Merge branch 'master' of scm.dev.nokia.troll.no:qt/berlin-staging-1 into master-integration

* 'master' of scm.dev.nokia.troll.no:qt/berlin-staging-1:
  avoid double reallocations in appending operations
  avoid double reallocation in string-growing replace() case
  optimize qHash() some more
  optimize QList::mid()
  optimization: use QList::reserve() in QSet::toList()
  add QList::reserve()
  optimization: get rid of QString::fromUtf16() usage, part 2
  add QString(const QChar *) c'tor

16 files changed, 184 insertions, 56 deletions

diff --git a/src/3rdparty/phonon/ds9/mediagraph.cpp b/src/3rdparty/phonon/ds9/mediagraph.cpp
index a467dd7..3e7a68b 100644
--- a/src/3rdparty/phonon/ds9/mediagraph.cpp
+++ b/src/3rdparty/phonon/ds9/mediagraph.cpp
@@ -379,7 +379,7 @@ namespace Phonon
             FILTER_INFO info;
             filter->QueryFilterInfo(&info);
 #ifdef GRAPH_DEBUG
-            qDebug() << "removeFilter" << QString::fromUtf16(info.achName);
+            qDebug() << "removeFilter" << QString((const QChar *)info.achName);
 #endif
             if (info.pGraph) {
                 info.pGraph->Release();
@@ -875,7 +875,7 @@ namespace Phonon
             {
                 FILTER_INFO info;
                 filter->QueryFilterInfo(&info);
-                qDebug() << Q_FUNC_INFO << QString::fromUtf16(info.achName);
+                qDebug() << Q_FUNC_INFO << QString((const QChar *)info.achName);
                 if (info.pGraph) {
                     info.pGraph->Release();
                 }
@@ -921,7 +921,7 @@ namespace Phonon
             {
                 FILTER_INFO info;
                 filter->QueryFilterInfo(&info);
-                qDebug() << "found a decoder filter" << QString::fromUtf16(info.achName);
+                qDebug() << "found a decoder filter" << QString((const QChar *)info.achName);
                 if (info.pGraph) {
                     info.pGraph->Release();
                 }
@@ -937,7 +937,7 @@ namespace Phonon
             {
                 FILTER_INFO info;
                 filter->QueryFilterInfo(&info);
-                qDebug() << Q_FUNC_INFO << QString::fromUtf16(info.achName);
+                qDebug() << Q_FUNC_INFO << QString((const QChar *)info.achName);
                 if (info.pGraph) {
                     info.pGraph->Release();
                 }
@@ -956,7 +956,7 @@ namespace Phonon
             {
                 FILTER_INFO info;
                 filter->QueryFilterInfo(&info);
-                qDebug() << Q_FUNC_INFO << QString::fromUtf16(info.achName);
+                qDebug() << Q_FUNC_INFO << QString((const QChar *)info.achName);
                 if (info.pGraph) {
                     info.pGraph->Release();
                 }
@@ -990,7 +990,7 @@ namespace Phonon
             {
                 FILTER_INFO info;
                 filter->QueryFilterInfo(&info);
-                qDebug() << "found a demuxer filter" << QString::fromUtf16(info.achName);
+                qDebug() << "found a demuxer filter" << QString((const QChar *)info.achName);
                 if (info.pGraph) {
                     info.pGraph->Release();
                 }
diff --git a/src/3rdparty/phonon/waveout/mediaobject.cpp b/src/3rdparty/phonon/waveout/mediaobject.cpp
index db71942..08af4ee 100644
--- a/src/3rdparty/phonon/waveout/mediaobject.cpp
+++ b/src/3rdparty/phonon/waveout/mediaobject.cpp
@@ -50,7 +50,7 @@ namespace Phonon
         {
             ushort b[256];
             waveOutGetErrorText(error, (LPWSTR)b, 256);
-            return QString::fromUtf16(b);
+            return QString((const QChar *)b);
         }
 
