Add string localization API

Source/Engine/Localization/Localization.cpp

@@ -153,3 +153,41 @@ void Localization::SetCurrentLanguageCulture(const CultureInfo& value)
     Instance.CurrentLanguage = value;
     Instance.OnLocalizationChanged();
 }
+
+String Localization::GetString(const String& id, const String& fallback)
+{
+    String result;
+    for (auto& e : Instance.LocalizedStringTables)
+    {
+        const auto table = e.Get();
+        const auto messages = table ? table->Entries.TryGet(id) : nullptr;
+        if (messages && messages->Count() != 0)
+        {
+            result = messages->At(0);
+            break;
+        }
+    }
+    if (result.IsEmpty())
+        result = fallback;
+    return result;
+}
+
+String Localization::GetPluralString(const String& id, int32 n, const String& fallback)
+{
+    CHECK_RETURN(n >= 1, fallback);
+    n--;
+    String result;
+    for (auto& e : Instance.LocalizedStringTables)
+    {
+        const auto table = e.Get();
+        const auto messages = table ? table->Entries.TryGet(id) : nullptr;
+        if (messages && messages->Count() > n)
+        {
+            result = messages->At(n);
+            break;
+        }
+    }
+    if (result.IsEmpty())
+        result = fallback;
+    return result;
+}

Source/Engine/Localization/Localization.h

@@ -41,4 +41,22 @@ public:
     /// Occurs when current culture or language gets changed. Can be used to refresh UI to reflect language changes.
     /// </summary>
     API_EVENT() static Delegate<> LocalizationChanged;
+
+public:
+    /// <summary>
+    /// Gets the localized string for the current language by using string id lookup.
+    /// </summary>
+    /// <param name="id">The message identifier.</param>
+    /// <param name="fallback">The optional fallback string value to use if localized string is missing.</param>
+    /// <returns>The localized text.</returns>
+    API_FUNCTION() static String GetString(const String& id, const String& fallback = String::Empty);
+
+    /// <summary>
+    /// Gets the localized plural string for the current language by using string id lookup.
+    /// </summary>
+    /// <param name="id">The message identifier.</param>
+    /// <param name="n">The value count for plural message selection.</param>
+    /// <param name="fallback">The optional fallback string value to use if localized string is missing.</param>
+    /// <returns>The localized text.</returns>
+    API_FUNCTION() static String GetPluralString(const String& id, int32 n, const String& fallback = String::Empty);
 };