chamilo / chamilo-lms

			// where ".." is a complete path segment, then replace that prefix

			// with "/" in the input buffer and remove the last segment and its

			// preceding "/" (if any) from the output buffer; otherwise,

			elseif (strpos($input, '/../') === 0) {

				$input = substr($input, 3);

				$output = substr_replace($output, '', strrpos($output, '/'));

			}

			elseif ($input === '/..') {

				$input = '/';

				$output = substr_replace($output, '', strrpos($output, '/'));

			// the output buffer, including the initial "/" character (if any)

			// and any subsequent characters up to, but not including, the next

			// "/" character or the end of the input buffer

			elseif (($pos = strpos($input, '/', 1)) !== false) {

				$output .= substr($input, 0, $pos);

				$input = substr_replace($input, '', 0, $pos);

			}

			else {

				$output .= $input;

				$input = '';