         class WorkerThread : public QThread
diff --git a/src/corelib/io/qprocess_symbian.cpp b/src/corelib/io/qprocess_symbian.cpp
index 75cde51..07d10ad 100644
--- a/src/corelib/io/qprocess_symbian.cpp
+++ b/src/corelib/io/qprocess_symbian.cpp
@@ -1002,7 +1002,7 @@ bool QProcessPrivate::waitForDeadChild()
             TExitCategoryName catName = symbianProcess->ExitCategory();
             qDebug() << "QProcessPrivate::waitForDeadChild() dead with exitCode"
                      << exitCode << ", crashed:" << crashed
-                     << ", category:" << QString::fromUtf16(catName.Ptr());
+                     << ", category:" << QString((const QChar *)catName.Ptr());
 #endif
         } else {
             QPROCESS_DEBUG_PRINT("QProcessPrivate::waitForDeadChild() not dead!");
diff --git a/src/corelib/tools/qhash.cpp b/src/corelib/tools/qhash.cpp
index 285f4c9..85a8b63 100644
--- a/src/corelib/tools/qhash.cpp
+++ b/src/corelib/tools/qhash.cpp
@@ -64,13 +64,11 @@ QT_BEGIN_NAMESPACE
 static uint hash(const uchar *p, int n)
 {
     uint h = 0;
-    uint g;
 
     while (n--) {
         h = (h << 4) + *p++;
-        g = h & 0xf0000000;
-        h ^= g >> 23;
-        h &= ~g;
+        h ^= (h & 0xf0000000) >> 23;
+        h &= 0x0fffffff;
     }
     return h;
 }
@@ -78,13 +76,11 @@ static uint hash(const uchar *p, int n)
 static uint hash(const QChar *p, int n)
 {
     uint h = 0;
-    uint g;
 
     while (n--) {
         h = (h << 4) + (*p++).unicode();
-        g = h & 0xf0000000;
-        h ^= g >> 23;
-        h &= ~g;
+        h ^= (h & 0xf0000000) >> 23;
+        h &= 0x0fffffff;
     }
     return h;
 }
diff --git a/src/corelib/tools/qlist.cpp b/src/corelib/tools/qlist.cpp
index ce62016..a468c77 100644
--- a/src/corelib/tools/qlist.cpp
+++ b/src/corelib/tools/qlist.cpp
@@ -125,22 +125,23 @@ QListData::Data *QListData::detach2()
 }
 
 /*!
- *  Detaches the QListData by reallocating new memory.
+ *  Detaches the QListData by allocating new memory for a list which possibly
+ *  has a different size than the copied one.
  *  Returns the old (shared) data, it is up to the caller to deref() and free()
  *  For the new data node_copy needs to be called.
  *
  *  \internal
  */
-QListData::Data *QListData::detach3()
+QListData::Data *QListData::detach(int alloc)
 {
     Data *x = d;
-    Data* t = static_cast<Data *>(qMalloc(DataHeaderSize + x->alloc * sizeof(void *)));
+    Data* t = static_cast<Data *>(qMalloc(DataHeaderSize + alloc * sizeof(void *)));
     Q_CHECK_PTR(t);
 
     t->ref = 1;
     t->sharable = true;
-    t->alloc = x->alloc;
-    if (!t->alloc) {
+    t->alloc = alloc;
+    if (!alloc) {
         t->begin = 0;
         t->end = 0;
     } else {
@@ -152,6 +153,34 @@ QListData::Data *QListData::detach3()
     return x;
 }
 
+/*!
+ *  Detaches the QListData by allocating new memory for a list which will be bigger
+ *  than the copied one and is expected to grow further.
+ *  Returns the old (shared) data, it is up to the caller to deref() and free()
+ *  For the new data node_copy needs to be called.
+ *
+ *  \internal
+ */
+QListData::Data *QListData::detach_grow(int alloc)
+{
+    return detach(grow(alloc));
+}
+
+/*!
+ *  Detaches the QListData by reallocating new memory.
+ *  Returns the old (shared) data, it is up to the caller to deref() and free()
+ *  For the new data node_copy needs to be called.
+ *
+ *  \internal
+ */
+#if QT_VERSION >= 0x050000
+#  error "Remove QListData::detach3(), it is only required for binary compatibility for 4.5.x to 4.6.x"
+#endif
+QListData::Data *QListData::detach3()
+{
+    return detach(d->alloc);
+}
+
 void QListData::realloc(int alloc)
 {
     Q_ASSERT(d->ref == 1);
@@ -580,6 +609,11 @@ void **QListData::erase(void **xi)
     \internal
 */
 
