Re: [xsl] String hashing code

[Abel Braaksma <abel.online@xxxxxxxxx>]

Deborah Pickett wrote:
> Since I can't be sure that only one XSLT processor instance will process
> *all* my files, I can't rely on the uniqueness of generate-id($node)
> where $node is a locally-scoped variable containing a document (` la
> Abel's UUID thread, which was nonetheless fascinating).

If you looked carefully, you must've seen it also uses a timestamp. 
Together it should provide uniqueness, both within one run and between 
runs. Unless of course you have a system where all are runs run 
simultaneously in the same microsecond (which is not likely since 
starting a processor alone takes somewhere between 20 and 400 ms). But I 
can't judge your system, perhaps relying on clock and node is not enough 
to guarantee stability?

If the problem you are facing is the possibility of names of files 
already existing, you can combine two methods. One: try the most 
randomizing way of creating a filename, two: use 
unparsed-text-available(...) to check whether a previous run already 
created that file, or better, let it loop with a counter until it finds 
a free "slot" (use the high significant bit of the random number of the 
UID or simply add another counter yourself).

These two techniques combined will guarantee that 0.1% that wasn't 
guaranteed by this "UUID"-lookalike algorithm ;)

HTH,
Cheers,
-- Abel --

PS: of course, using a hash can be a close to perfect solution too. But 
remember that on small strings hashes have the tendency to overlap in 
some xxx% of the cases. So, even with hashes, it is probably best to 
also add a both a counter (extra-run) and a function to provide 
uniqueness (intra-run).