[VT]: Add a way to track VT float attributes

This lets you use the VT state helper to deal with float attributes.
Previously, float values may not have been handled correctly.

examples/seeder_example/vt_application.cpp

@@ -76,7 +76,7 @@ bool SeederVtApplication::initialize()
 	VTClientUpdateHelper.add_tracked_numeric_value(currentAlarms2_ObjPtr);
 
 	// Track the attribute values we want to update
-	VTClientUpdateHelper.add_tracked_attribute(speed_OutNum, 8, 0.0036f);
+	VTClientUpdateHelper.add_tracked_attribute_float(speed_OutNum, 8, 0.0036f);
 	VTClientUpdateHelper.add_tracked_attribute(section1Status_OutRect, 5, solidGreen_FillAttr);
 	VTClientUpdateHelper.add_tracked_attribute(section2Status_OutRect, 5, solidYellow_FillAttr);
 	VTClientUpdateHelper.add_tracked_attribute(section3Status_OutRect, 5, solidRed_FillAttr);

isobus/include/isobus/isobus/isobus_virtual_terminal_client_state_tracker.hpp

@@ -99,6 +99,12 @@ namespace isobus
 		/// @param[in] initialValue The initial value of the attribute to track.
 		void add_tracked_attribute(std::uint16_t objectId, std::uint8_t attribute, std::uint32_t initialValue = 0);
 
+		/// @brief Adds a float attribute to track.
+		/// @param[in] objectId The object id of the attribute to track.
+		/// @param[in] attribute The attribute to track. Make sure it's a float attribute!
+		/// @param[in] initialValue The initial value of the attribute to track.
+		void add_tracked_attribute_float(std::uint16_t objectId, std::uint8_t attribute, float initialValue = 0.0f);
+
 		/// @brief Removes an attribute from tracking.
 		/// @param[in] objectId The object id of the attribute to remove from tracking.
 		/// @param[in] attribute The attribute to remove from tracking.
@@ -110,6 +116,12 @@ namespace isobus
 		/// @return The value of the attribute of the tracked object.
 		std::uint32_t get_attribute(std::uint16_t objectId, std::uint8_t attribute) const;
 
+		/// @brief Get the value of an attribute of a tracked object, if you tracked it with add_tracked_attribute_float.
+		/// @param[in] objectId The object id of the attribute to get.
+		/// @param[in] attribute The attribute to get.
+		/// @return The value of the attribute of the tracked object.
+		float get_attribute_float(std::uint16_t objectId, std::uint8_t attribute) const;
+
 	protected:
 		std::shared_ptr<ControlFunction> client; ///< The control function of the virtual terminal client to track.
 		std::shared_ptr<ControlFunction> server; ///< The control function of the server the client is connected to.
@@ -134,6 +146,7 @@ namespace isobus
 		std::uint8_t activeWorkingSetAddress = NULL_CAN_ADDRESS; ///< Holds the address of the control function that currently has
 		std::map<std::uint16_t, std::uint16_t> softKeyMasks; ///< Holds the data/alarms masks with their associated soft keys masks for tracked objects.
 		std::map<std::uint16_t, std::map<std::uint8_t, std::uint32_t>> attributeStates; ///< Holds the 'attribute' state of tracked objects.
+		std::map<std::uint16_t, std::map<std::uint8_t, float>> floatAttributeStates; ///< Holds the 'attribute' state of tracked objects, for attributes that use floats (scale, for example).
 		//! TODO: std::map<std::uint16_t, std::uint8_t> alarmMaskPrioritiesStates; ///< Holds the 'alarm mask priority' state of tracked objects.
 		//! TODO: std::map<std::uint16_t, std::pair<std::uint8_t, std::uint16_t>> listItemStates; ///< Holds the 'list item' state of tracked objects.
 		//! TODO: add lock/unlock mask state

isobus/include/isobus/isobus/isobus_virtual_terminal_client_update_helper.hpp

@@ -74,6 +74,18 @@ namespace isobus
 		/// @return True if the attribute was set successfully, false otherwise.
 		bool set_attribute(std::uint16_t objectId, std::uint8_t attribute, std::uint32_t value);
 
+		/// @brief Sets the value of a float attribute of a tracked object.
+		/// @attention ONLY use this function for float attributes defined in ISO11783-6,
+		/// otherwise you will get incorrect results. Scale on output numbers, for example, is a float.
+		/// @note If the to be tracked working set consists of more than the master,
+		/// this function is incompatible with a VT prior to version 4. For working sets consisting
+		/// of only the master, this function is compatible with any VT version.
+		/// @param[in] objectId The object id of the attribute to set.
+		/// @param[in] attribute The attribute to set.
+		/// @param[in] value The value to set the attribute to.
+		/// @return True if the attribute was set successfully, false otherwise.
+		bool set_attribute(std::uint16_t objectId, std::uint8_t attribute, float value);
+
 	private:
 		/// @brief Processes a numeric value change event
 		/// @param[in] event The numeric value change event to process.

