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  1. #include <iostream>
  2. #include <fstream>
  3. #include <vector>
  4.  
  5. class IReadable
  6. {
  7. public:
  8. 	IReadable(){};
  9. 	virtual ~IReadable(){};
  10. 	virtual IReadable& read(char *p,int n) = 0;
  11. };
  12.  
  13. class CFileReader: public IReadable
  14. {
  15. public:
  16. 	template <class T>
  17. 	CFileReader(T& v) : obj(&v) {};
  18. 	~CFileReader(){};
  19. 	IReadable& read(char *p,int n) {
  20. 		this->obj->read(p,n);
  21. 		return *(this->obj);
  22. 	}
  23. private:
  24. 	IReadable* obj;
  25. };
  26.  
  27. class CMemoryReader
  28. {
  29. public:
  30. 	CMemoryReader(){};
  31. 	~CMemoryReader(){};
  32. 	CMemoryReader& read(char *p,int n) { return *this; }; // do nothing
  33. private:
  34. 	char *mem;
  35. };
  36.  
  37. template <class T>
  38. class GenericReadable : public IReadable {
  39.   T & t_;
  40. public:
  41.   GenericReadable(T& t) : t_(t) {};
  42.   virtual IReadable& read(char *p,int n) {
  43.     t_.read(p, n);
  44.     return *this;
  45.   };
  46. };
  47.  
  48. template <class T>
  49. GenericReadable<T> make_readable(T& t) {
  50.   return GenericReadable<T>(t);
  51. };
  52.  
  53. int main(int argc,char **argv)
  54. {
  55. 	std::ifstream file("foo.bar",std::ifstream::binary);
  56.     auto fileReadable = make_readable(file);
  57.  
  58. 	CFileReader file_reader(fileReadable);
  59. 	CMemoryReader memory_reader;
  60.  
  61.     auto memReadable = make_readable(memory_reader);
  62.  
  63. 	std::vector<IReadable*> vv;
  64. 	vv.push_back(&file_reader);
  65. 	vv.push_back(&memReadable);
  66. 	char buff[8];
  67.  
  68. 	for(auto& reader : vv)
  69. 	{
  70. 		reader->read(buff,4);
  71. 	}
  72. 	return 0;
  73. }
Success #stdin #stdout 0s 4348KB
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https://ideone.com/27yhhu
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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