mirror of
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73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
/*
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*
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* (C) 2013-25 - ntop.org
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#ifndef _BLOOM_H_
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#define _BLOOM_H_
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/**
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* @file Bloom.h
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*
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* @brief Bloom class implementation.
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* @details A Bloom instance represents a bitmask that can be used as bloom
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* filter for strings.
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*/
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#include "ntop_includes.h"
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class Bloom {
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private:
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Bitmask *bitmask; /**< The bitmask */
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u_int32_t num_bloom_bits; /**< The bitmask size */
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u_int32_t mask; /**< The mask to be used for the hash */
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u_int32_t ntophash(char *str);
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public:
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Bloom(u_int32_t _num_bloom_bits);
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~Bloom();
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/**
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* Adds a new value to the bloom setting the relative bit in the bitmask.
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* @param str The value to set.
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*/
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inline void setBit(char *str) { bitmask->set_bit(ntophash(str)); }
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inline void setBit(u_int32_t value) { bitmask->set_bit(value & mask); }
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/**
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* Removes a value to the bloom unsetting the relative bit in the bitmask.
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* This is not the best thing that we could do with a bloom even though
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* if the user is aware of the limitation it can be used safely
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* @param str The value to set.
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*/
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inline void unsetBit(char *str) { bitmask->clear_bit(ntophash(str)); }
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inline void unsetBit(u_int32_t value) { bitmask->clear_bit(value & mask); }
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/**
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* Checks if a value is set in the bloom filter.
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* @param str The value to check.
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* @return True is the hash for the provided value is set, false otherwise.
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*/
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inline bool isSetBit(char *str) {
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return (bitmask->is_set_bit(ntophash(str)));
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}
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};
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#endif /* _BLOOM_H_ */
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