Function TimeGM

util/datetime/systime.cpp:184–207

Inverse of gmtime: converts struct tm to time_t, assuming the data in tm is UTC rather than local timezone. This implementation returns the number of seconds since 1970-01-01, converted to time_t. @note this code adopted from http://osdir.com/ml/web.wget.patches/2005-07/msg00010.html Subject: A more robust timegm - msg#00010

//!       http://osdir.com/ml/web.wget.patches/2005-07/msg00010.html
//!       Subject: A more robust timegm - msg#00010
time_t TimeGM(const struct tm* t) {
    // Only handles years after 1970
    if (Y_UNLIKELY(t->tm_year < 70)) {
        return (time_t)-1;
    }

    int days = 365 * (t->tm_year - 70);
    // Take into account the leap days between 1970 and YEAR-1
    days += (t->tm_year - 1 - 68) / 4 - ((t->tm_year - 1) / 100) + ((t->tm_year - 1 + 300) / 400);

    if (Y_UNLIKELY(t->tm_mon < 0 || t->tm_mon >= 12)) {
        return (time_t)-1;
    }
    if (IsLeapYear(1900 + t->tm_year)) {
        days += MONTH_TO_DAYS_LEAP[t->tm_mon];
    } else {
        days += MONTH_TO_DAYS[t->tm_mon];
    }

    days += t->tm_mday - 1;

    unsigned long secs = days * 86400ul + t->tm_hour * 3600 + t->tm_min * 60 + t->tm_sec;
    return (time_t)secs;
}

struct tm* GmTimeR(const time_t* timer, struct tm* tmbuf) {
    i64 time = static_cast<i64>(*timer);