isobus/src/isobus_virtual_terminal_client_state_tracker.cpp

@@ -160,6 +160,24 @@ namespace isobus
 		attributeMap[attribute] = initialValue;
 	}
 
+	void VirtualTerminalClientStateTracker::add_tracked_attribute_float(std::uint16_t objectId, std::uint8_t attribute, float initialValue)
+	{
+		if (floatAttributeStates.find(objectId) == floatAttributeStates.end())
+		{
+			floatAttributeStates[objectId] = {};
+		}
+
+		auto &attributeMap = floatAttributeStates.at(objectId);
+		if ((attributeMap.find(attribute) != attributeMap.end()) ||
+		    (floatAttributeStates.find(attribute) != floatAttributeStates.end()))
+		{
+			LOG_WARNING("[VTStateHelper] add_tracked_attribute: attribute '%lu' of objectId '%lu' already tracked", attribute, objectId);
+			return;
+		}
+
+		attributeMap[attribute] = initialValue;
+	}
+
 	void VirtualTerminalClientStateTracker::remove_tracked_attribute(std::uint16_t objectId, std::uint8_t attribute)
 	{
 		if (attributeStates.find(objectId) == attributeStates.end())
@@ -196,6 +214,37 @@ namespace isobus
 		return attributeMap.at(attribute);
 	}
 
+	float VirtualTerminalClientStateTracker::get_attribute_float(std::uint16_t objectId, std::uint8_t attribute) const
+	{
+		if (attributeStates.find(objectId) == attributeStates.end())
+		{
+			if (floatAttributeStates.find(objectId) == floatAttributeStates.end())
+			{
+				LOG_WARNING("[VTStateHelper] get_attribute_float: objectId '%lu' has no tracked float attributes", objectId);
+				return 0.0f;
+			}
+
+			const auto &floatAttributeMap = floatAttributeStates.at(objectId);
+			if (floatAttributeStates.find(attribute) == floatAttributeStates.end())
+			{
+				LOG_WARNING("[VTStateHelper] get_attribute_float: float attribute '%lu' of objectId '%lu' not tracked", attribute, objectId);
+				return 0;
+			}
+			return floatAttributeMap.at(attribute);
+		}
+		else
+		{
+			const auto &attributeMap = attributeStates.at(objectId);
+
+			if (attributeMap.find(attribute) != attributeMap.end())
+			{
+				LOG_WARNING("[VTStateHelper] get_attribute_float: attribute '%lu' of objectId '%lu' was tracked as an integer. You are calling the wrong function to get its value!", attribute, objectId);
+				return static_cast<float>(attributeMap.at(attribute));
+			}
+		}
+		return 0.0f;
+	}
+
 	void VirtualTerminalClientStateTracker::cache_active_mask(std::uint16_t maskId)
 	{
 		if (activeDataOrAlarmMask != maskId)

isobus/src/isobus_virtual_terminal_client_update_helper.cpp

@@ -172,4 +172,34 @@ namespace isobus
 		return success;
 	}
 
+	bool VirtualTerminalClientUpdateHelper::set_attribute(std::uint16_t objectId, std::uint8_t attribute, float value)
+	{
+		if (nullptr == client)
+		{
+			LOG_ERROR("[VTStateHelper] set_attribute: client is nullptr");
+			return false;
+		}
+		if (floatAttributeStates.find(objectId) == floatAttributeStates.end())
+		{
+			LOG_ERROR("[VTStateHelper] set_attribute: objectId %lu has no float attributes tracked", objectId);
+			return false;
+		}
+		if (floatAttributeStates.at(objectId).find(attribute) == floatAttributeStates.at(objectId).end())
+		{
+			LOG_WARNING("[VTStateHelper] set_attribute: float attribute %lu of objectId %lu not tracked", attribute, objectId);
+			return false;
+		}
+		if (floatAttributeStates.at(objectId).at(attribute) == value)
+		{
+			return true;
+		}
+
+		bool success = vtClient->send_change_attribute(objectId, attribute, value);
+		if (success)
+		{
+			floatAttributeStates[objectId][attribute] = value;
+		}
+		return success;
+	}
+
 } // namespace isobus