Add conversion functions for C++11 u16string and u32string

The patch adds convenience functions for working on C++11's new char
width specific unicode strings u16string and u32string.

[ChangeLog][QtCore][QString] Added methods for convenient conversion
to and from std::u16string and std::u32string.

Change-Id: I67c082e4755c592d61daaaaa70c8867ef0b23dcb
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/corelib/tools/qstring.h b/src/corelib/tools/qstring.h
index d20d08bc0c..0deb664dc7 100644
--- a/src/corelib/tools/qstring.h
+++ b/src/corelib/tools/qstring.h
@@ -733,6 +733,13 @@ public:
     static inline QString fromStdWString(const std::wstring &s);
     inline std::wstring toStdWString() const;
 
+#if defined(Q_COMPILER_UNICODE_STRINGS) || defined(Q_QDOC)
+    static inline QString fromStdU16String(const std::u16string &s);
+    inline std::u16string toStdU16String() const;
+    static inline QString fromStdU32String(const std::u32string &s);
+    inline std::u32string toStdU32String() const;
+#endif
+
 #if defined(Q_OS_MAC) || defined(Q_QDOC)
     static QString fromCFString(CFStringRef string);
     CFStringRef toCFString() const Q_DECL_CF_RETURNS_RETAINED;
@@ -1294,6 +1301,25 @@ inline std::wstring QString::toStdWString() const
 inline QString QString::fromStdWString(const std::wstring &s)
 { return fromWCharArray(s.data(), int(s.size())); }
 
+#if defined(Q_COMPILER_UNICODE_STRINGS)
+inline QString QString::fromStdU16String(const std::u16string &s)
+{ return fromUtf16(s.data(), int(s.size())); }
+
+inline std::u16string QString::toStdU16String() const
+{ return std::u16string(reinterpret_cast<const char16_t*>(utf16()), length()); }
+
+inline QString QString::fromStdU32String(const std::u32string &s)
+{ return fromUcs4(s.data(), int(s.size())); }
+
+inline std::u32string QString::toStdU32String() const
+{
+    std::u32string u32str(length(), char32_t(0));
+    int len = toUcs4_helper(d->data(), length(), reinterpret_cast<uint*>(&u32str[0]));
+    u32str.resize(len);
+    return u32str;
+}
+#endif
+
 #if !defined(QT_NO_DATASTREAM) || (defined(QT_BOOTSTRAPPED) && !defined(QT_BUILD_QMAKE))
 Q_CORE_EXPORT QDataStream &operator<<(QDataStream &, const QString &);
 Q_CORE_EXPORT QDataStream &operator>>(QDataStream &, QString &);