ITK  4.9.0
Insight Segmentation and Registration Toolkit
itkPromoteType.h
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5  * Licensed under the Apache License, Version 2.0 (the "License");
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14  * See the License for the specific language governing permissions and
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18 #ifndef itkPromoteType_h
19 #define itkPromoteType_h
20 
21 #include "itkMacro.h"
22 
23 // Simplification of boost::common_type
24 namespace itk {
25 
27 namespace mpl {
28 
29 namespace Details {
30 
37 template <int N, typename TA, typename TB> struct SizeToType;
38 
43 template <int N> struct Identity { typedef char Type[N]; };
44 
50 #define ITK_ASSOCIATE(N, Typed)\
51  template <typename TA, typename TB> struct SizeToType<N,TA,TB> { typedef Typed Type; };
52 
53  ITK_ASSOCIATE(1, TA);
54  ITK_ASSOCIATE(2, TB);
55 
56  ITK_ASSOCIATE(3, short);
57  ITK_ASSOCIATE(4, unsigned short);
58  ITK_ASSOCIATE(5, int);
59  ITK_ASSOCIATE(6, unsigned int);
60  ITK_ASSOCIATE(7, long);
61  ITK_ASSOCIATE(8, unsigned long);
62  ITK_ASSOCIATE(9, long long);
63  ITK_ASSOCIATE(10, unsigned long long);
64  ITK_ASSOCIATE(11, float);
65  ITK_ASSOCIATE(12, double);
66  ITK_ASSOCIATE(13, long double);
67 #undef ITK_ASSOCIATE
68 } // Details namespace
69 
90 template <typename TA, typename TB> struct PromoteType
91 {
92  static TA a;
93  static TB b;
94 
95  // Aimed at supporting overloads
96  template <typename T> static Details::Identity<1>::Type& Check(typename Details::SizeToType<1, TA, TB>::Type, T);
97  template <typename T> static Details::Identity<2>::Type& Check(typename Details::SizeToType<2, TA, TB>::Type, T);
98 
99  // Common numeric types
100  static Details::Identity<3 >::Type& Check(typename Details::SizeToType<3, TA, TB>::Type, int);
101  static Details::Identity<4 >::Type& Check(typename Details::SizeToType<4, TA, TB>::Type, int);
102  static Details::Identity<5 >::Type& Check(typename Details::SizeToType<5, TA, TB>::Type, int);
103  static Details::Identity<6 >::Type& Check(typename Details::SizeToType<6, TA, TB>::Type, int);
104  static Details::Identity<7 >::Type& Check(typename Details::SizeToType<7, TA, TB>::Type, int);
105  static Details::Identity<8 >::Type& Check(typename Details::SizeToType<8, TA, TB>::Type, int);
106  static Details::Identity<9 >::Type& Check(typename Details::SizeToType<9, TA, TB>::Type, int);
107  static Details::Identity<10>::Type& Check(typename Details::SizeToType<10, TA, TB>::Type, int);
108  static Details::Identity<11>::Type& Check(typename Details::SizeToType<11, TA, TB>::Type, int);
109  static Details::Identity<12>::Type& Check(typename Details::SizeToType<12, TA, TB>::Type, int);
110  static Details::Identity<13>::Type& Check(typename Details::SizeToType<13, TA, TB>::Type, int);
111 public:
127  typedef typename Details::SizeToType<sizeof Check(a+b, 0), TA, TB>::Type Type;
128 };
129 } // itk::mpl namespace
131 
133 } // itk namespace
134 
135 #endif // itkPromoteType_h