95 lines
1.9 KiB
C++
95 lines
1.9 KiB
C++
#include <iostream>
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#include <queue>
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#include <memory>
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#include <thread>
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#include <mutex>
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template <typename T>
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class queue
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{
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private:
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struct node
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{
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std::shared_ptr<T> data;
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std::unique_ptr<node> next;
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};
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std::mutex head_mutex;
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std::unique_ptr<node> head;
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std::mutex tail_mutex;
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node *tail;
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node *get_tail()
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{
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std::lock_guard<std::mutex> tail_lock(tail_mutex);
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return tail;
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}
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std::unique_ptr<node> pop_head()
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{
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std::lock_guard<std::mutex> head_lock(head_mutex);
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if (head.get() == get_tail()) {
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return nullptr;
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}
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std::unique_ptr<node> old_head = std::move(head);
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head = std::move(old_head->next);
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return old_head;
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}
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public:
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queue():head(new node),tail(head.get())
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{}
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queue(const queue& other) = delete;
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queue& operator=(const queue& other) = delete;
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std::shared_ptr<T> try_pop()
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{
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std::unique_ptr<node> old_head = pop_head();
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return old_head ? old_head->data : std::shared_ptr<T>();
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}
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void push(T new_value)
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{
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std::shared_ptr<T> new_data(
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std::make_shared<T>(std::move(new_value)));
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std::unique_ptr<node> p(new node);
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node *const new_tail = p.get();
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std::lock_guard<std::mutex> tail_lock(tail_mutex);
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tail->data = new_data;
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tail->next = std::move(p);
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tail = new_tail;
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}
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};
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void push(queue<int>* q)
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{
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for (int i = 0; i < 10; ++i) {
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printf("pushing %d\n", i);
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q->push(i);
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}
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}
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void pop(queue<int>* q)
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{
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int i = 0;
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while (true) {
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if (std::shared_ptr<int> p = q->try_pop()) {
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printf("poping %d\n", *p);
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++i;
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}
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if (i == 10) break;
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}
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}
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int main()
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{
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queue<int> q;
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std::thread th1(push,&q);
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std::thread th2(pop,&q);
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th1.join();
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th2.join();
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return 0;
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}
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