Queue.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2012 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 #ifndef QUEUE_H
00023 #define QUEUE_H
00024 
00025 #include <stdint.h>
00026 #include <string.h>
00027 
00028 #include "cmsis_os2.h"
00029 #include "mbed_rtos_storage.h"
00030 #include "platform/mbed_error.h"
00031 #include "platform/NonCopyable.h"
00032 #include "mbed_rtos1_types.h"
00033 
00034 namespace rtos {
00035 /** \addtogroup rtos */
00036 /** @{*/
00037 /**
00038  * \defgroup rtos_EventFlags EventFlags class
00039  * @{
00040  */
00041  
00042 /** The Queue class allow to control, send, receive, or wait for messages.
00043  A message can be a integer or pointer value  to a certain type T that is send
00044  to a thread or interrupt service routine.
00045   @tparam  T         data type of a single message element.
00046   @tparam  queue_sz  maximum number of messages in queue.
00047 
00048  @note
00049  Memory considerations: The queue control structures will be created on current thread's stack, both for the mbed OS
00050  and underlying RTOS objects (static or dynamic RTOS memory pools are not being used).
00051 */
00052 template<typename T, uint32_t queue_sz>
00053 class Queue : private mbed::NonCopyable<Queue<T, queue_sz> > {
00054 public:
00055     /** Create and initialize a message Queue. */
00056     Queue() {
00057         memset(&_obj_mem, 0, sizeof(_obj_mem));
00058         osMessageQueueAttr_t attr = { 0 };
00059         attr.mq_mem = _queue_mem;
00060         attr.mq_size = sizeof(_queue_mem);
00061         attr.cb_mem = &_obj_mem;
00062         attr.cb_size = sizeof(_obj_mem);
00063         _id = osMessageQueueNew(queue_sz, sizeof(T*), &attr);
00064         MBED_ASSERT(_id);
00065     }
00066 
00067     ~Queue() {
00068         osMessageQueueDelete(_id);
00069     }
00070 
00071     /** Check if the queue is empty
00072      *
00073      * @return True if the queue is empty, false if not
00074      */
00075     bool empty() const {
00076         return osMessageQueueGetCount(_id) == 0;
00077     }
00078 
00079     /** Check if the queue is full
00080      *
00081      * @return True if the queue is full, false if not
00082      */
00083     bool full() const {
00084         return osMessageQueueGetSpace(_id) == 0;
00085     }
00086 
00087     /** Put a message in a Queue.
00088       @param   data      message pointer.
00089       @param   millisec  timeout value or 0 in case of no time-out. (default: 0)
00090       @param   prio      priority value or 0 in case of default. (default: 0)
00091       @return  status code that indicates the execution status of the function:
00092                @a osOK the message has been put into the queue.
00093                @a osErrorTimeout the message could not be put into the queue in the given time.
00094                @a osErrorResource not enough space in the queue.
00095                @a osErrorParameter internal error or non-zero timeout specified in an ISR.
00096     */
00097     osStatus put(T* data, uint32_t millisec=0, uint8_t prio=0) {
00098         return osMessageQueuePut(_id, &data, prio, millisec);
00099     }
00100 
00101     /** Get a message or Wait for a message from a Queue. Messages are retrieved in a descending priority order or
00102         first in first out when the priorities are the same.
00103       @param   millisec  timeout value or 0 in case of no time-out. (default: osWaitForever).
00104       @return  event information that includes the message in event.value and the status code in event.status:
00105                @a osEventMessage message received.
00106                @a osOK no message is available in the queue and no timeout was specified.
00107                @a osEventTimeout no message has arrived during the given timeout period.
00108                @a osErrorParameter a parameter is invalid or outside of a permitted range.
00109     */
00110     osEvent get(uint32_t millisec=osWaitForever) {
00111         osEvent event;
00112         T *data = NULL;
00113         osStatus_t res = osMessageQueueGet(_id, &data, NULL, millisec);
00114 
00115         switch (res) {
00116             case osOK:
00117                 event.status = (osStatus)osEventMessage;
00118                 event.value.p = data;
00119                 break;
00120             case osErrorResource:
00121                 event.status = osOK;
00122                 break;
00123             case osErrorTimeout:
00124                 event.status = (osStatus)osEventTimeout;
00125                 break;
00126             case osErrorParameter:
00127             default:
00128                 event.status = osErrorParameter;
00129                 break;
00130         }
00131         event.def.message_id = _id;
00132 
00133         return event;
00134     }
00135 
00136 private:
00137     osMessageQueueId_t            _id;
00138     char                          _queue_mem[queue_sz * (sizeof(T*) + sizeof(mbed_rtos_storage_message_t))];
00139     mbed_rtos_storage_msg_queue_t _obj_mem;
00140 };
00141 /** @}*/
00142 /** @}*/
00143 
00144 }
00145 #endif
00146