<?
$dir = "./";

$filesizeslist = array();

if ((is_dir($dir)) && ($directoryhandler = opendir($dir)))
{
	while ($file = readdir($directoryhandler))
	{
		if (is_file($file) AND (!is_link($file)))
			$filesizeslist[$file] = filesize($file);
	}
}
closedir($directoryhandler);

asort($filesizeslist, SORT_NUMERIC);
$potentialduplicates = array();
$lastfilesize = -1;

foreach ($filesizeslist as $filename => $filesize)
{
	if ($filesize == $lastfilesize)
	{
		$potentialduplicates[$filename] = md5_file($filename);
		$potentialduplicates[$lastfilename] = md5_file($lastfilename);
	}

	$lastfilename = $filename;
	$lastfilesize = $filesize;
}

unset($filesizeslist);
asort($potentialduplicates);
$lasthash = -1;

foreach ($potentialduplicates as $filename => $hash)
{
	if ($hash == $lasthash)
		echo "The files \"$filename\" and \"$lastfilename\" are duplicates with a hash of $hash\n";

	$lastfilename = $filename;
	$lasthash = $hash;
}
?>