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#ifndef QPOINTERVALUEPAIR_P_H
#define QPOINTERVALUEPAIR_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>
#include <private/qflagpointer_p.h>

QT_BEGIN_NAMESPACE

// QPointerValuePair is intended to help reduce the memory consumption of a class.
// In the common case, QPointerValuePair behaves like a pointer.  In this mode, it
// consumes the same memory as a regular pointer.
// Additionally, QPointerValuePair can store an arbitrary value type in *addition*
// to the pointer.  In this case, it uses slightly more memory than the pointer and
// value type combined.
// Consequently, this class is most useful in cases where a pointer is always stored
// and a value type is rarely stored.
template<typename P, typename V>
class QPointerValuePair {
public:
    inline QPointerValuePair();
    inline QPointerValuePair(P *);
    inline ~QPointerValuePair();

    inline bool isNull() const;

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

    inline QPointerValuePair<P, V> &operator=(P *);

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

    inline bool hasValue() const;
    inline V &value();
    inline const V *constValue() const;

private:
    struct Value { P *pointer; V value; };
    QBiPointer<P, Value> d;
};

template<typename P, typename V>
QPointerValuePair<P, V>::QPointerValuePair()
{
}

template<typename P, typename V>
QPointerValuePair<P, V>::QPointerValuePair(P *p)
: d(p)
{
}

template<typename P, typename V>
QPointerValuePair<P, V>::~QPointerValuePair()
{
    if (d.isT2()) delete d.asT2();
}

template<typename P, typename V>
bool QPointerValuePair<P, V>::isNull() const
{
    if (d.isT1()) return 0 == d.asT1();
    else return d.asT2()->pointer == 0;
}

template<typename P, typename V>
bool QPointerValuePair<P, V>::flag() const
{
    return d.flag();
}

template<typename P, typename V>
void QPointerValuePair<P, V>::setFlag()
{
    d.setFlag();
}

template<typename P, typename V>
void QPointerValuePair<P, V>::clearFlag()
{
    d.clearFlag();
}

template<typename P, typename V>
void QPointerValuePair<P, V>::setFlagValue(bool v)
{
    d.setFlagValue(v);
}

template<typename P, typename V>
QPointerValuePair<P, V> &QPointerValuePair<P, V>::operator=(P *o)
{
    if (d.isT1()) d = o;
    else d.asT2()->pointer = o;
    return *this;
}

template<typename P, typename V>
P *QPointerValuePair<P, V>::operator->() const
{
    if (d.isT1()) return d.asT1();
    else return d.asT2()->pointer;
}

template<typename P, typename V>
P *QPointerValuePair<P, V>::operator*() const
{
    if (d.isT1()) return d.asT1();
    else return d.asT2()->pointer;
}

template<typename P, typename V>
bool QPointerValuePair<P, V>::hasValue() const
{
    return d.isT2();
}

template<typename P, typename V>
V &QPointerValuePair<P, V>::value()
{
    if (d.isT1()) {
        P *p = d.asT1();
        Value *value = new Value;
        value->pointer = p;
        d = value;
    }

    return d.asT2()->value;
}

// Will return null if hasValue() == false
template<typename P, typename V>
const V *QPointerValuePair<P, V>::constValue() const
{
    if (d.isT2()) return &d.asT2()->value;
    else return 0;
}

QT_END_NAMESPACE

#endif // QPOINTERVALUEPAIR_P_H
