File content as of revision 0:1496281373a5:

/* 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 MAIL_H
#define MAIL_H

#include <stdint.h>
#include <string.h>

#include "cmsis_os.h"

namespace rtos {

/** The Mail class allow to control, send, receive, or wait for mail.
 A mail is a memory block 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.
*/
template<typename T, uint32_t queue_sz>
class Mail {
public:
    /** Create and Initialise Mail queue. */
    Mail() {
    #ifdef CMSIS_OS_RTX
        memset(_mail_q, 0, sizeof(_mail_q));
        _mail_p[0] = _mail_q;
        
        memset(_mail_m, 0, sizeof(_mail_m));
        _mail_p[1] = _mail_m;
        
        _mail_def.pool = _mail_p;
        _mail_def.queue_sz = queue_sz;
        _mail_def.item_sz = sizeof(T);
    #endif
        _mail_id = osMailCreate(&_mail_def, NULL);
    }
    
    /** Allocate a memory block of type T
      @param   millisec  timeout value or 0 in case of no time-out. (default: 0).
      @return  pointer to memory block that can be filled with mail or NULL in case error.
    */
    T* alloc(uint32_t millisec=0) {
        return (T*)osMailAlloc(_mail_id, millisec);
    }
    
    /** Allocate a memory block of type T and set memory block to zero. 
      @param   millisec  timeout value or 0 in case of no time-out.  (default: 0).
      @return  pointer to memory block that can be filled with mail or NULL in case error.
    */
    T* calloc(uint32_t millisec=0) {
        return (T*)osMailCAlloc(_mail_id, 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. 
    */
    osStatus put(T *mptr) {
        return osMailPut(_mail_id, (void*)mptr);
    }
    
    /** Get a mail from a queue.
      @param   millisec  timeout value or 0 in case of no time-out. (default: osWaitForever).
      @return  event that contains mail information or error code.
    */
    osEvent get(uint32_t millisec=osWaitForever) {
        return osMailGet(_mail_id, millisec);
    }
    
    /** 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.
    */
    osStatus free(T *mptr) {
        return osMailFree(_mail_id, (void*)mptr);
    }

private:
    osMailQId    _mail_id;
    osMailQDef_t _mail_def;
#ifdef CMSIS_OS_RTX
    uint32_t     _mail_q[4+(queue_sz)];
    uint32_t     _mail_m[3+((sizeof(T)+3)/4)*(queue_sz)];
    void        *_mail_p[2];
#endif
};

}

#endif