On closer inspection, Bloom::Filter is a bit broken, unless I'm badly misreading it:
* The add() method doesn't actually add anything, because the new() method doesn't initialise the $self->{contents} hashref. it needs to be changed so that either the add method assigns directly to $self->{contents}, or the new() method changes 'keys' to 'contents'. that's probably just a typo.
* because $self->{contents} is not populated, _calculate_filter_length() always returns undef, so the default filter length is always used.
* because $self->{contents} is not populated, build_filter doesn't build a filter anyway.
* the use of == to compare bitstrings in check() is generating warnings, as you've seen. Its purpose is to test that ($a & $b) is the same as $a, ie that all the on bits in $a are also on in $b, and never mind the off bits. Someone better than me at pack(), ie anyone at all, will know how to test equivalence using the bitstrings themselves: meanwhile, you can make it work by testing with the unpacked versions.
* And anyway, it's not incremental. Every time you add a new key, the whole filter is rebuilt by way of a loop on $self->{contents}. This makes it more or less useless for your purposes: you presumably want an iterative check($_) || add($_) mechanism that can be placed in the equivalent of a while(<HUGE_FILE>) loop. As it stands, Bloom::Filter will perform another loop across your whole dataset-so-far for each input line, which might slow things down a bit.
You will need to roll your own, I think, unless the author can be persuaded to accommodate both approaches as well as fixing the bugs, but if you patch Bloom::Filter with this, at least your test script should work:
--- Filter.orig.pm Tue Apr 20 20:01:37 2004
+++ Filter.pm Tue Apr 20 20:04:34 2004
@@ -25,7 +25,7 @@
min_length => 20,
filter_length => 20,
%params,
- keys => {}
+ contents => {}
}, $class;
}
@@ -52,7 +52,7 @@
my $list = $self->{contents};
foreach my $add ( @addresses ) {
# convert email to SHA1 hash if necessary
- $add = sha1_base64( $add ) if $add =~ /@/o;
+ #$add = sha1_base64( $add ) if $add =~ /@/o;
$list->{$add}++;
}
$self->{reindex_flag} = 1;
@@ -83,7 +83,11 @@
# A match occurs if every bit we check is on
foreach my $key ( @keys ) {
my $mask = $self->_make_bitmask( $key );
- push @result, ($mask == ( $mask & $self->{filter} ));
+ #push @result, ($mask == ( $mask & $self->{filter} ));
+
+ my $m = unpack("b*", $mask);
+ push @result, ($m == unpack("b*", ($mask & $self->{filter})))
+;
+
}
return ( wantarray() ? @result : $result[0] );
}
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