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/* -*- 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 .
*/
#include <comphelper/date.hxx>
#include <cassert>
namespace comphelper::date
{
// Once upon a time the number of days we internally handled in tools' class
// Date was limited to MAX_DAYS 3636532. That changed with a full 16-bit year.
// Assuming the first valid positive date in a proleptic Gregorian calendar is
// 0001-01-01, this resulted in an end date of 9957-06-26.
// Hence we documented that years up to and including 9956 are handled.
/* XXX: it is unclear history why this value was chosen, the representable
* 9999-12-31 would be 3652060 days from 0001-01-01. Even 9998-12-31 to
* distinguish from a maximum possible date would be 3651695.
* There is connectivity/source/commontools/dbconversion.cxx that still has the
* same value to calculate with css::util::Date */
/* XXX can that dbconversion cope with years > 9999 or negative years at all?
* Database fields may be limited to positive 4 digits. */
constexpr sal_Int32 MIN_DAYS = -11968265; // -32768-01-01
constexpr sal_Int32 MAX_DAYS = 11967900; // 32767-12-31
constexpr sal_Int16 kYearMax = SAL_MAX_INT16;
constexpr sal_Int16 kYearMin = SAL_MIN_INT16;
constexpr sal_Int32 nNullDateDays = convertDateToDays(30, 12, 1899);
static_assert(nNullDateDays == 693594);
sal_Int32 convertDateToDaysNormalizing(sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear)
{
// Speed-up the common null-date 1899-12-30.
if (nYear == 1899 && nMonth == 12 && nDay == 30)
return nNullDateDays;
normalize(nDay, nMonth, nYear);
return convertDateToDays(nDay, nMonth, nYear);
}
bool isValidDate(sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear)
{
if (nYear == 0)
return false;
if (nMonth < 1 || 12 < nMonth)
return false;
if (nDay < 1 || (nDay > comphelper::date::getDaysInMonth(nMonth, nYear)))
return false;
return true;
}
void convertDaysToDate(sal_Int32 nDays, sal_uInt16& rDay, sal_uInt16& rMonth, sal_Int16& rYear)
{
if (nDays <= MIN_DAYS)
{
rDay = 1;
rMonth = 1;
rYear = kYearMin;
return;
}
if (nDays >= MAX_DAYS)
{
rDay = 31;
rMonth = 12;
rYear = kYearMax;
return;
}
// Day 0 is -0001-12-31, day 1 is 0001-01-01
const sal_Int16 nSign = (nDays <= 0 ? -1 : 1);
sal_Int32 nTempDays;
sal_Int32 i = 0;
bool bCalc;
do
{
rYear = static_cast<sal_Int16>((nDays / 365) - (i * nSign));
if (rYear == 0)
rYear = nSign;
nTempDays = nDays - YearToDays(rYear);
bCalc = false;
if (nTempDays < 1)
{
i += nSign;
bCalc = true;
}
else
{
if (nTempDays > 365)
{
if ((nTempDays != 366) || !isLeapYear(rYear))
{
i -= nSign;
bCalc = true;
}
}
}
} while (bCalc);
rMonth = 1;
while (nTempDays > getDaysInMonth(rMonth, rYear))
{
nTempDays -= getDaysInMonth(rMonth, rYear);
++rMonth;
}
rDay = static_cast<sal_uInt16>(nTempDays);
}
bool normalize(sal_uInt16& rDay, sal_uInt16& rMonth, sal_Int16& rYear)
{
if (isValidDate(rDay, rMonth, rYear))
return false;
if (rDay == 0 && rMonth == 0 && rYear == 0)
return false; // empty date
if (rDay == 0)
{
if (rMonth == 0)
; // nothing, handled below
else
--rMonth;
// Last day of month is determined at the end.
}
if (rMonth > 12)
{
rYear += rMonth / 12;
rMonth = rMonth % 12;
if (rYear == 0)
rYear = 1;
}
if (rMonth == 0)
{
--rYear;
if (rYear == 0)
rYear = -1;
rMonth = 12;
}
if (rYear < 0)
{
sal_uInt16 nDays;
while (rDay > (nDays = getDaysInMonth(rMonth, rYear)))
{
rDay -= nDays;
if (rMonth > 1)
--rMonth;
else
{
if (rYear == kYearMin)
{
rDay = 1;
rMonth = 1;
return true;
}
--rYear;
rMonth = 12;
}
}
}
else
{
sal_uInt16 nDays;
while (rDay > (nDays = getDaysInMonth(rMonth, rYear)))
{
rDay -= nDays;
if (rMonth < 12)
++rMonth;
else
{
if (rYear == kYearMax)
{
rDay = 31;
rMonth = 12;
return true;
}
++rYear;
rMonth = 1;
}
}
}
if (rDay == 0)
rDay = getDaysInMonth(rMonth, rYear);
return true;
}
} // namespace comphelper::date
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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