Adding missing file
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Daniel Larimer
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1 changed files with 621 additions and 0 deletions
621
include/fc/bloom_filter.hpp
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include/fc/bloom_filter.hpp
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#pragma once
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/*
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*********************************************************************
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* *
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* Open Bloom Filter *
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* *
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* Author: Arash Partow - 2000 *
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* URL: http://www.partow.net *
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* URL: http://www.partow.net/programming/hashfunctions/index.html *
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* *
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* Copyright notice: *
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* Free use of the Open Bloom Filter Library is permitted under the *
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* guidelines and in accordance with the most current version of the *
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* Common Public License. *
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* http://www.opensource.org/licenses/cpl1.0.php *
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* *
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*********************************************************************
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*/
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#include <algorithm>
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#include <cmath>
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#include <cstddef>
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#include <iterator>
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#include <limits>
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#include <string>
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#include <vector>
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#include <fc/reflect/reflect.hpp>
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namespace fc {
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static const std::size_t bits_per_char = 0x08; // 8 bits in 1 char(unsigned)
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static const unsigned char bit_mask[bits_per_char] = {
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0x01, //00000001
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0x02, //00000010
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0x04, //00000100
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0x08, //00001000
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0x10, //00010000
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0x20, //00100000
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0x40, //01000000
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0x80 //10000000
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};
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class bloom_parameters
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{
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public:
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bloom_parameters()
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: minimum_size(1),
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maximum_size(std::numeric_limits<unsigned long long int>::max()),
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minimum_number_of_hashes(1),
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maximum_number_of_hashes(std::numeric_limits<unsigned int>::max()),
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projected_element_count(10000),
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false_positive_probability(1.0 / projected_element_count),
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random_seed(0xA5A5A5A55A5A5A5AULL)
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{}
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virtual ~bloom_parameters()
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{}
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inline bool operator!()
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{
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return (minimum_size > maximum_size) ||
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(minimum_number_of_hashes > maximum_number_of_hashes) ||
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(minimum_number_of_hashes < 1) ||
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(0 == maximum_number_of_hashes) ||
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(0 == projected_element_count) ||
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(false_positive_probability < 0.0) ||
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(std::numeric_limits<double>::infinity() == std::abs(false_positive_probability)) ||
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(0 == random_seed) ||
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(0xFFFFFFFFFFFFFFFFULL == random_seed);
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}
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//Allowed min/max size of the bloom filter in bits
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unsigned long long int minimum_size;
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unsigned long long int maximum_size;
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//Allowed min/max number of hash functions
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unsigned int minimum_number_of_hashes;
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unsigned int maximum_number_of_hashes;
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//The approximate number of elements to be inserted
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//into the bloom filter, should be within one order
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//of magnitude. The default is 10000.
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unsigned long long int projected_element_count;
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//The approximate false positive probability expected
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//from the bloom filter. The default is the reciprocal
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//of the projected_element_count.
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double false_positive_probability;
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unsigned long long int random_seed;
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struct optimal_parameters_t
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{
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optimal_parameters_t()
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: number_of_hashes(0),
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table_size(0)
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{}
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unsigned int number_of_hashes;
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unsigned long long int table_size;
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};
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optimal_parameters_t optimal_parameters;
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virtual bool compute_optimal_parameters()
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{
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/*
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Note:
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The following will attempt to find the number of hash functions
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and minimum amount of storage bits required to construct a bloom
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filter consistent with the user defined false positive probability
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and estimated element insertion count.
