QtCore: don't convert single characters to QString for QTextCodec::fromUnicode()

Use the fromUnicode(QChar *, int size) overload instead.

Saves 0.5KiB text size on Linux GCC 4.9 AMD64 release builds.

Change-Id: I1a1081e09bff4c2116288b8c2616e1bb7ee2bb42
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/corelib/io/qsettings.cpp b/src/corelib/io/qsettings.cpp
index b9993c454e..458109888f 100644
--- a/src/corelib/io/qsettings.cpp
+++ b/src/corelib/io/qsettings.cpp
@@ -632,8 +632,9 @@ void QSettingsPrivate::iniEscapedString(const QString &str, QByteArray &result,
     int startPos = result.size();
 
     result.reserve(startPos + str.size() * 3 / 2);
+    const QChar *unicode = str.unicode();
     for (i = 0; i < str.size(); ++i) {
-        uint ch = str.at(i).unicode();
+        uint ch = unicode[i].unicode();
         if (ch == ';' || ch == ',' || ch == '=')
             needsQuotes = true;
 
@@ -687,7 +688,7 @@ void QSettingsPrivate::iniEscapedString(const QString &str, QByteArray &result,
 #ifndef QT_NO_TEXTCODEC
             } else if (useCodec) {
                 // slow
-                result += codec->fromUnicode(str.at(i));
+                result += codec->fromUnicode(&unicode[i], 1);
 #endif
             } else {
                 result += (char)ch;