int2chars.php

<?php

function num2chars($n) {	
	$cs = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
	$s = strlen($cs);
	$str = "";
	while($n) {
		$str = $cs{$n%$s}.$str;
		$n = floor($n/$s);
	}
	if ($str == "") { return $cs{0}; }
	return $str;
}


function chars2num($str) {	
	$cs = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
	$s = strlen($cs);
	$res = 0;
	$a = str_split($str);
	foreach ($a as $c) { $res = $res * $s + strrpos($cs,$c); }
	return $res;
}