date.hxx

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#pragma once
 
#include <sal/config.h>
#include <sal/types.h>
#include <comphelper/comphelperdllapi.h>
 
#include <cassert>
 
namespace comphelper::date
{
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);
}
 
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);
}
 
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;
}
 
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;
}
 
COMPHELPER_DLLPUBLIC sal_Int32 convertDateToDaysNormalizing(sal_uInt16 nDay, sal_uInt16 nMonth,
                                                            sal_Int16 nYear);
 
COMPHELPER_DLLPUBLIC bool isValidDate(sal_uInt16 nDay, sal_uInt16 nMonth, sal_Int16 nYear);
 
COMPHELPER_DLLPUBLIC void convertDaysToDate(sal_Int32 nDays, sal_uInt16& rDay, sal_uInt16& rMonth,
                                            sal_Int16& rYear);
 
COMPHELPER_DLLPUBLIC bool normalize(sal_uInt16& rDay, sal_uInt16& rMonth, sal_Int16& rYear);
 
} // namespace comphelper::date
 
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