IPUtils

IPv4 address to long

http://www.codeproject.com/Articles/28363/How-to-convert-IP-address-to-country-name

How do I convert an IP address to an IP number?

IP address (IPV4) is divided into four sub-blocks. Each sub-block has a different weight number, each powered by 256. The IP number is being used in the database because it is efficient to search between a range of numbers in the database.

The beginning IP number and the ending IP number are calculated based on the following formula:

 IP Number = 16777216*w + 65536*x + 256*y + z (1)

where:

 IP Address = w.x.y.z

For example, if the IP address is 202.186.13.4, then its IP number is 3401190660 based on the above formula.

 IP Address = 202.186.13.4

So, w = 202, x = 186, y = 13 and z = 4

 IP Number = 16777216*202 + 65536*186 + 256*13 + 4
           = 3388997632 + 12189696 + 3328 + 4
           = 3401190660

To reverse the IP number to the IP address:

 w = int ( IP Number / 16777216 ) % 256
 x = int ( IP Number / 65536 ) % 256
 y = int ( IP Number / 256 ) % 256
 z = int ( IP Number ) % 256

where, % is the mod operator and int returns the integer part of the division.