/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

 /*

  * Copyright (c) 2005,2006 INRIA

  *

  * This program is free software; you can redistribute it and/or modify

  * it under the terms of the GNU General Public License version 2 as

  * published by the Free Software Foundation;

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program; if not, write to the Free Software

  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  *

  * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

  */

 #include "simulator.h"

 #include "default-simulator-impl.h"

 #include "scheduler.h"

 #include "event-impl.h"

 #include "ns3/ptr.h"

 #include "ns3/pointer.h"

 #include "ns3/assert.h"

 #include "ns3/log.h"

 #include <math.h>

 NS_LOG_COMPONENT_DEFINE ("DefaultSimulatorImpl");

 namespace ns3 {

 NS_OBJECT_ENSURE_REGISTERED (DefaultSimulatorImpl);

 TypeId

 DefaultSimulatorImpl::GetTypeId (void)

 {

   static TypeId tid = TypeId ("ns3::DefaultSimulatorImpl")

     .SetParent<Object> ()

     .AddConstructor<DefaultSimulatorImpl> ()

     ;

   return tid;

 }

 DefaultSimulatorImpl::DefaultSimulatorImpl ()

 {

   m_stop = false;

   // uids are allocated from 4.

   // uid 0 is "invalid" events

   // uid 1 is "now" events

   // uid 2 is "destroy" events

   m_uid = 4; 

   // before ::Run is entered, the m_currentUid will be zero

   m_currentUid = 0;

   m_currentTs = 0;

   m_unscheduledEvents = 0;

 }

 DefaultSimulatorImpl::~DefaultSimulatorImpl ()

 {

   while (!m_events->IsEmpty ())

     {

       Scheduler::Event next = m_events->RemoveNext ();

       next.impl->Unref ();

     }

   m_events = 0;

 }

 void

 DefaultSimulatorImpl::Destroy ()

 {

   while (!m_destroyEvents.empty ()) 

     {

       Ptr<EventImpl> ev = m_destroyEvents.front ().PeekEventImpl ();

       m_destroyEvents.pop_front ();

       NS_LOG_LOGIC ("handle destroy " << ev);

       if (!ev->IsCancelled ())

         {

           ev->Invoke ();

         }

     }

 }

 void

 DefaultSimulatorImpl::SetScheduler (ObjectFactory schedulerFactory)

 {

   Ptr<Scheduler> scheduler = schedulerFactory.Create<Scheduler> ();

   if (m_events != 0)

     {

       while (!m_events->IsEmpty ())

         {

           Scheduler::Event next = m_events->RemoveNext ();

           scheduler->Insert (next);

         }

     }

   m_events = scheduler;

 }

 void

 DefaultSimulatorImpl::ProcessOneEvent (void)

 {

   Scheduler::Event next = m_events->RemoveNext ();

   NS_ASSERT (next.key.m_ts >= m_currentTs);

   --m_unscheduledEvents;

   NS_LOG_LOGIC ("handle " << next.key.m_ts);

   m_currentTs = next.key.m_ts;

   m_currentUid = next.key.m_uid;

   next.impl->Invoke ();

   next.impl->Unref ();

 }

 bool 

 DefaultSimulatorImpl::IsFinished (void) const

 {

   return m_events->IsEmpty () || m_stop;

 }

 uint64_t

 DefaultSimulatorImpl::NextTs (void) const

 {

   NS_ASSERT (!m_events->IsEmpty ());

   Scheduler::Event ev = m_events->PeekNext ();

   return ev.key.m_ts;

 }

 Time

 DefaultSimulatorImpl::Next (void) const

 {

   return TimeStep (NextTs ());

 }

 void

 DefaultSimulatorImpl::Run (void)

 {

   m_stop = false;

   while (!m_events->IsEmpty () && !m_stop) 

     {

       ProcessOneEvent ();

     }

   // If the simulator stopped naturally by lack of events, make a

   // consistency test to check that we didn't lose any events along the way.

