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/*
* Copyright 2007-2020 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 "Math.hxx"
#include "Calendar.hxx"
#include "Convert.hxx"
#include <time.h>
std::chrono::system_clock::time_point
PrecedingMidnightLocal(std::chrono::system_clock::time_point t) noexcept
try {
auto tm = LocalTime(t);
tm.tm_sec = 0;
tm.tm_min = 0;
tm.tm_hour = 0;
return MakeTime(tm);
} catch (...) {
/* best-effort fallback for this exotic error condition */
return t;
}
static void
IncrementMonth(struct tm &tm) noexcept
{
++tm.tm_mon;
if (tm.tm_mon >= 12) {
/* roll over to next year */
tm.tm_mon = 0;
++tm.tm_year;
}
}
void
EndOfMonth(struct tm &tm) noexcept
{
tm.tm_sec = 0;
tm.tm_min = 0;
tm.tm_hour = 0;
tm.tm_mday = 1;
IncrementMonth(tm);
}
void
IncrementDay(struct tm &tm) noexcept
{
const unsigned max_day = DaysInMonth(tm.tm_mon + 1, tm.tm_year + 1900);
++tm.tm_mday;
if ((unsigned)tm.tm_mday > max_day) {
/* roll over to next month */
tm.tm_mday = 1;
IncrementMonth(tm);
}
++tm.tm_wday;
if (tm.tm_wday >= 7)
tm.tm_wday = 0;
}
void
DecrementDay(struct tm &tm) noexcept
{
--tm.tm_mday;
if (tm.tm_mday < 1) {
/* roll over to previous month */
--tm.tm_mon;
if (tm.tm_mon < 0) {
/* roll over to previous eyar */
tm.tm_mon = 11;
--tm.tm_year;
}
const unsigned max_day = DaysInMonth(tm.tm_mon + 1,
tm.tm_year + 1900);
tm.tm_mday = max_day;
}
--tm.tm_wday;
if (tm.tm_wday < 0)
tm.tm_wday = 6;
}
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