ChibiOS/os/various/ch.hpp

/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file    ch.hpp
 * @brief   C++ wrapper classes and definitions.
 *
 * @addtogroup cpp_library
 * @{
 */

#include <ch.h>

#ifndef _CH_HPP_
#define _CH_HPP_

namespace chibios_rt {

  /**
   * @brief Class encapsulating the base system functionalities.
   */
  class System {
  public:
    /**
     * @brief   ChibiOS/RT initialization.
     * @details The system is initialized, the idle thread is spawned and the
     *          current instruction flow becomes the main thread with priority
     *          @p NORMALPRIO.
     */
    static void Init(void);

    /**
     * @brief   Kernel lock.
     * @note    On some ports it is faster to invoke chSysLock() directly because
     *          inlining.
     */
    static void Lock(void);

    /**
     * @brief   Kernel unlock.
     * @note    On some ports it is faster to invoke chSysUnlock() directly
     *          because inlining.
     */
    static void Unlock(void);

    /**
     * @brief   Returns the system time as system ticks.
     * @note    The system tick time interval is implementation dependent.
     *
     * @return          The system time.
     */
    static systime_t GetTime(void);
  };

  /**
   * @brief   Timer class.
   */
  class Timer {
  public:
    /**
     * @brief   Embedded @p VirtualTimer structure.
     */
    struct ::VirtualTimer timer;

    /**
     * @brief   Starts the timer.
     * @note    It must be called with the interrupts disabled.
     * @note    The associated function is invoked by an interrupt handler.
     *
     * @param[in] time      the time in system ticks
     * @param[in] vtfunc    the timer callback function
     * @param[in] par       the parameter for the callback function
     */
    void Set(systime_t time, vtfunc_t vtfunc, void *par);

    /**
     * @brief   Resets the timer.
     * @note    It must be called with the interrupts disabled.
     * @note    The timer MUST be active when this function is invoked.
     */
    void Reset();

    /**
     * @brief   Returns the timer status.
     *
     * @retval TRUE         The timer is armed.
     * @retval FALSE        The timer already fired its callback.
     */
    bool IsArmed(void);
  };

  /**
   * @brief   Base class for a ChibiOS/RT thread.
   * @details The thread body is the virtual function @p Main().
   */
  class BaseThread {
  public:
    /**
     * @brief   Pointer to the system thread.
     */
    ::Thread *thread_ref;

    /**
     * @brief   Thread constructor.
     * @details The thread object is initialized and a system thread is
     *          started.
     *
     * @param[in] workspace     pointer to the workspace area
     * @param[in] wsize         size of the workspace area
     * @param[in] prio          thread priority
     */
    BaseThread(void *workspace, size_t wsize, tprio_t prio);

    /**
     * @brief Thread exit.
     *
     * @param[in] msg           the exit message
     */
    static void Exit(msg_t msg);

#if CH_USE_WAITEXIT
    /**
     * @brief   Synchronization on Thread exit.
     *
     * @return                  The exit message from the thread.
     */
    msg_t Wait(void);
#endif /* CH_USE_WAITEXIT */

    /**
     * @brief   Resumes the thread.
     * @details The thread encapsulated into the object is resumed.
     */
    void Resume(void);

    /**
     * @brief   Changes the thread priority.
     *
     * @param[in] newprio       The new priority level
     */
    static void SetPriority(tprio_t newprio);

    /**
     * @brief   Requests thread termination.
     * @details A termination flag is pended on the thread, it is thread
     *          responsibility to detect it and exit.
     */
    void Terminate(void);

    /**
     * @brief   Suspends the thread execution for the specified number of
     *          system ticks.
     *
     * @param[in] n             the number of system ticks
     */
    static void Sleep(systime_t n);

    /**
     * @brief   Suspends the thread execution until the specified time arrives.
     *
     * @param[in]               time the system time
     */
    static void SleepUntil(systime_t time);

#if CH_USE_MESSAGES
    /**
     * @brief   Sends a message to the thread and returns the answer.
     *
     * @param[in] tp            the target thread
     * @param[in] msg           the sent message
     * @return                  The returned message.
     */
    static msg_t SendMessage(::Thread *tp, msg_t msg);

    /**
     * @brief   Sends a message to the thread and returns the answer.
     *
     * @param[in] msg           the sent message
     * @return                  The returned message.
     */
    msg_t SendMessage(msg_t msg);

