Merge "Fix comment to reflect that the value passed to head is actually the size"

    dst.write(b)

_MAX_OFFSET_WIDTH = 20

def _generate_extract_command(start, end, extract_name):

def _generate_extract_command(start, size, extract_name):

  """Generate the extract command.

  The length of this string must be constant no matter what the start and end

  Args:

    start: offset in bytes of the start of the wrapped file

    end: offset in bytes of the end of the wrapped file

    size: size in bytes of the wrapped file

    extract_name: of the file to create when extracted

  """

  if len(start_str) != _MAX_OFFSET_WIDTH + 1:

    raise Exception('Start offset too large (%d)' % start)

  end_str = ('%d' % end).rjust(_MAX_OFFSET_WIDTH)

  if len(end_str) != _MAX_OFFSET_WIDTH:

    raise Exception('End offset too large (%d)' % end)

  size_str = ('%d' % size).rjust(_MAX_OFFSET_WIDTH)

  if len(size_str) != _MAX_OFFSET_WIDTH:

    raise Exception('Size too large (%d)' % size)

  return "tail -c %s $0 | head -c %s > %s\n" % (start_str, end_str, extract_name)

  return "tail -c %s $0 | head -c %s > %s\n" % (start_str, size_str, extract_name)

def main(argv):