Re: [hybi] hum #3: Message

[Dave Cridland <[e-mail]>]

On Fri Aug  6 17:01:35 2010, Scott Ferguson wrote:
> As a practical matter, a 16-bit short length would be better  
> because buffer sizes are typically in the 1k to 64k range, and a  
> 16-bit length lets the implementation pre-allocate the frame header  
> for any message/chunk.
> 
> 
I'm happier with the "short" being 255 octets, because the only case  
we really need to minimize overhead is in mobile cases, where the  
power levels possible by transferring packets <128 octets are  
substantial and important.

I'm not wed to this, mind.

A good argument in favour is that it could be expected that more  
messages would be on both sides of the division with a 16-bit short  
length width. I'm not sure the predicate is true though.


> With an 8-bit length, the implementation either needs to shift  
> bytes in the buffer when the message is 255 bytes long or it needs  
> to preallocate the long frame header.

Indeed. I'm told, however, that this is not such a big deal. FWIW,  
unaliagned access to wrong-endian data is something I have experience  
of, and as far as I can tell, is not a substantial overhead.

Dave.
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