From 1d7696fb6aafcedfd01c6b517884e272909d2dcc Mon Sep 17 00:00:00 2001
From: Mark Liversedge <liversedge@gmail.com>
Date: Sat, 6 Aug 2011 17:45:20 +0100
Subject: [PATCH] Fit files sometimes go backwards

FIT record type '253' occasionally causes time to go
backwards, this might be a decoding error, but for now
we force time to go forward anyway.

Looking at bad files GPS data with this patch suggests
this is the correct behaviour.

Fixes #104.
---
 src/FitRideFile.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/FitRideFile.cpp b/src/FitRideFile.cpp
index 881a31f72..b3fc6bd5e 100644
--- a/src/FitRideFile.cpp
+++ b/src/FitRideFile.cpp
@@ -326,7 +326,11 @@ struct FitFileReaderState
                 continue;
 
             switch (field.num) {
-                case 253: time = value + qbase_time.toTime_t(); break;
+                case 253: time = value + qbase_time.toTime_t();
+                          // Time MUST NOT go backwards
+                          // You canny break the laws of physics, Jim
+                          if (time < last_time) time = last_time;
+                          break;
                 case 0: lati = value; break;
                 case 1: lngi = value; break;
                 case 2: alt = value / 5.0 - 500.0; break;