Add json utility class

inferno/src/inferno/util/json.h

@@ -0,0 +1,64 @@
+#ifndef JSON_UTIL_H
+#define JSON_UTIL_H
+
+#include <optional> // std::optional
+
+#include "nlohmann/json.hpp"
+
+#include "inferno/assert.h"
+
+namespace Inferno {
+
+	using json = nlohmann::json;
+	using json_const_iterator = nlohmann::json::const_iterator;
+
+	class Json {
+	public:
+		static const json& getValue(json_const_iterator& it)
+		{
+			return it.value();
+		}
+
+		template<typename T, typename C>
+		static std::optional<T> getType(const json& json, C check)
+		{
+			if (json.type() == check) {
+				return json.get<T>();
+			}
+
+			return {};
+		}
+
+		// ---------------------------------
+
+		static bool hasProperty(const json& json, json_const_iterator& it, const char* member)
+		{
+			it = json.find(member);
+			return it != json.end();
+		}
+
+		// ---------------------------------
+
+		template<typename T, typename C>
+		static std::optional<T> parseProperty(const json& json, const char* property, bool required, C check)
+		{
+			bool result;
+			json_const_iterator it;
+
+			// Has property
+			result = hasProperty(json, it, property);
+			ASSERT(!required || (required && result), "Json could not find property '{}'", property);
+
+			if (!result) {
+				return {};
+			}
+
+			// Return data found in iterator, empty if incorrect type
+			return getType<T>(getValue(it), check);
+		}
+	};
+
+} // namespace Inferno
+
+
+#endif // JSON_UTIL_H