def _read_string_data(f):
    'Read a data string (length is specified twice)'
    length = _read_long(f)
    if (length > 0):
        length = _read_long(f)
        string_data = _read_bytes(f, length)
        _align_32(f)
    else:
        string_data = ''
    return string_data
Read a data string (length is specified twice)
def _read_string_data(f):
    
    length = _read_long(f)
    if (length > 0):
        length = _read_long(f)
        string_data = _read_bytes(f, length)
        _align_32(f)
    else:
        string_data = 
    return string_data