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/*******************************************************************************
* Copyright (c) 2011 protos software gmbh (http://www.protos.de).
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* CONTRIBUTORS:
* Thomas Schuetz (initial contribution)
*
*******************************************************************************/
/**
* \file etMessageService.h
*
* this component implements a message service that delivers messages asynchronously
*
* \author Thomas Schuetz
*/
#ifndef _ETMESSAGESERVICE_H_
#define _ETMESSAGESERVICE_H_
#include <stddef.h>
#include "etDatatypes.h"
#include "messaging/etMessageQueue.h"
#include "messaging/etMessageReceiver.h"
#include "osal/etMutex.h"
#include "osal/etThread.h"
#include "osal/etSema.h"
#include "osal/etTimer.h"
/** the address of the message service */
#define MESSAGESERVICE_ADDRESS 1
/** the base address for other receivers */
#define BASE_ADDRESS 32
/** enumeration for execution modes */
typedef enum etMessageService_execmode {
EXECMODE_POLLED, /**< polled execution for data driven systems */
EXECMODE_BLOCKED, /**< blocked execution for asynchronous systems */
EXECMODE_MIXED /**< mixed execution for mixed systems */
} etMessageService_execmode;
/**
* the data structure for the message buffer (chunks of equal size)
*/
typedef struct etBuffer{
etUInt8 *buffer; /**< buffer points to the actual memory position for the message pool */
etUInt16 maxBlocks; /**< number of blocks for the message pool */
etUInt16 blockSize; /**< size of blocks for the message pool */
} etBuffer;
typedef struct etMessageService {
etMessageQueue messageQueue; /**< message queue that holds all used messages */
etMessageQueue messagePool; /**< message pool that holds all free messages */
etBuffer messageBuffer; /**< information about the message buffer that holds information about
the actual memory position and size for the message pool */
etDispatcherReceiveMessage msgDispatcher; /**< function pointer to the generated message dispatcher function */
etThread thread; /**< thread for the execution of the message service */
etMutex poolMutex; /**< mutex for synchronizing the access to the message pool */
etMutex queueMutex; /**< mutex for synchronizing the access to the message queue */
etSema executionSemaphore; /**< semaphore for waiting and waking up the execution */
etTimer timer; /**< timer for cyclic calls */
etMessageService_execmode execmode; /**< execution mode*/
} etMessageService;
/**
* initialization (construction)
*
* \param self the this pointer
* \param buffer the buffer for the message pool
* \param maxBlocks the number of (equal sized) message blocks in the buffer
* \param blockSize the size of each message block
* \param stackSize the stack size for the thread in which this service will run
* \param priority the thread priority
* \param interval the polling interval
* \param msgDispatcher the dispatcher method
* \param execmdoe the execution mode for this message service
*/
void etMessageService_init(
etMessageService* self,
etUInt8* buffer,
etUInt16 maxBlocks,
etUInt16 blockSize,
etStacksize stacksize,
etPriority priority,
etTime interval,
etDispatcherReceiveMessage msgDispatcher,
etMessageService_execmode execmode);
/**
* start of the message service (starts the associated thread)
*
* \param self the this pointer
*/
void etMessageService_start(etMessageService* self);
/**
* the polling method to be called cyclically
*
* \param self the this pointer
*/
void etMessageService_execute(etMessageService* self);
/**
* stops the message service thread
*
* \param self the this pointer
*/
void etMessageService_stop(etMessageService* self);
/**
* destroys the message service
*
* \param self the this pointer
*/
void etMessageService_destroy(etMessageService* self);
/**
* initialization of message pool
*
* \param self the this pointer
*/
void etMessageService_initMessagePool(etMessageService* self);
/**
* push a message to the queue. The queue access is synchronized. The method notifies the dispatch thread.
*
* \param self the this pointer
* \msg the message to push
*/
void etMessageService_pushMessage(etMessageService* self, etMessage* msg);
/**
* pop a message from the queue. The queue access is synchronized.
*
* \param self the this pointer
* \return the extracted message
*/
etMessage* etMessageService_popMessage(etMessageService* self);
/**
* get a chunk of uninitialized memory interpreted as \ref etMessage from the services memory management
*
* \param self the this pointer
* \param size the size of the message in bytes
* \return a message pointer to a chunk of memory with at least the required size
*/
etMessage* etMessageService_getMessageBuffer(etMessageService* self, etUInt16 size);
/**
* return a chunk of previously obtained memory to the message service memory management
*
* \param self the this pointer
* \param buffer the memory to be freed
*/
void etMessageService_returnMessageBuffer(etMessageService* self, etMessage* buffer);
/**
* returns the low water mark of the message pool
*
* \param self the this pointer
* \return the low water mark of the message pool
*/
etInt16 etMessageService_getMessagePoolLowWaterMark(etMessageService* self);
#endif /* RMESSAGESERVICE_H_ */
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