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Diffstat (limited to 'src/include/bloom_filter.hpp')
| -rw-r--r-- | src/include/bloom_filter.hpp | 544 |
1 files changed, 0 insertions, 544 deletions
diff --git a/src/include/bloom_filter.hpp b/src/include/bloom_filter.hpp deleted file mode 100644 index 41aba4bad47..00000000000 --- a/src/include/bloom_filter.hpp +++ /dev/null @@ -1,544 +0,0 @@ -/* - ******************************************************************* - * * - * Open Bloom Filter * - * * - * Author: Arash Partow - 2000 * - * 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 most current version * - * of the Boost Software License, Version 1.0 * - * http://www.opensource.org/licenses/bsl1.0.html * - * * - ******************************************************************* -*/ - - -#ifndef INCLUDE_BLOOM_FILTER_HPP -#define INCLUDE_BLOOM_FILTER_HPP - -#include <cstddef> -#include <algorithm> -#include <cmath> -#include <limits> -#include <string> -#include <vector> - - -static const std::size_t bits_per_char = 0x08; // 8 bits in 1 char(unsigned) -static const unsigned char bit_mask[bits_per_char] = { - 0x01, //00000001 - 0x02, //00000010 - 0x04, //00000100 - 0x08, //00001000 - 0x10, //00010000 - 0x20, //00100000 - 0x40, //01000000 - 0x80 //10000000 - }; - - -class bloom_filter -{ -protected: - - typedef unsigned int bloom_type; - typedef unsigned char cell_type; - -public: - - bloom_filter(const std::size_t& predicted_inserted_element_count, - const double& false_positive_probability, - const std::size_t& random_seed) - : bit_table_(0), - predicted_inserted_element_count_(predicted_inserted_element_count), - inserted_element_count_(0), - random_seed_((random_seed) ? random_seed : 0xA5A5A5A5), - desired_false_positive_probability_(false_positive_probability) - { - find_optimal_parameters(); - generate_unique_salt(); - raw_table_size_ = table_size_ / bits_per_char; - bit_table_ = new cell_type[raw_table_size_]; - std::fill_n(bit_table_,raw_table_size_,0x00); - } - - bloom_filter(const bloom_filter& filter) - { - this->operator=(filter); - } - - bloom_filter& operator = (const bloom_filter& filter) - { - if (this != &filter) { - salt_count_ = filter.salt_count_; - table_size_ = filter.table_size_; - raw_table_size_ = filter.raw_table_size_; - predicted_inserted_element_count_ = filter.predicted_inserted_element_count_; - inserted_element_count_ = filter.inserted_element_count_; - random_seed_ = filter.random_seed_; - desired_false_positive_probability_ = filter.desired_false_positive_probability_; - delete[] bit_table_; - bit_table_ = new cell_type[raw_table_size_]; - std::copy(filter.bit_table_,filter.bit_table_ + raw_table_size_,bit_table_); - salt_ = filter.salt_; - } - return *this; - } - - virtual ~bloom_filter() - { - delete[] bit_table_; - } - - inline bool operator!() const - { - return (0 == table_size_); - } - - inline void clear() - { - std::fill_n(bit_table_,raw_table_size_,0x00); - inserted_element_count_ = 0; - } - - inline void insert(const unsigned char* key_begin, const std::size_t& length) - { - std::size_t bit_index = 0; - std::size_t bit = 0; - for (std::size_t i = 0; i < salt_.size(); ++i) - { - compute_indices(hash_ap(key_begin,length,salt_[i]),bit_index,bit); - bit_table_[bit_index / bits_per_char] |= bit_mask[bit]; - } - ++inserted_element_count_; - } - - template<typename T> - inline void insert(const T& t) - { - // Note: T must be a C++ POD type. - insert(reinterpret_cast<const unsigned char*>(&t),sizeof(T)); - } - - inline void insert(const std::string& key) - { - insert(reinterpret_cast<const unsigned char*>(key.c_str()),key.size()); - } - - inline void