HasMember.h File Reference

Macros for checking the existence of class members. More...

#include <boost/type_traits/integral_constant.hpp>
#include <boost/type_traits/is_class.hpp>

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Namespaces
	mira
	specialize cv::DataType for our ImgPixel and inherit from cv::DataType<Vec>

Macros
#define	MIRA_MEMBER_DETECTOR_EX(Identifier, Member)
#define	MIRA_MEMBER_DETECTOR(Member)   MIRA_MEMBER_DETECTOR_EX(Member,Member)
#define	MIRA_HAS_MEMBER(Class, Identifier)   MIRAHasMemberCheck##Identifier<MIRAHasMemberCheckTrait<Class>::type>
	Macro checking the existence of a class member. More...
#define	MIRA_HAS_MEMBER_TEMPLATE(Class, Identifier)   MIRAHasMemberCheck##Identifier<typename MIRAHasMemberCheckTrait<Class>::type>

Detailed Description

Macros for checking the existence of class members.

Author

Erik Einhorn

Date

2010/06/30

Macro Definition Documentation

MIRA_MEMBER_DETECTOR_EX

#define MIRA_MEMBER_DETECTOR_EX	(		Identifier,
			Member
	)

Value:

template <typename Type>                                                       \
class MIRAHasMemberCheck##Identifier                                            \
{                                                                              \
    struct NotFound { char x[1]; };                                            \
    struct Found    { char x[2]; };                                            \
    struct BaseMixin {                                                         \
        void Member(){}                                                        \
    };                                                                         \
                                                                               \
    struct Base : public Type, public BaseMixin {};                            \
    template <typename T, T t>  class Helper{};                                \
                                                                               \
    template <typename U>                                                      \
    static NotFound deduce(U*, Helper<void (BaseMixin::*)(), &U::Member>* = 0);\
    static Found deduce(...);                                                  \
                                                                               \
public:                                                                        \
    enum { value = (sizeof(Found) == sizeof(deduce((Base*)(0))))};             \
    typedef boost::integral_constant<bool,                                     \
            (sizeof(Found) == sizeof(deduce((Base*)(0)))) > type;              \
                                                                               \
};

MIRA_MEMBER_DETECTOR

#define MIRA_MEMBER_DETECTOR

(

Member

)

MIRA_MEMBER_DETECTOR_EX(Member,Member)

MIRA_HAS_MEMBER

#define MIRA_HAS_MEMBER	(		Class,
			Identifier
	)		MIRAHasMemberCheck##Identifier<MIRAHasMemberCheckTrait<Class>::type>

Macro checking the existence of a class member.

class MyClass {
public:
    int i;
}
MIRA_MEMBER_DETECTOR(i)
if (MIRA_HAS_MEMBER(MyClass, i)::value) {
   ...
}

MIRA_HAS_MEMBER_TEMPLATE

#define MIRA_HAS_MEMBER_TEMPLATE	(		Class,
			Identifier
	)		MIRAHasMemberCheck##Identifier<typename MIRAHasMemberCheckTrait<Class>::type>