C++ Open Bloom Filter Library http://www.partow.net/programming/hashf…

…unctions/index.html

readme.md

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+## Description
+**C++ Bloom Filter Library**, has the following capabilities:
+
++ Optimal parameter selection based on expected false positive rate.
++ Union, intersection and difference operations between bloom filters.
++ Compression of in-use table (increase in false positive probability vs space)
++ Portable and efficient source code implementation.
+
+## Compatible Compilers
++ GNU Compiler Collection (4.1+)
++ Intel® C++ Compiler (9.x+)
++ Clang/LLVM (1.1+)
++ PGI C++ (10.x+)
++ Microsoft Visual Studio C++ Compiler (8.1+)
++ Comeau C++ Compiler (4.3+)
+
+For more information please visit: http://www.partow.net/programming/hashfunctions/index.html
+
+---
+
+## Simple Bloom Filter Example
+```javascript
+#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;
+         }
+      }
+
+      // Query the existence of invalid numbers
+      for (std::size_t i = -1; i > -100; --i)
+      {
+         if (filter.contains(i))
+         {
+            std::cout << "BF falsely contains: " << i << std::endl;
+         }
+      }
+   }
+
+   return 0;
+}
+```
+