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
|
/*
This file is part of GNUnet
(C) 2006, 2008, 2009 Christian Grothoff (and other contributing authors)
GNUnet is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 2, 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNUnet; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
/**
* @file util/peer.c
* @brief peer-ID table that assigns integer IDs to peer-IDs to save memory
* @author Christian Grothoff
*/
#include "platform.h"
#include "gnunet_peer_lib.h"
struct PeerEntry
{
/**
* The identifier itself
*/
struct GNUNET_PeerIdentity id;
/**
* Short version of the identifier; if the RC==0, then index of next
* free slot in table, otherwise equal to this slot in the table.
*/
GNUNET_PEER_Id pid;
/**
* Reference counter, 0 if this slot is not used.
*/
unsigned int rc;
};
/**
* Table with our interned peer IDs.
*/
static struct PeerEntry *table;
/**
* Hashmap of PeerIdentities to "struct PeerEntry"
* (for fast lookup). NULL until the library
* is actually being used.
*/
static struct GNUNET_CONTAINER_MultiHashMap *map;
/**
* Size of the "table".
*/
static unsigned int size;
/**
* Index of the beginning of the free list in the table; set to "size"
* if no slots are free in the table.
*/
static unsigned int free_list_start;
/**
* Search for a peer identity. The reference counter is not changed.
*
* @param pid identity to find
* @return the interned identity or 0.
*/
GNUNET_PEER_Id
GNUNET_PEER_search (const struct GNUNET_PeerIdentity *pid)
{
struct PeerEntry *e;
long off;
if (pid == NULL)
return 0;
if (NULL == map)
return 0;
off = (long) GNUNET_CONTAINER_multihashmap_get (map, &pid->hashPubKey);
e = (off == 0) ? NULL : &table[off];
if (e != NULL)
{
GNUNET_assert (e->rc > 0);
return e->pid;
}
else
{
return 0;
}
}
/**
* Intern an peer identity. If the identity is already known, its
* reference counter will be increased by one.
*
* @param pid identity to intern
* @return the interned identity.
*/
GNUNET_PEER_Id
GNUNET_PEER_intern (const struct GNUNET_PeerIdentity *pid)
{
GNUNET_PEER_Id ret;
struct PeerEntry *e;
unsigned int i;
long off;
if (pid == NULL)
return 0;
if (NULL == map)
map = GNUNET_CONTAINER_multihashmap_create (32);
off = (long) GNUNET_CONTAINER_multihashmap_get (map, &pid->hashPubKey);
e = (off == 0) ? NULL : &table[off];
if (e != NULL)
{
GNUNET_assert (e->rc > 0);
e->rc++;
return e->pid;
}
ret = free_list_start;
if (ret == size)
{
GNUNET_array_grow (table, size, size + 16);
for (i = ret; i < size; i++)
table[i].pid = i + 1;
}
if (ret == 0)
{
table[0].pid = 0;
table[0].rc = 1;
ret = 1;
}
GNUNET_assert (ret < size);
GNUNET_assert (table[ret].rc == 0);
free_list_start = table[ret].pid;
table[ret].id = *pid;
table[ret].rc = 1;
table[ret].pid = ret;
GNUNET_break (GNUNET_OK ==
GNUNET_CONTAINER_multihashmap_put (map,
&pid->hashPubKey,
(void *) (long) ret,
GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
return ret;
}
/**
* Decrement multiple RCs of peer identities by one.
*
* @param ids array of PIDs to decrement the RCs of
* @param count size of the ids array
*/
void
GNUNET_PEER_decrement_rcs (const GNUNET_PEER_Id * ids, unsigned int count)
{
int i;
GNUNET_PEER_Id id;
if (count == 0)
return;
for (i = count - 1; i >= 0; i--)
{
id = ids[i];
if (id == 0)
continue;
GNUNET_assert (id < size);
GNUNET_assert (table[id].rc > 0);
table[id].rc--;
if (table[id].rc == 0)
{
GNUNET_break (GNUNET_OK ==
GNUNET_CONTAINER_multihashmap_remove (map,
&table[id].id.hashPubKey,
(void*) (long) id));
table[id].pid = free_list_start;
free_list_start = id;
}
}
}
/**
* Change the reference counter of an interned PID.
*
* @param id identity to change the RC of
* @param delta how much to change the RC
*/
void
GNUNET_PEER_change_rc (GNUNET_PEER_Id id, int delta)
{
if (id == 0)
return;
GNUNET_assert (id < size);
GNUNET_assert (table[id].rc > 0);
GNUNET_assert ((delta >= 0) || (table[id].rc >= -delta));
table[id].rc += delta;
if (table[id].rc == 0)
{
GNUNET_break (GNUNET_OK ==
GNUNET_CONTAINER_multihashmap_remove (map,
&table[id].id.hashPubKey,
(void*) (long) id));
table[id].pid = free_list_start;
free_list_start = id;
}
}
/**
* Convert an interned PID to a normal peer identity.
*
* @param id interned PID to convert
* @param pid where to write the normal peer identity
*/
void
GNUNET_PEER_resolve (GNUNET_PEER_Id id, struct GNUNET_PeerIdentity *pid)
{
if (id == 0)
{
memset (pid, 0, sizeof (struct GNUNET_PeerIdentity));
GNUNET_break (0);
return;
}
GNUNET_assert (id < size);
GNUNET_assert (table[id].rc > 0);
*pid = table[id].id;
}
/* end of peer.c */
|