+/*! \fn void QList::detach_grow(int alloc)
+
+    \internal
+*/
+
 /*! \fn void QList::detachShared()
 
     \internal
@@ -647,6 +681,19 @@ void **QListData::erase(void **xi)
     Same as at().
 */
 
+/*! \fn QList::reserve(int alloc)
+
+    Reserve space for \a alloc elements.
+
+    If \a alloc is smaller than the current size of the list, nothing will happen.
+
+    Use this function to avoid repetetive reallocation of QList's internal
+    data if you can predict how many elements will be appended.
+    Note that the reservation applies only to the internal pointer array.
+
+    \since 4.7
+*/
+
 /*! \fn void QList::append(const T &value)
 
     Inserts \a value at the end of the list.
diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index 1d08c41..1edac03 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -72,9 +72,11 @@ struct Q_CORE_EXPORT QListData {
     };
     enum { DataHeaderSize = sizeof(Data) - sizeof(void *) };
 
+    Data *detach(int alloc);
+    Data *detach_grow(int alloc);
     Data *detach(); // remove in 5.0
     Data *detach2(); // remove in 5.0
-    Data *detach3();
+    Data *detach3(); // remove in 5.0
     void realloc(int alloc);
     static Data shared_null;
     Data *d;
@@ -120,6 +122,7 @@ public:
     inline int size() const { return p.size(); }
 
     inline void detach() { if (d->ref != 1) detach_helper(); }
+    inline void detach_grow(int by) { if (d->ref != 1) detach_helper_grow(d->end - d->begin + by); }
 
     inline void detachShared()
     {
@@ -140,6 +143,7 @@ public:
     const T &operator[](int i) const;
     T &operator[](int i);
 
+    void reserve(int size);
     void append(const T &t);
     void append(const QList<T> &t);
     void prepend(const T &t);
@@ -331,6 +335,8 @@ public:
 #endif
 
 private:
+    void detach_helper_grow(int alloc);
+    void detach_helper(int alloc);
     void detach_helper();
     void free(QListData::Data *d);
 
@@ -464,9 +470,20 @@ inline T QList<T>::takeLast()
 { T t = last(); removeLast(); return t; }
 
 template <typename T>
+Q_OUTOFLINE_TEMPLATE void QList<T>::reserve(int alloc)
+{
+    if (d->alloc < alloc) {
+        if (d->ref != 1)
+            detach_helper(alloc);
+        else
+            p.realloc(alloc);
+    }
+}
+
+template <typename T>
 Q_OUTOFLINE_TEMPLATE void QList<T>::append(const T &t)
 {
-    detach();
+    detach_grow(1);
     if (QTypeInfo<T>::isLarge || QTypeInfo<T>::isStatic) {
         Node *n = reinterpret_cast<Node *>(p.append());
         QT_TRY {
@@ -490,7 +507,7 @@ Q_OUTOFLINE_TEMPLATE void QList<T>::append(const T &t)
 template <typename T>
 inline void QList<T>::prepend(const T &t)
 {
-    detach();
+    detach_grow(1);
     if (QTypeInfo<T>::isLarge || QTypeInfo<T>::isStatic) {
         Node *n = reinterpret_cast<Node *>(p.prepend());
         QT_TRY {
@@ -514,7 +531,7 @@ inline void QList<T>::prepend(const T &t)
 template <typename T>
 inline void QList<T>::insert(int i, const T &t)
 {
-    detach();
+    detach_grow(1);
     if (QTypeInfo<T>::isLarge || QTypeInfo<T>::isStatic) {
         Node *n = reinterpret_cast<Node *>(p.insert(i));
         QT_TRY {
@@ -575,11 +592,20 @@ Q_OUTOFLINE_TEMPLATE QList<T> QList<T>::mid(int pos, int alength) const
         alength = size() - pos;
     if (pos == 0 && alength == size())
         return *this;
-    QList<T> cpy;
     if (pos + alength > size())
         alength = size() - pos;
-    for (int i = pos; i < pos + alength; ++i)
-        cpy += at(i);
+    QList<T> cpy;
+    cpy.reserve(alength);
+    cpy.d->end = alength;
+    QT_TRY {
+        cpy.node_copy(reinterpret_cast<Node *>(cpy.p.begin()),
+                      reinterpret_cast<Node *>(cpy.p.end()),
+                      reinterpret_cast<Node *>(p.begin() + pos));
+    } QT_CATCH(...) {
+        // restore the old end
+        cpy.d->end = 0;
+        QT_RETHROW;
+    }
     return cpy;
 }
 
