}
-int64_t FileTimeToInt64(FILETIME ft) {
- ULARGE_INTEGER result;
- result.LowPart = ft.dwLowDateTime;
- result.HighPart = ft.dwHighDateTime;
- return static_cast<int64_t>(result.QuadPart);
-}
-
-
// Return the local timezone offset in milliseconds east of UTC. This
// takes into account whether daylight saving is in effect at the time.
// Only times in the 32-bit Unix range may be passed to this function.
// Also, adding the time-zone offset to the input must not overflow.
// The function EquivalentTime() in date.js guarantees this.
int64_t Win32Time::LocalOffset(TimezoneCache* cache) {
- FILETIME local;
- SYSTEMTIME system_utc, system_local;
- FileTimeToSystemTime(&time_.ft_, &system_utc);
- SystemTimeToTzSpecificLocalTime(NULL, &system_utc, &system_local);
- SystemTimeToFileTime(&system_local, &local);
- return (FileTimeToInt64(local) - FileTimeToInt64(time_.ft_)) / kTimeScaler;
+ cache->InitializeIfNeeded();
+
+ Win32Time rounded_to_second(*this);
+ rounded_to_second.t() =
+ rounded_to_second.t() / 1000 / kTimeScaler * 1000 * kTimeScaler;
+ // Convert to local time using POSIX localtime function.
+ // Windows XP Service Pack 3 made SystemTimeToTzSpecificLocalTime()
+ // very slow. Other browsers use localtime().
+
+ // Convert from JavaScript milliseconds past 1/1/1970 0:00:00 to
+ // POSIX seconds past 1/1/1970 0:00:00.
+ double unchecked_posix_time = rounded_to_second.ToJSTime() / 1000;
+ if (unchecked_posix_time > INT_MAX || unchecked_posix_time < 0) {
+ return 0;
+ }
+ // Because _USE_32BIT_TIME_T is defined, time_t is a 32-bit int.
+ time_t posix_time = static_cast<time_t>(unchecked_posix_time);
+
+ // Convert to local time, as struct with fields for day, hour, year, etc.
+ tm posix_local_time_struct;
+ if (localtime_s(&posix_local_time_struct, &posix_time)) return 0;
+
+ if (posix_local_time_struct.tm_isdst > 0) {
+ return (cache->tzinfo_.Bias + cache->tzinfo_.DaylightBias) * -kMsPerMinute;
+ } else if (posix_local_time_struct.tm_isdst == 0) {
+ return (cache->tzinfo_.Bias + cache->tzinfo_.StandardBias) * -kMsPerMinute;
+ } else {
+ return cache->tzinfo_.Bias * -kMsPerMinute;
+ }
}