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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 05:54:39 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 05:54:39 +0000 |
commit | 267c6f2ac71f92999e969232431ba04678e7437e (patch) | |
tree | 358c9467650e1d0a1d7227a21dac2e3d08b622b2 /include/comphelper/date.hxx | |
parent | Initial commit. (diff) | |
download | libreoffice-267c6f2ac71f92999e969232431ba04678e7437e.tar.xz libreoffice-267c6f2ac71f92999e969232431ba04678e7437e.zip |
Adding upstream version 4:24.2.0.upstream/4%24.2.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'include/comphelper/date.hxx')
-rw-r--r-- | include/comphelper/date.hxx | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/include/comphelper/date.hxx b/include/comphelper/date.hxx new file mode 100644 index 0000000000..22247f71fe --- /dev/null +++ b/include/comphelper/date.hxx @@ -0,0 +1,123 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * This file incorporates work covered by the following license notice: + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed + * with this work for additional information regarding copyright + * ownership. The ASF licenses this file to you under the Apache + * License, Version 2.0 (the "License"); you may not use this file + * except in compliance with the License. You may obtain a copy of + * the License at http://www.apache.org/licenses/LICENSE-2.0 . + */ +#pragma once + +#include <sal/config.h> +#include <sal/types.h> +#include <comphelper/comphelperdllapi.h> + +#include <cassert> + +namespace comphelper::date +{ +/** Days until start of year from zero, so month and day of month can be added. + + year 1 => 0 days, year 2 => 365 days, ... + year -1 => -366 days, year -2 => -731 days, ... + + @param nYear + MUST be != 0. + */ +constexpr inline sal_Int32 YearToDays(sal_Int16 nYear) +{ + assert(nYear != 0); + auto val = [](int off, int y) { return off + y * 365 + y / 4 - y / 100 + y / 400; }; + return nYear < 0 ? val(-366, nYear + 1) : val(0, nYear - 1); +} + +/** Whether year is a leap year. + + Leap years BCE are -1, -5, -9, ... + See + https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar#Usage + https://en.wikipedia.org/wiki/0_(year)#History_of_astronomical_usage + + @param nYear + MUST be != 0. + */ +constexpr inline bool isLeapYear(sal_Int16 nYear) +{ + assert(nYear != 0); + if (nYear < 0) + nYear = -nYear - 1; + return (((nYear % 4) == 0) && ((nYear % 100) != 0)) || ((nYear % 400) == 0); +} + +/** Get number of days in month of year. + + @param nYear + MUST be != 0. + */ +constexpr inline sal_uInt16 getDaysInMonth(sal_uInt16 nMonth, sal_Int16 nYear) +{ + assert(1 <= nMonth && nMonth <= 12); + if (nMonth < 1 || 12 < nMonth) + return 0; + + constexpr sal_uInt16 aDaysInMonth[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; + sal_uInt16 n = aDaysInMonth[nMonth - 1]; + return nMonth == 2 && isLeapYear(nYear) ? n + 1 : n; +} + +/** Obtain days from zero for a given date, without normalizing. + + nDay, nMonth, nYear MUST form a valid proleptic Gregorian calendar date. + */ +constexpr inline sal_Int32 convertDateToDays(sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear) +{ + sal_Int32 nDays = YearToDays(nYear); + for (sal_uInt16 i = 1; i < nMonth; ++i) + nDays += getDaysInMonth(i, nYear); + nDays += nDay; + return nDays; +} + +/** Obtain days from zero for a given date, with normalizing. + + nDay, nMonth, nYear may be out-of-bounds and are adjusted/normalized. + + @param nYear + Must be != 0, unless nMonth > 12. + */ +COMPHELPER_DLLPUBLIC sal_Int32 convertDateToDaysNormalizing(sal_uInt16 nDay, sal_uInt16 nMonth, + sal_Int16 nYear); + +/** Whether date is a valid date. + */ +COMPHELPER_DLLPUBLIC bool isValidDate(sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear); + +/** Obtain date for a days from zero value. + */ +COMPHELPER_DLLPUBLIC void convertDaysToDate(sal_Int32 nDays, sal_uInt16& rDay, sal_uInt16& rMonth, + sal_Int16& rYear); + +/** Normalize date, i.e. add days or months to form a proper proleptic + Gregorian calendar date, unless all values are 0. + + @param rYear + Must be != 0, unless rMonth > 12. + + @return <TRUE/> if date was normalized, <FALSE/> if it was valid already + or empty (all values 0). + */ +COMPHELPER_DLLPUBLIC bool normalize(sal_uInt16& rDay, sal_uInt16& rMonth, sal_Int16& rYear); + +} // namespace comphelper::date + +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |