mirror of https://github.com/PentHertz/srsLTE.git
108 lines
2.7 KiB
C++
108 lines
2.7 KiB
C++
/*
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* Copyright 2013-2020 Software Radio Systems Limited
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*
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* This file is part of srsLTE.
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*
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* srsLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* srsLTE 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 Affero General Public License for more details.
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*
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* A copy of the GNU Affero General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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#include <assert.h>
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#include <condition_variable>
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#include <deque>
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#include <inttypes.h>
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#include <mutex>
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#ifndef SRSLTE_TTI_SEMPAHORE_H_
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#define SRSLTE_TTI_SEMPAHORE_H_
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namespace srslte {
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/**
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* Implements priority semaphore based on a FIFO queue wait . This class enqueues T type element identifiers (method
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* push) and waits until the enqueued object is the first (method wait). The first element is released by method
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* release. The method release_all waits for all the elements to be released.
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*
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* @tparam T Object identifier type
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*/
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template <class T>
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class tti_semaphore
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{
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private:
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std::mutex mutex; ///< Used for scope mutexes
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std::condition_variable cvar; ///< Used for notifying element identifier releases
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std::deque<T> fifo; ///< Queue to keep order
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public:
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/**
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* Waits for the first element of the queue match the element identifier provided.
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*
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* @param id the element identifier
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*/
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void wait(T id)
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{
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std::unique_lock<std::mutex> lock(mutex);
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// While the FIFO is not empty and the front ID does not match the provided element identifier, keep waiting
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while (not fifo.empty() and fifo.front() != id) {
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// Wait for a release
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cvar.wait(lock);
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}
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}
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/**
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* Enqueue (push) an element identifier to the queue
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*
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* @param id the element identifier
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*/
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void push(T id)
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{
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std::unique_lock<std::mutex> lock(mutex);
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// Append the element identifier
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fifo.push_back(id);
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}
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/**
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* Releases (pops) the first element
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*/
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void release()
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{
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std::unique_lock<std::mutex> lock(mutex);
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// Pop first element
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fifo.pop_front();
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// Notify release
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cvar.notify_all();
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}
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/**
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* Waits for all the elements to be released
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*/
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void wait_all()
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{
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std::unique_lock<std::mutex> lock(mutex);
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// Wait until the FIFO is empty
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while (not fifo.empty()) {
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cvar.wait(lock);
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}
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}
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};
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} // namespace srslte
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#endif // SRSLTE_TTI_SEMPAHORE_H_
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