From 0ac334781fcb5029e4ea9236a8e93f43169eb7f2 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 14 Apr 2014 09:00:30 +0300
Subject: [PATCH] Simplify sequence handling

Instead of checking all sequence points when another train reserves a
block, only check the first one.  The subsequent ones can be checked
when they become relevant.
---
 source/libr2c2/trainrouter.cpp | 56 ++++++++++++++++++----------------
 source/libr2c2/trainrouter.h   |  4 ++-
 2 files changed, 32 insertions(+), 28 deletions(-)

diff --git a/source/libr2c2/trainrouter.cpp b/source/libr2c2/trainrouter.cpp
index 2fac984..4b7e1bc 100644
--- a/source/libr2c2/trainrouter.cpp
+++ b/source/libr2c2/trainrouter.cpp
@@ -18,7 +18,9 @@ TrainRouter::TrainRouter(Train &t):
 	arriving(0),
 	destination(0),
 	destination_changed(false),
-	metrics_stale(false)
+	metrics_stale(false),
+	current_sequence(0),
+	sequence_check_pending(false)
 {
 	train.get_layout().signal_block_reserved.connect(sigc::mem_fun(this, &TrainRouter::block_reserved));
 	train.signal_advanced.connect(sigc::mem_fun(this, &TrainRouter::train_advanced));
@@ -65,8 +67,8 @@ bool TrainRouter::set_route(const Route *r)
 	destination = 0;
 	waypoints.clear();
 	sequence_points.clear();
-	pending_sequence_checks.clear();
 	current_sequence = 0;
+	sequence_check_pending = false;
 
 	route_changed();
 
@@ -195,8 +197,8 @@ void TrainRouter::tick(const Time::TimeDelta &dt)
 				routes.push_back(create_lead_route(0, planned_routes.front()));
 				routes.insert(routes.end(), planned_routes.begin(), planned_routes.end());
 				sequence_points = planner->get_sequence_for(train);
-				pending_sequence_checks.clear();
 				current_sequence = 0;
+				sequence_check_pending = false;
 
 				route_changed();
 			}
@@ -204,14 +206,12 @@ void TrainRouter::tick(const Time::TimeDelta &dt)
 		}
 	}
 
-	for(list<SequencePoint *>::iterator i=pending_sequence_checks.begin(); i!=pending_sequence_checks.end(); ++i)
-		if((*i)->preceding_train->get_ai_of_type<TrainRouter>()->get_current_sequence()>=(*i)->sequence_in)
-		{
-			(*i)->preceding_train = 0;
-			if(*i==&sequence_points.front())
-				train.stop_at(0);
-		}
-	pending_sequence_checks.clear();
+	if(sequence_check_pending)
+	{
+		if(sequence_points.front().is_cleared())
+			train.stop_at(0);
+		sequence_check_pending = false;
+	}
 
 	if(arriving==1 && !train.get_speed())
 	{
@@ -243,21 +243,14 @@ void TrainRouter::block_reserved(Block &block, Train *t)
 		if(!t)
 			return;
 
-		TrainRouter *other_router = 0;
-		for(list<SequencePoint>::iterator i=sequence_points.begin(); i!=sequence_points.end(); ++i)
-			if(i->block==&block && i->preceding_train==t)
-			{
-				if(!other_router)
-					other_router = t->get_ai_of_type<TrainRouter>();
-				if(other_router->get_current_sequence()>=i->sequence_in)
-				{
-					i->preceding_train = 0;
-					if(i==sequence_points.begin())
-						train.stop_at(0);
-				}
-				else
-					pending_sequence_checks.push_back(&*i);
-			}
+		SequencePoint &sp = sequence_points.front();
+		if(sp.preceding_train==t && sp.block==&block)
+		{
+			if(sp.is_cleared())
+				train.stop_at(0);
+			else
+				sequence_check_pending = true;
+		}
 
 		return;
 	}
@@ -298,7 +291,7 @@ void TrainRouter::block_reserved(Block &block, Train *t)
 		if(!sequence_points.empty())
 		{
 			SequencePoint &sp = sequence_points.front();
-			if(sp.preceding_train && sp.block==b_iter_next.block())
+			if(sp.block==b_iter_next.block() && !sp.is_cleared())
 				train.stop_at(&block);
 		}
 	}
@@ -462,6 +455,15 @@ TrainRouter::SequencePoint::SequencePoint(Block &b, unsigned o):
 	sequence_out(o)
 { }
 
+bool TrainRouter::SequencePoint::is_cleared() const
+{
+	if(!preceding_train)
+		return true;
+
+	TrainRouter *router = preceding_train->get_ai_of_type<TrainRouter>();
+	return router->get_current_sequence()>=sequence_in;
+}
+
 
 TrainRouter::Loader::Loader(TrainRouter &r):
 	DataFile::ObjectLoader<TrainRouter>(r)
diff --git a/source/libr2c2/trainrouter.h b/source/libr2c2/trainrouter.h
index cbaa520..47a409c 100644
--- a/source/libr2c2/trainrouter.h
+++ b/source/libr2c2/trainrouter.h
@@ -37,6 +37,8 @@ public:
 		unsigned sequence_out;
 
 		SequencePoint(Block &, unsigned);
+
+		bool is_cleared() const;
 	};
 
 private:
@@ -51,8 +53,8 @@ private:
 	std::vector<TrainRouteMetric *> metrics;
 	bool metrics_stale;
 	std::list<SequencePoint> sequence_points;
-	std::list<SequencePoint *> pending_sequence_checks;
 	unsigned current_sequence;
+	bool sequence_check_pending;
 	Msp::Time::TimeDelta delay;
 	Msp::RefPtr<TrainRoutePlanner> planner;
 
-- 
2.45.2