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// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QCALENDARMATH_P_H
#define QCALENDARMATH_P_H
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists for the convenience
// of q*calendar.cpp. This header file may change from version to version
// without notice, or even be removed.
//
// We mean it.
//
#include <QtCore/private/qglobal_p.h>
QT_BEGIN_NAMESPACE
namespace QRoundingDown {
/*
Division, rounding down (rather than towards zero).
From C++11 onwards, integer division is defined to round towards zero, so we
can rely on that when implementing this. This is only used with denominator b
> 0, so we only have to treat negative numerator, a, specially.
If a is a multiple of b, adding 1 before and subtracting it after dividing by
b gets us to where we should be (albeit by an eccentric path), since the
adding caused rounding up, undone by the subtracting. Otherwise, adding 1
doesn't change the result of dividing by b; and we want one less than that
result. This is equivalent to subtracting b - 1 and simply dividing, except
when that subtraction would underflow.
*/
template<typename Int> constexpr Int qDiv(Int a, unsigned b)
{ return a < 0 ? (a + 1) / int(b) - 1 : a / int(b); }
template<typename Int> constexpr Int qMod(Int a, unsigned b)
{ return a - qDiv(a, b) * b; }
} // QRoundingDown
QT_END_NAMESPACE
#endif // QCALENDARMATH_P_H
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