Hi,

I'm trying to write a filesystem, using the Obj-C interface, to
present read-only JPEG's that are generated on the fly from DPX files
stored elsewhere on the non-fuse filesystem.

I'm able to use contentsOfDirectoryAtPath: to add all the JPEG names
to the path, and seemed to discover that I would need to make the
NSFIleSize at least big enough in attributesOfItemAtPath: to trigger
open and read calls?  I was expecting the size and buffer values for
readFileAtPath: would match this?  However when readFileAtPath: is
called it's buffer and size is 512 or 768 bytes? The problem is I
don't know what the compressed size of the DPX > JPEG conversion will
be, so don't have an exact value to set in attributesOfItemAtPath:.
What I do is open the DPX file in openFileAtPath: and set it's file
descriptor in userData? In readFileAtPath: I can read all the DPX data
(up to 12Mb), create a compressed JPEG, but my buffer to put in is far
too small?!

It seems like I need the direct_io and iosize=N options but these
don't seem to do any more?  What I don't get from information about
direct_io is "This path makes the file size irrelevant--a read will go
on until the file system keeps returning data.".

There is probably a cleaner way to do this?

Thanks for any tips.

Peter
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