Re: hashing

[Ken Burtch <kburtch@sympatico.ca>]

I believe there's a simple string hash value generator (HashOf) included
in the strings package of my drawtools suite

http://www.pegasoft.ca

Ken B.


"chris.danx" wrote:
> 
> "Steven Deller" <deller@smsail.com> wrote in message
> news:mailman.1018477621.31315.comp.lang.ada@ada.eu.org...
> > > Subject: hashing
> > > Hi,
> > >
> > > Does anyone have a good hash function for strings (length is
> > > arbitary, number of buckets is determined when package is
> 
> I'll maybe look into that (if it doesn't involve reverse engineering C).  I
> found one that may suffice for the purposes of the exercise, it's nothing
> fancy but it should work.
> 
> Sum all ascii vals of chars in string, then take modulo bucket size.
> 
> > Other than that, I'd try one of the numerous ISO-defined hash functions,
> > such as CRC-32, etc.
> 
> ISO define hash functions?
> 
> > I did a web search on "hash function algorithms" and came up with
> > NUMEROUS interesting sites.
> 
> oops wrong search string, "hash function strings".  Got loads of stuff in
> code, but code is not as useful.  Algorithm/function descriptions
> (mathematics included) are better than code IMO, since they express
> algorithms functions in a programming language independant manner.  When we
> were learning about bstrees they gave us Ada code which made no sense at the
> time due to poor descriptions of the algorithms and considerations involved.
> However when we learned how to do bstrees in Haskell, just before easter
> break it made perfect sense since the lecturer took the time to describe the
> algorithms.  The code was secondary to the algorithm.
> 
> [snip]
> 
> > > p.p.s. should performance/complexity information be included?
> > >  I seem to recall a conversation on this a while back, but
> > > can't remember if ppl thought it was a good idea.
> >
> > Complexity information always raises its head at some point.  Best to
> > include it.
> 
> it does makes sense to include it and it'll definitely go in the gmgpl
> version...  But does complexity information come under the header of an
> implementation detail?  i don't think it does but if it does and I include
> it in the spec, my tutor might disagree and I'll get penalised.  This is one
> of my grumps about uni, not knowing what they want with things.  In first
> year, you'd get penalised for *not* putting pointless comments in.
> 
> Ignore that, I'm probably worrying about nothing!!!
> 
> Thanks,
> Chris

-- 
Ken O. Burtch: http://www.pegasoft.ca                 : Pegasoft
System Manager in a Box / Business Shell              : R.R.#1
Bio: 36;Bsc,UI,Lang,Games;Toons,Elves,SF,Pizza;Xian   : Jordan Station,
ON
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