76 lines
2.2 KiB
C++
76 lines
2.2 KiB
C++
/*! \file pispinlock.h
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* \brief PISpinlock
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*/
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/*
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PIP - Platform Independent Primitives
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PISpinlock
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Ivan Pelipenko peri4ko@yandex.ru
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef PISPINLOCK_H
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#define PISPINLOCK_H
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#include "piinit.h"
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#include <atomic>
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class PIP_EXPORT PISpinlock
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{
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public:
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NO_COPY_CLASS(PISpinlock)
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//! Constructs unlocked spinlock
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explicit PISpinlock() {flag.clear();}
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//! Destroy spinlock
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~PISpinlock() {}
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//! \brief Lock spinlock
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//! \details If spinlock is unlocked it set to locked state and returns immediate.
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//! If spinlock is already locked function blocks until spinlock will be unlocked
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void lock() {while (flag.test_and_set(std::memory_order_acquire));}
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//! \brief Unlock spinlock
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//! \details In any case this function returns immediate
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void unlock() {flag.clear(std::memory_order_release);}
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private:
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std::atomic_flag flag;
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};
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//! \brief PISpinlockLocker
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//! \details
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//! When a PISpinlockLocker object is created, it attempts to lock the spinlock it is given, if "condition" true.
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//! When control leaves the scope in which the PISpinlockLocker object was created,
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//! the PISpinlockLocker is destructed and the spinlock is released, if "condition" true.
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//! If "condition" false this class do nothing.
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//! The PISpinlockLocker class is non-copyable.
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class PIP_EXPORT PISpinlockLocker
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{
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public:
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NO_COPY_CLASS(PISpinlockLocker)
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PISpinlockLocker(PISpinlock & s, bool condition = true): spinlock(s), cond(condition) {if (cond) spinlock.lock();}
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~PISpinlockLocker() {if (cond) spinlock.unlock();}
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private:
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PISpinlock & spinlock;
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bool cond;
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};
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#endif // PISPINLOCK_H
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