+ /* Rebase from 1970 Unix epoch to fictitious year 0 (i.e. would-be
+ * year 1 BC had the Gregorian calendar already existed then) */
+ d.quot = 60LL * 60 * 24 * (4 * 146097 + 135140) + *timep;
+
+ d = lldiv (d.quot, 60); /* 60 seconds per minute */
+ if (*timep < 0)
+ {
+ d.rem += 60;
+ d.quot--;
+ }
+ tm->tm_sec = d.rem;
+
+ d = lldiv (d.quot, 60); /* 60 minutes per hour */
+ tm->tm_min = d.rem;
+
+ d = lldiv (d.quot, 24); /* 24 hours per day */
+ tm->tm_hour = d.rem;
+
+ tm->tm_wday = (d.quot + 6) % 7; /* 7 days per week */
+
+ d = lldiv (d.quot, 146097); /* 146097 days per 4 centuries */
+ tm->tm_year = 400 * d.quot;
+
+ if (d.rem >= 36525)
+ { /* Century with 24 leap years */
+ d.rem -= 36525;
+ tm->tm_year += 100;
+
+ d = lldiv (d.rem, 36524); /* 36524 days per normal century */
+ tm->tm_year += d.quot * 100;
+ if (d.rem >= 59) /* not in January or February of year 00 */
+ d.rem++; /* insert missing February 29th 00*/
+ }
+ tm->tm_year -= 1900; /* Rebase to 1900 for struct tm */
+
+ d = lldiv (d.rem, 1461); /* 1461 days per 4 years */
+ tm->tm_year += 4 * d.quot;
+
+ if (d.rem >= 366)
+ { /* Non-leap year */
+ d.rem -= 366;
+ tm->tm_year++;
+
+ d = lldiv (d.rem, 365); /* 365 days per normal year */
+ tm->tm_year += d.quot;
+ months = normal;
+ }
+ else
+ months = leap;
+ tm->tm_yday = d.rem;
+
+ for (tm->tm_mon = 0; d.rem >= months[tm->tm_mon]; tm->tm_mon++)
+ d.rem -= months[tm->tm_mon]; /* 28 to 31 days in a month */
+ tm->tm_mday = d.rem + 1;
+
+ tm->tm_isdst = 0; /* UTC time */
+ return tm;