chapter 3 code

ch3/stack.cpp

@@ -0,0 +1,68 @@
+#include <exception>
+#include <stack>
+#include <mutex>
+#include <memory>
+
+struct empty_stack: std::exception
+{
+    const char* what() const throw()
+    {
+        return "empty stack";
+    }
+    
+};
+
+template<typename T>
+class threadsafe_stack
+{
+private:
+    std::stack<T> data;
+    mutable std::mutex m;
+public:
+    threadsafe_stack(){}
+    threadsafe_stack(const threadsafe_stack& other)
+    {
+        std::lock_guard<std::mutex> lock(other.m);
+        data=other.data;
+    }
+    threadsafe_stack& operator=(const threadsafe_stack&) = delete;
+
+    void push(T new_value)
+    {
+        std::lock_guard<std::mutex> lock(m);
+        data.push(new_value);
+    }
+    std::shared_ptr<T> pop()
+    {
+        std::lock_guard<std::mutex> lock(m);
+        if(data.empty()) throw empty_stack();
+        std::shared_ptr<T> const res(std::make_shared<T>(data.top()));
+        data.pop();
+        return res;
+    }
+    void pop(T& value)
+    {
+        std::lock_guard<std::mutex> lock(m);
+        if(data.empty()) throw empty_stack();
+        value=data.top();
+        data.pop();
+    }
+    bool empty() const
+    {
+        std::lock_guard<std::mutex> lock(m);
+        return data.empty();
+    }
+};
+
+int main()
+{
+    threadsafe_stack<int> si;
+    si.push(5);
+    si.pop();
+    if(!si.empty())
+    {
+        int x;
+        si.pop(x);
+    }
+    
+}