    /**
     * @brief   Waits for a message.
     *
     * @return                  The sebder thread.
     */
    static Thread *WaitMessage(void);

    /**
     * @brief   Returns an enqueued message or @p NULL.
     *
     * @param[in] tp            the sender thread
     * @return                  The incoming message.
     */
    static msg_t GetMessage(Thread* tp);

    /**
     * @brief   Releases the next message in queue with a reply.
     *
     * @param[in] tp            the sender thread
     * @param[in] msg           the answer message
     */
    static void ReleaseMessage(Thread* tp, msg_t msg);

    /**
     * @brief   Returns true if there is at least one message in queue.
     *
     * @retval TRUE             A message is waiting in queue.
     * @retval FALSE            A message is not waiting in queue.
     */
    static bool IsPendingMessage(void);
#endif /* CH_USE_MESSAGES */

    /**
     * @brief   Thread body function.
     *
     * @return                  The exit message.
     */
    virtual msg_t Main(void);
  };

  /**
   * @brief   Enhanced threads template class.
   * @details This class introduces thread names and static working area
   *          allocation.
   *
   * @param N               the working area size for the thread class
   */
  template <int N>
  class EnhancedThread : public BaseThread {
  protected:
    WORKING_AREA(wa, N);                        // Thread working area.

  public:
    /**
     * @brief   The thread name.
     */
    const char *name;

    /**
     * @brief   Full constructor.
     * @details This constructor allows to set a priority level for the new
     *          thread.
     *
     * @param[in] tname         the name to be assigned to the thread
     * @param[in] prio          the priority to be assigned to the thread
     */
    EnhancedThread(const char *tname, tprio_t prio) :
          BaseThread(wa, sizeof wa, prio) {

      name = tname;
    }

    /**
     * @brief   Simplified constructor.
     * @details This constructor allows to create a thread by simply
     *          specifying a name. In is assumed @p NORMALPRIO as initial
     *          priority.
     *
     * @param[in] tname         the name to be assigned to the thread
     */
    EnhancedThread(const char *tname) :
          BaseThread(wa, sizeof wa, NORMALPRIO) {

      name = tname;
    }
  };

#if CH_USE_SEMAPHORES
  /**
   * @brief   Class encapsulating a semaphore.
   */
  class Semaphore {
  public:
    /**
     * @brief   Embedded @p ::Semaphore structure.
     */
    struct ::Semaphore sem;

    /**
     * @brief   Semaphore constructor.
     * @details The embedded @p ::Semaphore structure is initialized.
     *
     * @param[in] n             the semaphore counter value, must be greater
     *                          or equal to zero
     */
    Semaphore(cnt_t n);

    /**
     * @brief   Resets a semaphore.
     *
     * @param[in] n             the new semaphore counter value, must be
     *                          greater or equal to zero
     */
    void Reset(cnt_t n);

    /**
     * @brief   Wait operation on the semaphore.
     *
     * @retval RDY_OK           if the semaphore was signaled or not taken.
     * @retval RDY_RESET        if the semaphore was reset.
     */
    msg_t Wait(void);

    /**
     * @brief   Wait operation on the semaphore with timeout.
     *
     * @param[in] time          the number of ticks before the operation fails
     * @retval RDY_OK           if the semaphore was signaled or not taken.
     * @retval RDY_RESET        if the semaphore was reset.
     * @retval RDY_TIMEOUT      if the semaphore was not signaled or reset
     *                          within the specified timeout.
     */
    msg_t WaitTimeout(systime_t time);

    /**
     * @brief   Signal operation on the semaphore.
     * @details The semaphore is signaled, the next thread in queue, if any,
     *          is awakened.
     */
    void Signal(void);

#if CH_USE_SEMSW
    /**
     * @brief   Atomic signal and wait operations.
     *
     * @param[in] ssem          pointer to a @p Semaphore to be signaled
     * @param[in] wsem          pointer to a @p Semaphore to be wait on
     * @retval RDY_OK           if the semaphore was signaled or not taken.
     * @retval RDY_RESET        if the semaphore was reset.
     */
    static msg_t SignalWait(Semaphore *ssem, Semaphore *wsem);
#endif /* CH_USE_SEMSW */
  };
#endif /* CH_USE_SEMAPHORES */

#if CH_USE_MUTEXES
  /**
   * @brief   Class encapsulating a mutex.
   */
  class Mutex {
  public:
    /**
     * @brief   Embedded @p ::Mutex structure.
     */
    struct ::Mutex mutex;

