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  1. #include <iostream>
  2. #include <vector>
  3. #include <cstdint>
  4.  
  5.     template<class It>
  6.     struct range_t {
  7.       It b, e;
  8.       It begin() const { return b; }
  9.       It end() const { return e; }
  10.       std::size_t size() const { return end()-begin(); }
  11.     };
  12.  
  13.     template<class It>
  14.     range_t<It> range(It s, It f) { return {s,f}; }
  15.  
  16.     template<class T>
  17.     range_t< unsigned char* > as_bytes( T* t ) {
  18.       static_assert( std::is_trivially_copyable<T>::value, "bad idea if not trivilaly copyable" );
  19.       auto* ptr = reinterpret_cast<unsigned char*>(t);
  20.       return range(ptr, ptr+sizeof(T));
  21.     }
  22.     template<class T>
  23.     range_t< unsigned char const* > as_bytes( T const* t ) {
  24.       static_assert( std::is_trivially_copyable<T>::value, "bad idea if not trivilaly copyable" );
  25.       auto* ptr = reinterpret_cast<unsigned char const*>(t);
  26.       return range(ptr, ptr+sizeof(T));
  27.     }
  28.  
  29.     template<class T>
  30.     void push_bytes_in( std::vector<std::uint8_t>& target, T const* data ) {
  31.       auto bytes = as_bytes(data);
  32.       target.insert( target.end(), bytes.begin(), bytes.end() );
  33.     }
  34.     template<class T>
  35.     bool pop_bytes_out( std::vector<std::uint8_t>& src, T* data ) {
  36.       auto bytes = as_bytes(data);
  37.       if (bytes.size() > src.size()) return false;
  38.       std::copy( src.end()-bytes.size(), src.end(), bytes.begin() );
  39.       src.resize( src.size()-bytes.size() );
  40.       return true;
  41.     }
  42.  
  43.     struct some_data {
  44.       int x, y;
  45.       char buff[1024];
  46.     };
  47.  
  48.  
  49.  
  50. int main() {
  51. 	std::vector<std::uint8_t> bytes;
  52.  
  53. 	some_data data{1,2, "hello"};
  54. 	push_bytes_in( bytes, &data );
  55. 	some_data d2;
  56. 	if (!pop_bytes_out( bytes, &d2)) {
  57. 		std::cout << "failed\n";
  58. 		return -1;
  59. 	}
  60. 	std::cout << d2.buff << "\n";
  61. }
Success #stdin #stdout 0s 4240KB
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stdin
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Standard input is empty
stdout
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hello
https://ideone.com/JcyXzP
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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