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*/
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if (!(*this))
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return false;
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double min_m = std::numeric_limits<double>::infinity();
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double min_k = 0.0;
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double curr_m = 0.0;
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double k = 1.0;
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while (k < 1000.0)
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{
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double numerator = (- k * projected_element_count);
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double denominator = std::log(1.0 - std::pow(false_positive_probability, 1.0 / k));
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curr_m = numerator / denominator;
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if (curr_m < min_m)
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{
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min_m = curr_m;
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min_k = k;
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}
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k += 1.0;
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}
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optimal_parameters_t& optp = optimal_parameters;
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optp.number_of_hashes = static_cast<unsigned int>(min_k);
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optp.table_size = static_cast<unsigned long long int>(min_m);
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optp.table_size += (((optp.table_size % bits_per_char) != 0) ? (bits_per_char - (optp.table_size % bits_per_char)) : 0);
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if (optp.number_of_hashes < minimum_number_of_hashes)
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optp.number_of_hashes = minimum_number_of_hashes;
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else if (optp.number_of_hashes > maximum_number_of_hashes)
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optp.number_of_hashes = maximum_number_of_hashes;
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if (optp.table_size < minimum_size)
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optp.table_size = minimum_size;
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else if (optp.table_size > maximum_size)
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optp.table_size = maximum_size;
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return true;
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}
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};
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class bloom_filter
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{
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protected:
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typedef unsigned int bloom_type;
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typedef unsigned char cell_type;
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public:
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bloom_filter()
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: salt_count_(0),
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table_size_(0),
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raw_table_size_(0),
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projected_element_count_(0),
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inserted_element_count_(0),
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random_seed_(0),
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desired_false_positive_probability_(0.0)
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{}
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bloom_filter(const bloom_parameters& p)
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: projected_element_count_(p.projected_element_count),
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inserted_element_count_(0),
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random_seed_((p.random_seed * 0xA5A5A5A5) + 1),
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desired_false_positive_probability_(p.false_positive_probability)
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{
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salt_count_ = p.optimal_parameters.number_of_hashes;
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table_size_ = p.optimal_parameters.table_size;
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generate_unique_salt();
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raw_table_size_ = table_size_ / bits_per_char;
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bit_table_.resize( static_cast<std::size_t>(raw_table_size_) );
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//bit_table_ = new cell_type[static_cast<std::size_t>(raw_table_size_)];
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std::fill_n(bit_table_.data(),raw_table_size_,0x00);
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}
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bloom_filter(const bloom_filter& filter)
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{
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this->operator=(filter);
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}
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inline bool operator == (const bloom_filter& f) const
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{
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if (this != &f)
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{
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return
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(salt_count_ == f.salt_count_) &&
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(table_size_ == f.table_size_) &&
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(raw_table_size_ == f.raw_table_size_) &&
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(projected_element_count_ == f.projected_element_count_) &&
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(inserted_element_count_ == f.inserted_element_count_) &&
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(random_seed_ == f.random_seed_) &&
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(desired_false_positive_probability_ == f.desired_false_positive_probability_) &&
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(salt_ == f.salt_) &&
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std::equal(f.bit_table_.data(),f.bit_table_.data() + raw_table_size_,bit_table_.data());
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}
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else
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return true;
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}
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inline bool operator != (const bloom_filter& f) const
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{
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return !operator==(f);
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}
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inline bloom_filter& operator = (const bloom_filter& f)
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{
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if (this != &f)
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{
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salt_count_ = f.salt_count_;
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table_size_ = f.table_size_;
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raw_table_size_ = f.raw_table_size_;
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projected_element_count_ = f.projected_element_count_;
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inserted_element_count_ = f.inserted_element_count_;
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random_seed_ = f.random_seed_;
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desired_false_positive_probability_ = f.desired_false_positive_probability_;
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bit_table_.resize( raw_table_size_ );
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std::copy(f.bit_table_.data(),f.bit_table_.data() + raw_table_size_,bit_table_.data());
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salt_ = f.salt_;
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}
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return *this;
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}
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virtual ~bloom_filter()
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{
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}
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inline bool operator!() const
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{
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return (0 == table_size_);
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}
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inline void clear()
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{
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std::fill_n(bit_table_.data(),raw_table_size_,0x00);
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inserted_element_count_ = 0;
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}
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inline void insert(const unsigned char* key_begin, const std::size_t& length)
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{
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std::size_t bit_index = 0;
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std::size_t bit = 0;
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for (std::size_t i = 0; i < salt_.size(); ++i)
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{
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compute_indices(hash_ap(key_begin,length,salt_[i]),bit_index,bit);
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bit_table_[bit_index / bits_per_char] |= bit_mask[bit];
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}
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++inserted_element_count_;
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}
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template<typename T>
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inline void insert(const T& t)
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{
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// Note: T must be a C++ POD type.
