Integer\\IP converter

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Sticky	Created : 04 January 2010 System : Nintendo Wii Language : Flash Integer\\IP converter Converts between integers and IPs
Just two functions I wrote that convert an IP to an integer or vice versa. Useful for inserting into databases as an int only needs four bytes whereas a text representation of an IP can need up to 15 . This one converts from an integer into an IP. public static function intip($int, $rtl=true) { if(!is_numeric($int)) return false; $ip = array(); // basically it's just a whole bunch of division, ignoring remainders. $int -= pow(2, 24) * $ip[0] = (floor($int / pow(2, 24))); $int -= pow(2, 16) * $ip[1] = (floor($int / pow(2, 16))); $int -= pow(2, 8) * $ip[2] = (floor($int / pow(2, 8))); $int -= $ip[3] = (floor($int)); if(!$rtl) $ip = array_reverse($ip); return implode(".", $ip); } --v And this does the reverse, converting an IP to an integer. public static function ipint($ip, $rtl=true) { if(ereg("^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$", $ip) === false) return false; $ip = explode(".", $ip); if(!$rtl) $ip = array_reverse($ip); $result = $ip[3]; $result += $ip[2] * pow(2, 8); // $ip[2] << 8 $result += $ip[1] * pow(2, 16); // $ip[1] << 16 $result += $ip[0] * pow(2, 24); // $ip[0] << 24 return $result; } --v

Comments
Tuesday, 05 January 2010, 00:27
Jayenkai	wonders why you used powers rather than bitshifting. Nice and simple. This is one of those really simple space saving methods that everyone seems to completely forget about.
Tuesday, 05 January 2010, 04:09
Sticky	I used powers instead of bitshifting because I couldn't work out how to force it as an unsigned int - as soon as I bitshifted 24 it made it negative because it was signed. So, powers were just easier in the end.
Tuesday, 05 January 2010, 04:20
Jayenkai	Oh yeah.. hmm.. shrugs
Wednesday, 06 January 2010, 20:11
Scherererer	Your comment about negative numbers appearing in your integer inspired me to write a quick article on the way signed numbers are stored in a computer. www.socoder.net/index.php?article=21718 hope it helps! (particularly the comments on overflow)

Comments