From 486da2bb5bcb70beec81b7c3064a7b157999a855 Mon Sep 17 00:00:00 2001
From: asund <andrewsund@andrewsund.net>
Date: Mon, 25 Sep 2017 09:23:26 -0700
Subject: [PATCH] Small fixes to minmea_gettime * Handle four digit years
 provided by ZDA in minmea_gettime * Assume GPS epoch to allow dates prior
 2000 to be parsed

---
 minmea.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/minmea.c b/minmea.c
index 960cbbe..3b228dd 100644
--- a/minmea.c
+++ b/minmea.c
@@ -619,7 +619,11 @@ int minmea_gettime(struct timespec *ts, const struct minmea_date *date, const st
 
     struct tm tm;
     memset(&tm, 0, sizeof(tm));
-    tm.tm_year = 2000 + date->year - 1900;
+    tm.tm_year = date->year % 100;  // ZDA parser stores 4 digit year, filter centuries here so raw information is still preserved for user.
+    if (tm.tm_year < 80)    // GPS epoch begins 1980, assume a year range of 1980 to 2079 for the library.
+    {
+        tm.tm_year += 2000 - 1900;
+    }
     tm.tm_mon = date->month - 1;
     tm.tm_mday = date->day;
     tm.tm_hour = time_->hours;