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insert(reinterpret_cast<const unsigned char*>(&t),sizeof(T));
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}
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inline void insert(const std::string& key)
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{
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insert(reinterpret_cast<const unsigned char*>(key.c_str()),key.size());
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}
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inline void insert(const char* data, const std::size_t& length)
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{
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insert(reinterpret_cast<const unsigned char*>(data),length);
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}
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template<typename InputIterator>
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inline void insert(const InputIterator begin, const InputIterator end)
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{
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InputIterator itr = begin;
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while (end != itr)
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{
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insert(*(itr++));
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}
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}
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inline virtual bool contains(const unsigned char* key_begin, const std::size_t length) const
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{
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std::size_t bit_index = 0;
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std::size_t bit = 0;
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for (std::size_t i = 0; i < salt_.size(); ++i)
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{
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compute_indices(hash_ap(key_begin,length,salt_[i]),bit_index,bit);
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if ((bit_table_[bit_index / bits_per_char] & bit_mask[bit]) != bit_mask[bit])
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{
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return false;
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}
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}
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return true;
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}
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template<typename T>
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inline bool contains(const T& t) const
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{
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return contains(reinterpret_cast<const unsigned char*>(&t),static_cast<std::size_t>(sizeof(T)));
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}
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inline bool contains(const std::string& key) const
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{
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return contains(reinterpret_cast<const unsigned char*>(key.c_str()),key.size());
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}
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inline bool contains(const char* data, const std::size_t& length) const
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{
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return contains(reinterpret_cast<const unsigned char*>(data),length);
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}
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template<typename InputIterator>
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inline InputIterator contains_all(const InputIterator begin, const InputIterator end) const
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{
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InputIterator itr = begin;
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while (end != itr)
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{
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if (!contains(*itr))
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{
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return itr;
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}
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++itr;
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}
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return end;
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}
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template<typename InputIterator>
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inline InputIterator contains_none(const InputIterator begin, const InputIterator end) const
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{
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InputIterator itr = begin;
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while (end != itr)
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{
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if (contains(*itr))
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{
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return itr;
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}
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++itr;
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}
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return end;
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}
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inline virtual unsigned long long int size() const
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{
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return table_size_;
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}
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inline std::size_t element_count() const
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{
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return inserted_element_count_;
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}
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inline double effective_fpp() const
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{
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/*
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Note:
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The effective false positive probability is calculated using the
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designated table size and hash function count in conjunction with
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the current number of inserted elements - not the user defined
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predicated/expected number of inserted elements.
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*/
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return std::pow(1.0 - std::exp(-1.0 * salt_.size() * inserted_element_count_ / size()), 1.0 * salt_.size());
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}
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inline bloom_filter& operator &= (const bloom_filter& f)
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{
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/* intersection */
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if (
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(salt_count_ == f.salt_count_) &&
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(table_size_ == f.table_size_) &&
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(random_seed_ == f.random_seed_)
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)
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{
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for (std::size_t i = 0; i < raw_table_size_; ++i)
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{
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bit_table_[i] &= f.bit_table_[i];
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}
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}
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return *this;
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}
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inline bloom_filter& operator |= (const bloom_filter& f)
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{
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/* union */
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if (
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(salt_count_ == f.salt_count_) &&
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(table_size_ == f.table_size_) &&
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(random_seed_ == f.random_seed_)
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)
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{
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for (std::size_t i = 0; i < raw_table_size_; ++i)
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{
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bit_table_[i] |= f.bit_table_[i];
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}
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}
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return *this;
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}
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inline bloom_filter& operator ^= (const bloom_filter& f)
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{
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/* difference */
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if (
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(salt_count_ == f.salt_count_) &&
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(table_size_ == f.table_size_) &&
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(random_seed_ == f.random_seed_)
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)
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{
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for (std::size_t i = 0; i < raw_table_size_; ++i)
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{
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bit_table_[i] ^= f.bit_table_[i];
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}
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}
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return *this;
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}
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inline const cell_type* table() const
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{
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return bit_table_.data();
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}
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inline std::size_t hash_count()
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{
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return salt_.size();
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}
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protected:
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inline virtual void compute_indices(const bloom_type& hash, std::size_t& bit_index, std::size_t& bit) const
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{
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bit_index = hash % table_size_;
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bit = bit_index % bits_per_char;
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}
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void generate_unique_salt()
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{
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/*
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Note:
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A distinct hash function need not be implementation-wise
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distinct. In the current implementation "seeding" a common
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hash function with different values seems to be adequate.
