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  1. #include <iostream>
  2. #include <cstring>
  3.  
  4. template <typename T, typename PtrType>
  5. class BitReinterpretType
  6. {
  7. public:
  8.   explicit BitReinterpretType(PtrType* ptr) : m_ptr(ptr) {}
  9.  
  10.   inline const T& operator=(const T& source)
  11.   {
  12.     std::memcpy(m_ptr, &source, sizeof(source));
  13.     return source;
  14.   }
  15.  
  16.   inline operator T() const
  17.   {
  18.     T result;
  19.     std::memcpy(&result, m_ptr, sizeof(result));
  20.     return result;
  21.   }
  22.  
  23. private:
  24.   PtrType* m_ptr;
  25. };
  26.  
  27. template <typename T, typename PtrType>
  28. class BitReinterpretTypeConst
  29. {
  30. public:
  31.   explicit BitReinterpretTypeConst(const PtrType* ptr) : m_ptr(ptr) {}
  32.  
  33.   inline operator T() const
  34.   {
  35.     T result;
  36.     std::memcpy(&result, m_ptr, sizeof(result));
  37.     return result;
  38.   }
  39.  
  40. private:
  41.   const PtrType* m_ptr;
  42. };
  43.  
  44. template <typename T, typename PtrType>
  45. inline auto BitReinterpret(const PtrType* ptr) noexcept -> BitReinterpretTypeConst<T, PtrType>
  46. {
  47.   return BitReinterpretTypeConst<T, PtrType>{ptr};
  48. }
  49.  
  50. template <typename T, typename PtrType>
  51. inline auto BitReinterpret(PtrType* ptr) noexcept -> BitReinterpretType<T, PtrType>
  52. {
  53.   return BitReinterpretType<T, PtrType>{ptr};
  54. }
  55.  
  56. struct my_struct
  57. {
  58. 	int x;
  59. };
  60.  
  61. int main()
  62. {
  63. 	unsigned char data[20] = {0xff, 0xff, 0xff, 0xff, /*etc*/};
  64.  
  65. 	my_struct ms = BitReinterpret<my_struct>(data);
  66. 	std::cout << std::hex << ms.x <<std::endl;
  67.  
  68. 	ms.x = 123;
  69.  
  70. 	BitReinterpret<my_struct>(data) = ms;
  71. 	std::cout << std::hex << int(data[0]) <<std::endl;
  72. }
Success #stdin #stdout 0s 15232KB
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stdin
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Standard input is empty
stdout
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ffffffff
7b
https://ideone.com/091UPt
language:
C++14 (gcc 8.3)
created:
5 years ago
visibility:
public

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