80 lines
1.4 KiB
C++
80 lines
1.4 KiB
C++
#include <thread>
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#include <mutex>
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#include <functional>
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#include <queue>
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#include <condition_variable>
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#include <vector>
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class ThreadPool {
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public:
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ThreadPool(std::size_t size) : stop(false) {
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for (std::size_t i = 0; i < size; ++i) {
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workers.emplace_back([this] { spawn(); });
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}
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}
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virtual ~ThreadPool() {
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if (!stop) join();
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}
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void post(std::function<void()> f) {
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{
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std::unique_lock<std::mutex> lock(mutex);
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tasks.push(f);
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}
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condition.notify_one();
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}
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void join() {
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{
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std::unique_lock<std::mutex> lock(mutex);
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stop = true;
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}
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condition.notify_all();
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for (std::size_t i = 0; i < workers.size(); ++i) {
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workers[i].join();
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}
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}
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private:
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void spawn() {
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std::function<void()> task;
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bool task_queue_empty = tasks.empty();
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while (!stop || !task_queue_empty) {
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bool task_valid = false;
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{
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std::unique_lock<std::mutex> lock(mutex);
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condition.wait(lock, [this]() {
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return (!tasks.empty()) || (tasks.empty() && stop);
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});
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if (!tasks.empty()) {
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task = std::move(tasks.front());
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tasks.pop();
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task_valid = true;
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}
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task_queue_empty = tasks.empty();
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}
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if (task_valid) task();
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}
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}
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public:
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std::vector<std::thread> workers;
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std::queue<std::function<void()>> tasks;
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std::mutex mutex;
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std::condition_variable condition;
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bool stop;
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};
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inline void dispatch(ThreadPool &pool, std::function<void()> f) {
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pool.post(f);
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}
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