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  1. #include <iostream>
  2. #include <cstring>
  3.  
  4. template<typename ReturnType, typename... ParameterTypes>
  5. class IDelegateBinding
  6. {
  7. public:
  8.  
  9. 	virtual ReturnType Execute(void* Object, ParameterTypes... Parameters) = 0;
  10. };
  11.  
  12. template<typename ObjectType, typename ReturnType, typename... ParameterTypes>
  13. class FDelegateBinding : public IDelegateBinding<ReturnType, ParameterTypes...>
  14. {
  15. 	using MethodType = ReturnType (ObjectType::*)(ParameterTypes...);
  16.  
  17. 	MethodType BoundMethod;
  18.  
  19. public:
  20.  
  21. 	FDelegateBinding(MethodType Method)
  22. 		: BoundMethod(Method)
  23. 	{
  24. 	}
  25.  
  26. 	virtual ReturnType Execute(void* Object, ParameterTypes... Parameters) override
  27. 	{
  28. 		return (((ObjectType*)Object)->*BoundMethod)(Parameters...);
  29. 	}
  30. };
  31.  
  32. template<typename ReturnType, typename... ParameterTypes>
  33. class FDelegate
  34. {
  35. 	using DummyDelegateBinding = FDelegateBinding<class FDummyClass, ReturnType, ParameterTypes...>;
  36.  
  37. 	typename std::aligned_storage<sizeof(DummyDelegateBinding), alignof(DummyDelegateBinding)>::type Binding;
  38.  
  39. public:
  40.  
  41. 	FDelegate()
  42. 	{
  43. 		std::memset(&Binding, 0, sizeof(Binding));
  44. 	}
  45.  
  46. 	template<typename ClassName>
  47. 	void Bind(ReturnType (ClassName::*Method)(ParameterTypes...))
  48. 	{
  49. 		new (&Binding) FDelegateBinding<ClassName, ReturnType, ParameterTypes...>(Method);
  50. 	}
  51.  
  52. 	void Unbind()
  53. 	{
  54. 		std::memset(Binding, 0, sizeof(Binding));
  55. 	}
  56.  
  57. 	bool IsBound() const
  58. 	{
  59. 		return (void*&)Binding != nullptr;
  60. 	}
  61.  
  62. 	template<typename ObjectType>
  63. 	ReturnType Execute(ObjectType* Object, ParameterTypes... Parameters)
  64. 	{
  65. 		return ((IDelegateBinding<ReturnType, ParameterTypes...>&)Binding).Execute(Object, Parameters...);
  66. 	}
  67.  
  68. 	template<typename ObjectType>
  69. 	ReturnType ExecuteIfBound(ObjectType* Object, ParameterTypes... Parameters)
  70. 	{
  71. 		if (IsBound())
  72. 		{
  73. 			return Execute<ObjectType>(Object, Parameters...);
  74. 		}
  75. 	}
  76. };
  77.  
  78. class FSampleBase
  79. {
  80. protected:
  81.  
  82. 	FDelegate<void, int> NotifyFooInvoked;
  83.  
  84. public:
  85.  
  86. 	void Foo(int Value)
  87. 	{
  88. 		NotifyFooInvoked.ExecuteIfBound(this, Value);
  89. 	}
  90. };
  91.  
  92. class FSampleDerived : public FSampleBase
  93. {
  94. 	int SampleData;
  95.  
  96. public:
  97.  
  98. 	FSampleDerived(int Data)
  99. 		: SampleData(Data)
  100. 	{
  101. 		NotifyFooInvoked.Bind(&FSampleDerived::OnFooInvoked);
  102. 	}
  103.  
  104. 	void OnFooInvoked(int Value)
  105. 	{
  106. 		std::cout << "Foo Invoked: " << Value << " [Sample Data: " << SampleData << "]" << std::endl;
  107. 	}
  108. };
  109.  
  110. int main()
  111. {
  112. 	FSampleDerived FirstSample(11);
  113. 	FSampleDerived* SecondSample = (FSampleDerived*)std::malloc(sizeof(FSampleDerived));
  114.  
  115. 	std::memcpy(SecondSample, &FirstSample, sizeof(FSampleDerived));
  116.  
  117. 	FirstSample.Foo(1);
  118. 	SecondSample->Foo(2);
  119.  
  120. 	std::free(SecondSample);
  121.  
  122. 	return 0;
  123. }
Success #stdin #stdout 0s 4476KB
comments (?)
stdin 
Standard input is empty
stdout 
Foo Invoked: 1 [Sample Data: 11]
Foo Invoked: 2 [Sample Data: 11]
https://ideone.com/nbNmg1
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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