This implements a Bloom Filter in C++.

Clone the repository or copy the file bloom_filter.hpp into your project.

Use it like this:

#include <iostream>
#include "bloom_filter.hpp"

int main() {
  // Choose your parameters
  bloom_parameters params;
  params.projected_elements_count = 1000;
  params.false_positive_probability = 1e-4;
  if (!params) {
    std::cerr << "Invalid Bloom Filter parameters." << std::endl;
    return 1;
  }
  
  // Create a Bloom Filter
  BloomFilter<int> filter(params);
  filter.insert(0);
  filter.insert(12);
  
  // Query for membership
  filter.contains(0); // Returns a bool. In this case 'true'
  filter.contains(1); // Should return 'false' but false positives are possible
  filter.contains(12);  // Will return 'true'.
}

The code consists just of the header file bloom_filter.hpp, there are four examples that show you the various uses. Also implemented is a Compressible Bloom Filter. Have a look at bloom_filter_example03.cpp for details.

Classes:

• BloomFilter<T> this is the type safe implementation. typename T must be a C++ POD-type class. Any basic type (int, float, etc) will work.
• bloom_filter This is a generic Bloom Filter, it will take any POD-type object, look at its bit represenation and insert it into the filter.
• compressible_bloom_filter A compressible Bloom Filter.