Converts a string containing an (IPv4) Internet Protocol dotted address into a proper address.
The function works with the following notation:
192.0.2.235)0xC0.0x00.0x02.0xEB)0300.0000.0002.0353)192.0x00.0002.0353)The function will try to parse any inputs, so a non-complete address (10.0.0) also works; it will return NaN if the input is an invalid address.
long2ip: https://gist.github.com/1639378
| function( | |
| a, // input for a (in)valid or non-complete IPv4 dotted address | |
| b, // placeholder for the octet index | |
| c, // placeholder for the result of sum expressed in decimal | |
| d // placeholder for the current octet | |
| ) { | |
| for ( | |
| c = b = 0; // initialize the octet index and the result | |
| d = a.split('.')[b++]; // update the current octet, iterate if havn't handled all octets | |
| c += | |
| d >> 8 // if the current octet is not within the range of 0~255 | |
| | // or | |
| b > 4 ? // the octet index is greater than 4 | |
| NaN // make the result NaN | |
| : // else | |
| d * (1 << -8 * b) // calculate the number | |
| ) | |
| d = parseInt( // convert the current octet into decimal according to the prefix | |
| +d // parseInt omits extra words behind the first number, while + does not | |
| && // for example, parseInt regards '123abc' as 123, while + regards it as NaN | |
| d // so we use + to check if the octet is valid first | |
| ); | |
| return c | |
| } |
| function(a,b,c,d){for(c=b=0;d=a.split('.')[b++];c+=d>>8|b>4?NaN:d*(1<<-8*b))d=parseInt(+d&&d);return c} |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| Version 2, December 2004 | |
| Copyright (C) 2011 YOUR_NAME_HERE <YOUR_URL_HERE> | |
| Everyone is permitted to copy and distribute verbatim or modified | |
| copies of this license document, and changing it is allowed as long | |
| as the name is changed. | |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 0. You just DO WHAT THE FUCK YOU WANT TO. |
| { | |
| "name": "ip2long", | |
| "description": "Converts a string containing an (IPv4) Internet Protocol dotted address into a proper address.", | |
| "keywords": [ | |
| "ip", | |
| "phpjs", | |
| "ip2long", | |
| "long2ip", | |
| "octet" | |
| ] | |
| } |
| <!DOCTYPE html> | |
| <title>Foo</title> | |
| <div>Expected value: <b>3221226219,3221226219,3221226219,3221226219,167772160,NaN,NaN,NaN,NaN</b></div> | |
| <div>Actual value: <b id="ret"></b></div> | |
| <script> | |
| // write a small example that shows off the API for your example | |
| // and tests it in one fell swoop. | |
| var myFunction = function(a,b,c,d){for(c=b=0;d=a.split('.')[b++];c+=d>>8|b>4?NaN:d*(1<<-8*b))d=parseInt(+d&&d);return c} | |
| document.getElementById( "ret" ).innerHTML = | |
| [myFunction('192.0.2.235'), | |
| myFunction('0xC0.0x00.0x02.0xEB'), | |
| myFunction('0300.0000.0002.0353'), | |
| myFunction('192.0x00.0002.0353'), | |
| myFunction('10.0.0'), | |
| myFunction('10.-1.0.0'), | |
| myFunction('10.0.0.0.1'), | |
| myFunction('255.255.255.256'), | |
| myFunction('127.0A.0.1'), | |
| ] | |
| </script> |
Genius! I didn't know the bitwise shift operator accepts negative numbers before.
By using this trick, we are able to put the increment of the index outside, thus there will be no infinitive loop any more, so b= is not needed.
Awesome!, @subzey!
By the way, I use parseInt to convert numbers so octal numbers are supported now.
Very nice
-256 & dtrick, bravo, @tsaniel!Few more tricks can make this code 6 bytes shorter:
function(a,b,c,d){for(c=b=0;d=a.split('.')[b++];)c+=-256&d|b>4?NaN:d*(1<<-8*b);return c}