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#pragma once
/**
* Detect members in a class. From: http://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Member_Detector
*
* Usage:
* CREATE_DETECTOR(attribute)
* or
* CREATE_DETECTOR_MEMBER(suffix, member)
* where 'suffix' is used in the name of the detect-class, and "memeber" is checked for.
*
* detect_<attribute><T>::value -> true or false.
*/
#define CREATE_DETECTOR_MEMBER(suffix, member) \
template <class T> \
class detect_##suffix { \
struct Fallback { int member; }; \
struct Derived : T, Fallback {}; \
\
template <class U, U> struct Check; \
\
typedef char ArrayOfOne[1]; \
typedef char ArrayOfTwo[2]; \
\
template <class U> \
static ArrayOfOne &func(Check<int Fallback::*, &U::member> *); \
template <class U> \
static ArrayOfTwo &func(...); \
public: \
typedef detect_##suffix type; \
enum { value = sizeof(func<Derived>(0)) == sizeof(ArrayOfTwo) }; \
}; \
template <> \
class detect_##suffix<int> { \
public: \
enum { value = false }; \
}; \
template <> \
class detect_##suffix<nat> { \
public: \
enum { value = false }; \
}; \
template <> \
class detect_##suffix<byte> { \
public: \
enum { value = false }; \
}; \
template <> \
class detect_##suffix<char> { \
public: \
enum { value = false }; \
}; \
template <> \
class detect_##suffix<wchar_t> { \
public: \
enum { value = false }; \
}; \
template <> \
class detect_##suffix<bool> { \
public: \
enum { value = false }; \
}; \
template <> \
class detect_##suffix<void> { \
public: \
enum { value = false }; \
};
#define CREATE_DETECTOR(X) CREATE_DETECTOR_MEMBER(X, X)
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