From 2d60ffdb71d84f223c3f29626e66ae33c4b497be Mon Sep 17 00:00:00 2001
From: ian <ian>
Date: Wed, 30 Jul 2008 21:38:26 +0000
Subject: [PATCH] Hopefully-this-time-correct arrangements for dealing with
 uncertainty>maxinto.  safety.c r1.96 and r1.61 were definitely wrong ...

---
 hostside/safety.c | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/hostside/safety.c b/hostside/safety.c
index 21e1d9e..f7bd782 100644
--- a/hostside/safety.c
+++ b/hostside/safety.c
@@ -732,12 +732,15 @@ ErrorCode predict(Train *tra, struct timeval tnow, unsigned flags,
   u.desire_move= desire_move;
   u.desire_movposcomb= desire_movposcomb;
 
+  Distance detectable= ceil(tra->detectable * MARGIN_TRAINLENGTH);
+
   if (DEBUGP(safety,core)) {
     DPRINTF(safety,core," ***predicting*** %s%s ",
 	    tra->backwards?"-":"",tra->pname);
     qprintf_position(tra,DPRINTFA);
-    DPRINTFA(" %smaxspeed=%f%s stopdist=%d (speed %f, step %d%s)"
+    DPRINTFA(" det.able=%d %smaxspeed=%f%s stopdist=%d (speed %f, step %d%s)"
 	     " flags=%c%c%s desire=%s/%s\n",
+	     detectable,
 	     u.speed_info_specified ? "specified " : "",
 	     u.maxspeed, u.stopping ? "(stopping)" : "",
 	     u.stopping_distance,
@@ -772,17 +775,22 @@ ErrorCode predict(Train *tra, struct timeval tnow, unsigned flags,
    * so we must instead extend our idea of the length of the train.
    */
 
-  int tail_walkback= MARGIN_NOSE + tail_length(tra) +
-    ceil(tra->detectable * MARGIN_TRAINLENGTH);
-  int tail_advance_delaydist= MARGIN_TAIL;
+  int effective_uncertainty= tra->uncertainty;
+  int effective_length= MARGIN_NOSE + tail_length(tra) + detectable;
 
-  int effective_into_fdet= tra->maxinto - tra->uncertainty;
-  if (effective_into_fdet < 0) {
-    tail_advance_delaydist += effective_into_fdet;
-    effective_into_fdet -= effective_into_fdet;
-    assert(!effective_into_fdet);
+  if (effective_uncertainty > tra->maxinto) {
+    effective_length += tra->uncertainty - tra->maxinto;
+    effective_uncertainty= tra->maxinto;
   }
-  
+
+  int effective_into_fdet= tra->maxinto - effective_uncertainty;
+  int tail_advance_delaydist= MARGIN_TAIL;
+
+  DPRINTF(safety,core,"  predict eff.uncert=%d eff.len=%d"
+	  " eff.into_fdet=%d tail.adv.delay=%d\n",
+	  effective_uncertainty, effective_length, 
+	  effective_into_fdet, tail_advance_delaydist);
+
   u.fdetc.u= &u;
   u.fdetc.getmovpos= pred_getmovpos;
 
@@ -798,7 +806,7 @@ ErrorCode predict(Train *tra, struct timeval tnow, unsigned flags,
   u.tailc.getmovpos= pred_getmovpos;
   u.tailc.nextseg= initpresent_nextseg;
   u.tailc.trackend= pred_trackend_panic;
-  u.tailc.distance= tail_walkback;
+  u.tailc.distance= effective_length;
 
   u.tail= u.fdet;
 
@@ -837,7 +845,7 @@ ErrorCode predict(Train *tra, struct timeval tnow, unsigned flags,
     /* we actually know exactly where we are */
     u.fdetc.distance= 0;
   } else { /* stopping, but we're mid-segment */
-    u.fdetc.distance= tra->uncertainty;
+    u.fdetc.distance= effective_uncertainty;
   }
   u.elapsed= -u.fdetc.distance / u.maxspeed; /* imagine we're already there */
   u.fdetc.distance += u.stopping_distance + MARGIN_NOSE;
-- 
2.30.2