    /**
     * @brief   Mutex constructor.
     * @details The embedded @p ::Mutex structure is initialized.
     */
    Mutex(void);

    /**
     * @brief   Tries a lock operation on the mutex.
     *
     * @retval TRUE             if the mutex was successfully acquired
     * @retval FALSE            if the lock attempt failed.
     */
    bool TryLock(void);

    /**
     * @brief   Locks the mutex.
     * @details Performs a lock operation on the mutex, if the mutex is
     *          already locked then the thread enters the mutex priority
     *          queue and waits.
     */
    void Lock(void);

    /**
     * @brief   Unlocks the mutex.
     * @details Performs an unlock operation on the mutex, the next waiting
     *          thread, if any, is resumed and locks the mutex.
     */
    static void Unlock(void);

    /**
     * @brief   Unlocks all the mutexes owned by the invoking thread.
     * @details This operation is <b>MUCH MORE</b> efficient than releasing
     *          the mutexes one by one and not just because the call overhead,
     *          this function does not have any overhead related to the
     *          priority inheritance mechanism.
     */
    static void UnlockAll(void);
  };

#if CH_USE_CONDVARS
  /**
   * @brief   Class encapsulating a conditional variable.
   */
  class CondVar {
  public:
    /**
     * @brief   Embedded @p ::CondVar structure.
     */
    struct ::CondVar condvar;

    /**
     * @brief   CondVar constructor.
     * @details The embedded @p ::CondVar structure is initialized.
     */
    CondVar(void);

    /**
     * @brief   Signals the CondVar.
     * @details The next thread waiting on the @p CondVar, if any, is awakened.
     */
    void Signal(void);

    /**
     * @brief   Broadcasts the CondVar.
     * @details All the threads waiting on the @p CondVar, if any, are awakened.
     */
    void Broadcast(void);

    /**
     * @brief   Waits on the CondVar while releasing the controlling mutex.
     *
     * @return                  The wakep mode.
     * @retval RDY_OK           if the condvar was signaled using
     *                          @p chCondSignal().
     * @retval RDY_RESET        if the condvar was signaled using
     *                          @p chCondBroadcast().
     */
    msg_t Wait(void);

#if CH_USE_CONDVARS_TIMEOUT
    /**
     * @brief   Waits on the CondVar while releasing the controlling mutex.
     *
     * @param[in] time          the number of ticks before the operation fails
     * @return                  The wakep mode.
     * @retval RDY_OK if        the condvar was signaled using
     *                          @p chCondSignal().
     * @retval RDY_RESET        if the condvar was signaled using
     *                          @p chCondBroadcast().
     * @retval RDY_TIMEOUT      if the condvar was not signaled within the
     *                          specified timeout.
     */
    msg_t WaitTimeout(systime_t time);
#endif /* CH_USE_CONDVARS_TIMEOUT */
  };
#endif /* CH_USE_CONDVARS */
#endif /* CH_USE_MUTEXES */

#if CH_USE_EVENTS
  /**
   * @brief   Class encapsulating an event source.
   */
  class Event {
  public:
    /**
     * @brief   Embedded @p ::EventSource structure.
     */
    struct ::EventSource event;

    /**
     * @brief   Event constructor.
     * @details The embedded @p ::EventSource structure is initialized.
     */
    Event(void);

    /**
     * @brief   Registers a listener on the event source.
     *
     * @param[in] elp           pointer to the @p EventListener structure
     * @param[in] eid           numeric identifier assigned to the Event
     *                          Listener
     */
    void Register(EventListener *elp, eventid_t eid);

    /**
     * @brief   Registers an Event Listener on an Event Source.
     * @note    Multiple Event Listeners can specify the same bits to be added.
     *
     * @param[in] elp           pointer to the @p EventListener structure
     * @param[in] emask         the mask of event flags to be pended to the
     *                          thread when the event source is broadcasted
     */
    void RegisterMask(EventListener *elp, eventmask_t emask);

    /**
     * @brief   Unregisters a listener.
     * @details The specified listeners is no more signaled by the event
     *          source.
     *
     * @param[in] elp           the listener to be unregistered
     */
    void Unregister(EventListener *elp);

    /**
     * @brief   Broadcasts an event.
     * @details All the listeners registered on the event source are signaled.
     */
    void Broadcast(void);

