Candidate Boost Bloom Library

📢 Review announcement
Candidate Boost.Bloom will be officially reviewed for inclusion into Boost from May 13 to 22, 2025, see the review schedule page for details. All interested people are welcome to participate!

(Candidate) Boost.Bloom provides the class template boost::bloom::filter that can be configured to implement a classical Bloom filter as well as variations discussed in the literature such as block filters, multiblock filters, and more.

#include <boost/bloom/filter.hpp>
#include <cassert>
#include <string>

int main()
{
  // Bloom filter of strings with 5 bits set per insertion
  using filter = boost::bloom::filter<std::string, 5>;

  // create filter with a capacity of 1'000'000 **bits**
  filter f(1'000'000);

  // insert elements (they can't be erased, Bloom filters are insert-only)
  f.insert("hello");
  f.insert("Boost");
  //...

  // elements inserted are always correctly checked as such
  assert(f.may_contain("hello") == true);

  // elements not inserted may incorrectly be identified as such with a
  // false positive rate (FPR) which is a function of the array capacity,
  // the number of bits set per element and generally how the boost::bloom::filter
  // was specified
  if(f.may_contain("bye")) { // likely false
    //...
  }
}

Learn about Boost.Bloom

• Online documentation
• Some benchmarks

Install Boost.Bloom

Clone this repo, adjust your include paths and enjoy. Boost.Bloom is header-only and requires no building. A recent version of Boost is required.

Support

• Join the #boost discussion group at cpplang.slack.com (ask for an invite if you’re not a member of this workspace yet)
• File an issue

Contribute

• Pull requests against develop branch are most welcome. Note that by submitting patches you agree to license your modifications under the Boost Software License, Version 1.0.