#ifndef MESSAGEQUEUEMESSAGE_H_ #define MESSAGEQUEUEMESSAGE_H_ #include #include #include /** * @brief This class is the representation and data organizer * for interprocess messages. * * @details * To facilitate and standardize interprocess communication, this class was * created to handle a lightweight "interprocess message protocol". * * It adds a header with the sender's queue id to every sent message and * defines the maximum total message size. Specialized messages, such as * device commanding messages, can be created by inheriting from this class * and filling the buffer provided by getData with additional content. * * If larger amounts of data must be sent between processes, the data shall * be stored in the IPC Store object and only the storage id is passed in a * queue message.The class is used both to generate and send messages and to * receive messages from other tasks. * @ingroup message_queue */ class MessageQueueMessage: public MessageQueueMessageIF { public: /** * @brief The class is initialized empty with this constructor. * @details The messageSize attribute is set to the header's size and the * whole content is set to zero. */ MessageQueueMessage(); /** * @brief With this constructor the class is initialized with the given content. * @details * If the passed message size fits into the buffer, the passed data is * copied to the internal buffer and the messageSize information is set. * Otherwise, messageSize is set to the header's size and the whole * content is set to zero. * @param data The data to be put in the message. * @param size Size of the data to be copied. Must be smaller than * MAX_MESSAGE_SIZE and larger than MIN_MESSAGE_SIZE. */ MessageQueueMessage(uint8_t* data, size_t size); /** * @brief The size information of each message is stored in this attribute. * @details * It is public to simplify usage and to allow for passing the size * address as a pointer. Care must be taken when inheriting from this class, * as every child class is responsible for managing the size information by * itself. When using the class to receive a message, the size information * is updated automatically. * * Please note that the minimum size is limited by the size of the header * while the maximum size is limited by the maximum allowed message size. */ size_t messageSize; /** * @brief This constant defines the maximum size of the data content, excluding the header. * @details It may be changed if necessary, but in general should be kept as small as possible. */ static const size_t MAX_DATA_SIZE = 24; /** * @brief This constants defines the size of the header, which is added to every message. */ static const size_t HEADER_SIZE = sizeof(MessageQueueId_t); /** * @brief This constant defines the maximum total size in bytes of a sent message. * @details It is the sum of the maximum data and the header size. Be aware that this constant * is used to define the buffer sizes for every message queue in the system. So, a change * here may have significant impact on the required resources. */ static const size_t MAX_MESSAGE_SIZE = MAX_DATA_SIZE + HEADER_SIZE; /** * @brief Defines the minimum size of a message where only the * header is included */ static const size_t MIN_MESSAGE_SIZE = HEADER_SIZE; private: /** * @brief This is the internal buffer that contains the actual message data. */ uint8_t internalBuffer[MAX_MESSAGE_SIZE]; public: /** * @brief As no memory is allocated in this class, the destructor is empty. */ virtual ~MessageQueueMessage(); /** * @brief This method is used to get the complete data of the message. */ const uint8_t* getBuffer() const; /** * @brief This method is used to get the complete data of the message. */ uint8_t* getBuffer(); /** * @brief This method is used to fetch the data content of the message. * @details It shall be used by child classes to add data at the right position. */ const uint8_t* getData() const; /** * @brief This method is used to fetch the data content of the message. * @details It shall be used by child classes to add data at the right position. */ uint8_t* getData(); /** * @brief This method is used to extract the sender's message queue id information from a * received message. */ MessageQueueId_t getSender() const; /** * @brief With this method, the whole content and the message size is set to zero. */ void clear(); /** * @brief This is a debug method that prints the content (till messageSize) to the debug output. */ void print(); /** * @brief This method is used to set the sender's message queue id information prior to * sending the message. * @param setId The message queue id that identifies the sending message queue. */ void setSender(MessageQueueId_t setId); /** * @brief This helper function is used by the MessageQueue class to check the size of an * incoming message. * @details The method must be overwritten by child classes if size checks shall be more strict. * @return The default implementation returns HEADER_SIZE. */ virtual size_t getMinimumMessageSize() const; }; #endif /* MESSAGEQUEUEMESSAGE_H_ */