Mbed OS Reference | Mail.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2006-2019 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 MAIL_H
 #define MAIL_H
 
 #include <stdint.h>
 #include <string.h>
 
 #include "rtos/Queue.h"
 #include "rtos/MemoryPool.h"
 #include "rtos/mbed_rtos_types.h"
 #include "rtos/mbed_rtos_storage.h"
 #include "rtos/mbed_rtos1_types.h"
 
 #include "platform/mbed_toolchain.h"
 #include "platform/NonCopyable.h"
 
 #ifndef MBED_NO_GLOBAL_USING_DIRECTIVE
 using namespace rtos;
 #endif
 
 #if MBED_CONF_RTOS_PRESENT || defined(DOXYGEN_ONLY)
 
 namespace rtos {
 /** \addtogroup rtos-public-api */
 /** @{*/
 
 /**
  * \defgroup rtos_Mail Mail class
  * @{
  */
 
 /** The Mail class allows you to control, send, receive or wait for mail.
  * A mail is a memory block that is sent to a thread or interrupt service routine (ISR).
  * @tparam  T         Data type of a single mail message element.
  * @tparam  queue_sz  Maximum number of mail messages in queue.
  *
  * @note
  * Memory considerations: The mail data store and control structures are part of this class - they do not (themselves)
  * allocate memory on the heap, 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 Mail : private mbed::NonCopyable<Mail<T, queue_sz> > {
 public:
     /** Create and initialize Mail queue.
      *
      * @note You cannot call this function from ISR context.
      */
     Mail() { };
 
     /** Check if the mail queue is empty.
      *
      * @return State of queue.
      * @retval true  Mail queue is empty.
      * @retval false Mail queue contains mail.
      *
      * @note You may call this function from ISR context.
      */
     bool empty() const
     {
         return _queue.empty();
     }
 
     /** Check if the mail queue is full.
      *
      * @return State of queue.
      * @retval true  Mail queue is full.
      * @retval false Mail queue is not full.
      *
      * @note You may call this function from ISR context.
      */
     bool full() const
     {
         return _queue.full();
     }
 
     /** Allocate a memory block of type T, without blocking.
      *
      * @param   millisec  Not used (see note).
      *
      * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
      *
      * @note You may call this function from ISR context.
      * @note If blocking is required, use Mail::alloc_for or Mail::alloc_until
      */
     T *alloc(MBED_UNUSED uint32_t millisec = 0)
     {
         return _pool.alloc();
     }
 
     /** Allocate a memory block of type T, optionally blocking.
      *
      * @param   millisec  Timeout value, or osWaitForever.
      *
      * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
      *
      * @note You may call this function from ISR context if the millisec parameter is set to 0.
      */
     T *alloc_for(uint32_t millisec)
     {
         return _pool.alloc_for(millisec);
     }
 
     /** Allocate a memory block of type T, blocking.
      *
      * @param   millisec  Absolute timeout time, referenced to Kernel::get_ms_count().
      *
      * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
      *
      * @note You cannot call this function from ISR context.
      * @note the underlying RTOS may have a limit to the maximum wait time
      *   due to internal 32-bit computations, but this is guaranteed to work if the
      *   wait is <= 0x7fffffff milliseconds (~24 days). If the limit is exceeded,
      *   the wait will time out earlier than specified.
      */
     T *alloc_until(uint64_t millisec)
     {
         return _pool.alloc_until(millisec);
     }
 
     /** Allocate a memory block of type T, and set memory block to zero.
      *
      * @param   millisec  Not used (see note).
      *
      * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
      *
      * @note You may call this function from ISR context if the millisec parameter is set to 0.
      * @note If blocking is required, use Mail::calloc_for or Mail::calloc_until
      */
     T *calloc(MBED_UNUSED uint32_t millisec = 0)
     {
         return _pool.calloc();
     }
 
     /** Allocate a memory block of type T, optionally blocking, and set memory block to zero.
      *
      * @param   millisec  Timeout value, or osWaitForever.
      *
      * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
      *
      * @note You may call this function from ISR context if the millisec parameter is set to 0.
      */
     T *calloc_for(uint32_t millisec)
     {
         return _pool.calloc_for(millisec);
     }
 
     /** Allocate a memory block of type T, blocking, and set memory block to zero.
      *
      * @param   millisec  Absolute timeout time, referenced to Kernel::get_ms_count().
      *
      * @return  Pointer to memory block that you can fill with mail or nullptr in case error.
      *
      * @note You cannot call this function from ISR context.
      * @note the underlying RTOS may have a limit to the maximum wait time
      *   due to internal 32-bit computations, but this is guaranteed to work if the
      *   wait is <= 0x7fffffff milliseconds (~24 days). If the limit is exceeded,
      *   the wait will time out earlier than specified.
      */
     T *calloc_until(uint64_t millisec)
     {
         return _pool.calloc_until(millisec);
     }
 
     /** Put a mail in the queue.
      *
      * @param   mptr  Memory block previously allocated with Mail::alloc or Mail::calloc.
      *
      * @return  Status code that indicates the execution status of the function (osOK on success).
      *
      * @note You may call this function from ISR context.
      */
     osStatus put(T *mptr)
     {
         return _queue.put(mptr);
     }
 
     /** Get a mail from the queue.
      *
      * @param millisec Timeout value (default: osWaitForever).
      *
      * @return Event that contains mail information or error code.
      * @retval osEventMessage   Message received.
      * @retval osOK             No mail is available (and no timeout was specified).
      * @retval osEventTimeout   No mail has arrived during the given timeout period.
      * @retval osErrorParameter A parameter is invalid or outside of a permitted range.
      *
      * @note You may call this function from ISR context if the millisec parameter is set to 0.
      */
     osEvent get(uint32_t millisec = osWaitForever)
     {
         osEvent evt = _queue.get(millisec);
         if (evt.status == osEventMessage) {
             evt.status = osEventMail;
         }
         return evt;
     }
 
     /** Free a memory block from a mail.
      *
      * @param mptr Pointer to the memory block that was obtained with Mail::get.
      *
      * @return Status code that indicates the execution status of the function (osOK on success).
      *
      * @note You may call this function from ISR context.
      */
     osStatus free(T *mptr)
     {
         return _pool.free(mptr);
     }
 
 private:
     Queue<T, queue_sz> _queue;
     MemoryPool<T, queue_sz> _pool;
 };
 
 /** @}*/
 /** @}*/
 
 }
 
 #endif
 
 #endif
 
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