Added initial JSON configuration support

sdl_helpers.cpp

@@ -3,12 +3,14 @@
 #include <SDL2/SDL.h>
 #include <SDL2/SDL_image.h>
 
+#include <fstream>
 #include <map>
 #include <utility>
 
 #include <stdio.h>
 
 using namespace std;
+using nlohmann::json;
 
 map<pair<string, int>, TTF_Font*> font_map;
 
@@ -74,3 +76,49 @@ TTF_Font* get_font(const string& filename, int size)
 		return font;
 	}
 }
+
+bool read_config_json(json& cfg, const string& filename, ostream* log)
+{
+	ifstream cfg_file(filename);
+
+	if (!cfg_file.is_open())
+	{
+		if (nullptr != log)
+		{
+			*log << "Could not open config.json" << endl;
+		}
+		return false;
+	}
+
+	// Parse with comments
+	try
+	{
+		cfg = json::parse(cfg_file, nullptr, true, true);
+	}
+	catch (const std::exception &e)
+	{
+		if (nullptr != log)
+		{
+			*log << e.what() << endl;
+		}
+		return false;
+	}
+
+	return true;
+}
+
+void json_extract(const json& j, const string& key, string& out)
+{
+	if (j.contains(key) && j[key].is_string())
+	{
+		out = j[key];
+	}
+}
+
+void json_extract(const nlohmann::json& j, const string& key, int& out)
+{
+	if (j.contains(key) && j[key].is_number_integer())
+	{
+		out = j[key];
+	}
+}