* It's safe to assume that if the file is shorter than
the provided header, things will go poorly.
* Avoids a random vauge ReadBuffer error.
* This doesn't fix#15230, but makes the issue clearer.
Change-Id: I3471e6de384a0c9be94049ad891c01be980f7846
Reviewed-on: https://review.haiku-os.org/c/1679
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>