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allocator.h
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1 // Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
2 // Distributed under MIT license, or public domain if desired and
3 // recognized in your jurisdiction.
4 // See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
5 
6 #ifndef JSON_ALLOCATOR_H_INCLUDED
7 #define JSON_ALLOCATOR_H_INCLUDED
8 
9 #include <cstring>
10 #include <memory>
11 
12 #pragma pack(push, 8)
13 
14 namespace Json {
15 template <typename T> class SecureAllocator {
16 public:
17  // Type definitions
18  using value_type = T;
19  using pointer = T*;
20  using const_pointer = const T*;
21  using reference = T&;
22  using const_reference = const T&;
23  using size_type = std::size_t;
24  using difference_type = std::ptrdiff_t;
25 
30  // allocate using "global operator new"
31  return static_cast<pointer>(::operator new(n * sizeof(T)));
32  }
33 
40  // memset_s is used because memset may be optimized away by the compiler
41  memset_s(p, n * sizeof(T), 0, n * sizeof(T));
42  // free using "global operator delete"
43  ::operator delete(p);
44  }
45 
49  template <typename... Args> void construct(pointer p, Args&&... args) {
50  // construct using "placement new" and "perfect forwarding"
51  ::new (static_cast<void*>(p)) T(std::forward<Args>(args)...);
52  }
53 
54  size_type max_size() const { return size_t(-1) / sizeof(T); }
55 
56  pointer address(reference x) const { return std::addressof(x); }
57 
58  const_pointer address(const_reference x) const { return std::addressof(x); }
59 
63  void destroy(pointer p) {
64  // destroy using "explicit destructor"
65  p->~T();
66  }
67 
68  // Boilerplate
70  template <typename U> SecureAllocator(const SecureAllocator<U>&) {}
71  template <typename U> struct rebind { using other = SecureAllocator<U>; };
72 };
73 
74 template <typename T, typename U>
76  return true;
77 }
78 
79 template <typename T, typename U>
81  return false;
82 }
83 
84 } // namespace Json
85 
86 #pragma pack(pop)
87 
88 #endif // JSON_ALLOCATOR_H_INCLUDED
size_type max_size() const
Definition: allocator.h:54
const_pointer address(const_reference x) const
Definition: allocator.h:58
pointer address(reference x) const
Definition: allocator.h:56
const T & const_reference
Definition: allocator.h:22
std::ptrdiff_t difference_type
Definition: allocator.h:24
const T * const_pointer
Definition: allocator.h:20
std::size_t size_type
Definition: allocator.h:23
void destroy(pointer p)
Destroy an item in-place at pointer P.
Definition: allocator.h:63
void deallocate(pointer p, size_type n)
Release memory which was allocated for N items at pointer P.
Definition: allocator.h:39
pointer allocate(size_type n)
Allocate memory for N items using the standard allocator.
Definition: allocator.h:29
void construct(pointer p, Args &&... args)
Construct an item in-place at pointer P.
Definition: allocator.h:49
SecureAllocator(const SecureAllocator< U > &)
Definition: allocator.h:70
JSON (JavaScript Object Notation).
Definition: allocator.h:14
bool operator==(const SecureAllocator< T > &, const SecureAllocator< U > &)
Definition: allocator.h:75
bool operator!=(const SecureAllocator< T > &, const SecureAllocator< U > &)
Definition: allocator.h:80