Add json object parsing and helpers

inferno/src/inferno/util/json.h

@@ -111,7 +111,7 @@ namespace Inferno {
 				return {};
 			}
 
-			// Check if property is array
+			// Check if property is array []
 			ASSERT(getValue(it).is_array(), "Json property is not an array '{}'", property);
 
 			// Fill array with values
@@ -126,6 +126,45 @@ namespace Inferno {
 				}
 			}
 
+			// Return vector if it has any items, uninitialized optional otherwise
+			return values.size() > 0 ? std::optional { values } : std::nullopt;
+		}
+
+		template<typename T>
+		static std::optional<std::map<std::string, T>> parseObjectProperty(const json& json, const char* property, bool required, json::value_t check)
+		{
+			return parseObjectProperty<T>(json, property, required, std::vector { check });
+		}
+
+		template<typename T>
+		static std::optional<std::map<std::string, T>> parseObjectProperty(const json& json, const char* property, bool required, std::vector<json::value_t> checks)
+		{
+			bool exists;
+			json_const_iterator it;
+
+			// Has property
+			exists = hasProperty(json, it, property);
+			ASSERT(!required || (required && exists), "Json could not find required property '{}'", property);
+
+			if (!exists) {
+				return {};
+			}
+
+			// Check if property is an object {}
+			ASSERT(getValue(it).is_object(), "Json property is not an array '{}'", property);
+
+			std::map<std::string, T> values;
+			for (auto& [key, value] : getValue(it).items()) {
+				auto typedValue = getPropertyValue<T>(value, checks);
+				if (typedValue) {
+					values.emplace(std::move(key), typedValue.value());
+				}
+				else {
+					warnln("Json array property '{}' has type inconsistency", property);
+				}
+			}
+
+			// Return map if it has any items, uninitialized optional otherwise
 			return values.size() > 0 ? std::optional { values } : std::nullopt;
 		}
 
@@ -169,8 +208,33 @@ namespace Inferno {
 			return parseArrayProperty<uint32_t>(json, property, required, json::value_t::number_unsigned);
 		}
 
+		static std::optional<std::map<std::string, double>> parseDoubleObjectProperty(const json& json, const char* property, bool required)
+		{
+			return parseObjectProperty<double>(json, property, required, std::vector { json::value_t::number_integer, json::value_t::number_unsigned, json::value_t::number_float });
+		}
+
+		static std::optional<std::map<std::string, int32_t>> parseIntegerObjectProperty(const json& json, const char* property, bool required)
+		{
+			return parseObjectProperty<int32_t>(json, property, required, json::value_t::number_integer);
+		}
+
+		static std::optional<std::map<std::string, uint32_t>> parseUnsignedObjectProperty(const json& json, const char* property, bool required)
+		{
+			return parseObjectProperty<uint32_t>(json, property, required, json::value_t::number_unsigned);
+		}
+
 	};
 
 } // namespace Inferno
 
 #endif // JSON_UTIL_H
+
+// JSON syntax:
+//   [ ]        = std::map,    array (ordered)
+//   { }        = std::vector, object (unordered)
+//   "":        = std::string, property (key -> value)
+//   true/false = bool,        condition
+//   -3         = int64_t,     number
+//   5          = uint64_t,    number
+//   4.567      = double,      number
+//   "thing"    = std::string, text