text: /* mbed Microcontroller Library
   * Copyright (c) 2006-2012 ARM Limited
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  #ifndef QUEUE_H
  #define QUEUE_H
  
  #include <stdint.h>
  #include <string.h>
  
  #include "cmsis_os2.h"
  #include "mbed_rtos_storage.h"
  #include "platform/mbed_error.h"
  #include "platform/NonCopyable.h"
  #include "mbed_rtos1_types.h"
  
  namespace rtos {
  /** \addtogroup rtos */
  /** @{*/
  /**
   * \defgroup rtos_EventFlags EventFlags class
   * @{
   */
   
  /** The Queue class allow to control, send, receive, or wait for messages.
   A message can be a integer or pointer value  to a certain type T that is send
   to a thread or interrupt service routine.
    @tparam  T         data type of a single message element.
    @tparam  queue_sz  maximum number of messages in queue.
  
   @note
   Memory considerations: The queue control structures will be created on current thread's stack, both for the mbed OS
   and underlying RTOS objects (static or dynamic RTOS memory pools are not being used).
  */
  template<typename T, uint32_t queue_sz>
  class Queue : private mbed::NonCopyable<Queue<T, queue_sz> > {
  public:
      /** Create and initialize a message Queue. */
      Queue() {
          memset(&_obj_mem, 0, sizeof(_obj_mem));
          memset(&_attr, 0, sizeof(_attr));
          _attr.mq_mem = _queue_mem;
          _attr.mq_size = sizeof(_queue_mem);
          _attr.cb_mem = &_obj_mem;
          _attr.cb_size = sizeof(_obj_mem);
          _id = osMessageQueueNew(queue_sz, sizeof(T*), &_attr);
          MBED_ASSERT(_id);
      }
  
      ~Queue() {
          osMessageQueueDelete(_id);
      }
  
      /** Put a message in a Queue.
        @param   data      message pointer.
        @param   millisec  timeout value or 0 in case of no time-out. (default: 0)
        @param   prio      priority value or 0 in case of default. (default: 0)
        @return  status code that indicates the execution status of the function:
                 @a osOK the message has been put into the queue.
                 @a osErrorTimeout the message could not be put into the queue in the given time.
                 @a osErrorResource not enough space in the queue.
                 @a osErrorParameter internal error or non-zero timeout specified in an ISR.
      */
      osStatus put(T* data, uint32_t millisec=0, uint8_t prio=0) {
          return osMessageQueuePut(_id, &data, prio, millisec);
      }
  
      /** Get a message or Wait for a message from a Queue. Messages are retrieved in a descending priority order or
          first in first out when the priorities are the same.
        @param   millisec  timeout value or 0 in case of no time-out. (default: osWaitForever).
        @return  event information that includes the message in event.value and the status code in event.status:
                 @a osEventMessage message received.
                 @a osOK no message is available in the queue and no timeout was specified.
                 @a osEventTimeout no message has arrived during the given timeout period.
                 @a osErrorParameter a parameter is invalid or outside of a permitted range.
      */
      osEvent get(uint32_t millisec=osWaitForever) {
          osEvent event;
          T *data = NULL;
          osStatus_t res = osMessageQueueGet(_id, &data, NULL, millisec);
  
          switch (res) {
              case osOK:
                  event.status = (osStatus)osEventMessage;
                  event.value.p = data;
                  break;
              case osErrorResource:
                  event.status = osOK;
                  break;
              case osErrorTimeout:
                  event.status = (osStatus)osEventTimeout;
                  break;
              case osErrorParameter:
              default:
                  event.status = osErrorParameter;
                  break;
          }
          event.def.message_id = _id;
  
          return event;
      }
  
  private:
      osMessageQueueId_t            _id;
      osMessageQueueAttr_t          _attr;
      char                          _queue_mem[queue_sz * (sizeof(T*) + sizeof(mbed_rtos_storage_message_t))];
      mbed_rtos_storage_msg_queue_t _obj_mem;
  };
  /** @}*/
  /** @}*/
  
  }
  #endif
  
  