diff options
Diffstat (limited to 'src/corelib/tools')
| -rw-r--r-- | src/corelib/tools/qarraydata.h | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/src/corelib/tools/qarraydata.h b/src/corelib/tools/qarraydata.h index 5ed8d4ba95..d5d96efc08 100644 --- a/src/corelib/tools/qarraydata.h +++ b/src/corelib/tools/qarraydata.h @@ -43,6 +43,7 @@ #define QARRAYDATA_H #include <QtCore/qrefcount.h> +#include <string.h> QT_BEGIN_HEADER @@ -190,6 +191,84 @@ struct QArrayDataPointerRef & ~(Q_ALIGNOF(type) - 1) } \ /**/ +//////////////////////////////////////////////////////////////////////////////// +// Q_ARRAY_LITERAL + +// The idea here is to place a (read-only) copy of header and array data in an +// mmappable portion of the executable (typically, .rodata section). This is +// accomplished by hiding a static const instance of QStaticArrayData, which is +// POD. + +#if defined(Q_COMPILER_VARIADIC_MACROS) +#if defined(Q_COMPILER_LAMBDA) +// Hide array inside a lambda +#define Q_ARRAY_LITERAL(Type, ...) \ + ([]() -> QArrayDataPointerRef<Type> { \ + /* MSVC 2010 Doesn't support static variables in a lambda, but */ \ + /* happily accepts them in a static function of a lambda-local */ \ + /* struct :-) */ \ + struct StaticWrapper { \ + static QArrayDataPointerRef<Type> get() \ + { \ + Q_ARRAY_LITERAL_IMPL(Type, __VA_ARGS__) \ + return ref; \ + } \ + }; \ + return StaticWrapper::get(); \ + }()) \ + /**/ +#elif defined(Q_CC_GNU) +// Hide array within GCC's __extension__ {( )} block +#define Q_ARRAY_LITERAL(Type, ...) \ + __extension__ ({ \ + Q_ARRAY_LITERAL_IMPL(Type, __VA_ARGS__) \ + ref; \ + }) \ + /**/ +#endif +#endif // defined(Q_COMPILER_VARIADIC_MACROS) + +#if defined(Q_ARRAY_LITERAL) +#define Q_ARRAY_LITERAL_IMPL(Type, ...) \ + union { Type type_must_be_POD; } dummy; Q_UNUSED(dummy) \ + \ + /* Portable compile-time array size computation */ \ + Type data[] = { __VA_ARGS__ }; Q_UNUSED(data) \ + enum { Size = sizeof(data) / sizeof(data[0]) }; \ + \ + static const QStaticArrayData<Type, Size> literal = { \ + Q_STATIC_ARRAY_DATA_HEADER_INITIALIZER(Type, Size), { __VA_ARGS__ } }; \ + \ + QArrayDataPointerRef<Type> ref = \ + { static_cast<QTypedArrayData<Type> *>( \ + const_cast<QArrayData *>(&literal.header)) }; \ + /**/ +#else +// As a fallback, memory is allocated and data copied to the heap. + +// The fallback macro does NOT use variadic macros and does NOT support +// variable number of arguments. It is suitable for char arrays. + +namespace QtPrivate { + template <class T, size_t N> + inline QArrayDataPointerRef<T> qMakeArrayLiteral(const T (&array)[N]) + { + union { T type_must_be_POD; } dummy; Q_UNUSED(dummy) + + QArrayDataPointerRef<T> result = { QTypedArrayData<T>::allocate(N) }; + Q_CHECK_PTR(result.ptr); + + ::memcpy(result.ptr->data(), array, N * sizeof(T)); + result.ptr->size = N; + + return result; + } +} + +#define Q_ARRAY_LITERAL(Type, Array) \ + QT_PREPEND_NAMESPACE(QtPrivate::qMakeArrayLiteral)<Type>( Array ) +#endif // !defined(Q_ARRAY_LITERAL) + QT_END_NAMESPACE QT_END_HEADER |