65 lines
1.5 KiB
C++
65 lines
1.5 KiB
C++
#include <memory>
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#include <mutex>
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template<typename T>
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class threadsafe_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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{
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return nullptr;
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}
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std::unique_ptr<node> const 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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threadsafe_queue():
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head(new node),tail(head.get())
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{}
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threadsafe_queue(const threadsafe_queue& other)=delete;
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threadsafe_queue& operator=(const threadsafe_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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