def METHOD_NAME(fileobj):
    info = fileobj.read(8)
    if len(info) != 8:
        raise SMFError("truncated")
    chunklen = struct.unpack(">I", info[4:])[0]
    data = fileobj.read(chunklen)
    if len(data) != chunklen:
        raise SMFError("truncated")
    return info[:4], data