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Diffstat (limited to 'src/consensus/ibf.h')
-rw-r--r-- | src/consensus/ibf.h | 224 |
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diff --git a/src/consensus/ibf.h b/src/consensus/ibf.h deleted file mode 100644 index 2bf3ef7c7..000000000 --- a/src/consensus/ibf.h +++ /dev/null | |||
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1 | /* | ||
2 | This file is part of GNUnet | ||
3 | (C) 2012 Christian Grothoff (and other contributing authors) | ||
4 | |||
5 | GNUnet is free software; you can redistribute it and/or modify | ||
6 | it under the terms of the GNU General Public License as published | ||
7 | by the Free Software Foundation; either version 2, or (at your | ||
8 | option) any later version. | ||
9 | |||
10 | GNUnet is distributed in the hope that it will be useful, but | ||
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
13 | General Public License for more details. | ||
14 | |||
15 | You should have received a copy of the GNU General Public License | ||
16 | along with GNUnet; see the file COPYING. If not, write to the | ||
17 | Free Software Foundation, Inc., 59 Temple Place - Suite 330, | ||
18 | Boston, MA 02111-1307, USA. | ||
19 | */ | ||
20 | |||
21 | /** | ||
22 | * @file consensus/ibf.h | ||
23 | * @brief invertible bloom filter | ||
24 | * @author Florian Dold | ||
25 | */ | ||
26 | |||
27 | #ifndef GNUNET_CONSENSUS_IBF_H | ||
28 | #define GNUNET_CONSENSUS_IBF_H | ||
29 | |||
30 | #include "platform.h" | ||
31 | #include "gnunet_common.h" | ||
32 | #include "gnunet_util_lib.h" | ||
33 | |||
34 | #ifdef __cplusplus | ||
35 | extern "C" | ||
36 | { | ||
37 | #if 0 /* keep Emacsens' auto-indent happy */ | ||
38 | } | ||
39 | #endif | ||
40 | #endif | ||
41 | |||
42 | |||
43 | struct IBF_Key | ||
44 | { | ||
45 | uint64_t key_val; | ||
46 | }; | ||
47 | |||
48 | struct IBF_KeyHash | ||
49 | { | ||
50 | uint32_t key_hash_val; | ||
51 | }; | ||
52 | |||
53 | struct IBF_Count | ||
54 | { | ||
55 | int8_t count_val; | ||
56 | }; | ||
57 | |||
58 | /** | ||
59 | * Size of one ibf bucket in bytes | ||
60 | */ | ||
61 | #define IBF_BUCKET_SIZE (sizeof (struct IBF_Count) + sizeof (struct IBF_Key) + \ | ||
62 | sizeof (struct IBF_KeyHash)) | ||
63 | |||
64 | /** | ||
65 | * Invertible bloom filter (IBF). | ||
66 | * | ||
67 | * An IBF is a counting bloom filter that has the ability to restore | ||
68 | * the hashes of its stored elements with high probability. | ||
69 | */ | ||
70 | struct InvertibleBloomFilter | ||
71 | { | ||
72 | /** | ||
73 | * How many cells does this IBF have? | ||
74 | */ | ||
75 | uint32_t size; | ||
76 | |||
77 | /** | ||
78 | * In how many cells do we hash one element? | ||
79 | * Usually 4 or 3. | ||
80 | */ | ||
81 | uint8_t hash_num; | ||
82 | |||
83 | /** | ||
84 | * Xor sums of the elements' keys, used to identify the elements. | ||
85 | * Array of 'size' elements. | ||
86 | */ | ||
87 | struct IBF_Key *key_sum; | ||
88 | |||
89 | /** | ||
90 | * Xor sums of the hashes of the keys of inserted elements. | ||
91 | * Array of 'size' elements. | ||
92 | */ | ||
93 | struct IBF_KeyHash *key_hash_sum; | ||
94 | |||
95 | /** | ||
96 | * How many times has a bucket been hit? | ||
97 | * Can be negative, as a result of IBF subtraction. | ||
98 | * Array of 'size' elements. | ||
99 | */ | ||
100 | struct IBF_Count *count; | ||
101 | }; | ||
102 | |||
103 | |||
104 | /** | ||
105 | * Write buckets from an ibf to a buffer. | ||
106 | * Exactly (IBF_BUCKET_SIZE*ibf->size) bytes are written to buf. | ||
107 | * | ||
108 | * @param ibf the ibf to write | ||
109 | * @param start with which bucket to start | ||
110 | * @param count how many buckets to write | ||
111 | * @param buf buffer to write the data to | ||
112 | */ | ||
113 | void | ||
114 | ibf_write_slice (const struct InvertibleBloomFilter *ibf, uint32_t start, uint32_t count, void *buf); | ||
