From fafc91bc79152890e5c2f43f29811cb10a3a7ecb Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 8 Jul 2013 18:02:18 +0300
Subject: [PATCH] Some more refactoring of BlockAllocator

---
 source/libr2c2/blockallocator.cpp | 60 ++++++++++++++++---------------
 source/libr2c2/blockallocator.h   |  4 ++-
 2 files changed, 34 insertions(+), 30 deletions(-)

diff --git a/source/libr2c2/blockallocator.cpp b/source/libr2c2/blockallocator.cpp
index 215d746..2a24737 100644
--- a/source/libr2c2/blockallocator.cpp
+++ b/source/libr2c2/blockallocator.cpp
@@ -247,7 +247,7 @@ void BlockAllocator::reserve_more()
 	{
 		update_next_sensor(0);
 		// Immediately advance to just before the next sensor
-		advance_to(next_sensor ? next_sensor->get_block() : 0);
+		advance_front(next_sensor);
 	}
 }
 
@@ -273,7 +273,7 @@ bool BlockAllocator::reserve_block(const BlockIter &block)
 	}
 }
 
-void BlockAllocator::advance_to(const Block *block)
+void BlockAllocator::advance_front(const Block *block)
 {
 	BlockList::iterator end;
 	if(block)
@@ -289,6 +289,33 @@ void BlockAllocator::advance_to(const Block *block)
 		train.signal_advanced.emit(**i);
 }
 
+void BlockAllocator::advance_front(const Sensor *sensor)
+{
+	advance_front(sensor ? sensor->get_block() : 0);
+}
+
+void BlockAllocator::advance_back()
+{
+	const Vehicle &veh = train.get_vehicle(train.get_controller().get_reverse() ? 0 : train.get_n_vehicles()-1);
+	const Block &veh_block = veh.get_track()->get_block();
+
+	/* Sensors aren't guaranteed to be detriggered in order.  Go through the
+	block list and locate the first sensor that's still active. */
+	Sensor *last_inactive = 0;
+	for(BlockList::iterator i=blocks.begin(); (i!=cur_blocks_end && i->block()!=&veh_block); ++i)
+		if(Sensor *sensor = (*i)->get_sensor())
+		{
+			if(sensor->get_state())
+			{
+				if(last_inactive)
+					release_blocks_begin(i);
+				return;
+			}
+			else
+				last_inactive = sensor;
+		}
+}
+
 void BlockAllocator::release_blocks_begin(const BlockList::iterator &end)
 {
 	for(BlockList::iterator i=blocks.begin(); i!=end; )
@@ -375,7 +402,7 @@ void BlockAllocator::sensor_state_changed(Sensor &sensor, Sensor::State state)
 		if(&sensor==next_sensor)
 		{
 			update_next_sensor(next_sensor);
-			advance_to(next_sensor ? next_sensor->get_block() : 0);
+			advance_front(next_sensor);
 
 			if(active)
 				reserve_more();
@@ -384,32 +411,7 @@ void BlockAllocator::sensor_state_changed(Sensor &sensor, Sensor::State state)
 			train.get_layout().emergency("Sensor for "+train.get_name()+" triggered out of order");
 	}
 	else if(state==Sensor::INACTIVE)
-	{
-		const Vehicle &veh = train.get_vehicle(train.get_controller().get_reverse() ? 0 : train.get_n_vehicles()-1);
-		const Block &veh_block = veh.get_track()->get_block();
-
-		/* Sensors aren't guaranteed to be detriggered in order.  Go through the
-		block list and locate the first sensor that's still active. */
-		BlockList::iterator end = blocks.end();
-		for(BlockList::iterator i=blocks.begin(); i!=cur_blocks_end; ++i)
-		{
-			// Avoid freeing blocks that still hold the train's vehicles
-			if(&**i==&veh_block)
-				break;
-
-			if(Sensor *s = (*i)->get_sensor())
-			{
-				if(s->get_state()>=Sensor::MAYBE_INACTIVE)
-					break;
-				else
-					end = i;
-			}
-		}
-		
-		if(end!=blocks.end())
-			// Free blocks up to the last inactive sensor
-			release_blocks_begin(++end);
-	}
+		advance_back();
 }
 
 void BlockAllocator::update_next_sensor(Sensor *after)
diff --git a/source/libr2c2/blockallocator.h b/source/libr2c2/blockallocator.h
index 95cb910..ba939f7 100644
--- a/source/libr2c2/blockallocator.h
+++ b/source/libr2c2/blockallocator.h
@@ -65,7 +65,9 @@ public:
 private:
 	void reserve_more();
 	bool reserve_block(const BlockIter &);
-	void advance_to(const Block *);
+	void advance_front(const Block *);
+	void advance_front(const Sensor *);
+	void advance_back();
 	void release_blocks_begin(const BlockList::iterator &);
 	void release_blocks_end(const BlockList::iterator &);
 	void release_block(const BlockList::iterator &);
-- 
2.45.2