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41
42 #ifndef QVARIANT_P_H
43 #define QVARIANT_P_H
44
45 //
46 // W A R N I N G
47 // -------------
48 //
49 // This file is not part of the Qt API. It exists purely as an
50 // implementation detail. This header file may change from version to
51 // version without notice, or even be removed.
52 //
53 // We mean it.
54 //
55
56 // takes a type, returns the internal void* pointer cast
57 // to a pointer of the input type
58
59 #include <QtCore/qglobal.h>
60 #include <QtCore/qvariant.h>
61
62 QT_BEGIN_NAMESPACE
63
64 #ifdef Q_CC_SUN // Sun CC picks the wrong overload, so introduce awful hack
65
66 template <typename T>
67 inline T *v_cast(const QVariant::Private *nd, T * = 0)
68 {
69 QVariant::Private *d = const_cast<QVariant::Private *>(nd);
70 return ((sizeof(T) > sizeof(QVariant::Private::Data))
71 ? static_cast<T *>(d->data.shared->ptr)
72 : static_cast<T *>(static_cast<void *>(&d->data.c)));
73 }
74
75 #else // every other compiler in this world
76
77 template <typename T>
78 inline const T *v_cast(const QVariant::Private *d, T * = 0)
79 {
80 return ((sizeof(T) > sizeof(QVariant::Private::Data))
81 ? static_cast<const T *>(d->data.shared->ptr)
82 : static_cast<const T *>(static_cast<const void *>(&d->data.c)));
83 }
84
85 template <typename T>
86 inline T *v_cast(QVariant::Private *d, T * = 0)
87 {
88 return ((sizeof(T) > sizeof(QVariant::Private::Data))
89 ? static_cast<T *>(d->data.shared->ptr)
90 : static_cast<T *>(static_cast<void *>(&d->data.c)));
91 }
92
93 #endif
94
95
96 //a simple template that avoids to allocate 2 memory chunks when creating a QVariant
97 template <class T> class QVariantPrivateSharedEx : public QVariant::PrivateShared
98 {
99 public:
QVariantPrivateSharedEx()100 QVariantPrivateSharedEx() : QVariant::PrivateShared(&m_t) { }
QVariantPrivateSharedEx(const T & t)101 QVariantPrivateSharedEx(const T&t) : QVariant::PrivateShared(&m_t), m_t(t) { }
102
103 private:
104 T m_t;
105 };
106
107 // constructs a new variant if copy is 0, otherwise copy-constructs
108 template <class T>
109 inline void v_construct(QVariant::Private *x, const void *copy, T * = 0)
110 {
111 if (sizeof(T) > sizeof(QVariant::Private::Data)) {
112 x->data.shared = copy ? new QVariantPrivateSharedEx<T>(*static_cast<const T *>(copy))
113 : new QVariantPrivateSharedEx<T>;
114 x->is_shared = true;
115 } else {
116 if (copy)
117 new (&x->data.ptr) T(*static_cast<const T *>(copy));
118 else
119 new (&x->data.ptr) T;
120 }
121 }
122
123 template <class T>
v_construct(QVariant::Private * x,const T & t)124 inline void v_construct(QVariant::Private *x, const T &t)
125 {
126 if (sizeof(T) > sizeof(QVariant::Private::Data)) {
127 x->data.shared = new QVariantPrivateSharedEx<T>(t);
128 x->is_shared = true;
129 } else {
130 new (&x->data.ptr) T(t);
131 }
132 }
133
134 // deletes the internal structures
135 template <class T>
136 inline void v_clear(QVariant::Private *d, T* = 0)
137 {
138
139 if (sizeof(T) > sizeof(QVariant::Private::Data)) {
140 //now we need to cast
141 //because QVariant::PrivateShared doesn't have a virtual destructor
142 delete static_cast<QVariantPrivateSharedEx<T>*>(d->data.shared);
143 } else {
144 v_cast<T>(d)->~T();
145 }
146
147 }
148
149 Q_CORE_EXPORT const QVariant::Handler *qcoreVariantHandler();
150
151 QT_END_NAMESPACE
152
153 #endif // QVARIANT_P_H
154