convert (and simplify a bit) dht-kademlia example

[simgrid.git] / examples / c / dht-kademlia / routing_table.c

diff --git a/examples/c/dht-kademlia/routing_table.c b/examples/c/dht-kademlia/routing_table.c
new file mode 100644 (file)
index 0000000..b8204f8
--- /dev/null
+++ b/examples/c/dht-kademlia/routing_table.c
@@ -0,0 +1,82 @@
+/* Copyright (c) 2012-2020. The SimGrid Team.
+ * All rights reserved.                                                     */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include "routing_table.h"
+#include "node.h"
+
+XBT_LOG_NEW_DEFAULT_CATEGORY(dht_kademlia_routing_table, "Messages specific for this example");
+
+/** @brief Initialization of a node routing table.  */
+routing_table_t routing_table_init(unsigned int node_id)
+{
+  routing_table_t table = xbt_new(s_routing_table_t, 1);
+  table->buckets        = xbt_new(s_bucket_t, IDENTIFIER_SIZE + 1);
+  for (unsigned int i = 0; i < IDENTIFIER_SIZE + 1; i++) {
+    table->buckets[i].nodes = xbt_dynar_new(sizeof(unsigned int), NULL);
+    table->buckets[i].id    = i;
+  }
+  table->id = node_id;
+  return table;
+}
+
+/** @brief Frees the routing table */
+void routing_table_free(routing_table_t table)
+{
+  unsigned int i;
+  // Free the buckets.
+  for (i = 0; i <= IDENTIFIER_SIZE; i++) {
+    xbt_dynar_free(&table->buckets[i].nodes);
+  }
+  xbt_free(table->buckets);
+  xbt_free(table);
+}
+
+/**@brief prints the routing table, to debug stuff. */
+void routing_table_print(const_routing_table_t table)
+{
+  unsigned int j;
+  unsigned int value;
+  XBT_INFO("Routing table of %08x:", table->id);
+
+  for (unsigned int i = 0; i <= IDENTIFIER_SIZE; i++) {
+    if (!xbt_dynar_is_empty(table->buckets[i].nodes)) {
+      XBT_INFO("Bucket number %u: ", i);
+      xbt_dynar_foreach (table->buckets[i].nodes, j, value) {
+        XBT_INFO("Element %u: %08x", j, value);
+      }
+    }
+  }
+}
+
+/** @brief Finds an identifier in a bucket and returns its position or returns -1 if it doesn't exists
+ * @param bucket the bucket in which we try to find our identifier
+ * @param id the id
+ */
+unsigned int bucket_find_id(const_bucket_t bucket, unsigned int id)
+{
+  unsigned int i;
+  unsigned int current_id;
+  xbt_dynar_foreach (bucket->nodes, i, current_id) {
+    if (id == current_id) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+/** @brief Finds the corresponding bucket in a routing table for a given identifier
+ * @param table the routing table
+ * @param id the identifier
+ * @return the bucket in which the the identifier would be.
+ */
+bucket_t routing_table_find_bucket(const_routing_table_t table, unsigned int id)
+{
+  unsigned int xor_number = table->id ^ id;
+  unsigned int prefix     = get_node_prefix(xor_number, IDENTIFIER_SIZE);
+  xbt_assert(prefix <= IDENTIFIER_SIZE, "Tried to return a  bucket that doesn't exist.");
+  bucket_t bucket = &table->buckets[prefix];
+  return bucket;
+}