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>

2 files changed, 24 insertions, 0 deletions

diff --git a/tests/auto/corelib/tools/qstring/qstring.pro b/tests/auto/corelib/tools/qstring/qstring.pro
index 971e2fb782..1eda27e1ff 100644
--- a/tests/auto/corelib/tools/qstring/qstring.pro
+++ b/tests/auto/corelib/tools/qstring/qstring.pro
@@ -4,6 +4,7 @@ QT = core testlib
 SOURCES = tst_qstring.cpp
 DEFINES += QT_NO_CAST_TO_ASCII
 contains(QT_CONFIG,icu):DEFINES += QT_USE_ICU
+contains(QT_CONFIG,c++11): CONFIG += c++11
 DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0
 
 mac {
diff --git a/tests/auto/corelib/tools/qstring/tst_qstring.cpp b/tests/auto/corelib/tools/qstring/tst_qstring.cpp
index 875bf6571a..b0f0b24a67 100644
--- a/tests/auto/corelib/tools/qstring/tst_qstring.cpp
+++ b/tests/auto/corelib/tools/qstring/tst_qstring.cpp
@@ -59,6 +59,7 @@
 #include <locale.h>
 #include <qhash.h>
 
+#include <string>
 
 #define CREATE_REF(string)                                              \
     const QString padded = QString::fromLatin1(" %1 ").arg(string);     \
@@ -263,6 +264,7 @@ private slots:
     void assignQLatin1String();
     void isRightToLeft_data();
     void isRightToLeft();
+    void unicodeStrings();
 };
 
 template <class T> const T &verifyZeroTermination(const T &t) { return t; }
@@ -5222,6 +5224,27 @@ void tst_QString::fromUtf16_char16()
 #endif
 }
 
+void tst_QString::unicodeStrings()
+{
+#ifdef Q_COMPILER_UNICODE_STRINGS
+    QString s1, s2;
+    static const std::u16string u16str1(u"Hello Unicode World");
+    static const std::u32string u32str1(U"Hello Unicode World");
+    s1 = QString::fromStdU16String(u16str1);
+    s2 = QString::fromStdU32String(u32str1);
+    QCOMPARE(s1, QString("Hello Unicode World"));
+    QCOMPARE(s1, s2);
+
+    QCOMPARE(s2.toStdU16String(), u16str1);
+    QCOMPARE(s1.toStdU32String(), u32str1);
+
+    s1 = QString::fromStdU32String(std::u32string(U"\u221212\U000020AC\U00010000"));
+    QCOMPARE(s1, QString::fromUtf8("\342\210\222" "12" "\342\202\254" "\360\220\200\200"));
+#else
+    QSKIP("Compiler does not support C++11 unicode strings");
+#endif
+}
+
 void tst_QString::latin1String()
 {
     QString s("Hello");