From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 20 Dec 2009 19:34:12 +0000 (+0000)
Subject: Improve the block reservation algorithm
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;ds=inline;h=93ca5f1774e218c313edd88024f82c80714d8e7c;p=r2c2.git

Improve the block reservation algorithm
---

diff --git a/source/libmarklin/train.cpp b/source/libmarklin/train.cpp
index 462ff1d..8f8ee49 100644
--- a/source/libmarklin/train.cpp
+++ b/source/libmarklin/train.cpp
@@ -139,6 +139,17 @@ bool Train::free_block(Block *block)
 	return false;
 }
 
+int Train::get_entry_to_block(Block *block) const
+{
+	for(list<BlockRef>::const_iterator i=cur_blocks.begin(); i!=cur_blocks.end(); ++i)
+		if(i->block==block)
+			return i->entry;
+	for(list<BlockRef>::const_iterator i=rsv_blocks.begin(); i!=rsv_blocks.end(); ++i)
+		if(i->block==block)
+			return i->entry;
+	return -1;
+}
+
 void Train::tick(const Time::TimeStamp &t, const Time::TimeDelta &dt)
 {
 	if(try_reserve && t>try_reserve)
@@ -313,31 +324,67 @@ unsigned Train::reserve_more()
 
 	pending_block = 0;
 
+	// See how many blocks we already have
 	unsigned nsens = 0;
 	for(list<BlockRef>::const_iterator i=rsv_blocks.begin(); i!=rsv_blocks.end(); ++i)
 		if(i->block->get_sensor_id())
 			++nsens;
 
 	bool got_more = false;
-	while(nsens<3)
+	BlockRef *good = last;
+	unsigned good_sens = nsens;
+	while(good_sens<3)
 	{
-		int exit = last->block->traverse(last->entry);
-		if(exit<0)
+		// Traverse to the next block
+		unsigned exit = last->block->traverse(last->entry);
+		Block *link = last->block->get_link(exit);
+		if(!link)
 			break;
 
-		Block *link = last->block->get_link(exit);
-		if(!link || !link->reserve(this))
+		int entry = link->get_endpoint_by_link(*last->block);
+		if(!link->reserve(this))
 		{
+			// If we found another train going in the same direction as us, we can keep the blocks we got
+			int other_entry = link->get_train()->get_entry_to_block(link);
+			if(other_entry==entry || link->traverse(entry)==link->traverse(other_entry))
+			{
+				good = last;
+				good_sens = nsens;
+			}
 			pending_block = link;
 			break;
 		}
 
-		if(route && link->get_turnout_id())
+		if(link->get_turnout_id())
 		{
-			int path = route->get_turnout(link->get_turnout_id());
+			const Block::Endpoint &ep = link->get_endpoints()[entry];
+			const Endpoint &track_ep = ep.track->get_type().get_endpoints()[ep.track_ep];
+
+			if(track_ep.paths&(track_ep.paths-1))
+			{
+				// We're facing the points - keep the blocks reserved so far
+				good = last;
+				good_sens = nsens;
+			}
+
 			Turnout &turnout = trfc_mgr.get_control().get_turnout(link->get_turnout_id());
-			if(path>=0 && path!=turnout.get_path())
+
+			// Figure out what path we'd like to take on the turnout
+			int path = -1;
+			if(route)
+				path = route->get_turnout(link->get_turnout_id());
+			if(path<0)
+				path = turnout.get_path();
+			if(!((track_ep.paths>>path)&1))
 			{
+				for(unsigned i=0; track_ep.paths>>i; ++i)
+					if((track_ep.paths>>i)&1)
+						path = i;
+			}
+
+			if(path!=turnout.get_path())
+			{
+				// The turnout is set to wrong path - switch and wait for it
 				link->reserve(0);
 				pending_block = link;
 				turnout.set_path(path);
@@ -345,7 +392,7 @@ unsigned Train::reserve_more()
 			}
 		}
 
-		rsv_blocks.push_back(BlockRef(link, link->get_endpoint_by_link(*last->block)));
+		rsv_blocks.push_back(BlockRef(link, entry));
 		last = &rsv_blocks.back();
 		if(last->block->get_sensor_id())
 		{
@@ -354,14 +401,13 @@ unsigned Train::reserve_more()
 		}
 	}
 
-	while(!rsv_blocks.empty() && !last->block->get_sensor_id())
+	// Unreserve blocks that were not good
+	while(!rsv_blocks.empty() && last!=good)
 	{
 		last->block->reserve(0);
 		rsv_blocks.erase(--rsv_blocks.end());
 		if(!rsv_blocks.empty())
 			last = &rsv_blocks.back();
-		else
-			last = 0;
 	}
 
 	if(got_more)
diff --git a/source/libmarklin/train.h b/source/libmarklin/train.h
index bacb246..3fc7131 100644
--- a/source/libmarklin/train.h
+++ b/source/libmarklin/train.h
@@ -92,6 +92,7 @@ public:
 	const Point &get_position() const { return pos; }
 	void place(Block *, unsigned);
 	bool free_block(Block *);
+	int get_entry_to_block(Block *) const;
 	void tick(const Msp::Time::TimeStamp &, const Msp::Time::TimeDelta &);
 	void save(std::list<Msp::DataFile::Statement> &) const;
 private: