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** Alternatively, this file may be used under the terms of the GNU Lesser
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** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
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****************************************************************************/

#ifndef QFLAGPOINTER_P_H
#define QFLAGPOINTER_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <QtCore/qglobal.h>

QT_BEGIN_NAMESPACE

namespace QtPrivate {
template <typename T> struct QFlagPointerAlignment
{
    enum : size_t { Value = Q_ALIGNOF(T) };
};
template <> struct QFlagPointerAlignment<void>
{
    enum : size_t { Value = ~size_t(0) };
};
}

template<typename T>
class QFlagPointer {
public:
    inline QFlagPointer();
    inline QFlagPointer(T *);
    inline QFlagPointer(const QFlagPointer<T> &o);

    inline bool isNull() const;

    inline bool flag() const;
    inline void setFlag();
    inline void clearFlag();
    inline void setFlagValue(bool);

    inline bool flag2() const;
    inline void setFlag2();
    inline void clearFlag2();
    inline void setFlag2Value(bool);

    inline QFlagPointer<T> &operator=(const QFlagPointer &o);
    inline QFlagPointer<T> &operator=(T *);

    inline T *operator->() const;
    inline T *operator*() const;

    inline T *data() const;

    inline explicit operator bool() const;

private:
    quintptr ptr_value = 0;

    static const quintptr FlagBit = 0x1;
    static const quintptr Flag2Bit = 0x2;
    static const quintptr FlagsMask = FlagBit | Flag2Bit;
};

template<typename T, typename T2>
class QBiPointer {
public:
    inline QBiPointer();
    inline QBiPointer(T *);
    inline QBiPointer(T2 *);
    inline QBiPointer(const QBiPointer<T, T2> &o);

    inline bool isNull() const;
    inline bool isT1() const;
    inline bool isT2() const;

    inline bool flag() const;
    inline void setFlag();
    inline void clearFlag();
    inline void setFlagValue(bool);

    inline QBiPointer<T, T2> &operator=(const QBiPointer<T, T2> &o);
    inline QBiPointer<T, T2> &operator=(T *);
    inline QBiPointer<T, T2> &operator=(T2 *);

    inline T *asT1() const;
    inline T2 *asT2() const;

private:
    quintptr ptr_value = 0;

    static const quintptr FlagBit = 0x1;
    static const quintptr Flag2Bit = 0x2;
    static const quintptr FlagsMask = FlagBit | Flag2Bit;
};

template<typename T>
QFlagPointer<T>::QFlagPointer()
{
}

template<typename T>
QFlagPointer<T>::QFlagPointer(T *v)
: ptr_value(quintptr(v))
{
    Q_STATIC_ASSERT_X(Q_ALIGNOF(T) >= 4, "Type T does not have sufficient alignment");
    Q_ASSERT((ptr_value & FlagsMask) == 0);
}

template<typename T>
QFlagPointer<T>::QFlagPointer(const QFlagPointer<T> &o)
: ptr_value(o.ptr_value)
{
}

template<typename T>
bool QFlagPointer<T>::isNull() const
{
    return 0 == (ptr_value & (~FlagsMask));
}

template<typename T>
bool QFlagPointer<T>::flag() const
{
    return ptr_value & FlagBit;
}

template<typename T>
void QFlagPointer<T>::setFlag()
{
    ptr_value |= FlagBit;
}

template<typename T>
void QFlagPointer<T>::clearFlag()
{
    ptr_value &= ~FlagBit;
}

template<typename T>
void QFlagPointer<T>::setFlagValue(bool v)
{
    if (v) setFlag();
    else clearFlag();
}

template<typename T>
bool QFlagPointer<T>::flag2() const
{
    return ptr_value & Flag2Bit;
}

template<typename T>
void QFlagPointer<T>::setFlag2()
{
    ptr_value|= Flag2Bit;
}

template<typename T>
void QFlagPointer<T>::clearFlag2()
{
    ptr_value &= ~Flag2Bit;
}

template<typename T>
void QFlagPointer<T>::setFlag2Value(bool v)
{
    if (v) setFlag2();
    else clearFlag2();
}

