inline int utc_minutes_offset()

in src/main/cpp/sdk/common/spdlog/details/os.h [249:311]

• 49 lines of code
• 5 McCabe index (conditional complexity)

inline int utc_minutes_offset(const std::tm &tm = details::os::localtime())
{

#ifdef _WIN32
#if _WIN32_WINNT < _WIN32_WINNT_WS08
    TIME_ZONE_INFORMATION tzinfo;
    auto rv = GetTimeZoneInformation(&tzinfo);
#else
    DYNAMIC_TIME_ZONE_INFORMATION tzinfo;
    auto rv = GetDynamicTimeZoneInformation(&tzinfo);
#endif
    if (rv == TIME_ZONE_ID_INVALID)
        throw spdlog::spdlog_ex("Failed getting timezone info. ", errno);

    int offset = -tzinfo.Bias;
    if (tm.tm_isdst)
    {
        offset -= tzinfo.DaylightBias;
    }
    else
    {
        offset -= tzinfo.StandardBias;
    }
    return offset;
#else

#if defined(sun) || defined(__sun) || defined(_AIX)
    // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
    struct helper
    {
        static long int calculate_gmt_offset(const std::tm &localtm = details::os::localtime(), const std::tm &gmtm = details::os::gmtime())
        {
            int local_year = localtm.tm_year + (1900 - 1);
            int gmt_year = gmtm.tm_year + (1900 - 1);

            long int days = (
                // difference in day of year
                localtm.tm_yday -
                gmtm.tm_yday

                // + intervening leap days
                + ((local_year >> 2) - (gmt_year >> 2)) - (local_year / 100 - gmt_year / 100) +
                ((local_year / 100 >> 2) - (gmt_year / 100 >> 2))

                // + difference in years * 365 */
                + (long int)(local_year - gmt_year) * 365);

            long int hours = (24 * days) + (localtm.tm_hour - gmtm.tm_hour);
            long int mins = (60 * hours) + (localtm.tm_min - gmtm.tm_min);
            long int secs = (60 * mins) + (localtm.tm_sec - gmtm.tm_sec);

            return secs;
        }
    };

    auto offset_seconds = helper::calculate_gmt_offset(tm);
#else
    auto offset_seconds = tm.tm_gmtoff;
#endif

    return static_cast<int>(offset_seconds / 60);
#endif
}