insert(const char* data, const std::size_t& length) - { - insert(reinterpret_cast<const unsigned char*>(data),length); - } - - template<typename InputIterator> - inline void insert(const InputIterator begin, const InputIterator end) - { - InputIterator itr = begin; - while (end != itr) - { - insert(*(itr++)); - } - } - - inline virtual bool contains(const unsigned char* key_begin, const std::size_t length) const - { - std::size_t bit_index = 0; - std::size_t bit = 0; - for (std::size_t i = 0; i < salt_.size(); ++i) - { - compute_indices(hash_ap(key_begin,length,salt_[i]),bit_index,bit); - if ((bit_table_[bit_index / bits_per_char] & bit_mask[bit]) != bit_mask[bit]) - { - return false; - } - } - return true; - } - - template<typename T> - inline bool contains(const T& t) const - { - return contains(reinterpret_cast<const unsigned char*>(&t),static_cast<std::size_t>(sizeof(T))); - } - - inline bool contains(const std::string& key) const - { - return contains(reinterpret_cast<const unsigned char*>(key.c_str()),key.size()); - } - - inline bool contains(const char* data, const std::size_t& length) const - { - return contains(reinterpret_cast<const unsigned char*>(data),length); - } - - template<typename InputIterator> - inline InputIterator contains_all(const InputIterator begin, const InputIterator end) const - { - InputIterator itr = begin; - while (end != itr) - { - if (!contains(*itr)) - { - return itr; - } - ++itr; - } - return end; - } - - template<typename InputIterator> - inline InputIterator contains_none(const InputIterator begin, const InputIterator end) const - { - InputIterator itr = begin; - while (end != itr) - { - if (contains(*itr)) - { - return itr; - } - ++itr; - } - return end; - } - - inline virtual std::size_t size() const - { - return table_size_; - } - - inline std::size_t element_count() const - { - return inserted_element_count_; - } - - inline double effective_fpp() const - { - /* - Note: - The effective false positive probability is calculated using the - designated table size and hash function count in conjunction with - the current number of inserted elements - not the user defined - predicated/expected number of inserted elements. - */ - return std::pow(1.0 - std::exp(-1.0 * salt_.size() * inserted_element_count_ / size()), 1.0 * salt_.size()); - } - - inline bloom_filter& operator &= (const bloom_filter& filter) - { - /* intersection */ - if ( - (salt_count_ == filter.salt_count_) && - (table_size_ == filter.table_size_) && - (random_seed_ == filter.random_seed_) - ) - { - for (std::size_t i = 0; i < raw_table_size_; ++i) - { - bit_table_[i] &= filter.bit_table_[i]; - } - } - return *this; - } - - inline bloom_filter& operator |= (const bloom_filter& filter) - { - /* union */ - if ( - (salt_count_ == filter.salt_count_) && - (table_size_ == filter.table_size_) && - (random_seed_ == filter.random_seed_) - ) - { - for (std::size_t i = 0; i < raw_table_size_; ++i) - { - bit_table_[i] |= filter.bit_table_[i]; - } - } - return *this; - } - - inline bloom_filter& operator ^= (const bloom_filter& filter) - { - /* difference */ - if ( - (salt_count_ == filter.salt_count_) && - (table_size_ == filter.table_size_) && - (random_seed_ == filter.random_seed_) - ) - { - for (std::size_t i = 0; i < raw_table_size_; ++i) - { - bit_table_[i] ^= filter.bit_table_[i]; - } - } - return *this; - } - - inline const cell_type* table() const - { - return bit_table_; - } - -protected: - - inline virtual void compute_indices(const bloom_type& hash, std::size_t& bit_index, std::size_t& bit) const - { - bit_index = hash % table_size_; - bit = bit_index % bits_per_char; - } - - void