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      The perl code will produce the same hash for "abc.html" as for "bca.html"

Which underscores the point I made earlier about adding collision detection and rehashing logic to whatever algorithm you use. One workround I've seen:

| handwaving here... my @i = split(//,$url); # put each letter in it's own bin my $j=0; # Initailize our my $k=1; # hashing increment values my @m=(); # workspace foreach my $n(@i){ my $q=ord($n); # ASCII for character $k += $j; # Increment our hash offset $q += $k; # add our "old" value $j = $k; # store that. push @m,$q; # save the offsetted value } my $hashval=0; #initialize our hash value # Generate that map { $hashval = ($hashval + $_) % 10000} @m;
Using that method ABC.html and CBA.html now have different values because each letter position's value gets bumped up increasingly from left to right.


Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg

In reply to Re^5: Using filepath method to identify an .html page by blue_cowdawg
in thread Using filepath method to identify an .html page by Nik

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