C++ 枚举扩展，兼容任何类型

template 
struct __ext_enum
{
public:
    typedef T type_value;
    typedef int type_index;

    static T value(int index) {
        auto baseAddr = (const char*)(EnumExt_T::get());
        return T (*(const T*)(baseAddr + sizeof(T) *index));
    }

    static type_index index(const T &elem)
    {
        for (int i = 0; i < EnumExt_T::count(); i++) {
            if (value(i) == elem)
                return i;
        }
        return -1;
    }

    static int len() {
        return sizeof(EnumExt_T);
    }

    static int count() {
        return len() == 0 ? 0 : len() / sizeof(type_value);
    }

    static auto get(){
        static EnumExt_T instance;
        return &instance;
    }

    static QList toQList() {
        QList result;
        for (int i = 0; i < EnumExt_T::count(); i++) {
            result << EnumExt_T::value(i);
        }
        return result;
    }

    static bool contains(const type_value &value) {
        for (int i = 0; i < EnumExt_T::count(); i++) {
            if (value == EnumExt_T::value(i))
                return true;
        }
        return false;
    }

    static QJsonArray toArray(){
        QJsonArray result;
        for (int i = 0; i < EnumExt_T::count(); i++) {
            result << EnumExt_T::value(i);
        }
        return result;
    }
};

#define enum_exp public: const type_value
#define enum_def(name, type) class name : public __ext_enum
#define enum_type(name) name::type_value

#include 

enum_def(FailureHandlingKind, std::string)
{
    enum_exp Abort = "abort";
    enum_exp Transactional = "transactional";
    enum_exp Undo = "undo";
    enum_exp TextOnlyTransactional = "textOnlyTransactional";
};

int main(int argc, char *argv[])
{
	std::cout << FailureHandlingKind::get()->value(0) << std::endl;
	std::cout << FailureHandlingKind::get()->index("undo") << std::endl;
}

如果不想使用转换函数 QList QJsonArray，可将相关函数屏蔽