1 files changed, 157 insertions, 0 deletions
diff --git a/indirect.h b/indirect.h
new file mode 100644
index 0000000..da93955
--- /dev/null
+++ b/indirect.h
@@ -0,0 +1,157 @@
+#pragma once
+
+#include <stdexcept>
+
+using namespace std;
+
+
+class NullIndirectError : public runtime_error{
+public:
+	NullIndirectError();
+	NullIndirectError(const string &what_arg);
+	NullIndirectError(const char *what_arg);
+};
+
+
+template <typename T>
+class Indirect{
+	T *ptr;
+
+	class Dummy{};
+
+	Indirect(Dummy);
+
+public:
+	template <typename ...Args>
+	Indirect(Args... args);
+
+	Indirect(const Indirect &other);
+	Indirect(Indirect &&other);
+
+	~Indirect();
+
+	Indirect<T>& operator=(const T &value);
+	Indirect<T>& operator=(T &&value);
+
+	Indirect<T>& operator=(const Indirect<T> &other);
+	Indirect<T>& operator=(Indirect<T> &&other);
+
+	bool isEmpty() const;
+
+	T& operator*();
+	const T& operator*() const;
+
+	static Indirect<T> makeEmpty();
+};
+
+template <typename T>
+Indirect<T>::Indirect(Dummy)
+	:ptr(nullptr){}
+
+template <typename T>
+Indirect<T> Indirect<T>::makeEmpty(){
+	return Indirect<T>(Indirect::Dummy());
+};
+
+
+template <typename T>
+template <typename ...Args>
+Indirect<T>::Indirect(Args... args)
+	:ptr(new T(args...)){}
+
+template <typename T>
+Indirect<T>::Indirect(const Indirect &other){
+	if(!other.ptr){
+		ptr=nullptr;
+	} else {
+		ptr=new T(*other.ptr);
+	}
+}
+
+template <typename T>
+Indirect<T>::Indirect(Indirect &&other){
+	if(!other.ptr){
+		ptr=nullptr;
+	} else {
+		ptr=new T(move(*other.ptr));
+		other.ptr=nullptr;
+	}
+}
+
+template <typename T>
+Indirect<T>::~Indirect(){
+	if(ptr){
+		delete ptr;
+	}
+}
+
+
+template <typename T>
+Indirect<T>& Indirect<T>::operator=(const T &value){
+	if(!ptr){
+		ptr=new T(value);
+	} else {
+		*ptr=value;
+	}
+	return *this;
+}
+
+template <typename T>
+Indirect<T>& Indirect<T>::operator=(T &&value){
+	if(!ptr){
+		ptr=new T(value);
+	} else {
+		*ptr=value;
+	}
+	return *this;
+}
+
+
+template <typename T>
+Indirect<T>& Indirect<T>::operator=(const Indirect<T> &other){
+	if(ptr){
+		delete ptr;
+	}
+	if(!other.ptr){
+		ptr=nullptr;
+	} else {
+		ptr=new T(*other.ptr);
+	}
+	return *this;
+}
+
+template <typename T>
+Indirect<T>& Indirect<T>::operator=(Indirect<T> &&other){
+	if(ptr){
+		delete ptr;
+	}
+	if(!other.ptr){
+		ptr=nullptr;
+	} else {
+		ptr=new T(move(*other.ptr));
+		other.ptr=nullptr;
+	}
+	return *this;
+}
+
+
+template <typename T>
+bool Indirect<T>::isEmpty() const {
+	return ptr!=nullptr;
+}
+
+template <typename T>
+T& Indirect<T>::operator*(){
+	if(!ptr){
+		throw NullIndirectError();
+	}
+	return *ptr;
+}
+
+template <typename T>
+const T& Indirect<T>::operator*() const {
+	if(!ptr){
+		throw NullIndirectError();
+	}
+	return *ptr;
+}