🚀 go-pugleaf

In article <19990714.205259.0AA80202.Tuaa@pierrot.co.uk>, Terrance Richard 
Boyes wrote:
> One problem with message-ids is how to hash them uniquely, they
> tend to be relatively large, so any prime-multiplication
> type method would result in huge numbers. I did a few experiments
> last night with simple things like adding up all the ASCII values
> (and a variant splitting the message-id into <lhs@rhs>) and
> there is a lot of overflow.

Try a CRC - that might work better. Or just extract the first n digits from 
the ID, modulus some prime number. If you use a linked list of matching 
hashes inside each hash table node, you can get pretty efficient.

If you only have 32K entries, I imagine almost any reasonable method is 
going to be reasonably quick on a modern computer. I would try something 
fairly primitive out, and only worry about the finer details if you find a 
performance problem. If you lookup is properly isolated from the rest of the 
program, you can always tweak it later if there is a problem.

-- 
Nikki Locke, Trumphurst Ltd.      PC & Unix consultancy & programming
nikki@trmphrst.demon.co.uk            http://www.trumphurst.com/