1 files changed, 242 insertions, 0 deletions

diff --git a/src/lib/util/peer.c b/src/lib/util/peer.c
new file mode 100644
index 000000000..e5c15b098
--- /dev/null
+++ b/src/lib/util/peer.c
@@ -0,0 +1,242 @@
+/*
+      This file is part of GNUnet
+     Copyright (C) 2006, 2008, 2009 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 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_util_lib.h"
+
+#define LOG(kind, ...) GNUNET_log_from (kind, "util-peer", __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;
+
+/**
+ * Peermap of PeerIdentities to "struct PeerEntry"
+ * (for fast lookup).  NULL until the library
+ * is actually being used.
+ */
+static struct GNUNET_CONTAINER_MultiPeerMap *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;
+
+  if (NULL == pid)
+    return 0;
+  if (NULL == map)
+    return 0;
+  e = GNUNET_CONTAINER_multipeermap_get (map, pid);
+  if (NULL == e)
+    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;
+
+  if (NULL == pid)
+    return 0;
+  if (NULL == map)
+    map = GNUNET_CONTAINER_multipeermap_create (32, GNUNET_YES);
+  e = GNUNET_CONTAINER_multipeermap_get (map, pid);
+  if (NULL != e)
+  {
+    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 (unsigned int i = ret; i < size; i++)
+    {
+      table[i] = GNUNET_new (struct PeerEntry);
+      table[i]->pid = i + 1;
+    }
+  }
+  if (0 == ret)
+  {
+    memset (&table[0]->id, 0, sizeof(struct GNUNET_PeerIdentity));
+    table[0]->pid = 0;
+    table[0]->rc = 1;
+    ret = 1;
+  }
+  GNUNET_assert (ret < size);
+  GNUNET_assert (0 == table[ret]->rc);
+  free_list_start = table[ret]->pid;
+  table[ret]->id = *pid;
+  table[ret]->rc = 1;
+  table[ret]->pid = ret;
+  GNUNET_break (GNUNET_OK ==
+                GNUNET_CONTAINER_multipeermap_put (map,
+                                                   &table[ret]->id,
+                                                   table[ret],
+                                                   GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+  return ret;
+}
+
+
+void
+GNUNET_PEER_decrement_rcs (const GNUNET_PEER_Id *ids, unsigned int count)
+{
+  int i;
+  GNUNET_PEER_Id id;
+
+  if (0 == count)
+    return;
+  for (i = count - 1; i >= 0; i--)
+  {
+    id = ids[i];
+    if (0 == id)
+      continue;
+    GNUNET_assert (id < size);
+    GNUNET_assert (table[id]->rc > 0);
+    table[id]->rc--;
+    if (0 == table[id]->rc)
+    {
+      GNUNET_break (GNUNET_OK ==
+                    GNUNET_CONTAINER_multipeermap_remove (map,
+                                                          &table[id]->id,
+                                                          table[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 (0 == id)
+    return;
+  GNUNET_assert (id < size);
+  GNUNET_assert (table[id]->rc > 0);
+  GNUNET_assert ((delta >= 0) ||
+                 (table[id]->rc >= (unsigned int) (-delta)));
+  table[id]->rc += delta;
+  if (0 == table[id]->rc)
+  {
+    GNUNET_break (GNUNET_OK ==
+                  GNUNET_CONTAINER_multipeermap_remove (map,
+                                                        &table[id]->id,
+                                                        table[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 (0 == id)
+  {
+    memset (pid, 0, sizeof(struct GNUNET_PeerIdentity));
+    return;
+  }
+  GNUNET_assert (id < size);
+  GNUNET_assert (table[id]->rc > 0);
+  *pid = table[id]->id;
+}
+
+
+const struct GNUNET_PeerIdentity *
+GNUNET_PEER_resolve2 (GNUNET_PEER_Id id)
+{
+  GNUNET_assert (id < size);
+  GNUNET_assert (table[id]->rc > 0);
+  return &table[id]->id;
+}
+
+
+/* end of peer.c */