@@ -599,10 +625,10 @@ Q_OUTOFLINE_TEMPLATE T QList<T>::value(int i, const T& defaultValue) const
 }
 
 template <typename T>
-Q_OUTOFLINE_TEMPLATE void QList<T>::detach_helper()
+Q_OUTOFLINE_TEMPLATE void QList<T>::detach_helper_grow(int alloc)
 {
     Node *n = reinterpret_cast<Node *>(p.begin());
-    QListData::Data *x = p.detach3();
+    QListData::Data *x = p.detach_grow(alloc);
     QT_TRY {
         node_copy(reinterpret_cast<Node *>(p.begin()), reinterpret_cast<Node *>(p.end()), n);
     } QT_CATCH(...) {
@@ -616,6 +642,29 @@ Q_OUTOFLINE_TEMPLATE void QList<T>::detach_helper()
 }
 
 template <typename T>
+Q_OUTOFLINE_TEMPLATE void QList<T>::detach_helper(int alloc)
+{
+    Node *n = reinterpret_cast<Node *>(p.begin());
+    QListData::Data *x = p.detach(alloc);
+    QT_TRY {
+        node_copy(reinterpret_cast<Node *>(p.begin()), reinterpret_cast<Node *>(p.end()), n);
+    } QT_CATCH(...) {
+        qFree(d);
+        d = x;
+        QT_RETHROW;
+    }
+
+    if (!x->ref.deref())
+        free(x);
+}
+
+template <typename T>
+Q_OUTOFLINE_TEMPLATE void QList<T>::detach_helper()
+{
+    detach_helper(d->alloc);
+}
+
+template <typename T>
 Q_OUTOFLINE_TEMPLATE QList<T>::~QList()
 {
     if (d && !d->ref.deref())
@@ -701,7 +750,7 @@ Q_OUTOFLINE_TEMPLATE typename QList<T>::iterator QList<T>::erase(typename QList<
 template <typename T>
 Q_OUTOFLINE_TEMPLATE QList<T> &QList<T>::operator+=(const QList<T> &l)
 {
-    detach();
+    detach_grow(l.size());
     Node *n = reinterpret_cast<Node *>(p.append2(l.p));
     QT_TRY{
         node_copy(n, reinterpret_cast<Node *>(p.end()), reinterpret_cast<Node *>(l.p.begin()));
diff --git a/src/corelib/tools/qset.h b/src/corelib/tools/qset.h
index 6525880..9acbed4 100644
--- a/src/corelib/tools/qset.h
+++ b/src/corelib/tools/qset.h
@@ -292,6 +292,7 @@ template <typename T>
 Q_OUTOFLINE_TEMPLATE QList<T> QSet<T>::toList() const
 {
     QList<T> result;
+    result.reserve(size());
     typename QSet<T>::const_iterator i = constBegin();
     while (i != constEnd()) {
         result.append(*i);
diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index dec59b7..cce313b 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -989,6 +989,40 @@ QString::QString(const QChar *unicode, int size)
     }
 }
 
+/*!
+    \since 4.7
+
+    Constructs a string initialized with the characters of the QChar array
+    \a unicode, which must be terminated with a 0.
+
+    QString makes a deep copy of the string data. The unicode data is copied as
+    is and the Byte Order Mark is preserved if present.
+*/
+QString::QString(const QChar *unicode)
+{
+     if (!unicode) {
+         d = &shared_null;
+         d->ref.ref();
+     } else {
+         int size = 0;
+         while (unicode[size] != 0)
+             ++size;
+         if (!size) {
+             d = &shared_empty;
+             d->ref.ref();
+         } else {
+             d = (Data*) qMalloc(sizeof(Data)+size*sizeof(QChar));
+             Q_CHECK_PTR(d);
+             d->ref = 1;
+             d->alloc = d->size = size;
+             d->clean = d->asciiCache = d->simpletext = d->righttoleft = d->capacity = 0;
+             d->data = d->array;
+             memcpy(d->array, unicode, size * sizeof(QChar));
+             d->array[size] = '\0';
+         }
+     }
+}
+
 
