NAME

Algorithm::BloomFilter - A bloom filter implementation in Perl 6

SYNOPSIS

use Algorithm::BloomFilter;

my $filter = Algorithm::BloomFilter.new(
  capacity   => 100,
  error-rate => 0.01,
);

$filter.add("foo-bar");

$filter.check("foo-bar"); # True

$filter.check("bar-foo"); # False with possible false-positive

DESCRIPTION

Algorithm::BloomFilter is a pure Perl 6 implementation of Bloom Filter, mostly based on Bloom::Filter from Perl 5.

Digest::MurmurHash3 is used for hashing from version 0.1.0.

METHODS

new(Rat:D :$error-rate, Int:D :$capacity)

Creates a Bloom::Filter instance.

add(Cool:D $key)

Adds a given key to filter instance.

check(Cool:D $key) returns Bool

Checks if a given key is in filter instance.

INTERNAL METHODS

calculate-shortest-filter-length(Int:D :$num-keys, Rat:D $error-rate) returns Hash[Int]

Calculates and returns filter's length and a number of hash functions.

create-salts(Int:D :$count) returns Seq[Int]

Creates and returns $count unique and random uint32 salts.

get-cells(Cool:D $key, Int:D :$filter-length, Int:D :$blankvec, Int:D :@salts) returns List

Calculates and returns positions to check in a bit vector.

AUTHOR

yowcow yowcow@cpan.org

COPYRIGHT AND LICENSE

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.