   NS_ASSERT(!m_events->IsEmpty () || m_unscheduledEvents == 0);

 }

 void

 DefaultSimulatorImpl::RunOneEvent (void)

 {

   ProcessOneEvent ();

 }

 void 

 DefaultSimulatorImpl::Stop (void)

 {

   m_stop = true;

 }

 //

 // Schedule an event for a _relative_ time in the future.

 //

 EventId

 DefaultSimulatorImpl::Schedule (Time const &time, EventImpl *event)

 {

   Time tAbsolute = time + Now();

   NS_ASSERT (tAbsolute.IsPositive ());

   NS_ASSERT (tAbsolute >= TimeStep (m_currentTs));

   Scheduler::Event ev;

   ev.impl = event;

   ev.key.m_ts = (uint64_t) tAbsolute.GetTimeStep ();

   ev.key.m_uid = m_uid;

   m_uid++;

   ++m_unscheduledEvents;

   m_events->Insert (ev);

   return EventId (event, ev.key.m_ts, ev.key.m_uid);

 }

 EventId

 DefaultSimulatorImpl::ScheduleNow (EventImpl *event)

 {

   Scheduler::Event ev;

   ev.impl = event;

   ev.key.m_ts = m_currentTs;

   ev.key.m_uid = m_uid;

   m_uid++;

   ++m_unscheduledEvents;

   m_events->Insert (ev);

   return EventId (event, ev.key.m_ts, ev.key.m_uid);

 }

 EventId

 DefaultSimulatorImpl::ScheduleDestroy (EventImpl *event)

 {

   EventId id (Ptr<EventImpl> (event, false), m_currentTs, 2);

   m_destroyEvents.push_back (id);

   m_uid++;

   return id;

 }

 Time

 DefaultSimulatorImpl::Now (void) const

 {

   return TimeStep (m_currentTs);

 }

 Time 

 DefaultSimulatorImpl::GetDelayLeft (const EventId &id) const

 {

   if (IsExpired (id))

     {

       return TimeStep (0);

     }

   else

     {

       return TimeStep (id.GetTs () - m_currentTs);

     }

 }

 void

 DefaultSimulatorImpl::Remove (const EventId &id)

 {

   if (id.GetUid () == 2)

     {

       // destroy events.

       for (DestroyEvents::iterator i = m_destroyEvents.begin (); i != m_destroyEvents.end (); i++)

         {

           if (*i == id)

             {

               m_destroyEvents.erase (i);

               break;

             }

          }

       return;

     }

   if (IsExpired (id))

     {

       return;

     }

   Scheduler::Event event;

   event.impl = id.PeekEventImpl ();

   event.key.m_ts = id.GetTs ();

   event.key.m_uid = id.GetUid ();

   m_events->Remove (event);

   event.impl->Cancel ();

   // whenever we remove an event from the event list, we have to unref it.

   event.impl->Unref ();

   --m_unscheduledEvents;

 }

 void

 DefaultSimulatorImpl::Cancel (const EventId &id)

 {

   if (!IsExpired (id))

     {

       id.PeekEventImpl ()->Cancel ();

     }

 }

 bool

 DefaultSimulatorImpl::IsExpired (const EventId &ev) const

 {

   if (ev.GetUid () == 2)

     {

       if (ev.PeekEventImpl () == 0 ||

           ev.PeekEventImpl ()->IsCancelled ())

         {

           return true;

         }

       // destroy events.

       for (DestroyEvents::const_iterator i = m_destroyEvents.begin (); i != m_destroyEvents.end (); i++)

         {

           if (*i == ev)

             {

               return false;

             }

          }

       return true;

     }

   if (ev.PeekEventImpl () == 0 ||

       ev.GetTs () < m_currentTs ||

       (ev.GetTs () == m_currentTs &&

        ev.GetUid () <= m_currentUid) ||

       ev.PeekEventImpl ()->IsCancelled ()) 

     {

       return true;

     }

   else

     {

       return false;

     }

 }

 Time 

 DefaultSimulatorImpl::GetMaximumSimulationTime (void) const

 {

   // XXX: I am fairly certain other compilers use other non-standard

   // post-fixes to indicate 64 bit constants.

   return TimeStep (0x7fffffffffffffffLL);

 }

 } // namespace ns3