Chunk IPv4 range into multiple sub-chunks

One of my non-programmer-but-in-IT friends came to me last week, asking help to chunk a range of IPv4 addresses into N small chunks. And, here's the PHP code I came up with within 10 mins.

	<?php
	/**
	* Copyright (C) 2016 Prabhas Gupte
	*
	* This is free script: you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 3 of the License, or
	* (at your option) any later version.
	*
	* This script is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should also see <http://www.gnu.org/licenses/gpl.txt>
	*/
	function chunkIPRange($ipRange, $numberOfChunks = 2) {
	list($startIP, $endIP) = explode('-', $ipRange);
	$startIPNumeric = ip2long($startIP);
	$endIPNumeric = ip2long($endIP);
	$expandedRange = range($startIPNumeric, $endIPNumeric);
	$size = count($expandedRange);
	$chunkSize = floor($size / $numberOfChunks) + ($size % $numberOfChunks);
	$rangeChunks = array_chunk($expandedRange, $chunkSize);
	$chunkNumber = 0;
	$chunks = array();
	foreach ($rangeChunks as &$chunk) {
	$chunkStart = array_shift($chunk);
	$chunkEnd = array_pop($chunk);
	$chunkStart = long2ip($chunkStart);
	$chunkEnd = long2ip($chunkEnd);
	$chunks[$chunkNumber] = (($chunkStart !== $chunkEnd) && ($chunkEnd !== '0.0.0.0')) ? "$chunkStart-$chunkEnd" : "$chunkStart";
	$chunkNumber++;
	}
	unset($rangeChunks);
	return $chunks;
	} // chunkIPRange
	print_r(chunkIPRange('10.10.10.1-10.10.20.10', 3));
	print_r(chunkIPRange('172.16.0.1-172.16.1.10'));
	?>

view raw chunkIPRange.php hosted with ❤ by GitHub

What it simply does is, explode the input range, and convert start and end IP address into long, using ip2long(). Then, using range() expand it into a whole list. Once that is done, then decide number of elements that should go into each chunk - remember, the optional argument to this function tells how many chunks are to be prepared. the formula is there on code line number 11.

Once you have this number, call array_chunk() to create chunks. Finally, iterate over them, get start and end IP of each of them (which are still long numbers), convert them back to IPv4 address using long2ip() and create the range string for them.

Do you find it useful? Copy it! Have any suggestion, let me know in the comment!!