bloom_filter_example01.cpp

/*
 *********************************************************************
 *                                                                   *
 *                           Open Bloom Filter                       *
 *                                                                   *
 * Description: Basic Bloom Filter Usage                             *
 * Author: Arash Partow - 2000                                       *
 * URL: http://www.partow.net                                        *
 * URL: http://www.partow.net/programming/hashfunctions/index.html   *
 *                                                                   *
 * Copyright notice:                                                 *
 * Free use of the Open Bloom Filter Library is permitted under the  *
 * guidelines and in accordance with the MIT License.                *
 * http://www.opensource.org/licenses/MIT                            *
 *                                                                   *
 *********************************************************************
*/


/*
   Description: This example demonstrates basic usage of the Bloom filter.
                Initially some values are inserted then they are subsequently
                queried, noting any false positives or errors.
*/


#include <iostream>
#include <string>

#include "bloom_filter.hpp"

int main()
{
   bloom_parameters parameters;

   // How many elements roughly do we expect to insert?
   parameters.projected_element_count = 1000;

   // Maximum tolerable false positive probability? (0,1)
   parameters.false_positive_probability = 0.0001; // 1 in 10000

   // Simple randomizer (optional)
   parameters.random_seed = 0xA5A5A5A5;

   if (!parameters)
   {
      std::cout << "Error - Invalid set of bloom filter parameters!" << std::endl;
      return 1;
   }

   parameters.compute_optimal_parameters();

   //Instantiate Bloom Filter
   bloom_filter filter(parameters);

   std::string str_list[] = { "AbC", "iJk", "XYZ" };

   // Insert into Bloom Filter
   {
      // Insert some strings
      for (std::size_t i = 0; i < (sizeof(str_list) / sizeof(std::string)); ++i)
      {
         filter.insert(str_list[i]);
      }

      // Insert some numbers
      for (std::size_t i = 0; i < 100; ++i)
      {
         filter.insert(i);
      }
   }

   // Query Bloom Filter
   {
      // Query the existence of strings
      for (std::size_t i = 0; i < (sizeof(str_list) / sizeof(std::string)); ++i)
      {
         if (filter.contains(str_list[i]))
         {
            std::cout << "BF contains: " << str_list[i] << std::endl;
         }
      }

      // Query the existence of numbers
      for (std::size_t i = 0; i < 100; ++i)
      {
         if (filter.contains(i))
         {
            std::cout << "BF contains: " << i << std::endl;
         }
      }

      std::string invalid_str_list[] = { "AbCX", "iJkX", "XYZX" };

      // Query the existence of invalid strings
      for (std::size_t i = 0; i < (sizeof(invalid_str_list) / sizeof(std::string)); ++i)
      {
         if (filter.contains(invalid_str_list[i]))
         {
            std::cout << "BF falsely contains: " << invalid_str_list[i] << std::endl;
         }
      }

      // Query the existence of invalid numbers
      for (int i = -1; i > -100; --i)
      {
         if (filter.contains(i))
         {
            std::cout << "BF falsely contains: " << i << std::endl;
         }
      }
   }

   return 0;
}