<?
/*
	Contains all the functions necessary to implement the original keygen algorithm
	Some important notes:
	The original keygen depends on c++ style handling of mathematical operations on 32 bit integers.
	PHP differs in the way that it does mathematics, and due to the lack of 64 bit data types it
	becomes a pain in the ass to replicate what is a very simple algorithm in PHP.
	To ensure exact replication custom functions for multiplication and mod are required that
	exactly mimmick the way c++ does it.
	Also, judicious use of settype is required to clip the overflowing bits - PHP tends to want to
	convert to float after an overflow, which will eventually cause loss of precision in lower bits.
	
	Anyway, it should work for all numbers in the 32bit unsigned range and thus should produce an
	identical key for all valid PC ID #'s (as per the original keySolver.exe program anyway).
	
	Ric, 06/10/2006
*/

/*
	performs a c++ style unsigned long multiply
*/
function CStyleMultiply($num1,$num2) {
	settype($num1,'integer');
	settype($num2,'integer');
	$accumulator = 0;

	for ($bit = 0; $bit < 32; $bit += 1) {
		$shifted=$num1 << $bit;
		if ( ( $num2 >> $bit ) & 1 ) {
			$accumulator+=$shifted;
			//ensure the result stays as an integer
			settype($accumulator,'integer');
		}
	}
	return $accumulator;
}

/*
	performs a c++ style unsigned long mod
*/
function CStyleMod($num,$mod) {
	settype($num,'float');
	if ( $num < 0 ) $num += 4294967296;
	settype($mod,'float');
	if ( $mod < 0 ) $mod += 4294967296;
	if ( $num == $mod ) return 0;
	if ( $num < $mod ) return $num;
	$rem=$num;
	while ( $rem >= 0 ) {
		$rem -= $mod;
	}
	if ($rem < 0 ) $rem += $mod;
	settype($rem,'integer');
	return $rem;
}

/*
	this is the actual key generation algorithm
	supply it with the PC ID # and it will give you the hex key back
*/
function GenerateKey($theID) {

	//clip theID to a 32bit integer before we even start
	settype($theID,'integer');
	
	//implement 'key = theID >> 2'
	$key=($theID >> 2);
	//php will not clear most significant 2 bits after shift so we do it manually
	$key = $key & 1073741823;
	settype($key,'integer');
	
	//implement 'if key == 0 key = theID << 24'
	if ($key == 0) $key = $theID << 24;
	settype($key,'integer');
	$key = CStyleMultiply($key,111111);
	settype($key,'integer');
	
	//implement 'key += theID << 4'
	$shl = $theID << 4;
	settype($shl,'integer');
	$key += $shl;
	settype($key,'integer');
	
	//implement 'key *= theID % temp'
	$modded = CStyleMod($theID,$key);
	settype($modded,'integer');
	$key = CStyleMultiply($key,$modded);
	settype($key,'integer');
	
	//got the numeric key code - just convert it to a positive unsigned long equiv and then to hex
	settype($key,'float');
	if ( $key < 0 ) $key += 4294967296;
	$hex = strtoupper(base_convert($key,10,16));
	return $hex;
}
?>