[Guy Harris <guy@xxxxxxxxxxxx>]

On Oct 6, 2003, at 5:15 AM, Brad Hards wrote:

> OK, I'm confused again.
> How do I desegment a message like the attached one?

You'd dissect it with what I suspect won't be code that's as simple as 
you'd like, because RFB doesn't have a nice message size field at the 
beginning of all messages. :-)

If number-of-rectangles is non-zero, you know that you need at least 12 
bytes more in the packet, for the fixed-length portion of the first 
rectangle.  So, at that point, if you don't have those 12 bytes, you 
tell the desegmentation code you need it, and return.

Once you have those 12 bytes, you compute how many bytes of rectangle 
data you need, based on the width, height, and, presumably, encoding 
and, if you don't have all of them, you ask for them.

Unfortunately, that only works for the first rectangle - you are 
correct, you'll need state attached to the conversation to handle the 
rest, to keep track of which rectangle you're reassembling.

The state I'd attach would be the number of rectangles.  Once you've 
fully desegmented a rectangle, decrement that number by 1 and, if it's 
non-zero, keep desegmenting, otherwise dissect the packet.