115 | |||
116 | |||
117 | /** | ||
118 | * Read buckets from a buffer into an ibf. | ||
119 | * | ||
120 | * @param buf pointer to the buffer to read from | ||
121 | * @param start which bucket to start at | ||
122 | * @param count how many buckets to read | ||
123 | * @param ibf the ibf to read from | ||
124 | */ | ||
125 | void | ||
126 | ibf_read_slice (const void *buf, uint32_t start, uint32_t count, struct InvertibleBloomFilter *ibf); | ||
127 | |||
128 | |||
129 | /** | ||
130 | * Create a key from a hashcode. | ||
131 | * | ||
132 | * @param hash the hashcode | ||
133 | * @return a key | ||
134 | */ | ||
135 | struct IBF_Key | ||
136 | ibf_key_from_hashcode (const struct GNUNET_HashCode *hash); | ||
137 | |||
138 | |||
139 | /** | ||
140 | * Create a hashcode from a key, by replicating the key | ||
141 | * until the hascode is filled | ||
142 | * | ||
143 | * @param key the key | ||
144 | * @param dst hashcode to store the result in | ||
145 | */ | ||
146 | void | ||
147 | ibf_hashcode_from_key (struct IBF_Key key, struct GNUNET_HashCode *dst); | ||
148 | |||
149 | |||
150 | /** | ||
151 | * Create an invertible bloom filter. | ||
152 | * | ||
153 | * @param size number of IBF buckets | ||
154 | * @param hash_num number of buckets one element is hashed in, usually 3 or 4 | ||
155 | * @return the newly created invertible bloom filter | ||
156 | */ | ||
157 | struct InvertibleBloomFilter * | ||
158 | ibf_create (uint32_t size, uint8_t hash_num); | ||
159 | |||
160 | |||
161 | /** | ||
162 | * Insert an element into an IBF. | ||
163 | * | ||
164 | * @param ibf the IBF | ||
165 | * @param key the element's hash code | ||
166 | */ | ||
167 | void | ||
168 | ibf_insert (struct InvertibleBloomFilter *ibf, struct IBF_Key key); | ||
169 | |||
170 | |||
171 | /** | ||
172 | * Subtract ibf2 from ibf1, storing the result in ibf1. | ||
173 | * The two IBF's must have the same parameters size and hash_num. | ||
174 | * | ||
175 | * @param ibf1 IBF that is subtracted from | ||
176 | * @param ibf2 IBF that will be subtracted from ibf1 | ||
177 | */ | ||
178 | void | ||
179 | ibf_subtract (struct InvertibleBloomFilter *ibf1, const struct InvertibleBloomFilter *ibf2); | ||
180 | |||
181 | |||
182 | /** | ||
183 | * Decode and remove an element from the IBF, if possible. | ||
184 | * | ||
185 | * @param ibf the invertible bloom filter to decode | ||
186 | * @param ret_side sign of the cell's count where the decoded element came from. | ||
187 | * A negative sign indicates that the element was recovered | ||
188 | * resides in an IBF that was previously subtracted from. | ||
189 | * @param ret_id receives the hash code of the decoded element, if successful | ||
190 | * @return GNUNET_YES if decoding an element was successful, | ||
191 | * GNUNET_NO if the IBF is empty, | ||
192 | * GNUNET_SYSERR if the decoding has failed | ||
193 | */ | ||
194 | int | ||
195 | ibf_decode (struct InvertibleBloomFilter *ibf, int *ret_side, struct IBF_Key *ret_id); | ||
196 | |||
197 | |||
198 | /** | ||
199 | * Create a copy of an IBF, the copy has to be destroyed properly. | ||
200 | * | ||
201 | * @param ibf the IBF to copy | ||
202 | */ | ||
203 | struct InvertibleBloomFilter * | ||
204 | ibf_dup (const struct InvertibleBloomFilter *ibf); | ||
205 | |||
206 | /** | ||
207 | * Destroy all resources associated with the invertible bloom filter. | ||
208 | * No more ibf_*-functions may be called on ibf after calling destroy. | ||
209 | * | ||
210 | * @param ibf the intertible bloom filter to destroy | ||
211 | */ | ||
212 | void | ||
213 | ibf_destroy (struct InvertibleBloomFilter *ibf); | ||
214 | |||
215 | |||
216 | #if 0 /* keep Emacsens' auto-indent happy */ | ||
217 | { | ||
218 | #endif | ||
219 | #ifdef __cplusplus | ||
220 | } | ||
221 | #endif | ||
222 | |||
223 | #endif | ||
224 | |||