Port QLocalePrivate::*ToCode() to QLatin1String

The returned data is in US-ASCII (or else Latin-1), and resides in
consecutive memory. We can therefore return it in a QLatin1String,
which, however, will in general not be NUL-terminated.

Many users use the return value as part of a QStringBuilder
expression, and those which are not are not pessimized further by
this change.

The caller in qtimezoneprivate_icu looks as if it could simply zero
-terminate the return value and use it as-is, as opposed to
converting to UTF-8, but I left the code equivalent to the original
just the same.

Change-Id: I0e628af8c1320fcff8d0aacf160e859681d2b85a
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 7 insertions, 8 deletions

diff --git a/src/corelib/tools/qlocale_p.h b/src/corelib/tools/qlocale_p.h
index f7adb021b6..1c6e3e850b 100644
--- a/src/corelib/tools/qlocale_p.h
+++ b/src/corelib/tools/qlocale_p.h
@@ -349,14 +349,13 @@ public:
 
     QByteArray bcp47Name(char separator = '-') const;
 
-    // ### QByteArray::fromRawData would be more optimal
-    inline QString languageCode() const { return QLocalePrivate::languageToCode(QLocale::Language(m_data->m_language_id)); }
-    inline QString scriptCode() const { return QLocalePrivate::scriptToCode(QLocale::Script(m_data->m_script_id)); }
-    inline QString countryCode() const { return QLocalePrivate::countryToCode(QLocale::Country(m_data->m_country_id)); }
-
-    static QString languageToCode(QLocale::Language language);
-    static QString scriptToCode(QLocale::Script script);
-    static QString countryToCode(QLocale::Country country);
+    inline QLatin1String languageCode() const { return QLocalePrivate::languageToCode(QLocale::Language(m_data->m_language_id)); }
+    inline QLatin1String scriptCode() const { return QLocalePrivate::scriptToCode(QLocale::Script(m_data->m_script_id)); }
+    inline QLatin1String countryCode() const { return QLocalePrivate::countryToCode(QLocale::Country(m_data->m_country_id)); }
+
+    static QLatin1String languageToCode(QLocale::Language language);
+    static QLatin1String scriptToCode(QLocale::Script script);
+    static QLatin1String countryToCode(QLocale::Country country);
     static QLocale::Language codeToLanguage(const QChar *code, int len) Q_DECL_NOTHROW;
     static QLocale::Language codeToLanguage(const QString &code) Q_DECL_NOTHROW { return codeToLanguage(code.data(), code.size()); }
     static QLocale::Language codeToLanguage(const QStringRef &code) Q_DECL_NOTHROW { return codeToLanguage(code.data(), code.size()); }