221.7.217.91')
IP to Integer
有時候我們要判斷某個IP是否在某個段內,如何實現呢? 一個簡單辦法就是把IP轉換成Integer,然後判斷整數是否在某個範圍內就可以實現這個判斷。
轉換的算法如下:
比如我們要轉換的IP爲: 058.062.042.000
First Octet: 058
Second Octet: 062
Third Octet: 042
Fourth Octet: 000
計算公式如下:
(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
網上有現成的服務,比如下面這個地址:
http://www.aboutmyip.com/AboutMyXApp/IP2Integer.jsp
SQL Server 的一個例子如下:
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
調用範例:
select dbo.ipStringToInt('058.062.042.000')
整數轉換如下:
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
調用範例:
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(); } } }
參考資料:
How should I store an IP address in SQL Server?
http://sqlserver2000.databases.aspfaq.com/how-should-i-store-an-ip-address-in-sql-server.html
How to convert an IPv4 address into a integer in C#?
http://stackoverflow.com/questions/461742/how-to-convert-an-ipv4-address-into-a-integer-in-c