private function remove_dot_segments($input)
    {
        $output = '';
        while (strpos($input, './') !== false || strpos($input, '/.') !== false || $input === '.' || $input === '..')
        {
            // A: If the input buffer begins with a prefix of "../" or "./", then remove that prefix from the input buffer; otherwise,
            if (strpos($input, '../') === 0)
            {
                $input = substr($input, 3);
            }
            elseif (strpos($input, './') === 0)
            {
                $input = substr($input, 2);
            }
            // B: if the input buffer begins with a prefix of "/./" or "/.", where "." is a complete path segment, then replace that prefix with "/" in the input buffer; otherwise,
            elseif (strpos($input, '/./') === 0)
            {
                $input = substr($input, 2);
            }
            elseif ($input === '/.')
            {
                $input = '/';
            }
            // C: if the input buffer begins with a prefix of "/../" or "/..", where ".." is a complete path segment, then replace that prefix with "/" in the input buffer and remove the last segment and its preceding "/" (if any) from the output buffer; otherwise,
            elseif (strpos($input, '/../') === 0)
            {
                $input = substr($input, 3);
                $output = substr_replace($output, '', strrpos($output, '/'));
            }
            elseif ($input === '/..')
            {
                $input = '/';
                $output = substr_replace($output, '', strrpos($output, '/'));
            }
            // D: if the input buffer consists only of "." or "..", then remove that from the input buffer; otherwise,
            elseif ($input === '.' || $input === '..')
            {
                $input = '';
            }
            // E: move the first path segment in the input buffer to the end of the output buffer, including the initial "/" character (if any) and any subsequent characters up to, but not including, the next "/" character or the end of the input buffer
            elseif (($pos = strpos($input, '/', 1)) !== false)
            {
                $output .= substr($input, 0, $pos);
                $input = substr_replace($input, '', 0, $pos);
            }
            else
            {
                $output .= $input;
                $input = '';
            }
        }
        return $output . $input;
    }