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/****************************************************************************
**
** Copyright (C) 2020 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:COMM$
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** $QT_END_LICENSE$
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
**
******************************************************************************/
#ifndef QCOMPARE_H
#define QCOMPARE_H
#if 0
#pragma qt_class(QtCompare)
#endif
#include <QtCore/qglobal.h>
QT_BEGIN_NAMESPACE
namespace QtPrivate {
using CompareUnderlyingType = qint8;
// [cmp.categories.pre] / 1
enum class Ordering : CompareUnderlyingType
{
Equal = 0,
Equivalent = Equal,
Less = -1,
Greater = 1
};
enum class Uncomparable : CompareUnderlyingType
{
Unordered = -127
};
// [cmp.categories.pre] / 3, but using a safe bool trick
// and also rejecting std::nullptr_t (unlike the example)
class CompareAgainstLiteralZero {
public:
using SafeZero = void (CompareAgainstLiteralZero::*)();
Q_IMPLICIT constexpr CompareAgainstLiteralZero(SafeZero) noexcept {}
template <typename T, std::enable_if_t<!std::is_same_v<T, int>, bool> = false>
CompareAgainstLiteralZero(T) = delete;
};
} // namespace QtPrivate
// [cmp.partialord]
class QPartialOrdering
{
public:
static const QPartialOrdering Less;
static const QPartialOrdering Equivalent;
static const QPartialOrdering Greater;
static const QPartialOrdering Unordered;
friend constexpr bool operator==(QPartialOrdering p, QtPrivate::CompareAgainstLiteralZero) noexcept
{ return p.isOrdered() && p.m_order == 0; }
friend constexpr bool operator!=(QPartialOrdering p, QtPrivate::CompareAgainstLiteralZero) noexcept
{ return p.isOrdered() && p.m_order != 0; }
friend constexpr bool operator< (QPartialOrdering p, QtPrivate::CompareAgainstLiteralZero) noexcept
{ return p.isOrdered() && p.m_order < 0; }
friend constexpr bool operator<=(QPartialOrdering p, QtPrivate::CompareAgainstLiteralZero) noexcept
{ return p.isOrdered() && p.m_order <= 0; }
friend constexpr bool operator> (QPartialOrdering p, QtPrivate::CompareAgainstLiteralZero) noexcept
{ return p.isOrdered() && p.m_order > 0; }
friend constexpr bool operator>=(QPartialOrdering p, QtPrivate::CompareAgainstLiteralZero) noexcept
{ return p.isOrdered() && p.m_order >= 0; }
friend constexpr bool operator==(QtPrivate::CompareAgainstLiteralZero, QPartialOrdering p) noexcept
{ return p.isOrdered() && 0 == p.m_order; }
friend constexpr bool operator!=(QtPrivate::CompareAgainstLiteralZero, QPartialOrdering p) noexcept
{ return p.isOrdered() && 0 != p.m_order; }
friend constexpr bool operator< (QtPrivate::CompareAgainstLiteralZero, QPartialOrdering p) noexcept
{ return p.isOrdered() && 0 < p.m_order; }
friend constexpr bool operator<=(QtPrivate::CompareAgainstLiteralZero, QPartialOrdering p) noexcept
{ return p.isOrdered() && 0 <= p.m_order; }
friend constexpr bool operator> (QtPrivate::CompareAgainstLiteralZero, QPartialOrdering p) noexcept
{ return p.isOrdered() && 0 > p.m_order; }
friend constexpr bool operator>=(QtPrivate::CompareAgainstLiteralZero, QPartialOrdering p) noexcept
{ return p.isOrdered() && 0 >= p.m_order; }
friend constexpr bool operator==(QPartialOrdering p1, QPartialOrdering p2) noexcept
{ return p1.m_order == p2.m_order; }
friend constexpr bool operator!=(QPartialOrdering p1, QPartialOrdering p2) noexcept
{ return p1.m_order != p2.m_order; }
private:
constexpr explicit QPartialOrdering(QtPrivate::Ordering order) noexcept
: m_order(static_cast<QtPrivate::CompareUnderlyingType>(order))
{}
constexpr explicit QPartialOrdering(QtPrivate::Uncomparable order) noexcept
: m_order(static_cast<QtPrivate::CompareUnderlyingType>(order))
{}
// instead of the exposition only is_ordered member in [cmp.partialord],
// use a private function
constexpr bool isOrdered() noexcept
{ return m_order != static_cast<QtPrivate::CompareUnderlyingType>(QtPrivate::Uncomparable::Unordered); }
QtPrivate::CompareUnderlyingType m_order;
};
inline constexpr QPartialOrdering QPartialOrdering::Less(QtPrivate::Ordering::Less);
inline constexpr QPartialOrdering QPartialOrdering::Equivalent(QtPrivate::Ordering::Equivalent);
inline constexpr QPartialOrdering QPartialOrdering::Greater(QtPrivate::Ordering::Greater);
inline constexpr QPartialOrdering QPartialOrdering::Unordered(QtPrivate::Uncomparable::Unordered);
QT_END_NAMESPACE
#endif // QCOMPARE_H
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