aboutsummaryrefslogtreecommitdiff
path: root/src/set/gnunet-service-set_union_strata_estimator.c
blob: eee0ec8d3509cc29aa5c5ec0aeee5f613edb449f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
/*
      This file is part of GNUnet
      Copyright (C) 2012 GNUnet e.V.

      GNUnet is free software: you can redistribute it and/or modify it
      under the terms of the GNU Affero General Public License as published
      by the Free Software Foundation, either version 3 of the License,
      or (at your option) any later version.

      GNUnet is distributed in the hope that it will be useful, but
      WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      Affero General Public License for more details.

      You should have received a copy of the GNU Affero General Public License
      along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
/**
 * @file set/gnunet-service-set_union_strata_estimator.c
 * @brief invertible bloom filter
 * @author Florian Dold
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "ibf.h"
#include "gnunet-service-set_union_strata_estimator.h"


/**
 * Should we try compressing the strata estimator? This will
 * break compatibility with the 0.10.1-network.
 */
#define FAIL_10_1_COMPATIBILTIY 1


/**
 * Write the given strata estimator to the buffer.
 *
 * @param se strata estimator to serialize
 * @param[out] buf buffer to write to, must be of appropriate size
 * @return number of bytes written to @a buf
 */
size_t
strata_estimator_write (const struct StrataEstimator *se,
                        void *buf)
{
  char *sbuf = buf;
  unsigned int i;
  size_t osize;

  GNUNET_assert (NULL != se);
  for (i = 0; i < se->strata_count; i++)
  {
    ibf_write_slice (se->strata[i],
                     0,
                     se->ibf_size,
                     &sbuf[se->ibf_size * IBF_BUCKET_SIZE * i]);
  }
  osize = se->ibf_size * IBF_BUCKET_SIZE * se->strata_count;
#if FAIL_10_1_COMPATIBILTIY
  {
    char *cbuf;
    size_t nsize;

    if (GNUNET_YES ==
        GNUNET_try_compression (buf,
                                osize,
                                &cbuf,
                                &nsize))
    {
      GNUNET_memcpy (buf, cbuf, nsize);
      osize = nsize;
      GNUNET_free (cbuf);
    }
  }
#endif
  return osize;
}


/**
 * Read strata from the buffer into the given strata
 * estimator.  The strata estimator must already be allocated.
 *
 * @param buf buffer to read from
 * @param buf_len number of bytes in @a buf
 * @param is_compressed is the data compressed?
 * @param[out] se strata estimator to write to
 * @return #GNUNET_OK on success
 */
int
strata_estimator_read (const void *buf,
                       size_t buf_len,
                       int is_compressed,
                       struct StrataEstimator *se)
{
  unsigned int i;
  size_t osize;
  char *dbuf;

  dbuf = NULL;
  if (GNUNET_YES == is_compressed)
  {
    osize = se->ibf_size * IBF_BUCKET_SIZE * se->strata_count;
    dbuf = GNUNET_decompress (buf,
                              buf_len,
                              osize);
    if (NULL == dbuf)
    {
      GNUNET_break_op (0);    /* bad compressed input data */
      return GNUNET_SYSERR;
    }
    buf = dbuf;
    buf_len = osize;
  }

  if (buf_len != se->strata_count * se->ibf_size * IBF_BUCKET_SIZE)
  {
    GNUNET_break (0);  /* very odd error */
    GNUNET_free_non_null (dbuf);
    return GNUNET_SYSERR;
  }

  for (i = 0; i < se->strata_count; i++)
  {
    ibf_read_slice (buf, 0, se->ibf_size, se->strata[i]);
    buf += se->ibf_size * IBF_BUCKET_SIZE;
  }
  GNUNET_free_non_null (dbuf);
  return GNUNET_OK;
}


/**
 * Add a key to the strata estimator.
 *
 * @param se strata estimator to add the key to
 * @param key key to add
 */
void
strata_estimator_insert (struct StrataEstimator *se,
                         struct IBF_Key key)
{
  uint64_t v;
  unsigned int i;

  v = key.key_val;
  /* count trailing '1'-bits of v */
  for (i = 0; v & 1; v >>= 1, i++)
    /* empty */;
  ibf_insert (se->strata[i], key);
}


