From 342ed24c321474f6307d6bc5d7c57d285c15c91a Mon Sep 17 00:00:00 2001
From: Arnaud Giersch <arnaud.giersch@univ-fcomte.fr>
Date: Tue, 24 Apr 2018 14:41:19 +0200
Subject: [PATCH] Kill useless array powers2 and simplify code.

---
 examples/s4u/dht-chord/s4u-dht-chord-node.cpp |  4 +-
 examples/s4u/dht-chord/s4u-dht-chord.cpp      | 37 ++++---------------
 examples/s4u/dht-chord/s4u-dht-chord.hpp      |  1 -
 3 files changed, 9 insertions(+), 33 deletions(-)

diff --git a/examples/s4u/dht-chord/s4u-dht-chord-node.cpp b/examples/s4u/dht-chord/s4u-dht-chord-node.cpp
index 0db3cef31d..d7ab98a633 100644
--- a/examples/s4u/dht-chord/s4u-dht-chord-node.cpp
+++ b/examples/s4u/dht-chord/s4u-dht-chord-node.cpp
@@ -184,7 +184,7 @@ void Node::setPredecessor(int predecessor_id)
 void Node::fixFingers()
 {
   XBT_DEBUG("Fixing fingers");
-  int id = findSuccessor(id_ + powers2[next_finger_to_fix]);
+  int id = findSuccessor(id_ + (1U << next_finger_to_fix));
   if (id != -1) {
     if (id != fingers_[next_finger_to_fix]) {
       setFinger(next_finger_to_fix, id);
@@ -201,7 +201,7 @@ void Node::printFingerTable()
     XBT_VERB("My finger table:");
     XBT_VERB("Start | Succ");
     for (int i = 0; i < nb_bits; i++) {
-      XBT_VERB(" %3d  | %3d", (id_ + powers2[i]) % nb_keys, fingers_[i]);
+      XBT_VERB(" %3u  | %3d", (id_ + (1U << i)) % nb_keys, fingers_[i]);
     }
 
     XBT_VERB("Predecessor: %d", pred_id_);
diff --git a/examples/s4u/dht-chord/s4u-dht-chord.cpp b/examples/s4u/dht-chord/s4u-dht-chord.cpp
index d7613fb87b..b675aa10ff 100644
--- a/examples/s4u/dht-chord/s4u-dht-chord.cpp
+++ b/examples/s4u/dht-chord/s4u-dht-chord.cpp
@@ -11,32 +11,6 @@ simgrid::xbt::Extension<simgrid::s4u::Host, HostChord> HostChord::EXTENSION_ID;
 int nb_bits  = 24;
 int nb_keys  = 0;
 int timeout  = 50;
-int* powers2 = nullptr;
-
-/* Global initialization of the Chord simulation. */
-static void chord_init()
-{
-  // compute the powers of 2 once for all
-  powers2 = new int[nb_bits];
-  int pow = 1;
-  for (int i = 0; i < nb_bits; i++) {
-    powers2[i] = pow;
-    pow        = pow << 1;
-  }
-  nb_keys = pow;
-  XBT_DEBUG("Sets nb_keys to %d", nb_keys);
-
-  HostChord::EXTENSION_ID = simgrid::s4u::Host::extension_create<HostChord>();
-
-  std::vector<simgrid::s4u::Host*> list = simgrid::s4u::Engine::getInstance()->get_all_hosts();
-  for (auto const& host : list)
-    host->extension_set(new HostChord(host));
-}
-
-static void chord_exit()
-{
-  delete[] powers2;
-}
 
 int main(int argc, char* argv[])
 {
@@ -64,7 +38,13 @@ int main(int argc, char* argv[])
 
   e.load_platform(options[0]);
 
-  chord_init(); // FIXME: inline me
+  /* Global initialization of the Chord simulation. */
+  nb_keys = 1U << nb_bits;
+  XBT_DEBUG("Sets nb_keys to %d", nb_keys);
+
+  HostChord::EXTENSION_ID = simgrid::s4u::Host::extension_create<HostChord>();
+  for (auto const& host : simgrid::s4u::Engine::getInstance()->get_all_hosts())
+    host->extension_set(new HostChord(host));
 
   e.register_actor<Node>("node");
   e.load_deployment(options[1]);
@@ -72,8 +52,5 @@ int main(int argc, char* argv[])
   e.run();
 
   XBT_INFO("Simulated time: %g", e.get_clock());
-
-  chord_exit();
-
   return 0;
 }
diff --git a/examples/s4u/dht-chord/s4u-dht-chord.hpp b/examples/s4u/dht-chord/s4u-dht-chord.hpp
index 240a555b0b..ea6e86b6f1 100644
--- a/examples/s4u/dht-chord/s4u-dht-chord.hpp
+++ b/examples/s4u/dht-chord/s4u-dht-chord.hpp
@@ -21,7 +21,6 @@
 extern int nb_bits;
 extern int nb_keys;
 extern int timeout;
-extern int* powers2;
 
 class HostChord {
   RngStream stream_;
-- 
2.20.1