From cb4e53ba1b8ea41b978190de6668e9862b9cfea8 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 7 Jun 2013 19:18:04 +0300
Subject: [PATCH] Streamline various block-related algorithms

---
 source/libr2c2/block.cpp     | 75 +++++++++++-------------------------
 source/libr2c2/block.h       |  3 +-
 source/libr2c2/blockiter.cpp | 24 +++++-------
 source/libr2c2/trackiter.cpp |  4 +-
 4 files changed, 36 insertions(+), 70 deletions(-)

diff --git a/source/libr2c2/block.cpp b/source/libr2c2/block.cpp
index bf77433..f681816 100644
--- a/source/libr2c2/block.cpp
+++ b/source/libr2c2/block.cpp
@@ -20,41 +20,29 @@ Block::Block(Layout &l, Track &start):
 	turnout_id(start.get_turnout_id()),
 	train(0)
 {
-	tracks.insert(&start);
-	start.set_block(this);
+	add_track(start);
 
-	list<Track *> queue;
-	queue.push_back(&start);
-
-	while(!queue.empty())
+	if(start.get_type().is_turnout())
 	{
-		Track *track = queue.front();
-		queue.erase(queue.begin());
-
-		const vector<Track *> &links = track->get_links();
-		for(unsigned i=0; i<links.size(); ++i)
-			if(links[i] && !tracks.count(links[i]))
-			{
-				if(links[i]->get_sensor_id()==sensor_id && links[i]->get_turnout_id()==turnout_id)
-				{
-					queue.push_back(links[i]);
-					add_track(*links[i]);
-					links[i]->set_block(this);
-				}
-				else
-					endpoints.push_back(Endpoint(track, i));
-			}
+		unsigned nls = start.get_n_link_slots();
+		for(unsigned i=0; i<nls; ++i)
+			endpoints.push_back(Endpoint(&start, i));
 	}
-
-	determine_id();
-
-	for(unsigned i=0; i<endpoints.size(); ++i)
+	else
 	{
-		unsigned path = 1<<i;
-		endpoints[i].paths |= path;
-		find_paths(endpoints[i].track_iter(), path);
+		unsigned nls = start.get_n_link_slots();
+		for(unsigned i=0; i<nls; ++i)
+		{
+			TrackIter iter = TrackIter(&start, i).flip();
+			for(; (iter && check_validity(*iter)==VALID); iter=iter.next())
+				add_track(*iter);
+			if((iter = iter.flip()))
+				endpoints.push_back(Endpoint(iter.track(), iter.entry()));
+		}
 	}
 
+	determine_id();
+
 	sensor = new TrackCircuit(layout, *this);
 
 	layout.add_block(*this);
@@ -79,6 +67,11 @@ Block::~Block()
 	delete sensor;
 }
 
+void Block::on_track_added(Track &track)
+{
+	track.set_block(this);
+}
+
 TrackChain::Validity Block::check_validity(Track &track) const
 {
 	if(track.get_sensor_id()!=sensor_id || track.get_turnout_id()!=turnout_id)
@@ -172,27 +165,6 @@ bool Block::reserve(Train *t)
 		return false;
 }
 
-void Block::find_paths(const TrackIter &track, unsigned path)
-{
-	unsigned mask = track.endpoint().paths;
-	for(unsigned i=0; mask>>i; ++i)
-		if(mask&(1<<i))
-		{
-			TrackIter next = track.next(i);
-			if(!next)
-				continue;
-			else if(has_track(*next))
-				find_paths(track.next(i), path);
-			else
-			{
-				next = next.flip();
-				for(vector<Endpoint>::iterator j=endpoints.begin(); j!=endpoints.end(); ++j)
-					if(j->track==next.track() && j->track_ep==next.entry())
-						j->paths |= path;
-			}
-		}
-}
-
 void Block::determine_id()
 {
 	if(sensor_id)
@@ -218,8 +190,7 @@ void Block::determine_id()
 Block::Endpoint::Endpoint(Track *t, unsigned e):
 	track(t),
 	track_ep(e),
-	link(0),
-	paths(0)
+	link(0)
 { }
 
 TrackIter Block::Endpoint::track_iter() const
diff --git a/source/libr2c2/block.h b/source/libr2c2/block.h
index 7d6211b..4309290 100644
--- a/source/libr2c2/block.h
+++ b/source/libr2c2/block.h
@@ -22,7 +22,6 @@ public:
 		Track *track;
 		unsigned track_ep;
 		Block *link;
-		unsigned paths;
 
 		Endpoint(Track *, unsigned);
 
@@ -44,6 +43,7 @@ public:
 	~Block();
 
 private:
+	virtual void on_track_added(Track &);
 	virtual Validity check_validity(Track &) const;
 
 public:
@@ -61,7 +61,6 @@ public:
 	bool reserve(Train *);
 	Train *get_train() const { return train; }
 private:
-	void find_paths(const TrackIter &, unsigned);
 	void determine_id();
 };
 
diff --git a/source/libr2c2/blockiter.cpp b/source/libr2c2/blockiter.cpp
index 038600b..a3f6d87 100644
--- a/source/libr2c2/blockiter.cpp
+++ b/source/libr2c2/blockiter.cpp
@@ -40,24 +40,18 @@ const Block::Endpoint &BlockIter::endpoint() const
 int BlockIter::get_exit(const Route *route) const
 {
 	const vector<Block::Endpoint> &eps = _block->get_endpoints();
-	TrackIter t_iter = track_iter();
-
-	while(t_iter)
+	if(_block->get_turnout_id())
 	{
-		if(!_block->has_track(*t_iter))
-			throw logic_error("internal error (block traversal escaped the block)");
-
+		/* The endpoints of a turnout block exactly correspond to the endpoints
+		of the track. */
+		TrackIter t_iter = track_iter();
 		unsigned path = (route ? route->get_path(*t_iter) : t_iter->get_active_path());
-		TrackIter t_exit = t_iter.reverse(path);
-
-		for(unsigned i=0; i<eps.size(); ++i)
-			if(eps[i].track==t_exit.track() && eps[i].track_ep==t_exit.entry())
-				return i;
-
-		t_iter = t_exit.flip();
+		return t_iter.reverse(path).entry();
 	}
-
-	return -1;
+	else if(eps.size()==2)
+		return 1-_entry;
+	else
+		return -1;
 }
 
 BlockIter BlockIter::next(const Route *route) const
diff --git a/source/libr2c2/trackiter.cpp b/source/libr2c2/trackiter.cpp
index e07c71c..da949e7 100644
--- a/source/libr2c2/trackiter.cpp
+++ b/source/libr2c2/trackiter.cpp
@@ -37,7 +37,9 @@ BlockIter TrackIter::block_iter() const
 
 	if(!_track->get_type().is_turnout())
 	{
-		TrackIter rev = reverse();
+		/* Since there was no endpoint match, the preceding track can't be in a
+		different block. */
+		TrackIter rev = flip();
 		TrackIter last;
 		while(rev && &rev.track()->get_block()==&block)
 		{
-- 
2.43.0