optimization: get rid of QString::fromUtf16() usage

QString::fromUtf16() is slow - it does a BOM check and optionally byte
swapping, which is utterly pointless when converting internal data
structures which are raw utf16 in host byte order anyway. so replace
it with QString::fromRawData() (for short-lived strings) or
QString(const QChar *, int) (otherwise) if possible.

Reviewed-by: axis
Reviewed-by: mariusSO
Reviewed-by: Bill King

2 files changed, 3 insertions, 3 deletions

diff --git a/src/sql/drivers/sqlite/qsql_sqlite.cpp b/src/sql/drivers/sqlite/qsql_sqlite.cpp
index 9dbefaf..9fff552 100644
--- a/src/sql/drivers/sqlite/qsql_sqlite.cpp
+++ b/src/sql/drivers/sqlite/qsql_sqlite.cpp
@@ -245,9 +245,9 @@ bool QSQLiteResultPrivate::fetchNext(QSqlCachedResult::ValueCache &values, int i
                 values[i + idx] = QVariant(QVariant::String);
                 break;
             default:
-                values[i + idx] = QString::fromUtf16(static_cast<const ushort *>(
+                values[i + idx] = QString(reinterpret_cast<const QChar *>(
                             sqlite3_column_text16(stmt, i)),
-                            sqlite3_column_bytes16(stmt, i) / sizeof(ushort));
+                            sqlite3_column_bytes16(stmt, i) / sizeof(QChar));
                 break;
             }
         }
diff --git a/src/sql/kernel/qsqlresult.cpp b/src/sql/kernel/qsqlresult.cpp
index 5f12b55..3d63f88 100644
--- a/src/sql/kernel/qsqlresult.cpp
+++ b/src/sql/kernel/qsqlresult.cpp
@@ -136,7 +136,7 @@ static QString qFieldSerial(int i)
         i >>= 4;
     }
 
-    return QString::fromUtf16(arr, int(ptr - arr) + 1);
+    return QString(reinterpret_cast<const QChar *>(arr), int(ptr - arr) + 1);
 }
 
 static bool qIsAlnum(QChar ch)