Add QStringView::toWCharArray() to match QString

QCollator needs it to add support for QStringView.
In any case, it extends the mirror of QString's API.
Naturally, we can reimplement QString's version using it.

Change-Id: I5a23a3f2a98c7d59597b5e935542a93764b5e350
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/src/corelib/tools/qstringview.cpp b/src/corelib/tools/qstringview.cpp
index b97e989110..c863ca7ce2 100644
--- a/src/corelib/tools/qstringview.cpp
+++ b/src/corelib/tools/qstringview.cpp
@@ -38,6 +38,7 @@
 ****************************************************************************/
 
 #include "qstringview.h"
+#include "qstring.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -794,4 +795,34 @@ QT_BEGIN_NAMESPACE
     \sa QString::isRightToLeft()
 */
 
+/*!
+    \since 5.14
+
+    Transcribes this string into the given \a array.
+
+    Caller is responsible for ensuring \a array is large enough to hold the \t
+    wchar_t encoding of this string (allocating the array with the same length
+    as the string is always sufficient). The array is encoded in UTF-16 on
+    platforms where \t wchar_t is 2 bytes wide (e.g. Windows); otherwise (Unix
+    systems), \t wchar_t is assumed to be 4 bytes wide and the data is written
+    in UCS-4.
+
+    \note This function writes no null terminator to the end of \a array.
+
+    Returns the number of \t wchar_t entries written to \a array.
+
+    \sa QString::toWCharArray()
+*/
+
+int QStringView::toWCharArray(wchar_t *array) const
+{
+    if (sizeof(wchar_t) == sizeof(QChar)) {
+        memcpy(array, data(), sizeof(QChar) * size());
+        return size();
+    } else {
+        return QString::toUcs4_helper(reinterpret_cast<const ushort *>(data()), int(size()),
+                                      reinterpret_cast<uint *>(array));
+    }
+}
+
 QT_END_NAMESPACE