/**
 * Remove a key from the strata estimator.
 *
 * @param se strata estimator to remove the key from
 * @param key key to remove
 */
void
strata_estimator_remove (struct StrataEstimator *se,
                         struct IBF_Key key)
{
  uint64_t v;
  unsigned int i;

  v = key.key_val;
  /* count trailing '1'-bits of v */
  for (i = 0; v & 1; v >>= 1, i++)
    /* empty */;
  ibf_remove (se->strata[i], key);
}


/**
 * Create a new strata estimator with the given parameters.
 *
 * @param strata_count number of stratas, that is, number of ibfs in the estimator
 * @param ibf_size size of each ibf stratum
 * @param ibf_hashnum hashnum parameter of each ibf
 * @return a freshly allocated, empty strata estimator, NULL on error
 */
struct StrataEstimator *
strata_estimator_create (unsigned int strata_count,
                         uint32_t ibf_size,
                         uint8_t ibf_hashnum)
{
  struct StrataEstimator *se;
  unsigned int i;
  unsigned int j;

  se = GNUNET_new (struct StrataEstimator);
  se->strata_count = strata_count;
  se->ibf_size = ibf_size;
  se->strata = GNUNET_new_array (strata_count,
                                 struct InvertibleBloomFilter *);
  for (i = 0; i < strata_count; i++)
  {
    se->strata[i] = ibf_create (ibf_size, ibf_hashnum);
    if (NULL == se->strata[i])
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Failed to allocate memory for strata estimator\n");
      for (j = 0; j < i; j++)
        ibf_destroy (se->strata[i]);
      GNUNET_free (se);
      return NULL;
    }
  }
  return se;
}


/**
 * Estimate set difference with two strata estimators,
 * i.e. arrays of IBFs.
 * Does not not modify its arguments.
 *
 * @param se1 first strata estimator
 * @param se2 second strata estimator
 * @return the estimated difference
 */
unsigned int
strata_estimator_difference (const struct StrataEstimator *se1,
                             const struct StrataEstimator *se2)
{
  unsigned int count;

  GNUNET_assert (se1->strata_count == se2->strata_count);
  count = 0;
  for (int i = se1->strata_count - 1; i >= 0; i--)
  {
    struct InvertibleBloomFilter *diff;
    /* number of keys decoded from the ibf */

    /* FIXME: implement this without always allocating new IBFs */
    diff = ibf_dup (se1->strata[i]);
    ibf_subtract (diff, se2->strata[i]);
    for (int ibf_count = 0; GNUNET_YES; ibf_count++)
    {
      int more;

      more = ibf_decode (diff, NULL, NULL);
      if (GNUNET_NO == more)
      {
        count += ibf_count;
        break;
      }
      /* Estimate if decoding fails or would not terminate */
      if ((GNUNET_SYSERR == more) || (ibf_count > diff->size))
      {
        ibf_destroy (diff);
        return count * (1 << (i + 1));
      }
    }
    ibf_destroy (diff);
  }
  return count;
}


/**
 * Make a copy of a strata estimator.
 *
 * @param se the strata estimator to copy
 * @return the copy
 */
struct StrataEstimator *
strata_estimator_dup (struct StrataEstimator *se)
{
  struct StrataEstimator *c;
  unsigned int i;

  c = GNUNET_new (struct StrataEstimator);
  c->strata_count = se->strata_count;
  c->ibf_size = se->ibf_size;
  c->strata = GNUNET_new_array (se->strata_count,
                                struct InvertibleBloomFilter *);
  for (i = 0; i < se->strata_count; i++)
    c->strata[i] = ibf_dup (se->strata[i]);
  return c;
}


/**
 * Destroy a strata estimator, free all of its resources.
 *
 * @param se strata estimator to destroy.
 */
void
strata_estimator_destroy (struct StrataEstimator *se)
{
  unsigned int i;

  for (i = 0; i < se->strata_count; i++)
    ibf_destroy (se->strata[i]);
  GNUNET_free (se->strata);
  GNUNET_free (se);
}