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1 files changed, 212 insertions, 0 deletions

diff --git a/src/util/peer.c b/src/util/peer.c
new file mode 100644
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--- /dev/null
+++ b/src/util/peer.c
@@ -0,0 +1,212 @@
+/*
+      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;
+
+
+/**
+ * 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;
+
+  if (pid == NULL)
+    return 0;
+  if (NULL == map)
+    map = GNUNET_CONTAINER_multihashmap_create (32);
+  e = GNUNET_CONTAINER_multihashmap_get (map,
+                                         &pid->hashPubKey);
+  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_CONTAINER_multihashmap_put (map,
+                                     &pid->hashPubKey,
+                                     &table[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];
+      GNUNET_assert (id < size);
+      GNUNET_assert (table[id].rc > 0);
+      table[id].rc--;
+      if (table[id].rc == 0)
+        {
+          GNUNET_CONTAINER_multihashmap_remove (map,
+                                                &table[id].id.hashPubKey,
+                                                &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 (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_CONTAINER_multihashmap_remove (map,
+                                            &table[id].id.hashPubKey,
+                                            &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 (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 */