74 lines
1.8 KiB
C++
74 lines
1.8 KiB
C++
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#include <iostream>
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#include <thread>
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#include <vector>
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#include <queue>
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#include <functional>
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#include <mutex>
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#include <condition_variable>
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class ThreadPool {
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public:
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ThreadPool(size_t num_threads);
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~ThreadPool();
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void enqueue(std::function<void()> task);
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private:
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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 queue_mutex;
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std::condition_variable condition;
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bool stop;
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};
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ThreadPool::ThreadPool(size_t num_threads) : stop(false) {
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for (size_t i = 0; i < num_threads; ++i) {
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workers.emplace_back([this] {
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while (true) {
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std::function<void()> task;
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{
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std::unique_lock<std::mutex> lock(this->queue_mutex);
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this->condition.wait(lock, [this] { return this->stop || !this->tasks.empty(); });
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if (this->stop && this->tasks.empty()) {
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return;
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}
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task = std::move(this->tasks.front());
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this->tasks.pop();
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}
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task();
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}
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});
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}
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}
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ThreadPool::~ThreadPool() {
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{
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std::unique_lock<std::mutex> lock(queue_mutex);
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stop = true;
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}
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condition.notify_all();
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for (std::thread& worker : workers) {
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worker.join();
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}
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}
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void ThreadPool::enqueue(std::function<void()> task) {
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{
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std::unique_lock<std::mutex> lock(queue_mutex);
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if (stop) {
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throw std::runtime_error("enqueue on stopped ThreadPool");
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}
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tasks.emplace(task);
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}
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condition.notify_one();
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}
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int main() {
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ThreadPool pool(4);
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for (int i = 0; i < 8; ++i) {
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pool.enqueue([i] {
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std::cout << "Task " << i << " is running on thread " << std::this_thread::get_id() << '\n';
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});
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}
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return 0;
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}
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