[PATCH v2 7/8] Abort if the system time cannot handle one of our timestamps

[Johannes Schindelin]

We are about to switch to a new data type for time stamps that is
definitely not smaller or equal, but larger or equal to time_t.

So before using the system functions to process or format timestamps,
let's make extra certain that they can handle what we feed them.

Signed-off-by: Johannes Schindelin <johannes.schinde...@gmx.de>
---
 date.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/date.c b/date.c
index 92ab31aa441..db3435df3e4 100644
--- a/date.c
+++ b/date.c
@@ -43,10 +43,13 @@ static time_t gm_time_t(timestamp_t time, int tz)
 {
        int minutes;
 
+       if (date_overflows(time))
+               die("Timestamp too large for this system: %"PRItime, time);
+
        minutes = tz < 0 ? -tz : tz;
        minutes = (minutes / 100)*60 + (minutes % 100);
        minutes = tz < 0 ? -minutes : minutes;
-       return time + minutes * 60;
+       return (time_t)time + minutes * 60;
 }
 
 /*
@@ -56,7 +59,12 @@ static time_t gm_time_t(timestamp_t time, int tz)
  */
 static struct tm *time_to_tm(timestamp_t time, int tz)
 {
-       time_t t = gm_time_t(time, tz);
+       time_t t;
+
+       if (date_overflows(time))
+               die("Timestamp too large for this system: %"PRItime, time);
+
+       t = gm_time_t((time_t)time, tz);
        return gmtime(&t);
 }
 
@@ -70,7 +78,10 @@ static int local_tzoffset(timestamp_t time)
        struct tm tm;
        int offset, eastwest;
 
-       t = time;
+       if (date_overflows(time))
+               die("Timestamp too large for this system: %"PRItime, time);
+
+       t = (time_t)time;
        localtime_r(&t, &tm);
        t_local = tm_to_time_t(&tm);
 
-- 
2.12.2.windows.1