1Algorithm::BloomFilter(U3s)er Contributed Perl DocumentatAilognorithm::BloomFilter(3)
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NAME

6       Algorithm::BloomFilter - A simple bloom filter data structure
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SYNOPSIS

9         use Algorithm::BloomFilter;
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11         my $filter = Algorithm::BloomFilter->new($absolute_nbits, $n_hashes);
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13         $filter->add("foo", "bar", "baz");
14         if ($filter->test("bar")) {
15           print "Eureka! 'bar' is in!\n";
16         }
17

DESCRIPTION

19       This module implements a simple bloom filter in C/XS.
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METHODS

22   new
23       Constructor, takes two arguments: The absolute number of bits to use
24       for the bloom filter storage (this will be rounded up to the nearest
25       power of 2) and the number of hash functions to evaluate for each
26       entry.
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28       "Algorithm::BloomFilter" uses SipHash internally. The C part can also
29       use other hash functions, but the XS wrapper currently only supports
30       SipHash.
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32   add
33       Given a list of values (that will be converted to byte strings), add
34       those values to the bloom filter.
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36   test
37       Given a value (which will be converted to a byte string for this
38       operation), test whether that value is part of the set represented by
39       the bloom filter.
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41   merge
42       Given another bloom filter of exactly the same configuration (same hash
43       function, same number of hash function variants, same number of bits),
44       computes a union of the two filters and stores the result in the
45       invocant bloom filter.
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47   serialize
48       Serializes the bloom filter into a string and returns it.
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50   deserialize
51       Class method. Given a previously serialized bloom filter as a string,
52       reconstructs the bloom filter. Returns the newly created
53       "Algorithm::BloomFilter" object.
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55       Beware that serialize/deserialize haven't been tested across systems
56       with differing endianess, etc. Please do your own testing (and possibly
57       submit patches to this caveat).
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CAVEATS

60       Requires a "uint64_t" type. Untested on endianness other than x86_64's
61       (little endian).
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SEE ALSO

64       Wikipedia: <http://en.wikipedia.org/wiki/Bloom_filter>
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AUTHOR

67       Steffen Mueller, <smueller@cpan.org>
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70       Copyright (C) 2014-2015 by Steffen Mueller
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72       This library is free software; you can redistribute it and/or modify it
73       under the same terms as Perl itself, either Perl version 5.8.0 or, at
74       your option, any later version of Perl 5 you may have available.
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78perl v5.34.0                      2021-07-22         Algorithm::BloomFilter(3)
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