[cc to ctypes-users, hope you don't mind.  And please keep the list on
the cc]

Nicolas Pinault <nicolasp@[...].com>  writes:

>  Yes, I'm writting a python package to be able to access ATA/SCSI
>  drives directly from python. I need this to create a disk analysis
>  tool written in python. So, I use ctypes to access WNASPI32.dll
>  functions. The structures used to access the aspi dll is standart to
>  ctypes (little endian). But aspi dll need scsi structures as input and
>  output. Scsi structures are byte reversed (big endian). Of course, I
>  could avoid bit fields by hard coding bit manipulation into bytes,
>  shorts and longs. But this makes code much less readable and
>  maintanaible.  As disks are very large today, performance is a
>  critical.

Sounds cool.  I'll try to implement the big endian structures, with
support for bit fields, in C and add it to ctypes.

As far is I have found out, the MS C compiler (with native == little
endian byte ordering) starts bit field definitions from LSB to MSB
inside an int: "Bit fields are allocated within an integer from
least-significant to most-significant bit."

And it seems that not only the byte order, but also the *bit order* in
the SCSI structures needs to change.  Can you confirm this?

Thomas




-------------------------------------------------------
SF.Net email is sponsored by:
Tame your development challenges with Apache's Geronimo App Server. Download
it for free - -and be entered to win a 42" plasma tv or your very own
Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php
_______________________________________________
ctypes-users mailing list
ctypes-users@[...].net
https://lists.sourceforge.net/lists/listinfo/ctypes-users