ibrcommon/ibrcommon/data/BloomFilter.h

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/*
 * BloomFilter.h
 *
 * This bloom filter implementation is based on
 * Open Bloom Filter (http://www.partow.net) written by Arash Partow.
 *
 */

#include <cstddef>
#include <algorithm>
#include <cmath>
#include <limits>
#include <string>
#include <vector>
#include <list>

#ifndef BLOOMFILTER_H_
#define BLOOMFILTER_H_

namespace ibrcommon
{
        typedef unsigned int bloom_type;
        typedef unsigned char cell_type;

        class HashProvider
        {
        public:
                virtual size_t count() const = 0;

                virtual void clear() = 0;
                virtual const std::list<bloom_type> hash(const unsigned char* begin, std::size_t remaining_length) const = 0;
        };

        class DefaultHashProvider : public HashProvider
        {
        public:
                DefaultHashProvider(size_t salt_count);
                virtual ~DefaultHashProvider();

                bool operator==(const DefaultHashProvider &provider) const;
                size_t count() const;
                void clear();

                const std::list<bloom_type> hash(const unsigned char* begin, std::size_t remaining_length) const;

        private:
                void add(bloom_type hash);
                void generate_salt();
                bloom_type hash_ap(const unsigned char* begin, std::size_t remaining_length, bloom_type hash) const;

                std::vector<bloom_type> _salt;
                std::size_t salt_count_;
        };

        class BloomFilter
        {
        protected:
                static const std::size_t bits_per_char = 0x08;    // 8 bits in 1 char(unsigned)
                static const unsigned char bit_mask[bits_per_char];

        public:
                BloomFilter(std::size_t table_size = 8196, std::size_t salt_count = 2);
                BloomFilter(const BloomFilter& filter);
                virtual ~BloomFilter();

                void load(const cell_type* data, size_t len);

                BloomFilter& operator=(const BloomFilter& filter);

                bool operator!() const;
                void clear();

                void insert(const unsigned char* key_begin, const std::size_t length);

                template<typename T>
                void insert(const T& t)
                {
                        insert(reinterpret_cast<const unsigned char*>(&t),sizeof(T));
                }

                void insert(const std::string& key);

                void insert(const char* data, const std::size_t& length);

                template<typename InputIterator>
                void insert(const InputIterator begin, const InputIterator end)
                {
                        InputIterator it = begin;
                        while(it != end)
                        {
                                insert(*(it++));
                        }
                }

                virtual bool contains(const unsigned char* key_begin, const std::size_t length) const;

                template<typename T>
                bool contains(const T& t) const
                {
                        return contains(reinterpret_cast<const unsigned char*>(&t),static_cast<std::size_t>(sizeof(T)));
                }

                bool contains(const std::string& key) const;

                bool contains(const char* data, const std::size_t& length) const;

                template<typename InputIterator>
                InputIterator contains_all(const InputIterator begin, const InputIterator end) const
                {
                        InputIterator it = begin;
                        while(it != end)
                        {
                                if (!contains(*it))
                                {
                                        return it;
                                }
                                ++it;
                        }
                        return end;
                }

                template<typename InputIterator>
                InputIterator contains_none(const InputIterator begin, const InputIterator end) const
                {
                        InputIterator it = begin;
                        while(it != end)
                        {
                                if (contains(*it))
                                {
                                        return it;
                                }
                                ++it;
                        }
                        return end;
                }

                virtual std::size_t size() const;

                BloomFilter& operator &= (const BloomFilter& filter);
                BloomFilter& operator |= (const BloomFilter& filter);
                BloomFilter& operator ^= (const BloomFilter& filter);

                const cell_type* table() const;

                float getAllocation() const;

        protected:
                virtual void compute_indices(const bloom_type& hash, std::size_t& bit_index, std::size_t& bit) const;
                DefaultHashProvider _hashp;

                unsigned char*          bit_table_;
                std::size_t             table_size_;

                unsigned int _itemcount;
                std::size_t salt_count_;
        };
}


#endif /* BLOOMFILTER_H_ */