    /**
     * @brief   Clears specified events from the pending events mask.
     *
     * @param[in] mask          the events to be cleared
     * @return                  The pending events that were cleared.
     */
    static eventmask_t ClearFlags(eventmask_t mask);

    /**
     * @brief   Makes an events mask pending in the current thread.
     * @details This functon is @b much faster than using @p Broadcast().
     *
     * @param[in] mask          the events to be pended
     * @return                  The current pending events mask.
     */
    static eventmask_t AddFlags(eventmask_t mask);

    /**
     * @brief   Invokes the event handlers associated with a mask.
     *
     * @param[in] mask          mask of the events to be dispatched
     * @param[in] handlers      an array of @p evhandler_t. The array must be
     *                          have indexes from zero up the higher registered
     *                          event identifier.
     */
    static void Dispatch(const evhandler_t handlers[], eventmask_t mask);

    /**
     * @brief   Waits for a single event.
     * @details A pending event among those specified in @p ewmask is selected,
     *          cleared and its mask returned.
     * @note    One and only one event is served in the function, the one with
     *          the lowest event id. The function is meant to be invoked into
     *          a loop in order to serve all the pending events.<br>
     *          This means that Event Listeners with a lower event identifier
     *          have an higher priority.
     *
     * @param[in] ewmask        mask of the events that the function should
     *                          wait for, @p ALL_EVENTS enables all the events
     * @return                  The mask of the lowest id served and cleared
     *                          event.
     */
    static eventmask_t WaitOne(eventmask_t ewmask);

    /**
     * @brief   Waits for any of the specified events.
     * @details The function waits for any event among those specified in
     *          @p ewmask to become pending then the events are cleared and
     *          returned.
     *
     * @param[in] ewmask        mask of the events that the function should
     *                          wait for, @p ALL_EVENTS enables all the events
     * @return                  The mask of the served and cleared events.
     */
    static eventmask_t WaitAny(eventmask_t ewmask);

    /**
     * @brief   Waits for all the specified event flags then clears them.
     * @details The function waits for all the events specified in @p ewmask
     *          to become pending then the events are cleared and returned.
     *
     * @param[in] ewmask        mask of the event ids that the function should
     *                          wait for
     * @return                  The mask of the served and cleared events.
     */
    static eventmask_t WaitAll(eventmask_t ewmask);

#if CH_USE_EVENTS_TIMEOUT
    /**
     * @brief   Waits for a single event.
     * @details A pending event among those specified in @p ewmask is selected,
     *          cleared and its mask returned.
     * @note    One and only one event is served in the function, the one with
     *          the lowest event id. The function is meant to be invoked into
     *          a loop in order to serve all the pending events.<br>
     *          This means that Event Listeners with a lower event identifier
     *          have an higher priority.
     *
     * @param[in] ewmask        mask of the events that the function should
     *                          wait for, @p ALL_EVENTS enables all the events
     *
     * @param[in] time          the number of ticks before the operation timouts
     * @return                  The mask of the lowest id served and cleared
     *                          event.
     * @retval 0                if the specified timeout expired.
     */
    static eventmask_t WaitOneTimeout(eventmask_t ewmask, systime_t time);

    /**
     * @brief   Waits for any of the specified events.
     * @details The function waits for any event among those specified in
     *          @p ewmask to become pending then the events are cleared and
     *          returned.
     *
     * @param[in] ewmask        mask of the events that the function should
     *                          wait for, @p ALL_EVENTS enables all the events
     * @param[in] time          the number of ticks before the operation
     *                          timouts
     * @return                  The mask of the served and cleared events.
     * @retval 0                if the specified timeout expired.
     */
    static eventmask_t WaitAnyTimeout(eventmask_t ewmask, systime_t time);

    /**
     * @brief   Waits for all the specified event flags then clears them.
     * @details The function waits for all the events specified in @p ewmask
     *          to become pending then the events are cleared and returned.
     *
     * @param[in] ewmask        mask of the event ids that the function should
     *                          wait for
     * @param[in] time          the number of ticks before the operation
     *                          timouts
     * @return                  The mask of the served and cleared events.
     * @retval 0                if the specified timeout expired.
     */
    static eventmask_t WaitAllTimeout(eventmask_t ewmask, systime_t time);

#endif /* CH_USE_EVENTS_TIMEOUT */
  };
#endif /* CH_USE_EVENTS */
}

#endif /* _CH_HPP_ */

/** @} */