public static function hexdump($data, $htmloutput = true, $uppercase = false, $return = false)
    {
        // Init
        $hexi = '';
        $ascii = '';
        $dump = $htmloutput ? '<pre>' : '';
        $offset = 0;
        $len = mb_strlen($data, 'ASCII');

        // Upper or lower case hexidecimal
        $hexFormat = $uppercase ? 'X' : 'x';

        // Iterate string
        for ($i = $j = 0; $i < $len; $i++) {
            // Convert to hexidecimal
            // We must use concatenation here because the $hexFormat value
            // is needed for sprintf() to parse the format
            $hexi .= sprintf('%02' .  $hexFormat . ' ', ord($data[$i]));

            // Replace non-viewable bytes with '.'
            if (ord($data[$i]) >= 32) {
                $ascii .= $htmloutput ? htmlentities($data[$i]) : $data[$i];
            } else {
                $ascii .= '.';
            }

            // Add extra column spacing
            if ($j === 7) {
                $hexi .= ' ';
                $ascii .= ' ';
            }

            // Add row
            if (++$j === 16 || $i === $len - 1) {
                // Join the hexi / ascii output
                // We must use concatenation here because the $hexFormat value
                // is needed for sprintf() to parse the format
                $dump .= sprintf('%04' . $hexFormat . '  %-49s  %s', $offset, $hexi, $ascii);

                // Reset vars
                $hexi = $ascii = '';
                $offset += 16;
                $j = 0;

                // Add newline
                if ($i !== $len - 1) {
                    $dump .= PHP_EOL;
                }
            }
        }

        // Finish dump
        $dump .= $htmloutput ? '</pre>' : '';
        $dump .= PHP_EOL;

        if ($return) {
            return $dump;
        }

        echo $dump;
    }