World of Warcraft MogIt addon's link functions Lua -> PHP

mogit.php

<?php
	class MogIt {
		private $charset;
		private $base;
		private $maxlen;
		
		function __construct($charset = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ", $maxlen = 3)
		{
			$this->charset = $charset;
			$this->base = strlen($charset);
			$this->maxlen = $maxlen;
		}
		
		function toBase($num) {
			$base = $this->base;
			$charset = $this->charset;
			
			$str = "";
			while($num > 0)
			{
				$str = $charset[($num%$base)] . $str;
				$num = floor($num/$base);
			}
			
			return $str;
		}
		
		function fromBase($str) {
			$base = $this->base;
			$charset = $this->charset;
			
			$len = strlen($str);
			
			$num = 0;
			for($i = 0; $i < $len; $i++)
			{
				$num += (strpos($charset, $str[$i])) * pow($base, $len-$i - 1);
			}
			
			return $num;
		}
		
		function setToLink($set) {
			$maxlen = $this->maxlen;
			
			$link = "[MogIt:";
			foreach($set as $k => $v)
			{
				$link .= sprintf("%0".$maxlen."s", $this->toBase($v));
			}
			
			$link .= "]";
			
			return $link;
		}
		
		function linkToSet($link) {
			$maxlen = $this->maxlen;
					
			$set = array();
			$matches = preg_match("/MogIt:([^]]+)/", $link, $items);
			
			if(!$matches)
				return $set;
			
			$len = strlen($items[1]);
			$max = floor($len/$maxlen);
			
			for($i = 0; $i < $max; $i++)
			{
				$set[] = $this->fromBase(substr($items[1], $i*$maxlen, $maxlen));
			}
			
			return $set;
		}
	}
?>