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Diffstat (limited to 'src/util/peer.c')
| -rw-r--r-- | src/util/peer.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/src/util/peer.c b/src/util/peer.c new file mode 100644 index 0000000..2444cb9 --- /dev/null +++ b/src/util/peer.c @@ -0,0 +1,241 @@ +/* + 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" + +#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__) + + +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) + return 0; + GNUNET_assert (e->rc > 0); + return e->pid; +} + + +/** + * 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 */ |