generate_unique_salt() - { - /* - Note: - A distinct hash function need not be implementation-wise - distinct. In the current implementation "seeding" a common - hash function with different values seems to be adequate. - */ - const unsigned int predef_salt_count = 128; - static const bloom_type predef_salt[predef_salt_count] = - { - 0xAAAAAAAA, 0x55555555, 0x33333333, 0xCCCCCCCC, - 0x66666666, 0x99999999, 0xB5B5B5B5, 0x4B4B4B4B, - 0xAA55AA55, 0x55335533, 0x33CC33CC, 0xCC66CC66, - 0x66996699, 0x99B599B5, 0xB54BB54B, 0x4BAA4BAA, - 0xAA33AA33, 0x55CC55CC, 0x33663366, 0xCC99CC99, - 0x66B566B5, 0x994B994B, 0xB5AAB5AA, 0xAAAAAA33, - 0x555555CC, 0x33333366, 0xCCCCCC99, 0x666666B5, - 0x9999994B, 0xB5B5B5AA, 0xFFFFFFFF, 0xFFFF0000, - 0xB823D5EB, 0xC1191CDF, 0xF623AEB3, 0xDB58499F, - 0xC8D42E70, 0xB173F616, 0xA91A5967, 0xDA427D63, - 0xB1E8A2EA, 0xF6C0D155, 0x4909FEA3, 0xA68CC6A7, - 0xC395E782, 0xA26057EB, 0x0CD5DA28, 0x467C5492, - 0xF15E6982, 0x61C6FAD3, 0x9615E352, 0x6E9E355A, - 0x689B563E, 0x0C9831A8, 0x6753C18B, 0xA622689B, - 0x8CA63C47, 0x42CC2884, 0x8E89919B, 0x6EDBD7D3, - 0x15B6796C, 0x1D6FDFE4, 0x63FF9092, 0xE7401432, - 0xEFFE9412, 0xAEAEDF79, 0x9F245A31, 0x83C136FC, - 0xC3DA4A8C, 0xA5112C8C, 0x5271F491, 0x9A948DAB, - 0xCEE59A8D, 0xB5F525AB, 0x59D13217, 0x24E7C331, - 0x697C2103, 0x84B0A460, 0x86156DA9, 0xAEF2AC68, - 0x23243DA5, 0x3F649643, 0x5FA495A8, 0x67710DF8, - 0x9A6C499E, 0xDCFB0227, 0x46A43433, 0x1832B07A, - 0xC46AFF3C, 0xB9C8FFF0, 0xC9500467, 0x34431BDF, - 0xB652432B, 0xE367F12B, 0x427F4C1B, 0x224C006E, - 0x2E7E5A89, 0x96F99AA5, 0x0BEB452A, 0x2FD87C39, - 0x74B2E1FB, 0x222EFD24, 0xF357F60C, 0x440FCB1E, - 0x8BBE030F, 0x6704DC29, 0x1144D12F, 0x948B1355, - 0x6D8FD7E9, 0x1C11A014, 0xADD1592F, 0xFB3C712E, - 0xFC77642F, 0xF9C4CE8C, 0x31312FB9, 0x08B0DD79, - 0x318FA6E7, 0xC040D23D, 0xC0589AA7, 0x0CA5C075, - 0xF874B172, 0x0CF914D5, 0x784D3280, 0x4E8CFEBC, - 0xC569F575, 0xCDB2A091, 0x2CC016B4, 0x5C5F4421 - }; - - if (salt_count_ <= predef_salt_count) - { - std::copy(predef_salt, - predef_salt + salt_count_, - std::back_inserter(salt_)); - for (unsigned int i = 0; i < salt_.size(); ++i) - { - /* - Note: - This is done to integrate the user defined random seed, - so as to allow for the generation of unique bloom filter - instances. - */ - salt_[i] = salt_[i] * salt_[(i + 3) % salt_.size()] + random_seed_; - } - } - else - { - std::copy(predef_salt,predef_salt + predef_salt_count,std::back_inserter(salt_)); - srand(static_cast<unsigned int>(random_seed_)); - while (salt_.size() < salt_count_) - { - bloom_type current_salt = static_cast<bloom_type>(rand()) * static_cast<bloom_type>(rand()); - if (0 == current_salt) continue; - if (salt_.end() == std::find(salt_.begin(), salt_.end(), current_salt)) - { - salt_.push_back(current_salt); - } - } - } - } - - void find_optimal_parameters() - { - /* - Note: - The following will attempt to find the number of hash functions - and minimum amount of storage bits required to construct a bloom - filter consistent with the user defined false positive probability - and estimated element insertion count. - */ - - double min_m = std::numeric_limits<double>::infinity(); - double min_k = 0.0; - double curr_m = 0.0; - double k = 1.0; - while (k < 1000.0) - { - double numerator = (- k * predicted_inserted_element_count_); - double denominator = std::log(1.0 - std::pow(desired_false_positive_probability_, 1.0 / k)); - curr_m = numerator / denominator; - - if (curr_m < min_m) - { - min_m = curr_m; - min_k = k; - } - k += 1.0; - } - - salt_count_ = static_cast<std::size_t>(min_k); - table_size_ = static_cast<std::size_t>(min_m); - table_size_ += (((table_size_ % bits_per_char) != 0) ? (bits_per_char - (table_size_ % bits_per_char)) : 0); - } - - inline bloom_type hash_ap(const unsigned char* begin, std::size_t remaining_length, bloom_type hash) const - { - const unsigned char* itr = begin; - - while (remaining_length >= 4) - { - hash ^= (hash << 7) ^ (*itr++) * (hash >> 3); - hash ^= (~((hash << 11) + ((*itr++) ^ (hash >> 5)))); - hash ^= (hash << 7) ^ (*itr++) * (hash >> 3); - hash ^= (~((hash << 11) + ((*itr++) ^ (hash >> 5)))); - remaining_length -= 4; - } - - while (remaining_length >= 2) - { - hash ^= (hash << 7) ^ (*itr++) * (hash >> 3); - hash ^= (~((hash << 11) + ((*itr++) ^ (hash >> 5)))); - remaining_length -= 2; - } - - if (remaining_length) - { - hash ^= (hash << 7) ^ (*itr) * (hash >> 3); - } - - return hash; - } - - std::vector<bloom_type> salt_; - unsigned char* bit_table_; - std::size_t salt_count_; - std::size_t table_size_; - std::size_t raw_table_size_; - std::size_t predicted_inserted_element_count_; - std::size_t inserted_element_count_; - std::size_t random_seed_; - double desired_false_positive_probability_; -}; - -inline bloom_filter operator & (const bloom_filter& a, const bloom_filter& b) -{ - bloom_filter result = a; - result &= b; - return result; -} - -inline bloom_filter operator | (const bloom_filter& a, const bloom_filter& b) -{ - bloom_filter result = a; - result |= b; - return result; -} - -inline bloom_filter operator ^ (const bloom_filter& a, const bloom_filter& b) -{ - bloom_filter result = a; - result ^= b; - return result; -} - - -class compressible_bloom_filter : public bloom_filter -{ -public: - - compressible_bloom_filter(const std::size_t& predicted_element_count, - const double& false_positive_probability, - const std::size_t& random_seed) - : bloom_filter(predicted_element_count,false_positive_probability,random_seed) - { - size_list.push_back(table_size_); - } - - inline virtual std::size_t size() const - { - return size_list.back(); - } - - inline bool compress(const double& percentage) - { - if ((0.0 >= percentage) || (percentage >= 100.0)) - { - return false; - } - - std::size_t original_table_size = size_list.back(); - std::size_t new_table_size = static_cast<std::size_t>((size_list.back() * (1.0 - (percentage / 100.0)))); - new_table_size -= (((new_table_size % bits_per_char) != 0) ? (new_table_size % bits_per_char) : 0); - - if ((bits_per_char > new_table_size) || (new_table_size >= original_table_size)) - { - return false; - } - - desired_false_positive_probability_ = effective_fpp(); - cell_type* tmp = new cell_type[new_table_size / bits_per_char]; - std::copy(bit_table_, bit_table_ + (new_table_size / bits_per_char), tmp); - cell_type* itr = bit_table_ + (new_table_size / bits_per_char); - cell_type* end = bit_table_ + (original_table_size / bits_per_char); - cell_type* itr_tmp = tmp; - - while (end != itr) - { - *(itr_tmp++) |= (*itr++); - } - - delete[] bit_table_; - bit_table_ = tmp; - size_list.push_back(new_table_size); - - return true; - } - -private: - - inline virtual void compute_indices(const bloom_type& hash, std::size_t& bit_index, std::size_t& bit) const - { - bit_index = hash; - for (std::size_t i = 0; i < size_list.size(); ++i) - { - bit_index %= size_list[i]; - } - bit = bit_index % bits_per_char; - } - - std::vector<std::size_t> size_list; -}; - -#endif - - -/* - Note 1: - If it can be guaranteed that bits_per_char will be of the form 2^n then - the following optimization can be used: - - hash_table[bit_index >> n] |= bit_mask[bit_index & (bits_per_char - 1)]; - - Note 2: - For performance reasons where possible when allocating memory it should - be aligned (aligned_alloc) according to the architecture being used. -*/ |