 /*!
     Constructs a string of the given \a size with every character set
@@ -1766,13 +1800,14 @@ void QString::replace_helper(uint *indices, int nIndices, int blen, const QChar
     }
 
     QT_TRY {
-        detach();
         if (blen == alen) {
             // replace in place
+            detach();
             for (int i = 0; i < nIndices; ++i)
                 memcpy(d->data + indices[i], afterBuffer, alen * sizeof(QChar));
         } else if (alen < blen) {
             // replace from front
+            detach();
             uint to = indices[0];
             if (alen)
                 memcpy(d->data+to, after, alen*sizeof(QChar));
@@ -3867,7 +3902,7 @@ QString QString::fromUtf8(const char *str, int size)
     host byte order is assumed.
 
     This function is comparatively slow.
-    Use QString(const ushort *, int) if possible.
+    Use QString(const ushort *, int) or QString(const ushort *) if possible.
 
     QString makes a deep copy of the Unicode data.
 
diff --git a/src/corelib/tools/qstring.h b/src/corelib/tools/qstring.h
index 702a21a..8de3c7d 100644
--- a/src/corelib/tools/qstring.h
+++ b/src/corelib/tools/qstring.h
@@ -91,7 +91,8 @@ class Q_CORE_EXPORT QString
 {
 public:
     inline QString();
-    QString(const QChar *unicode, int size);
+    QString(const QChar *unicode, int size); // Qt5: don't cap size < 0
+    explicit QString(const QChar *unicode); // Qt5: merge with the above
     QString(QChar c);
     QString(int size, QChar c);
     inline QString(const QLatin1String &latin1);
diff --git a/src/multimedia/audio/qaudiodeviceinfo_win32_p.cpp b/src/multimedia/audio/qaudiodeviceinfo_win32_p.cpp
index 955a880..67dc90c 100644
--- a/src/multimedia/audio/qaudiodeviceinfo_win32_p.cpp
+++ b/src/multimedia/audio/qaudiodeviceinfo_win32_p.cpp
@@ -218,7 +218,7 @@ void QAudioDeviceInfoInternal::updateLists()
 	for(i=0;i<iNumDevs;i++) {
 	    if(waveOutGetDevCaps(i, &woc, sizeof(WAVEOUTCAPS))
 	        == MMSYSERR_NOERROR) {
-		tmp = QString::fromUtf16((const unsigned short*)woc.szPname);
+		tmp = QString((const QChar *)woc.szPname);
 		if(tmp.compare(device) == 0) {
 		    match = true;
 		    fmt = woc.dwFormats;
@@ -238,7 +238,7 @@ void QAudioDeviceInfoInternal::updateLists()
 	for(i=0;i<iNumDevs;i++) {
 	    if(waveInGetDevCaps(i, &woc, sizeof(WAVEINCAPS))
 	        == MMSYSERR_NOERROR) {
-		tmp = QString::fromUtf16((const unsigned short*)woc.szPname);
+		tmp = QString((const QChar *)woc.szPname);
 		if(tmp.compare(device) == 0) {
 		    match = true;
 		    fmt = woc.dwFormats;
@@ -347,7 +347,7 @@ QList<QByteArray> QAudioDeviceInfoInternal::availableDevices(QAudio::Mode mode)
 	for(i=0;i<iNumDevs;i++) {
 	    if(waveOutGetDevCaps(i, &woc, sizeof(WAVEOUTCAPS))
 	        == MMSYSERR_NOERROR) {
-	        devices.append(QString::fromUtf16((const unsigned short*)woc.szPname).toLocal8Bit().constData());
+	        devices.append(QString((const QChar *)woc.szPname).toLocal8Bit().constData());
 	    }
 	}
     } else {
@@ -357,7 +357,7 @@ QList<QByteArray> QAudioDeviceInfoInternal::availableDevices(QAudio::Mode mode)
 	for(i=0;i<iNumDevs;i++) {
 	    if(waveInGetDevCaps(i, &woc, sizeof(WAVEINCAPS))
 	        == MMSYSERR_NOERROR) {
-	        devices.append(QString::fromUtf16((const unsigned short*)woc.szPname).toLocal8Bit().constData());
+	        devices.append(QString((const QChar *)woc.szPname).toLocal8Bit().constData());
 	    }
 	}
 
