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  1. /** Trying this again. Simpler approach, maybe...
  2. **/
  3.  
  4. #include <cstddef>
  5. #include <limits>
  6. #include <new>
  7. #include <stdexcept>
  8. #include <iostream>
  9. #include <cstdlib>
  10.  
  11. template <typename T> class MemoryManager
  12. {
  13.     public:
  14.     /** Typedefs **/
  15.         typedef T * pointer;
  16.         typedef const T * const_pointer;
  17.         typedef T& reference;
  18.         typedef const T& const_reference;
  19.         typedef T value_type;
  20.         typedef size_t size_type;
  21.         typedef ptrdiff_t difference_type;
  22.  
  23.         T* allocate(size_t n) const;
  24.         void deallocate(T* const buffer, size_t) const;
  25.         void construct(T* const ptr, const T& value) const;
  26.         size_t max_size() const;
  27.         MemoryManager() {};
  28.  
  29.         template <typename U> struct rebind
  30.         {
  31.             typedef MemoryManager<U> other;
  32.         };
  33. };
  34.  
  35. template <typename T>
  36. T* MemoryManager<T>::allocate(size_t n) const
  37. {
  38.     if(n == 0)
  39.         return NULL;
  40.  
  41.     if(n > max_size())
  42.     {
  43.         throw std::length_error("Integer overflow at MemoryManager::allocate()");
  44.     }
  45.  
  46.     T* buffer = static_cast<T*>(malloc(n * sizeof(T)));
  47.  
  48.     if(buffer == NULL)
  49.     {
  50.         throw std::bad_alloc();
  51.     }
  52.  
  53.     std::cout << (n * sizeof(T)) << " bytes allocated.\n";
  54.     return buffer;
  55. }
  56.  
  57. template <typename T>
  58. void MemoryManager<T>::deallocate(T* const buffer, size_t) const
  59. {
  60.     free(buffer);
  61.     std::cout << "Buffer deallocated.\n";
  62. }
  63.  
  64. template <typename T>
  65. void MemoryManager<T>::construct(T* const ptr, const T& value) const
  66. {
  67.     void* const placement = static_cast<void*>(ptr);
  68.     new (placement) T(value);
  69. }
  70.  
  71. template <typename T>
  72. size_t MemoryManager<T>::max_size() const
  73. {
  74.     return std::numeric_limits<size_t>::max();
  75. }
  76.  
  77. #include <vector>
  78. #include <iostream>
  79. int main()
  80. {
  81.     auto f = [&](int i){std::cout<< i << "\t";};
  82.  
  83. 	std::vector<int, MemoryManager<int> > v = {1,2,3,4,5};
  84.  
  85. 	for(int i : v)
  86. 	{
  87. 		f(i);
  88. 	}
  89. }
Success #stdin #stdout 0s 2984KB
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stdin
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Standard input is empty
stdout
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20 bytes allocated.
1	2	3	4	5	Buffer deallocated.
https://ideone.com/pTt7vh
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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