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Use lambdas for generating static data for QStringLiteral

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This means it will work on C++0x compilers that support lambdas (all
of them once they've completed supporting the functionality). Olivier
had the idea and the initial code.

Change-Id: I11ef7da4058ed18f4ea99ada070891a68ed54f55
Reviewed-on: http://codereview.qt.nokia.com/1380
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Olivier Goffart <olivier.goffart@nokia.com>
This commit is contained in:
Thiago Macieira 2011-07-08 14:10:02 +02:00 committed by Qt by Nokia
parent 6efe729881
commit cd80fcb5d6
1 changed files with 36 additions and 29 deletions
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65
src/corelib/tools/qstring.h
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@ -96,28 +96,16 @@ template<int N> struct QConstStringDataPtr
const QConstStringData<N> *ptr; const QConstStringData<N> *ptr;
}; };
#if defined(Q_CC_GNU) #if defined(Q_COMPILER_UNICODE_STRINGS)
// We need to create a QStringData in the .rodata section of memory
// and the only way to do that is to create a "static const" variable.
// To do that, we need the __extension__ {( )} trick which only GCC supports
# if defined(Q_COMPILER_UNICODE_STRINGS)
template<int n> struct QConstStringData template<int n> struct QConstStringData
{ {
const QStringData str; const QStringData str;
const char16_t data[n]; const char16_t data[n];
operator const QStringData &() const { return str; } operator const QStringData &() const { return str; }
}; };
#define QT_QSTRING_UNICODE_MARKER u""
# define QStringLiteral(str) \ #elif defined(Q_OS_WIN) || (defined(__SIZEOF_WCHAR_T__) && __SIZEOF_WCHAR_T__ == 2) || defined(WCHAR_MAX) && (WCHAR_MAX - 0 < 65536)
__extension__ ({ \
enum { Size = sizeof(u"" str)/2 }; \
static const QConstStringData<Size> qstring_literal = \
{ { Q_REFCOUNT_INITIALIZER(-1), Size -1, 0, 0, { 0 } }, u"" str }; \
QConstStringDataPtr<Size> holder = { &qstring_literal }; \
holder; })
# elif defined(Q_OS_WIN) || (defined(__SIZEOF_WCHAR_T__) && __SIZEOF_WCHAR_T__ == 2) || defined(WCHAR_MAX) && (WCHAR_MAX - 0 < 65536)
// wchar_t is 2 bytes // wchar_t is 2 bytes
template<int n> struct QConstStringData template<int n> struct QConstStringData
{ {
@ -125,26 +113,45 @@ template<int n> struct QConstStringData
const wchar_t data[n]; const wchar_t data[n];
operator const QStringData &() const { return str; } operator const QStringData &() const { return str; }
}; };
# define QStringLiteral(str) \ #define QT_QSTRING_UNICODE_MARKER L""
__extension__ ({ \
enum { Size = sizeof(L"" str)/2 }; \
static const QConstStringData<Size> qstring_literal = \
{ { Q_REFCOUNT_INITIALIZER(-1), Size -1, 0, 0, { 0 } }, L"" str }; \
QConstStringDataPtr<Size> holder = { &qstring_literal }; \
holder; })
# endif
#endif
#ifndef QStringLiteral
// not GCC, or GCC in C++98 mode with 4-byte wchar_t
// fallback, uses QLatin1String as next best options
#else
template<int n> struct QConstStringData template<int n> struct QConstStringData
{ {
const QStringData str; const QStringData str;
const ushort data[n]; const ushort data[n];
operator const QStringData &() const { return str; } operator const QStringData &() const { return str; }
}; };
#endif
#if defined(QT_QSTRING_UNICODE_MARKER)
# if defined(Q_COMPILER_LAMBDA)
# define QStringLiteral(str) ([]() { \
enum { Size = sizeof(QT_QSTRING_UNICODE_MARKER str)/2 }; \
static const QConstStringData<Size> qstring_literal = \
{ { Q_REFCOUNT_INITIALIZER(-1), Size -1, 0, 0, { 0 } }, QT_QSTRING_UNICODE_MARKER str }; \
QConstStringDataPtr<Size> holder = { &qstring_literal }; \
return holder; }())
# elif defined(Q_CC_GNU)
// We need to create a QStringData in the .rodata section of memory
// and the only way to do that is to create a "static const" variable.
// To do that, we need the __extension__ {( )} trick which only GCC supports
# define QStringLiteral(str) \
__extension__ ({ \
enum { Size = sizeof(QT_QSTRING_UNICODE_MARKER str)/2 }; \
static const QConstStringData<Size> qstring_literal = \
{ { Q_REFCOUNT_INITIALIZER(-1), Size -1, 0, 0, { 0 } }, QT_QSTRING_UNICODE_MARKER str }; \
QConstStringDataPtr<Size> holder = { &qstring_literal }; \
holder; })
# endif
#endif
#ifndef QStringLiteral
// no lambdas, not GCC, or GCC in C++98 mode with 4-byte wchar_t
// fallback, uses QLatin1String as next best options
# define QStringLiteral(str) QLatin1String(str) # define QStringLiteral(str) QLatin1String(str)
#endif #endif
@ -576,7 +583,7 @@ public:
template <int n> template <int n>
inline QString(const QConstStringData<n> &dd) : d(const_cast<QStringData *>(&dd.str)) {} inline QString(const QConstStringData<n> &dd) : d(const_cast<QStringData *>(&dd.str)) {}
template <int N> template <int N>
inline QString(QConstStringDataPtr<N> dd) : d(const_cast<QStringData *>(&dd.ptr->str)) {} Q_DECL_CONSTEXPR inline QString(QConstStringDataPtr<N> dd) : d(const_cast<QStringData *>(&dd.ptr->str)) {}
private: private:
#if defined(QT_NO_CAST_FROM_ASCII) && !defined(Q_NO_DECLARED_NOT_DEFINED) #if defined(QT_NO_CAST_FROM_ASCII) && !defined(Q_NO_DECLARED_NOT_DEFINED)