diff --git a/src/multimedia/audio/qaudioinput_win32_p.cpp b/src/multimedia/audio/qaudioinput_win32_p.cpp
index 84fd2a5..cc4fdee 100644
--- a/src/multimedia/audio/qaudioinput_win32_p.cpp
+++ b/src/multimedia/audio/qaudioinput_win32_p.cpp
@@ -255,7 +255,7 @@ bool QAudioInputPrivate::open()
         if(waveInGetDevCaps(ii, &wic, sizeof(WAVEINCAPS))
 	    == MMSYSERR_NOERROR) {
 	    QString tmp;
-	    tmp = QString::fromUtf16((const unsigned short*)wic.szPname);
+	    tmp = QString((const QChar *)wic.szPname);
 	    if(tmp.compare(QLatin1String(m_device)) == 0) {
 	        devId = ii;
 		break;
diff --git a/src/multimedia/audio/qaudiooutput_win32_p.cpp b/src/multimedia/audio/qaudiooutput_win32_p.cpp
index c31e048..bce45c1 100644
--- a/src/multimedia/audio/qaudiooutput_win32_p.cpp
+++ b/src/multimedia/audio/qaudiooutput_win32_p.cpp
@@ -250,7 +250,7 @@ bool QAudioOutputPrivate::open()
         if(waveOutGetDevCaps(ii, &woc, sizeof(WAVEOUTCAPS))
 	    == MMSYSERR_NOERROR) {
 	    QString tmp;
-	    tmp = QString::fromUtf16((const unsigned short*)woc.szPname);
+	    tmp = QString((const QChar *)woc.szPname);
             if(tmp.compare(QLatin1String(m_device)) == 0) {
 	        devId = ii;
 		break;
diff --git a/src/sql/drivers/db2/qsql_db2.cpp b/src/sql/drivers/db2/qsql_db2.cpp
index d5b3984..ea0b42e 100644
--- a/src/sql/drivers/db2/qsql_db2.cpp
+++ b/src/sql/drivers/db2/qsql_db2.cpp
@@ -109,7 +109,7 @@ public:
 
 static QString qFromTChar(SQLTCHAR* str)
 {
-    return QString::fromUtf16(str);
+    return QString((const QChar *)str);
 }
 
 // dangerous!! (but fast). Don't use in functions that
@@ -833,7 +833,7 @@ bool QDB2Result::exec()
                 break;
             case QVariant::String:
                 if (bindValueType(i) & QSql::Out)
-                    values[i] = QString::fromUtf16((ushort*)tmpStorage.takeFirst().constData());
+                    values[i] = QString((const QChar *)tmpStorage.takeFirst().constData());
                 break;
             default: {
                 values[i] = QString::fromAscii(tmpStorage.takeFirst().constData());
diff --git a/src/sql/drivers/oci/qsql_oci.cpp b/src/sql/drivers/oci/qsql_oci.cpp
index 01c4124..b5c85e6 100644
--- a/src/sql/drivers/oci/qsql_oci.cpp
+++ b/src/sql/drivers/oci/qsql_oci.cpp
@@ -364,8 +364,8 @@ static void qOraOutValue(QVariant &value, QList<QByteArray> &storage)
         value = qMakeDate(storage.takeFirst());
         break;
     case QVariant::String:
-        value = QString::fromUtf16(
-                reinterpret_cast<const ushort *>(storage.takeFirst().constData()));
+        value = QString(
+                reinterpret_cast<const QChar *>(storage.takeFirst().constData()));
         break;
     default:
         break; //nothing
@@ -454,7 +454,7 @@ QString qOraWarn(OCIError *err, int *errorCode)
                 OCI_HTYPE_ERROR);
     if (errorCode)
         *errorCode = errcode;
-    return QString::fromUtf16(reinterpret_cast<const ushort *>(errbuf));
+    return QString(reinterpret_cast<const QChar *>(errbuf));
 }
 
