Calvin-L / calbloom

A dirt-simple Bloom filter library for C++

Calvin's Bloom Filter Library

This is a dirt-simple Bloom filter for C++.

How to use this library

#include <calbloom/BloomFilter.hpp>
#include <random>
#include <cassert>

int main() {

    // Source of randomness.  Pick your favorite from <random>!
    std::mt19937_64 generator;

    // Construct a new Bloom filter with the given parameters.
    int nbuckets = 100000;
    int nhashes = 4;
    calbloom::BloomFilter filter(nbuckets, nhashes, generator);

    bool isNew = filter.insert(10);
    assert(isNew);

    isNew = filter.insert(10);
    assert(!isNew);

    assert(!filter.mightContain(9));
    assert(filter.mightContain(10));
    assert(!filter.mightContain(11));

    return 0;
}

See also: test/main.cpp.

This library is built on caluhash. See the docs there for how to implement hashing for custom types (so that you can insert non-integer values).

How to include this library in your project

If you use CMake:

cmake_minimum_required(VERSION 3.14) # or higher

...

include(FetchContent)
FetchContent_Declare(
    calbloom_repo
    GIT_REPOSITORY https://github.com/Calvin-L/calbloom.git
    GIT_TAG        main)
FetchContent_MakeAvailable(calbloom_repo)

...

target_link_libraries(YOUR_TARGET_HERE PRIVATE calbloom)

## If you need to hash custom types, you probably need to include caluhash as
## as well as calbloom.
#
# FetchContent_Declare(
#     caluhash_repo
#     GIT_REPOSITORY https://github.com/Calvin-L/caluhash.git
#     GIT_TAG        main)
# FetchContent_MakeAvailable(caluhash_repo)
#
# target_link_libraries(YOUR_TARGET_HERE PRIVATE caluhash)

Note that you may want to replace main with a specific revision for stable builds.