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*/
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const unsigned int predef_salt_count = 128;
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static const bloom_type predef_salt[predef_salt_count] =
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{
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0xAAAAAAAA, 0x55555555, 0x33333333, 0xCCCCCCCC,
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0x66666666, 0x99999999, 0xB5B5B5B5, 0x4B4B4B4B,
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0xAA55AA55, 0x55335533, 0x33CC33CC, 0xCC66CC66,
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0x66996699, 0x99B599B5, 0xB54BB54B, 0x4BAA4BAA,
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0xAA33AA33, 0x55CC55CC, 0x33663366, 0xCC99CC99,
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0x66B566B5, 0x994B994B, 0xB5AAB5AA, 0xAAAAAA33,
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0x555555CC, 0x33333366, 0xCCCCCC99, 0x666666B5,
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0x9999994B, 0xB5B5B5AA, 0xFFFFFFFF, 0xFFFF0000,
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0xB823D5EB, 0xC1191CDF, 0xF623AEB3, 0xDB58499F,
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0xC8D42E70, 0xB173F616, 0xA91A5967, 0xDA427D63,
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0xB1E8A2EA, 0xF6C0D155, 0x4909FEA3, 0xA68CC6A7,
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0xC395E782, 0xA26057EB, 0x0CD5DA28, 0x467C5492,
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0xF15E6982, 0x61C6FAD3, 0x9615E352, 0x6E9E355A,
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0x689B563E, 0x0C9831A8, 0x6753C18B, 0xA622689B,
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0x8CA63C47, 0x42CC2884, 0x8E89919B, 0x6EDBD7D3,
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0x15B6796C, 0x1D6FDFE4, 0x63FF9092, 0xE7401432,
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0xEFFE9412, 0xAEAEDF79, 0x9F245A31, 0x83C136FC,
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0xC3DA4A8C, 0xA5112C8C, 0x5271F491, 0x9A948DAB,
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0xCEE59A8D, 0xB5F525AB, 0x59D13217, 0x24E7C331,
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0x697C2103, 0x84B0A460, 0x86156DA9, 0xAEF2AC68,
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0x23243DA5, 0x3F649643, 0x5FA495A8, 0x67710DF8,
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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()] + static_cast<bloom_type>(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);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
inline bloom_type hash_ap(const unsigned char* begin, std::size_t remaining_length, bloom_type hash) const
|
||||
{
|
||||
const unsigned char* itr = begin;
|
||||
unsigned int loop = 0;
|
||||
while (remaining_length >= 8)
|
||||
{
|
||||
const unsigned int& i1 = *(reinterpret_cast<const unsigned int*>(itr)); itr += sizeof(unsigned int);
|
||||
const unsigned int& i2 = *(reinterpret_cast<const unsigned int*>(itr)); itr += sizeof(unsigned int);
|
||||
hash ^= (hash << 7) ^ i1 * (hash >> 3) ^
|
||||
(~((hash << 11) + (i2 ^ (hash >> 5))));
|
||||
remaining_length -= 8;
|
||||
}
|
||||
if (remaining_length)
|
||||
{
|
||||
if (remaining_length >= 4)
|
||||
{
|
||||
const unsigned int& i = *(reinterpret_cast<const unsigned int*>(itr));
|
||||
if (loop & 0x01)
|
||||
hash ^= (hash << 7) ^ i * (hash >> 3);
|
||||
else
|
||||
hash ^= (~((hash << 11) + (i ^ (hash >> 5))));
|
||||
++loop;
|
||||
remaining_length -= 4;
|
||||
itr += sizeof(unsigned int);
|
||||
}
|
||||
if (remaining_length >= 2)
|
||||
{
|
||||
const unsigned short& i = *(reinterpret_cast<const unsigned short*>(itr));
|
||||
if (loop & 0x01)
|
||||
hash ^= (hash << 7) ^ i * (hash >> 3);
|
||||
else
|
||||
hash ^= (~((hash << 11) + (i ^ (hash >> 5))));
|
||||
++loop;
|
||||
remaining_length -= 2;
|
||||
itr += sizeof(unsigned short);
|
||||
}
|
||||
if (remaining_length)
|
||||
{
|
||||
hash += ((*itr) ^ (hash * 0xA5A5A5A5)) + loop;
|
||||
}
|
||||
}
|
||||
return hash;
|
||||
}
|
||||
|
||||
public:
|
||||
std::vector<bloom_type> salt_;
|
||||
std::vector<unsigned char> bit_table_;
|
||||
unsigned int salt_count_;
|
||||
unsigned long long int table_size_;
|
||||
unsigned long long int raw_table_size_;
|
||||
unsigned long long int projected_element_count_;
|
||||
unsigned int inserted_element_count_;
|
||||
unsigned long long int 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;
|
||||
}
|
||||
|
||||
|
||||
} // namespace fc
|
||||
|
||||
|
||||
FC_REFLECT( fc::bloom_filter, (salt_)(bit_table_)(salt_count_)(table_size_)(raw_table_size_)(projected_element_count_)(inserted_element_count_)(random_seed_)(desired_false_positive_probability_) )
|
||||
FC_REFLECT( fc::bloom_parameters::optimal_parameters_t, (number_of_hashes)(table_size) )
|
||||
FC_REFLECT( fc::bloom_parameters, (minimum_size)(maximum_size)(minimum_number_of_hashes)(maximum_number_of_hashes)(projected_element_count)(false_positive_probability)(random_seed)(optimal_parameters) )
|
||||
|
||||
/*
|
||||
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.
|
||||
*/
|
||||
Loading…
Reference in a new issue