From 17c80dc005ddfd8aa2b4b80c3eed43918458d6cf Mon Sep 17 00:00:00 2001
From: Cristiano Tapparello <cristiano.tapparello@rochester.edu>
Date: Fri, 11 Mar 2016 15:04:49 -0500
Subject: [PATCH] energy: Fixes for negative remaining energy and bug 2310

---
 src/energy/model/basic-energy-source.cc  | 15 ++++++++++-----
 src/energy/model/li-ion-energy-source.cc | 17 ++++++++++-------
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/src/energy/model/basic-energy-source.cc b/src/energy/model/basic-energy-source.cc
index 70fb65fe7..2a05042a8 100644
--- a/src/energy/model/basic-energy-source.cc
+++ b/src/energy/model/basic-energy-source.cc
@@ -207,10 +207,6 @@ BasicEnergySource::HandleEnergyDrainedEvent (void)
   NS_LOG_FUNCTION (this);
   NS_LOG_DEBUG ("BasicEnergySource:Energy depleted!");
   NotifyEnergyDrained (); // notify DeviceEnergyModel objects
-  if (m_remainingEnergyJ <= 0)
-    {
-      m_remainingEnergyJ = 0; // energy never goes below 0
-    }
 }
 
 void
@@ -230,7 +226,16 @@ BasicEnergySource::CalculateRemainingEnergy (void)
   NS_ASSERT (duration.GetSeconds () >= 0);
   // energy = current * voltage * time
   double energyToDecreaseJ = totalCurrentA * m_supplyVoltageV * duration.GetSeconds ();
-  m_remainingEnergyJ -= energyToDecreaseJ;
+
+  if (m_remainingEnergyJ < energyToDecreaseJ) 
+    {
+      m_remainingEnergyJ = 0; // energy never goes below 0
+    } 
+  else 
+    {
+      m_remainingEnergyJ -= energyToDecreaseJ;
+    }  
+
   NS_LOG_DEBUG ("BasicEnergySource:Remaining energy = " << m_remainingEnergyJ);
 }
 
diff --git a/src/energy/model/li-ion-energy-source.cc b/src/energy/model/li-ion-energy-source.cc
index 6a290783e..84a2d6bfb 100644
--- a/src/energy/model/li-ion-energy-source.cc
+++ b/src/energy/model/li-ion-energy-source.cc
@@ -253,8 +253,6 @@ void
 LiIonEnergySource::DoDispose (void)
 {
   NS_LOG_FUNCTION (this);
-  // calculate remaining energy at the end of simulation
-  CalculateRemainingEnergy ();
   BreakDeviceEnergyModelRefCycle ();  // break reference cycle
 }
 
@@ -266,10 +264,6 @@ LiIonEnergySource::HandleEnergyDrainedEvent (void)
   NS_LOG_DEBUG ("LiIonEnergySource:Energy depleted at node #" <<
                 GetNode ()->GetId ());
   NotifyEnergyDrained (); // notify DeviceEnergyModel objects
-  if (m_remainingEnergyJ <= 0)
-    {
-      m_remainingEnergyJ = 0; // energy never goes below 0
-    }
 }
 
 
@@ -282,7 +276,16 @@ LiIonEnergySource::CalculateRemainingEnergy (void)
   NS_ASSERT (duration.GetSeconds () >= 0);
   // energy = current * voltage * time
   double energyToDecreaseJ = totalCurrentA * m_supplyVoltageV * duration.GetSeconds ();
-  m_remainingEnergyJ -= energyToDecreaseJ;
+
+  if (m_remainingEnergyJ < energyToDecreaseJ) 
+    {
+      m_remainingEnergyJ = 0; // energy never goes below 0
+    } 
+  else 
+    {
+      m_remainingEnergyJ -= energyToDecreaseJ;
+    }  
+
   m_drainedCapacity += (totalCurrentA * duration.GetSeconds () / 3600);
   // update the supply voltage
   m_supplyVoltageV = GetVoltage (totalCurrentA);