added helper for handling the "view" in rps

Signed-off-by: Julius Bünger <buenger@mytum.de>

1 files changed, 256 insertions, 0 deletions

diff --git a/src/rps/gnunet-service-rps_view.c b/src/rps/gnunet-service-rps_view.c
new file mode 100644
index 000000000..2cf0287bb
--- /dev/null
+++ b/src/rps/gnunet-service-rps_view.c
@@ -0,0 +1,256 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C)
+
+     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 3, 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 rps/gnunet-service-rps_view.c
+ * @brief wrapper around the "local view"
+ * @author Julius Bünger
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet-service-rps_view.h"
+#include <inttypes.h>
+
+
+/**
+ * Array containing the peers
+ */
+static struct GNUNET_PeerIdentity *array;
+
+/**
+ * (Maximum) length of the view
+ */
+static uint32_t length;
+
+/**
+ * Multipeermap containing the peers
+ */
+static struct GNUNET_CONTAINER_MultiPeerMap *mpm;
+
+
+/**
+ * Create an empty view.
+ *
+ * @param len the maximum length for the view
+ */
+void
+View_create (uint32_t len)
+{
+  length = len;
+  array = GNUNET_new_array (len, struct GNUNET_PeerIdentity);
+  mpm = GNUNET_CONTAINER_multipeermap_create (len, GNUNET_NO); /* might even be
+                                                                * set to _YES */
+}
+
+/**
+ * Change length of view
+ *
+ * @param len the (maximum) length for the view
+ */
+void
+View_change_len (uint32_t len)
+{
+  uint32_t i;
+  uint32_t *index;
+
+  if (GNUNET_CONTAINER_multipeermap_size (mpm) < len)
+  { /* Simply shrink */
+    /* We might simply clear and free the left over space */
+    GNUNET_array_grow (array, length, len);
+  }
+  else /* We have to remove elements */
+  {
+    /* TODO find a way to preserve indices */
+    for (i = 0; i < len; i++)
+    {
+      index = GNUNET_CONTAINER_multipeermap_get (mpm, &array[i]);
+      GNUNET_assert (NULL != index);
+      GNUNET_free (index);
+    }
+    GNUNET_array_grow (array, length, len);
+    GNUNET_CONTAINER_multipeermap_destroy (mpm);
+    mpm = GNUNET_CONTAINER_multipeermap_create (len, GNUNET_NO);
+    for (i = 0; i < len; i++)
+    {
+      index = GNUNET_new (uint32_t);
+      *index = i;
+      GNUNET_CONTAINER_multipeermap_put (mpm, &array[i], index,
+          GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST);
+    }
+  }
+  GNUNET_assert (length == len);
+}
+
+/**
+ * Get the view as an array
+ *
+ * @return the view in array representation
+ */
+const struct GNUNET_PeerIdentity *
+View_get_as_array ()
+{
+  return array;
+}
+
+/**
+ * Get the size of the view
+ *
+ * @return current number of actually contained peers
+ */
+unsigned int
+View_size ()
+{
+  return GNUNET_CONTAINER_multipeermap_size (mpm);
+}
+
+/**
+ * Insert peer into the view
+ *
+ * @param peer the peer to insert
+ *
+ * @return GNUNET_OK if peer was actually inserted
+ *         GNUNET_NO if peer was not inserted
+ */
+int
+View_put (const struct GNUNET_PeerIdentity *peer)
+{
+  uint32_t *index;
+
+  if ((length <= View_size ()) || /* If array is 'full' */
+      (GNUNET_YES == View_contains_peer (peer)))
+  {
+    return GNUNET_NO;
+  }
+  else
+  {
+    index = GNUNET_new (uint32_t);
+    *index = (uint32_t) View_size ();
+    array[*index] = *peer;
+    GNUNET_CONTAINER_multipeermap_put (mpm, peer, index,
+        GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST);
+    return GNUNET_OK;
+  }
+}
+
+/**
+ * Check whether view contains a peer
+ *
+ * @param peer the peer to check for
+ *
+ * @return GNUNET_OK if view contains peer
+ *         GNUNET_NO otherwise
+ */
+int
+View_contains_peer (const struct GNUNET_PeerIdentity *peer)
+{
+  return GNUNET_CONTAINER_multipeermap_contains (mpm, peer);
+}
+
+/**
+ * Remove peer from view
+ *
+ * @param peer the peer to remove
+ *
+ * @return GNUNET_OK if view contained peer and removed it successfully
+ *         GNUNET_NO if view does not contain peer
+ */
+int
+View_remove_peer (const struct GNUNET_PeerIdentity *peer)
+{
+  uint32_t *index;
+
+  if (GNUNET_YES == View_contains_peer (peer))
+  {
+    index = GNUNET_CONTAINER_multipeermap_get (mpm, peer);
+    GNUNET_assert (NULL != index);
+    if (*index == GNUNET_CONTAINER_multipeermap_size (mpm) - 1)
+    { /* Last peer in array - simply remove */
+    }
+    else
+    { /* Fill the 'gap' in the array with the last peer */
+      array[*index] = array[View_size ()];
+    }
+    GNUNET_CONTAINER_multipeermap_remove_all (mpm, peer);
+    return GNUNET_OK;
+  }
+  else
+  {
+    return GNUNET_NO;
+  }
+}
+
+/**
+ * Get a peer by index
+ *
+ * @param index the index of the peer to get
+ *
+ * @return peer to the corresponding index.
+ *         NULL if this index is not known
+ */
+const struct GNUNET_PeerIdentity *
+View_get_peer_by_index (uint32_t index)
+{
+  if (index < GNUNET_CONTAINER_multipeermap_size (mpm))
+  {
+    return &array[index];
+  }
+  else
+  {
+    return NULL;
+  }
+}
+
+/**
+ * Clear the custom peer map
+ *
+ * @param c_peer_map the custom peer map to look in
+ *
+ * @return size of the map
+ */
+void
+View_clear ()
+{
+  uint32_t i;
+  uint32_t *index;
+
+  for (i = 0; i < GNUNET_CONTAINER_multipeermap_size (mpm); i++)
+  { /* Need to free indices stored at peers */
+    index = GNUNET_CONTAINER_multipeermap_get (mpm, &array[i]);
+    GNUNET_assert (NULL != index);
+    GNUNET_free (index);
+    GNUNET_CONTAINER_multipeermap_remove_all (mpm, &array[i]);
+  }
+  GNUNET_assert (0 == GNUNET_CONTAINER_multipeermap_size (mpm));
+}
+
+/**
+ * Destroy peermap.
+ *
+ * @param c_peer_map the map to destroy
+ */
+void
+View_destroy ()
+{
+  View_clear ();
+  GNUNET_free (array);
+  GNUNET_CONTAINER_multipeermap_destroy (mpm);
+}
+
+/* end of gnunet-service-rps_view.c */