/******************************************************************************** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.**** This file is part of the QtCore module of the Qt Toolkit.**** This file may be used under the terms of the GNU General Public** License version 2.0 as published by the Free Software Foundation** and appearing in the file LICENSE.GPL included in the packaging of** this file.  Please review the following information to ensure GNU** General Public Licensing requirements will be met:** http://www.trolltech.com/products/qt/opensource.html**** If you are unsure which license is appropriate for your use, please** review the following information:** http://www.trolltech.com/products/qt/licensing.html or contact the** sales department at sales@trolltech.com.**** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.******************************************************************************/#ifndef QSHAREDDATA_H#define QSHAREDDATA_H#include <QtCore/qglobal.h>#include <QtCore/qatomic.h>QT_BEGIN_HEADERQT_MODULE(Core)template <class T> class QSharedDataPointer;class Q_CORE_EXPORT QSharedData{public:    QAtomic ref;    inline QSharedData() : ref(0) { }    inline QSharedData(const QSharedData &) : ref(0) { }private:    // using the assignment operator would lead to corruption in the ref-counting    QSharedData &operator=(const QSharedData &);};template <class T> class QSharedDataPointer{public:    inline void detach() { if (d && d->ref != 1) detach_helper(); }    inline T &operator*() { detach(); return *d; }    inline const T &operator*() const { return *d; }    inline T *operator->() { detach(); return d; }    inline const T *operator->() const { return d; }    inline operator T *() { detach(); return d; }    inline operator const T *() const { return d; }    inline T *data() { detach(); return d; }    inline const T *data() const { return d; }    inline const T *constData() const { return d; }    inline bool operator==(const QSharedDataPointer<T> &other) const { return d == other.d; }    inline bool operator!=(const QSharedDataPointer<T> &other) const { return d != other.d; }    inline QSharedDataPointer() { d = 0; }    inline ~QSharedDataPointer() { if (d && !d->ref.deref()) delete d; }    explicit QSharedDataPointer(T *data);    inline QSharedDataPointer(const QSharedDataPointer<T> &o) : d(o.d) { if (d) d->ref.ref(); }    inline QSharedDataPointer<T> & operator=(const QSharedDataPointer<T> &o) {        if (o.d != d) {            T *x = o.d;            if (x) x->ref.ref();            x = qAtomicSetPtr(&d, x);            if (x && !x->ref.deref())                delete x;        }        return *this;    }    inline QSharedDataPointer &operator=(T *o) {        if (o != d) {            T *x = o;            if (x) x->ref.ref();            x = qAtomicSetPtr(&d, x);            if (x && !x->ref.deref())                delete x;        }        return *this;    }    inline bool operator!() const { return !d; }private:    void detach_helper();    T *d;};template <class T>Q_INLINE_TEMPLATE QSharedDataPointer<T>::QSharedDataPointer(T *adata) : d(adata){ if (d) d->ref.ref(); }template <class T>Q_OUTOFLINE_TEMPLATE void QSharedDataPointer<T>::detach_helper(){    T *x = new T(*d);    x->ref.ref();    x = qAtomicSetPtr(&d, x);    if (!x->ref.deref())        delete x;}QT_END_HEADER#endif // QSHAREDDATA_H