[sane-devel] Network protocol packet sizes

Dave Close dclose@anim.dreamworks.com
Thu, 14 Mar 2002 10:09:21 -0800

I wrote:
>Two, some (admittedly broken)
>frontends may depend on the ability to read a full scan line in one
>function call, and won't always succeed.

Nick Lamb responded:
>We had better find out about this sooner rather than later. There used to
>be backends that relied on you wanting a whole scan line at a time, or
>always asking for a multiple of 3 bytes or... The correct solution is
>to fix the broken code, not try to sweep everything under a rug.

I agree (and already agreed) that any such frontend would be broken and
should be fixed. However, the SANE API allows a frontend to request a
specific read size. Yes, it's called a maximum buffer size, but the
implication is that that is the optimum size transfer for the frontend.
A properly written backend should attempt to honor that request and not
respond with less without a good reason.
Dave Close                    Dreamworks SKG, Animation Technology
+1 818 695 6962               Glendale California 91201-3007
dclose@anim.dreamworks.com    http://www.dreamworks.com/