Re: Hash Code
Lew wrote:
Eric Sosman wrote:
Tom Anderson wrote:
On Tue, 20 May 2008, Roedy Green wrote:
To save time, you might just embed a table of primes, say the ones
just under the powers of two.
Or use this clever trick:
http://www.concentric.net/~ttwang/tech/hashsize.htm
Note that this trick applies only to Hashtable, not
to the newer HashMap and HashSet. (In fairness to the
trick's author, HashMap and HashSet didn't yet exist
when the paper was written.)
For that matter, in that it relies on undocumented behavior of
Hashtable, this trick conceivably would not work for future or non-Sun
versions of Hashtable itself.
Out of curiosity, what about the implementations of HashMap and HashSet
(same underlying structure) makes the hash-size trick not work for them?
A look at the source (undocumented implementation internals
again) shows that they use power-of-two table sizes.
--
Eric Sosman
esosman@ieee-dot-org.invalid
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