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Diffstat (limited to 'src/qml/qml/ftw/qpointervaluepair_p.h')
| -rw-r--r-- | src/qml/qml/ftw/qpointervaluepair_p.h | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/src/qml/qml/ftw/qpointervaluepair_p.h b/src/qml/qml/ftw/qpointervaluepair_p.h new file mode 100644 index 0000000000..7b0caf49bc --- /dev/null +++ b/src/qml/qml/ftw/qpointervaluepair_p.h @@ -0,0 +1,196 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/ +** +** This file is part of the QtQml module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** GNU Lesser General Public License Usage +** This file may be used under the terms of the GNU Lesser General Public +** License version 2.1 as published by the Free Software Foundation and +** appearing in the file LICENSE.LGPL included in the packaging of this +** file. Please review the following information to ensure the GNU Lesser +** General Public License version 2.1 requirements will be met: +** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain additional +** rights. These rights are described in the Nokia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU General +** Public License version 3.0 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 the GNU General +** Public License version 3.0 requirements will be met: +** http://www.gnu.org/copyleft/gpl.html. +** +** Other Usage +** Alternatively, this file may be used in accordance with the terms and +** conditions contained in a signed written agreement between you and Nokia. +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#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 |