lib/danog/PHP/StructClass.php
public function unpack($format_maybe_data, $data = null)
    {
        if ($this->format === null) {
            $format = $format_maybe_data;
        } else {
            $format = $this->format;
            $data = $format_maybe_data;
        }

        return $this->struct->unpack($format, $data);
    }
public function unpack($format_maybe_data, $data = null)
    {
        if ($this->format === null) {
            $format = $format_maybe_data;
        } else {
            $format = $this->format;
            $data = $format_maybe_data;
        }

        return $this->struct->unpack($format, $data);
    }
unpack.

Unpacks data into an array

@param	$format_maybe_data	Format string (may be data if class is istantiated with format string)
@param	$data	            Data to decode

@return Decoded data