[Serusers] How to calculate new HASH_TABLE_SIZE value when extending parser?

[Maxim Sobolev]

Hi,

I am currently trying to extend ser's parser to allow it recognize
User-Agent headers, but stuck into the magic HASH_TABLE_SIZE value.
Is there any algorithm to calculate it when adding support for a
new header type? Maybe there is some documentation, apart from
comments in the code itself, on extending parser, or at least on
its inner details? If so, it would be nice to obtain it if possible.

Thanks!

-Maxim