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53 lines
1.4 KiB
53 lines
1.4 KiB
4 months ago
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/*
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* Copyright (C) 2021 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <condition_variable>
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#include <functional>
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#include <memory>
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#include <mutex>
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namespace cuttlefish {
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class Semaphore {
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public:
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Semaphore(const unsigned int init_val = 0, const unsigned int cap = 30000)
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: count_{init_val}, capacity_{cap} {}
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void SemWait() {
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std::unique_lock<std::mutex> lock(mtx_);
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resoure_cv_.wait(lock, [this]() -> bool { return count_ > 0; });
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--count_;
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room_cv_.notify_one();
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}
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void SemPost() {
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std::unique_lock<std::mutex> lock(mtx_);
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room_cv_.wait(lock, [this]() -> bool { return count_ <= capacity_; });
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++count_;
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resoure_cv_.notify_one();
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}
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private:
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std::mutex mtx_;
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std::condition_variable resoure_cv_;
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std::condition_variable room_cv_;
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unsigned int count_;
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const unsigned int capacity_; // inclusive upper limit
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};
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} // namespace cuttlefish
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