fixed a bug involving scheduler keeping a running thread in the ready queue

when that thread had just been given the cpu.
fixed a bug involving text-simulation displaying the wrong timestamp for
each snaphot. Now the first snapshot printed is correctly tagged "-1".

added (for the sake of lazyness) a method to readyqueue letting anyone
delete the first element on the queue. Not having this would imply
rebuilding the whole queue each time a thread was selected to run.

Small commits avoid complex mergings.


git-svn-id: svn://svn.gna.org/svn/sgpemv2/trunk@814 3ecf2c5c-341e-0410-92b4-d18e462d057c

src/backend/ready_queue.cc

@@ -70,3 +70,9 @@ ReadyQueue::append(Thread& thread)
 {
 	_scheds.push_back(&thread);
 }
+
+void
+ReadyQueue::erase_first()
+{
+  _scheds.erase(_scheds.begin());
+}

src/backend/ready_queue.hh

@@ -42,6 +42,7 @@ namespace sgpem
 		Thread&    get_item_at(position index) throw (std::out_of_range);
 		const Thread& get_item_at(position index) const throw (std::out_of_range);
 		void       append(Thread& schedulable);
+    void       erase_first();
 		
   private:
 		typedef std::vector<Thread*> Threads;

src/backend/scheduler.cc

@@ -314,6 +314,10 @@ Scheduler::step_forward(History& history, CPUPolicy& cpu_policy) throw(UserInter
 					DynamicThread& new_running = (DynamicThread&) _ready_queue->get_item_at(0);
 					new_running.set_state(Schedulable::state_running);
 					new_running.set_last_acquisition(current_instant);
+          // removes running element from the ready queue
+          // since no method was provided to erase an item in the queue, we should rebuild it.
+          // this is pointless. I just added the method.
+          _ready_queue->erase_first();
 				}
 					
 

src/text_simulation.cc

@@ -1417,8 +1417,16 @@ TextSimulation::update(const History& changed_history)
 {
   ostringstream oss;
 
-  oss << ">>>> " << changed_history.get_size() - 1 << _("\nREADY QUEUE: { ");
-  
+  /// since the history stores snapshots starting from
+  /// and including instant -1, the first snapshot on
+  /// the queue, i.e. changed_history[0] is actually
+  /// the snapshot corresponding to instant -1.
+  /// therefore, the last snapshot on the history refers
+  /// to instant (history.get_size() - 2).
+  // this is a damn uint, so we must hack and hack
+  int printed_instant = changed_history.get_size() > 1 ? changed_history.get_size() - 2 : -1;
+  oss << ">>>> " << printed_instant << _("\nREADY QUEUE: { ");
+
   p_stdout(oss.str());
 
   oss.str(string());