From e6b1539f7bcbbe60fc2f20c1555b86bf3eeddb2e Mon Sep 17 00:00:00 2001
From: Mirko Banchi <mk.banchi@gmail.com>
Date: Wed, 3 Feb 2010 20:34:49 +0100
Subject: [PATCH] WifiMacQueue now supports head pushing

---
 src/devices/wifi/edca-txop-n.cc    | 12 ++++++++++++
 src/devices/wifi/edca-txop-n.h     |  1 +
 src/devices/wifi/wifi-mac-queue.cc | 26 ++++++++++++++++++++------
 src/devices/wifi/wifi-mac-queue.h  |  1 +
 4 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/src/devices/wifi/edca-txop-n.cc b/src/devices/wifi/edca-txop-n.cc
index 68b9f8db0..0a773dd10 100644
--- a/src/devices/wifi/edca-txop-n.cc
+++ b/src/devices/wifi/edca-txop-n.cc
@@ -687,4 +687,16 @@ EdcaTxopN::SetMsduAggregator (Ptr<MsduAggregator> aggr)
   m_aggregator = aggr;
 }
 
+void
+EdcaTxopN::PushFront (Ptr<const Packet> packet, const WifiMacHeader &hdr)
+{
+  NS_LOG_FUNCTION (this << packet << &hdr);
+  WifiMacTrailer fcs;
+  uint32_t fullPacketSize = hdr.GetSerializedSize () + packet->GetSize () + fcs.GetSerializedSize ();
+  WifiRemoteStation *station = GetStation (hdr.GetAddr1 ());
+  station->PrepareForQueue (packet, fullPacketSize);
+  m_queue->PushFront (packet, hdr);
+  StartAccessIfNeeded ();
+}
+
 } //namespace ns3
diff --git a/src/devices/wifi/edca-txop-n.h b/src/devices/wifi/edca-txop-n.h
index 298eb2700..a52d8fe85 100644
--- a/src/devices/wifi/edca-txop-n.h
+++ b/src/devices/wifi/edca-txop-n.h
@@ -130,6 +130,7 @@ public:
   
   void Queue (Ptr<const Packet> packet, const WifiMacHeader &hdr);
   void SetMsduAggregator (Ptr<MsduAggregator> aggr);
+  void PushFront (Ptr<const Packet> packet, const WifiMacHeader &hdr);
 
 private:
   /**
diff --git a/src/devices/wifi/wifi-mac-queue.cc b/src/devices/wifi/wifi-mac-queue.cc
index 731e17398..7c39895b8 100644
--- a/src/devices/wifi/wifi-mac-queue.cc
+++ b/src/devices/wifi/wifi-mac-queue.cc
@@ -111,18 +111,19 @@ WifiMacQueue::Cleanup (void)
 
   Time now = Simulator::Now ();
   uint32_t n = 0;
-  PacketQueueI end = m_queue.begin ();
-  for (PacketQueueI i = m_queue.begin (); i != m_queue.end (); i++) 
+  for (PacketQueueI i = m_queue.begin (); i != m_queue.end ();) 
     {
       if (i->tstamp + m_maxDelay > now) 
         {
-          end = i;
-          break;
+          i++;
+        }
+      else
+        {
+          i = m_queue.erase (i);
+          n++;
         }
-      n++;
     }
   m_size -= n;
-  m_queue.erase (m_queue.begin (), end);
 }
 
 Ptr<const Packet>
@@ -260,4 +261,17 @@ WifiMacQueue::Remove (Ptr<const Packet> packet)
   return false;
 }
 
+void
+WifiMacQueue::PushFront (Ptr<const Packet> packet, const WifiMacHeader &hdr)
+{
+  Cleanup ();
+  if (m_size == m_maxSize)
+    {
+      return;
+    }
+  Time now = Simulator::Now ();
+  m_queue.push_front (Item (packet, hdr, now));
+  m_size++;
+}
+
 } // namespace ns3
diff --git a/src/devices/wifi/wifi-mac-queue.h b/src/devices/wifi/wifi-mac-queue.h
index 10b3c1eeb..944abec9d 100644
--- a/src/devices/wifi/wifi-mac-queue.h
+++ b/src/devices/wifi/wifi-mac-queue.h
@@ -61,6 +61,7 @@ public:
   Time GetMaxDelay (void) const;
 
   void Enqueue (Ptr<const Packet> packet, const WifiMacHeader &hdr);
+  void PushFront (Ptr<const Packet> packet, const WifiMacHeader &hdr);
   Ptr<const Packet> Dequeue (WifiMacHeader *hdr);
   Ptr<const Packet> Peek (WifiMacHeader *hdr);
   /**