/src/ntopng/include/Bloom.h
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1 | | /* |
2 | | * |
3 | | * (C) 2013-25 - ntop.org |
4 | | * |
5 | | * |
6 | | * This program is free software; you can redistribute it and/or modify |
7 | | * it under the terms of the GNU General Public License as published by |
8 | | * the Free Software Foundation; either version 3 of the License, or |
9 | | * (at your option) any later version. |
10 | | * |
11 | | * This program is distributed in the hope that it will be useful, |
12 | | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | | * GNU General Public License for more details. |
15 | | * |
16 | | * You should have received a copy of the GNU General Public License |
17 | | * along with this program; if not, write to the Free Software Foundation, |
18 | | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
19 | | * |
20 | | */ |
21 | | |
22 | | #ifndef _BLOOM_H_ |
23 | | #define _BLOOM_H_ |
24 | | |
25 | | /** |
26 | | * @file Bloom.h |
27 | | * |
28 | | * @brief Bloom class implementation. |
29 | | * @details A Bloom instance represents a bitmask that can be used as bloom |
30 | | * filter for strings. |
31 | | */ |
32 | | |
33 | | #include "ntop_includes.h" |
34 | | |
35 | | class Bloom { |
36 | | private: |
37 | | Bitmask *bitmask; /**< The bitmask */ |
38 | | u_int32_t num_bloom_bits; /**< The bitmask size */ |
39 | | u_int32_t mask; /**< The mask to be used for the hash */ |
40 | | |
41 | | u_int32_t ntophash(char *str); |
42 | | |
43 | | public: |
44 | | Bloom(u_int32_t _num_bloom_bits); |
45 | | ~Bloom(); |
46 | | |
47 | | /** |
48 | | * Adds a new value to the bloom setting the relative bit in the bitmask. |
49 | | * @param str The value to set. |
50 | | */ |
51 | 0 | inline void setBit(char *str) { bitmask->set_bit(ntophash(str)); } |
52 | 0 | inline void setBit(u_int32_t value) { bitmask->set_bit(value & mask); } |
53 | | |
54 | | /** |
55 | | * Removes a value to the bloom unsetting the relative bit in the bitmask. |
56 | | * This is not the best thing that we could do with a bloom even though |
57 | | * if the user is aware of the limitation it can be used safely |
58 | | * @param str The value to set. |
59 | | */ |
60 | 0 | inline void unsetBit(char *str) { bitmask->clear_bit(ntophash(str)); } |
61 | 0 | inline void unsetBit(u_int32_t value) { bitmask->clear_bit(value & mask); } |
62 | | |
63 | | /** |
64 | | * Checks if a value is set in the bloom filter. |
65 | | * @param str The value to check. |
66 | | * @return True is the hash for the provided value is set, false otherwise. |
67 | | */ |
68 | 4.18k | inline bool isSetBit(char *str) { |
69 | 4.18k | return (bitmask->is_set_bit(ntophash(str))); |
70 | 4.18k | } |
71 | | }; |
72 | | |
73 | | #endif /* _BLOOM_H_ */ |