3DS: Detect system language and select the appropriate translation

CMakeLists.txt

@@ -507,6 +507,7 @@ if(NINTENDO_3DS)
     Source/platform/ctr/messagebox.cpp
     Source/platform/ctr/random.cpp
     Source/platform/ctr/sockets.cpp
+    Source/platform/ctr/locale.cpp
     Source/platform/ctr/asio/net/if.c
     Source/platform/ctr/asio/sys/socket.c
     Source/platform/ctr/asio/sys/uio.c)

Source/options.cpp

@@ -18,6 +18,10 @@
 #include <psp2/system_param.h>
 #endif
 
+#ifdef __3DS__
+#include "platform/ctr/locale.hpp"
+#endif
+
 #define SI_SUPPORT_IOSTREAMS
 #include <SimpleIni.h>
 
@@ -329,6 +333,8 @@ void LoadOptions()
 	sceAppUtilSystemParamGetInt(SCE_SYSTEM_PARAM_ID_LANG, &language);
 	std::string locale = std::string(vita_locales[language]);
 	sceAppUtilShutdown();
+#elif defined(__3DS__)
+	std::string locale = n3ds::GetLocale();
 #else
 	std::string locale = std::locale("").name().substr(0, 5);
 #endif

Source/platform/ctr/locale.cpp

@@ -0,0 +1,66 @@
+#include "platform/ctr/locale.hpp"
+
+#include <3ds.h>
+
+namespace devilution {
+namespace n3ds {
+
+namespace {
+
+class CFGUService {
+public:
+	CFGUService()
+	{
+		cfguInit();
+	}
+
+	~CFGUService()
+	{
+		cfguExit();
+	}
+};
+
+}
+
+std::string GetLocale()
+{
+	CFGUService cfguService;
+
+	u8 language;
+	Result res = CFGU_GetSystemLanguage(&language);
+
+	if (!R_SUCCEEDED(res))
+		return "";
+
+	switch (language) {
+	case CFG_LANGUAGE_JP:
+		return "ja";
+	case CFG_LANGUAGE_EN:
+		return "en";
+	case CFG_LANGUAGE_FR:
+		return "fr";
+	case CFG_LANGUAGE_DE:
+		return "de";
+	case CFG_LANGUAGE_IT:
+		return "it";
+	case CFG_LANGUAGE_ES:
+		return "es";
+	case CFG_LANGUAGE_ZH:
+		return "zh_CN";
+	case CFG_LANGUAGE_KO:
+		return "ko_KR";
+	case CFG_LANGUAGE_NL:
+		return "nl";
+	case CFG_LANGUAGE_PT:
+		return "pt_BR";
+	case CFG_LANGUAGE_RU:
+		return "ru";
+	case CFG_LANGUAGE_TW:
+		return "zh_TW";
+	default:
+		return "";
+	}
+}
+
+} // namespace n3ds
+} // namespace devilution

Source/platform/ctr/locale.hpp

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <string>
+
+namespace devilution {
+namespace n3ds {
+
+std::string GetLocale();
+
+} // namespace n3ds
+} // namespace devilution