template<typename T>
QFlagPointer<T> &QFlagPointer<T>::operator=(const QFlagPointer &o)
{
    ptr_value = o.ptr_value;
    return *this;
}

template<typename T>
QFlagPointer<T> &QFlagPointer<T>::operator=(T *o)
{
    Q_ASSERT((quintptr(o) & FlagsMask) == 0);

    ptr_value = quintptr(o) | (ptr_value & FlagsMask);
    return *this;
}

template<typename T>
T *QFlagPointer<T>::operator->() const
{
    return (T *)(ptr_value & ~FlagsMask);
}

template<typename T>
T *QFlagPointer<T>::operator*() const
{
    return (T *)(ptr_value & ~FlagsMask);
}

template<typename T>
T *QFlagPointer<T>::data() const
{
    return (T *)(ptr_value & ~FlagsMask);
}

template<typename T>
QFlagPointer<T>::operator bool() const
{
    return data() != nullptr;
}

template<typename T, typename T2>
QBiPointer<T, T2>::QBiPointer()
{
}

template<typename T, typename T2>
QBiPointer<T, T2>::QBiPointer(T *v)
: ptr_value(quintptr(v))
{
    Q_STATIC_ASSERT_X(QtPrivate::QFlagPointerAlignment<T>::Value >= 4,
                      "Type T does not have sufficient alignment");
    Q_ASSERT((quintptr(v) & FlagsMask) == 0);
}

template<typename T, typename T2>
QBiPointer<T, T2>::QBiPointer(T2 *v)
: ptr_value(quintptr(v) | Flag2Bit)
{
    Q_STATIC_ASSERT_X(QtPrivate::QFlagPointerAlignment<T2>::Value >= 4,
                      "Type T2 does not have sufficient alignment");
    Q_ASSERT((quintptr(v) & FlagsMask) == 0);
}

template<typename T, typename T2>
QBiPointer<T, T2>::QBiPointer(const QBiPointer<T, T2> &o)
: ptr_value(o.ptr_value)
{
}

template<typename T, typename T2>
bool QBiPointer<T, T2>::isNull() const
{
    return 0 == (ptr_value & (~FlagsMask));
}

template<typename T, typename T2>
bool QBiPointer<T, T2>::isT1() const
{
    return !(ptr_value & Flag2Bit);
}

template<typename T, typename T2>
bool QBiPointer<T, T2>::isT2() const
{
    return ptr_value & Flag2Bit;
}

template<typename T, typename T2>
bool QBiPointer<T, T2>::flag() const
{
    return ptr_value & FlagBit;
}

template<typename T, typename T2>
void QBiPointer<T, T2>::setFlag()
{
    ptr_value |= FlagBit;
}

template<typename T, typename T2>
void QBiPointer<T, T2>::clearFlag()
{
    ptr_value &= ~FlagBit;
}

template<typename T, typename T2>
void QBiPointer<T, T2>::setFlagValue(bool v)
{
    if (v) setFlag();
    else clearFlag();
}

template<typename T, typename T2>
QBiPointer<T, T2> &QBiPointer<T, T2>::operator=(const QBiPointer<T, T2> &o)
{
    ptr_value = o.ptr_value;
    return *this;
}

template<typename T, typename T2>
QBiPointer<T, T2> &QBiPointer<T, T2>::operator=(T *o)
{
    Q_ASSERT((quintptr(o) & FlagsMask) == 0);

    ptr_value = quintptr(o) | (ptr_value & FlagBit);
    return *this;
}

template<typename T, typename T2>
QBiPointer<T, T2> &QBiPointer<T, T2>::operator=(T2 *o)
{
    Q_ASSERT((quintptr(o) & FlagsMask) == 0);

    ptr_value = quintptr(o) | (ptr_value & FlagBit) | Flag2Bit;
    return *this;
}

template<typename T, typename T2>
T *QBiPointer<T, T2>::asT1() const
{
    Q_ASSERT(isT1());
    return (T *)(ptr_value & ~FlagsMask);
}

template<typename T, typename T2>
T2 *QBiPointer<T, T2>::asT2() const
{
    Q_ASSERT(isT2());
    return (T2 *)(ptr_value & ~FlagsMask);
}

QT_END_NAMESPACE

#endif // QFLAGPOINTER_P_H