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
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