+ int time_sec, time_year, time_month, time_day;
+ long time_jd;
+
+ /* Convert time and offset into julian day and seconds */
+ if (!julian_adj(tm, off_day, offset_sec, &time_jd, &time_sec))
+ return 0;
+
+ /* Convert Julian day back to date */
+
+ julian_to_date(time_jd, &time_year, &time_month, &time_day);
+
+ if (time_year < 1900 || time_year > 9999)
+ return 0;
+
+ /* Update tm structure */
+
+ tm->tm_year = time_year - 1900;
+ tm->tm_mon = time_month - 1;
+ tm->tm_mday = time_day;
+
+ tm->tm_hour = time_sec / 3600;
+ tm->tm_min = (time_sec / 60) % 60;
+ tm->tm_sec = time_sec % 60;
+
+ return 1;
+
+}
+
+int OPENSSL_gmtime_diff(int *pday, int *psec,
+ const struct tm *from, const struct tm *to)
+ {
+ int from_sec, to_sec, diff_sec;
+ long from_jd, to_jd, diff_day;
+ if (!julian_adj(from, 0, 0, &from_jd, &from_sec))
+ return 0;
+ if (!julian_adj(to, 0, 0, &to_jd, &to_sec))
+ return 0;
+ diff_day = to_jd - from_jd;
+ diff_sec = to_sec - from_sec;
+ /* Adjust differences so both positive or both negative */
+ if (diff_day > 0 && diff_sec < 0)
+ {
+ diff_day--;
+ diff_sec += SECS_PER_DAY;
+ }
+ if (diff_day < 0 && diff_sec > 0)
+ {
+ diff_day++;
+ diff_sec -= SECS_PER_DAY;
+ }
+
+ if (pday)
+ *pday = (int)diff_day;
+ if (psec)
+ *psec = diff_sec;
+
+ return 1;
+
+ }
+
+
+/* Convert tm structure and offset into julian day and seconds */
+static int julian_adj(const struct tm *tm, int off_day, long offset_sec,
+ long *pday, int *psec)
+ {