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/* $Id $ */
/** @file
* IPRT - Local Time, Posix.
*/
/*
* Copyright (C) 2006-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#define LOG_GROUP RTLOGGROUP_TIME
#define RTTIME_INCL_TIMEVAL
#include <iprt/types.h>
#include <iprt/assert.h>
#include <sys/time.h>
#include <time.h>
#include <iprt/time.h>
/**
* This tries to find the UTC offset for a given timespec.
*
* It does probably not take into account changes in daylight
* saving over the years or similar stuff.
*
* @returns UTC offset in nanoseconds.
* @param pTime The time.
* @param fCurrentTime Whether the input is current time or not.
* This is for avoid infinit recursion on errors in the fallback path.
*/
static int64_t rtTimeLocalUTCOffset(PCRTTIMESPEC pTime, bool fCurrentTime)
{
RTTIMESPEC Fallback;
/*
* Convert to time_t.
*/
int64_t i64UnixTime = RTTimeSpecGetSeconds(pTime);
time_t UnixTime = i64UnixTime;
if (UnixTime != i64UnixTime)
return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
/*
* Explode it as both local and UTC time.
*/
struct tm TmLocal;
if ( !localtime_r(&UnixTime, &TmLocal)
|| !TmLocal.tm_year)
return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
struct tm TmUtc;
if (!gmtime_r(&UnixTime, &TmUtc))
return fCurrentTime ? 0 : rtTimeLocalUTCOffset(RTTimeNow(&Fallback), true);
/*
* Calc the difference (if any).
* We ASSUME that the difference is less that 24 hours.
*/
if ( TmLocal.tm_hour == TmUtc.tm_hour
&& TmLocal.tm_min == TmUtc.tm_min
&& TmLocal.tm_sec == TmUtc.tm_sec
&& TmLocal.tm_mday == TmUtc.tm_mday)
return 0;
int cLocalSecs = TmLocal.tm_hour * 3600
+ TmLocal.tm_min * 60
+ TmLocal.tm_sec;
int cUtcSecs = TmUtc.tm_hour * 3600
+ TmUtc.tm_min * 60
+ TmUtc.tm_sec;
if (TmLocal.tm_mday != TmUtc.tm_mday)
{
/*
* Must add 24 hours to the value that is ahead of the other.
*
* To determine which is ahead was busted for a long long time (bugref:9078),
* so here are some examples and two different approaches.
*
* TmLocal TmUtc => Add 24:00 to => Diff
* 2007-04-02 01:00 2007-04-01 23:00 => TmLocal => +02:00
* 2007-04-01 01:00 2007-03-31 23:00 => TmLocal => +02:00
* 2007-03-31 01:00 2007-03-30 23:00 => TmLocal => +02:00
*
* 2007-04-01 01:00 2007-04-02 23:00 => TmUtc => -02:00
* 2007-03-31 23:00 2007-04-01 01:00 => TmUtc => -02:00
* 2007-03-30 23:00 2007-03-31 01:00 => TmUtc => -02:00
*
*/
#if 0
/* Using day of month turned out to be a little complicated. */
if ( ( TmLocal.tm_mday > TmUtc.tm_mday
&& (TmUtc.tm_mday != 1 || TmLocal.tm_mday < 28) )
|| (TmLocal.tm_mday == 1 && TmUtc.tm_mday >= 28) )
{
cLocalSecs += 24*60*60;
Assert( TmLocal.tm_yday - TmUtc.tm_yday == 1
|| (TmLocal.tm_yday == 0 && TmUtc.tm_yday >= 364 && TmLocal.tm_year == TmUtc.tm_year + 1));
}
else
{
cUtcSecs += 24*60*60;
Assert( TmUtc.tm_yday - TmLocal.tm_yday == 1
|| (TmUtc.tm_yday == 0 && TmLocal.tm_yday >= 364 && TmUtc.tm_year == TmLocal.tm_year + 1));
}
#else
/* Using day of year and year is simpler. */
if ( ( TmLocal.tm_year == TmUtc.tm_year
&& TmLocal.tm_yday > TmUtc.tm_yday)
|| TmLocal.tm_year > TmUtc.tm_year)
{
cLocalSecs += 24*60*60;
Assert( TmLocal.tm_yday - TmUtc.tm_yday == 1
|| (TmLocal.tm_yday == 0 && TmUtc.tm_yday >= 364 && TmLocal.tm_year == TmUtc.tm_year + 1));
}
else
{
cUtcSecs += 24*60*60;
Assert( TmUtc.tm_yday - TmLocal.tm_yday == 1
|| (TmUtc.tm_yday == 0 && TmLocal.tm_yday >= 364 && TmUtc.tm_year == TmLocal.tm_year + 1));
}
#endif
}
return (cLocalSecs - cUtcSecs) * INT64_C(1000000000);
}
/**
* Gets the current delta between UTC and local time.
*
* @code
* RTTIMESPEC LocalTime;
* RTTimeSpecAddNano(RTTimeNow(&LocalTime), RTTimeLocalDeltaNano());
* @endcode
*
* @returns Returns the nanosecond delta between UTC and local time.
*/
RTDECL(int64_t) RTTimeLocalDeltaNano(void)
{
RTTIMESPEC Time;
return rtTimeLocalUTCOffset(RTTimeNow(&Time), true /* current time, skip fallback */);
}
/**
* Gets the delta between UTC and local time at the given time.
*
* @code
* RTTIMESPEC LocalTime;
* RTTimeNow(&LocalTime);
* RTTimeSpecAddNano(&LocalTime, RTTimeLocalDeltaNanoFor(&LocalTime));
* @endcode
*
* @param pTimeSpec The time spec giving the time to get the delta for.
* @returns Returns the nanosecond delta between UTC and local time.
*/
RTDECL(int64_t) RTTimeLocalDeltaNanoFor(PCRTTIMESPEC pTimeSpec)
{
AssertPtr(pTimeSpec);
return rtTimeLocalUTCOffset(pTimeSpec, false /* current time, skip fallback */);
}
/**
* Explodes a time spec to the localized timezone.
*
* @returns pTime.
* @param pTime Where to store the exploded time.
* @param pTimeSpec The time spec to exploded. (UTC)
*/
RTDECL(PRTTIME) RTTimeLocalExplode(PRTTIME pTime, PCRTTIMESPEC pTimeSpec)
{
RTTIMESPEC LocalTime = *pTimeSpec;
int64_t cNsUtcOffset = rtTimeLocalUTCOffset(&LocalTime, true /* current time, skip fallback */);
RTTimeSpecAddNano(&LocalTime, cNsUtcOffset);
pTime = RTTimeExplode(pTime, &LocalTime);
if (pTime)
{
pTime->fFlags = (pTime->fFlags & ~RTTIME_FLAGS_TYPE_MASK) | RTTIME_FLAGS_TYPE_LOCAL;
pTime->offUTC = cNsUtcOffset / RT_NS_1MIN;
}
return pTime;
}
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