mpd/src/time/Zone.cxx
2022-06-01 22:35:04 +02:00

67 lines
2.0 KiB
C++

/*
* Copyright 2007-2022 CM4all GmbH
* All rights reserved.
*
* author: Max Kellermann <mk@cm4all.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "Zone.hxx"
#ifdef _WIN32
#include <profileapi.h>
#include <sysinfoapi.h>
#include <timezoneapi.h>
#else
#include <time.h>
#endif
int
GetTimeZoneOffset() noexcept
{
#ifdef _WIN32
TIME_ZONE_INFORMATION TimeZoneInformation;
DWORD tzi = GetTimeZoneInformation(&TimeZoneInformation);
int offset = -TimeZoneInformation.Bias * 60;
if (tzi == TIME_ZONE_ID_STANDARD)
offset -= TimeZoneInformation.StandardBias * 60;
if (tzi == TIME_ZONE_ID_DAYLIGHT)
offset -= TimeZoneInformation.DaylightBias * 60;
return offset;
#else
time_t t = 1234567890;
struct tm tm;
tm.tm_isdst = 0;
struct tm *p = &tm;
gmtime_r(&t, p);
return t - mktime(p);
#endif
}