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Diffstat (limited to 'include/distortos/Semaphore.hpp')
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diff --git a/include/distortos/Semaphore.hpp b/include/distortos/Semaphore.hpp deleted file mode 100644 index 26ca298..0000000 --- a/include/distortos/Semaphore.hpp +++ /dev/null @@ -1,245 +0,0 @@ -/** - * \file - * \brief Semaphore class header - * - * \author Copyright (C) 2014-2015 Kamil Szczygiel http://www.distortec.com http://www.freddiechopin.info - * - * \par License - * This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not - * distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. - */ - -#ifndef INCLUDE_DISTORTOS_SEMAPHORE_HPP_ -#define INCLUDE_DISTORTOS_SEMAPHORE_HPP_ - -#include "distortos/internal/scheduler/ThreadList.hpp" - -#include "distortos/TickClock.hpp" - -namespace distortos -{ - -/** - * \brief Semaphore is the basic synchronization primitive - * - * Similar to POSIX semaphores - http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_16 - * - * \ingroup synchronization - */ - -class Semaphore -{ -public: - - /// type used for semaphore's "value" - using Value = unsigned int; - - /** - * \brief Semaphore constructor - * - * Similar to sem_init() - http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_init.html# - * - * \param [in] value is the initial value of the semaphore, if this value is greater than maxValue, it will be - * truncated - * \param [in] maxValue is the max value of the semaphore before post() returns EOVERFLOW, default - max for Value - * type - */ - - constexpr explicit Semaphore(const Value value, const Value maxValue = std::numeric_limits<Value>::max()) : - blockedList_{}, - value_{value <= maxValue ? value : maxValue}, - maxValue_{maxValue} - { - - } - - /** - * \brief Semaphore destructor - * - * Similar to sem_destroy() - http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_destroy.html# - * - * It is safe to destroy a semaphore upon which no threads are currently blocked. The effect of destroying a - * semaphore upon which other threads are currently blocked is system error. - */ - - ~Semaphore() - { - - } - - /** - * \brief Gets current value of semaphore. - * - * Similar to sem_getvalue() - http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_getvalue.html# - * - * \return current value of semaphore, positive value if semaphore is not locked, zero otherwise - */ - - Value getValue() const - { - return value_; - } - - /** - * \brief Unlocks the semaphore. - * - * Similar to sem_post() - http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_post.html# - * - * This function shall unlock the semaphore by performing a semaphore unlock operation. If the semaphore value - * resulting from this operation is positive, then no threads were blocked waiting for the semaphore to become - * unlocked; the semaphore value is simply incremented. Otherwise one of the threads blocked waiting for the - * semaphore shall be allowed to return successfully from its call to lock() - the highest priority waiting thread - * shall be unblocked, and if there is more than one highest priority thread blocked waiting for the semaphore, then - * the highest priority thread that has been waiting the longest shall be unblocked. - * - * \return zero if the calling process successfully "posted" the semaphore, error code otherwise: - * - EOVERFLOW - the maximum allowable value for a semaphore would be exceeded; - */ - - int post(); - - /** - * \brief Tries to lock the semaphore. - * - * Similar to sem_trywait() - http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_trywait.html# - * - * This function shall lock the semaphore only if the semaphore is currently not locked; that is, if the semaphore - * value is currently positive. Otherwise, it shall not lock the semaphore. Upon successful return, the state of the - * semaphore shall be locked and shall remain locked until unlock() function is executed. - * - * \return zero if the calling process successfully performed the semaphore lock operation, error code otherwise: - * - EAGAIN - semaphore was already locked, so it cannot be immediately locked by the tryWait() operation; - */ - - int tryWait(); - - /** - * \brief Tries to lock the semaphore for given duration of time. - * - * Similar to sem_timedwait() - http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_timedwait.html# - * - * If the semaphore is already locked, the calling thread shall block until the semaphore becomes available as in - * wait() function. If the semaphore cannot be locked without waiting for another thread to unlock the semaphore, - * this wait shall be terminated when the specified timeout expires. - * - * Under no circumstance shall the function fail with a timeout if the semaphore can be locked immediately. The - * validity of the duration parameter need not be checked if the semaphore can be locked immediately. - * - * \param [in] duration is the duration after which the wait will be terminated without locking the semaphore - * - * \return zero if the calling process successfully performed the semaphore lock operation, error code otherwise: - * - EINTR - the wait was interrupted by an unmasked, caught signal; - * - ETIMEDOUT - the semaphore could not be locked before the specified timeout expired; - */ - - int tryWaitFor(TickClock::duration duration); - - /** - * \brief Tries to lock the semaphore for given duration of time. - * - * Template variant of tryWaitFor(TickClock::duration duration). - * - * \tparam Rep is type of tick counter - * \tparam Period is std::ratio type representing the tick period of the clock, in seconds - * - * \param [in] duration is the duration after which the wait will be terminated without locking the semaphore - * - * \return zero if the calling process successfully performed the semaphore lock operation, error code otherwise: - * - EINTR - the wait was interrupted by an unmasked, caught signal; - * - ETIMEDOUT - the semaphore could not be locked before the specified timeout expired; - */ - - template<typename Rep, typename Period> - int tryWaitFor(const std::chrono::duration<Rep, Period> duration) - { - return tryWaitFor(std::chrono::duration_cast<TickClock::duration>(duration)); - } - - /** - * \brief Tries to lock the semaphore until given time point. - * - * Similar to sem_timedwait() - http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_timedwait.html# - * - * If the semaphore is already locked, the calling thread shall block until the semaphore becomes available as in - * wait() function. If the semaphore cannot be locked without waiting for another thread to unlock the semaphore, - * this wait shall be terminated when the specified timeout expires. - * - * Under no circumstance shall the function fail with a timeout if the semaphore can be locked immediately. The - * validity of the timePoint parameter need not be checked if the semaphore can be locked immediately. - * - * \param [in] timePoint is the time point at which the wait will be terminated without locking the semaphore - * - * \return zero if the calling process successfully performed the semaphore lock operation, error code otherwise: - * - EINTR - the wait was interrupted by an unmasked, caught signal; - * - ETIMEDOUT - the semaphore could not be locked before the specified timeout expired; - */ - - int tryWaitUntil(TickClock::time_point timePoint); - - /** - * \brief Tries to lock the semaphore until given time point. - * - * Template variant of tryWaitUntil(TickClock::time_point timePoint). - * - * \tparam Duration is a std::chrono::duration type used to measure duration - * - * \param [in] timePoint is the time point at which the wait will be terminated without locking the semaphore - * - * \return zero if the calling process successfully performed the semaphore lock operation, error code otherwise: - * - EINTR - the wait was interrupted by an unmasked, caught signal; - * - ETIMEDOUT - the semaphore could not be locked before the specified timeout expired; - */ - - template<typename Duration> - int tryWaitUntil(const std::chrono::time_point<TickClock, Duration> timePoint) - { - return tryWaitUntil(std::chrono::time_point_cast<TickClock::duration>(timePoint)); - } - - /** - * \brief Locks the semaphore. - * - * Similar to sem_wait() - http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_trywait.html# - * - * This function shall lock the semaphore by performing a semaphore lock operation on that semaphore. If the - * semaphore value is currently zero, then the calling thread shall not return from the call to lock() until it - * either locks the semaphore or the call is interrupted by a signal. Upon successful return, the state of the - * semaphore shall be locked and shall remain locked until unlock() function is executed. - * - * \return zero if the calling process successfully performed the semaphore lock operation, error code otherwise: - * - EINTR - the wait was interrupted by an unmasked, caught signal; - */ - - int wait(); - - Semaphore(const Semaphore&) = delete; - Semaphore(Semaphore&&) = default; - const Semaphore& operator=(const Semaphore&) = delete; - Semaphore& operator=(Semaphore&&) = delete; - -private: - - /** - * \brief Internal version of tryWait(). - * - * Internal version with no interrupt masking. - * - * \return zero if the calling process successfully performed the semaphore lock operation, error code otherwise: - * - EAGAIN - semaphore was already locked, so it cannot be immediately locked by the tryWait() operation; - */ - - int tryWaitInternal(); - - /// ThreadControlBlock objects blocked on this semaphore - internal::ThreadList blockedList_; - - /// internal value of the semaphore - Value value_; - - /// max value of the semaphore - Value maxValue_; -}; - -} // namespace distortos - -#endif // INCLUDE_DISTORTOS_SEMAPHORE_HPP_ |