 void qOraWarning(const char* msg, OCIError *err)
@@ -989,8 +989,7 @@ int QOCICols::readPiecewise(QVector<QVariant> &values, int index)
         } else {
             if (isStringField) {
                 QString str = values.at(fieldNum + index).toString();
-                str += QString::fromUtf16(reinterpret_cast<const ushort *>(col),
-                                          chunkSize / 2);
+                str += QString(reinterpret_cast<const QChar *>(col), chunkSize / 2);
                 values[fieldNum + index] = str;
                 fieldInf[fieldNum].ind = 0;
             } else {
@@ -1457,7 +1456,7 @@ bool QOCICols::execBatch(QOCIResultPrivate *d, QVector<QVariant> &boundValues, b
                     break;
 
                 case SQLT_STR:
-                    (*list)[r] =  QString::fromUtf16(reinterpret_cast<ushort *>(data
+                    (*list)[r] =  QString(reinterpret_cast<const QChar *>(data
                                                                 + r * columns[i].maxLen));
                     break;
 
@@ -1608,7 +1607,7 @@ void QOCICols::getValues(QVector<QVariant> &v, int index)
             }
             // else fall through
         case QVariant::String:
-            v[index + i] = QString::fromUtf16(reinterpret_cast<const ushort *>(fld.data));
+            v[index + i] = QString(reinterpret_cast<const QChar *>(fld.data));
             break;
         case QVariant::ByteArray:
             if (fld.len > 0)
@@ -2102,7 +2101,7 @@ bool QOCIDriver::open(const QString & db,
         qWarning("QOCIDriver::open: could not get Oracle server version.");
     } else {
         QString versionStr;
-        versionStr = QString::fromUtf16(reinterpret_cast<ushort *>(vertxt));
+        versionStr = QString(reinterpret_cast<const QChar *>(vertxt));
         QRegExp vers(QLatin1String("([0-9]+)\\.[0-9\\.]+[0-9]"));
         if (vers.indexIn(versionStr) >= 0)
             d->serverVersion = vers.cap(1).toInt();
diff --git a/src/sql/drivers/odbc/qsql_odbc.cpp b/src/sql/drivers/odbc/qsql_odbc.cpp
index 18bc743..fab3ab3 100644
--- a/src/sql/drivers/odbc/qsql_odbc.cpp
+++ b/src/sql/drivers/odbc/qsql_odbc.cpp
@@ -1558,7 +1558,7 @@ bool QODBCResult::exec()
             case QVariant::String:
                 if (d->unicode) {
                     if (bindValueType(i) & QSql::Out)
-                        values[i] = QString::fromUtf16((ushort*)tmpStorage.takeFirst().constData());
+                        values[i] = QString((QChar *)tmpStorage.takeFirst().constData());
                     break;
                 }
                 // fall through
diff --git a/src/sql/drivers/sqlite/qsql_sqlite.cpp b/src/sql/drivers/sqlite/qsql_sqlite.cpp
index d3be304..24dcad9 100644
--- a/src/sql/drivers/sqlite/qsql_sqlite.cpp
+++ b/src/sql/drivers/sqlite/qsql_sqlite.cpp
@@ -95,7 +95,7 @@ static QSqlError qMakeError(sqlite3 *access, const QString &descr, QSqlError::Er
                             int errorCode = -1)
 {
     return QSqlError(descr,
-                     QString::fromUtf16(static_cast<const ushort *>(sqlite3_errmsg16(access))),
+                     QString(reinterpret_cast<const QChar *>(sqlite3_errmsg16(access))),
                      type, errorCode);
 }
 
@@ -162,13 +162,13 @@ void QSQLiteResultPrivate::initColumns(bool emptyResultset)
     q->init(nCols);
 
     for (int i = 0; i < nCols; ++i) {
-        QString colName = QString::fromUtf16(
-                    static_cast<const ushort *>(sqlite3_column_name16(stmt, i))
+        QString colName = QString(reinterpret_cast<const QChar *>(
+                    sqlite3_column_name16(stmt, i))
                     ).remove(QLatin1Char('"'));
 
         // must use typeName for resolving the type to match QSqliteDriver::record
-        QString typeName = QString::fromUtf16(
-                    static_cast<const ushort *>(sqlite3_column_decltype16(stmt, i)));
+        QString typeName = QString(reinterpret_cast<const QChar *>(
+                    sqlite3_column_decltype16(stmt, i)));
 
         int dotIdx = colName.lastIndexOf(QLatin1Char('.'));
         QSqlField fld(colName.mid(dotIdx == -1 ? 0 : dotIdx + 1), qGetColumnType(typeName));