Electroneum
sfinae_helpers.h
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28 
29 #pragma once
30 
31 // the loose definitions of types in this file are, well, loose.
32 //
33 // these helpers aren't here for absolute type certainty at compile-time,
34 // but rather to help with templated functions telling types apart.
35 
36 namespace sfinae
37 {
38 
39  typedef char true_type;
40 
41  struct false_type { true_type a[2]; };
42 
43  template <typename T>
45  {
46  private:
47 
48  // does not have const iterator
49  template <typename C> static false_type c_iter(typename C::const_iterator*);
50  template <typename C> static true_type c_iter(...);
51 
52  // does not have value_type
53  template <typename C> static false_type v_type(typename C::value_type*);
54  template <typename C> static true_type v_type(...);
55 
56  // does not have key_type
57  template <typename C> static false_type k_type(typename C::key_type*);
58  template <typename C> static true_type k_type(...);
59 
60  // does not have mapped_type
61  template <typename C> static false_type m_type(typename C::mapped_type*);
62  template <typename C> static true_type m_type(...);
63 
64  public:
65 
66  static const bool value = (
67  (
68  sizeof(c_iter<T>(0)) == sizeof(true_type) &&
69  sizeof(v_type<T>(0)) == sizeof(true_type) &&
70  sizeof(k_type<T>(0)) == sizeof(true_type) &&
71  sizeof(m_type<T>(0)) == sizeof(true_type)
72  )
74  );
75 
76  typedef T type;
77  };
78 
79  template <typename T>
81  {
82  private:
83 
84  // has const iterator
85  template <typename C> static true_type c_iter(typename C::const_iterator*);
86  template <typename C> static false_type c_iter(...);
87 
88  // has value_type
89  template <typename C> static true_type v_type(typename C::value_type*);
90  template <typename C> static false_type v_type(...);
91 
92  // does not have key_type
93  template <typename C> static false_type k_type(typename C::key_type*);
94  template <typename C> static true_type k_type(...);
95 
96  // does not have mapped_type
97  template <typename C> static false_type m_type(typename C::mapped_type*);
98  template <typename C> static true_type m_type(...);
99 
100  public:
101 
102  static const bool value = (
103  sizeof(c_iter<T>(0)) == sizeof(true_type) &&
104  sizeof(v_type<T>(0)) == sizeof(true_type) &&
105  sizeof(k_type<T>(0)) == sizeof(true_type) &&
106  sizeof(m_type<T>(0)) == sizeof(true_type) &&
108  );
109 
110  typedef T type;
111  };
112 
113  template <typename T>
114  struct is_map_like
115  {
116  private:
117 
118  // has const iterator
119  template <typename C> static true_type c_iter(typename C::const_iterator*);
120  template <typename C> static false_type c_iter(...);
121 
122  // has value_type
123  template <typename C> static true_type v_type(typename C::value_type*);
124  template <typename C> static false_type v_type(...);
125 
126  // has key_type
127  template <typename C> static true_type k_type(typename C::key_type*);
128  template <typename C> static false_type k_type(...);
129 
130  // has mapped_type
131  template <typename C> static true_type m_type(typename C::mapped_type*);
132  template <typename C> static false_type m_type(...);
133 
134  public:
135 
136  static const bool value = (
137  sizeof(c_iter<T>(0)) == sizeof(true_type) &&
138  sizeof(v_type<T>(0)) == sizeof(true_type) &&
139  sizeof(k_type<T>(0)) == sizeof(true_type) &&
140  sizeof(m_type<T>(0)) == sizeof(true_type) &&
142  );
143 
144  typedef T type;
145  };
146 
147 } // namespace sfinae
const uint32_t T[512]
static const bool value
const GenericPointer< typename T::ValueType > T2 value
Definition: pointer.h:1225
char true_type
static const bool value
static const bool value