--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/servlib/prophet/Node.cc	Thu Apr 21 14:57:45 2011 +0100
@@ -0,0 +1,155 @@
+/*
+ *    Copyright 2007 Baylor University
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#include "Node.h"
+#include <time.h>       // for time()
+#include <netinet/in.h> // for ntoh*,hton*
+#include <math.h>       // for pow()
+
+namespace prophet {
+
+const double
+NodeParams::DEFAULT_P_ENCOUNTER = 0.75;
+
+const double
+NodeParams::DEFAULT_BETA = 0.25;
+
+const double
+NodeParams::DEFAULT_GAMMA = 0.99;
+
+const u_int
+NodeParams::DEFAULT_KAPPA = 100;
+
+Node::Node(const NodeParams* params)
+    : p_value_(0.0), relay_(DEFAULT_RELAY), custody_(DEFAULT_CUSTODY),
+      internet_gateway_(DEFAULT_INTERNET), dest_id_(""), heap_pos_(0)
+{
+    // store local copy of NodeParams
+    if (params != NULL)
+        params_ = new NodeParams(*params);
+    else
+        // take the default if nothing was specified
+        params_ = new NodeParams();
+
+    // read in current epoch
+    age_ = time(0);
+}
+
+Node::Node(const Node& n)
+    : p_value_(n.p_value_), relay_(n.relay_),
+      custody_(n.custody_), internet_gateway_(n.internet_gateway_),
+      dest_id_(n.dest_id_), age_(n.age_), heap_pos_(n.heap_pos_)
+{
+    // store local copy of NodeParams
+    params_ = new NodeParams(*n.params_);
+}
+
+Node::Node(const std::string& dest_id,
+           bool relay, bool custody, bool internet,
+           const NodeParams* params)
+    : params_(NULL), p_value_(0.0), relay_(relay),
+      custody_(custody), internet_gateway_(internet), dest_id_(dest_id),
+      heap_pos_(0)
+{
+    // store local copy of NodeParams
+    if (params != NULL)
+        params_ = new NodeParams(*params);
+    else
+        // take the default if nothing was specified
+        params_ = new NodeParams();
+
+    // read in current epoch
+    age_ = time(0);
+}
+
+Node::~Node()
+{
+    delete params_;
+}
+
+void
+Node::update_pvalue()
+{
+    // validate before proceeding
+    if (!(p_value_ >= 0.0 && p_value_ <= 1.0)) return;
+    if (params_ == NULL) return;
+
+    // new p_value is P_(A,B), previous p_value_ is P_(A,B)_old
+    // params_->encounter_ is P_encounter
+    // A is the local node
+    // B is the node just encountered, represented by this ProphetNode instance
+    p_value_ = p_value_ + (1.0 - p_value_) * params_->encounter_;
+
+    // update age to reflect data "freshness"
+    age_ = time(0);
+}
+
+void
+Node::update_transitive(double ab, double bc)
+{
+    // validate before proceeding
+    if (!(p_value_ >= 0.0 && p_value_ <= 1.0)) return;
+    if (!(ab >= 0.0 && ab <= 1.0)) return;
+    if (!(bc >= 0.0 && bc <= 1.0)) return;
+    if (p_value_ > bc) return;
+    if (params_ == NULL) return;
+
+    // new p_value_ is P_(A,C), previous p_value is P_(A,C)_old
+    // params_->beta_ is beta
+    // A is the local node
+    // B is the node just encountered (originator of RIB)
+    // C is the node represented by this ProphetNode instance
+    p_value_ = (p_value_ * params_->beta_) + (1.0 - params_->beta_) * ab * bc * params_->encounter_;
+
+    // update age to reflect data "freshness"
+    age_ = time(0);
+}
+
+void
+Node::update_age()
+{
+    // validate before proceeding
+    if (!(p_value_ >= 0.0 && p_value_ <= 1.0)) return;
+    if (params_ == NULL) return;
+
+    // new p_value_ is P_(A,B), previous p_value is P_(A,B)_old
+    // params_->gamma_ is gamma
+    // timeunits is k
+    u_int32_t now = time(0);
+
+    double agefactor = 1.0;
+
+    u_int timeunits = time_to_units(now - age_);
+    if (timeunits > 0)
+        agefactor = pow( params_->gamma_, timeunits );
+
+    p_value_ *= agefactor;
+
+    // update age to reflect data "freshness"
+    age_ = time(0);
+}
+
+u_int
+Node::time_to_units(u_int32_t timediff) const
+{
+    // prevent div by 0
+    if (params_->kappa_ == 0.0) return 0;
+
+    // kappa is in units of milliseconds per timeunit
+    return (u_int) (timediff * 1000 / params_->kappa_);
+}
+
+}; // namespace prophet