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Revise implementation of jerry_port_get_local_time_zone_adjustment on…
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… Win32

Handle the limitation of Win32 date API properly.

JerryScript-DCO-1.0-Signed-off-by: Yonggang Luo [email protected]
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lygstate committed Nov 14, 2024
1 parent 43f5026 commit da3d472
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Showing 2 changed files with 32 additions and 2 deletions.
33 changes: 31 additions & 2 deletions jerry-port/win/jerry-port-win-date.c
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,18 @@
#define UNIX_EPOCH_IN_TICKS 116444736000000000ull /* difference between 1970 and 1601 */
#define TICKS_PER_MS 10000ull /* 1 tick is 100 nanoseconds */

/*
* If you take the limit of SYSTEMTIME (last millisecond in 30827) then you end up with
* a FILETIME of 0x7fff35f4f06c58f0 by using SystemTimeToFileTime(). However, if you put
* 0x7fffffffffffffff into FileTimeToSystemTime() then you will end up in the year 30828,
* although this date is invalid for SYSTEMTIME. Any larger value (0x8000000000000000 and above)
* causes FileTimeToSystemTime() to fail.
* https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-systemtime
* https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-filetime
*/
#define UNIX_EPOCH_DATE_1601_01_02 -11644387200000LL /* unit: ms */
#define UNIX_EPOCH_DATE_30827_12_29 9106702560000000LL /* unit: ms */

/**
* Convert unix time to a FILETIME value.
*
Expand All @@ -44,7 +56,7 @@ unix_time_to_filetime (double t, LPFILETIME ft_p)

ft_p->dwLowDateTime = (DWORD) ll;
ft_p->dwHighDateTime = (DWORD) (ll >> 32);
} /* unix_time_to_file_time */
} /* unix_time_to_filetime */

/**
* Convert a FILETIME to a unix time value.
Expand All @@ -58,7 +70,7 @@ filetime_to_unix_time (LPFILETIME ft_p)
date.HighPart = ft_p->dwHighDateTime;
date.LowPart = ft_p->dwLowDateTime;
return (double) (((LONGLONG) date.QuadPart - UNIX_EPOCH_IN_TICKS) / TICKS_PER_MS);
} /* FileTimeToUnixTimeMs */
} /* filetime_to_unix_time */

/**
* Default implementation of jerry_port_local_tza.
Expand All @@ -74,6 +86,23 @@ jerry_port_local_tza (double unix_ms)
SYSTEMTIME utc_sys;
SYSTEMTIME local_sys;

/*
* If the time is earlier than the date 1601-01-02, then always using date 1601-01-02 to
* query time zone adjustment. This date (1601-01-02) will make sure both UTC and local
* time succeed with Win32 API. The date 1601-01-01 may lead to a win32 api failure, as
* after converting between local time and utc time, the time may be earlier than 1601-01-01
* in UTC time, that exceeds the FILETIME representation range.
*/
if (unix_ms < (double) UNIX_EPOCH_DATE_1601_01_02)
{
unix_ms = (double) UNIX_EPOCH_DATE_1601_01_02;
}

/* Like above, do not use the last supported day */
if (unix_ms > (double) UNIX_EPOCH_DATE_30827_12_29)
{
unix_ms = (double) UNIX_EPOCH_DATE_30827_12_29;
}
unix_time_to_filetime (unix_ms, &utc);

if (FileTimeToSystemTime (&utc, &utc_sys) && SystemTimeToTzSpecificLocalTime (NULL, &utc_sys, &local_sys)
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1 change: 1 addition & 0 deletions tests/jerry/date-getters.js
Original file line number Diff line number Diff line change
Expand Up @@ -97,6 +97,7 @@ assert (isNaN (d.getTimezoneOffset()));
/* 5. test case */
assert (new Date(2013, -1).getMonth() === 11);
assert (new Date(-2, -2).getFullYear() === -3);
assert (new Date(30888, 2).getFullYear() === 30888);
assert (new Date(-1, -1).getFullYear() === -2);
assert (new Date(-1, -1, -1).getMonth() === 10);
assert (new Date(-1, -1, -1, -1).getDate() === 28);
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