optimization: get rid of QString::fromUtf16() usage, part 2

QString::fromUtf16() is slow - it does a BOM check and optionally byte
swapping, which is utterly irrelevant when converting internal data
structures which are raw utf16 in host byte order. so replace it with
QString::fromUnicode() where possible (which seems to be everywhere).

the reasoning is the same as in commit e0fda52f, so not getting further
reviews.

Reviewed-by: denis
Reviewed-by: joao

4 files changed, 15 insertions, 16 deletions

diff --git a/src/sql/drivers/db2/qsql_db2.cpp b/src/sql/drivers/db2/qsql_db2.cpp
index d5b398429d..ea0b42e0d7 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 01c4124c9f..b5c85e696b 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 18bc743670..fab3ab3c2b 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 d3be304b02..24dcad9f18 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));