c++ - 具有重写运算符的模板类

Question

我想添加一个运算符覆盖来执行内联赋值/__set__s。

模板:-

class CBase {
    public :
        static void SetupVmeInterface(CVmeInterface *in);

    protected :
        static CVmeInterface *pVmeInterface;
};


template <class T> class TCVmeAccess : public CBase {
    public:
        TCVmeAccess(int address);

        T get()
        {
            unsigned long temp = pVmeInterface->ReadAddress(Address);
            T ret = *reinterpret_cast<T*>(&temp);
            return ret;
        };

        T *operator->();
        unsigned long asLong();

        bool set(T data)
        {
            unsigned long write_data = *reinterpret_cast<unsigned long*>(&data);
            return pVmeInterface->WriteAddress(Address, write_data);
        };

        // void operator->(T);
        void operator=(T data)
        { set(data); }

    private :
        int Address;
};

将在模板中使用的结构:-

typedef struct
{
    int a: 1; // 0
    int b: 1; // 1
    int c: 1; // 2
    int d: 1; // 3
    int NotUsed : 28; // 31-4
} _HVPSUControl;

代码主体:-

TCVmeAccess<_HVPSUControl> HVPSUControl(constHVPSUControlBlock);
_HVPSUControl hvpsu = HVPSUControl.get(); // Yep, good, but not as nice as...
int a = HVPSUControl2.get().OperationalRequestPort; // yep, also good, but...
int b = HVPSUControl->a; // works, and is all go so far

HVPSUControl.set(hvpsu); // works, but need _HVPSUControl type
HVPSUControl = hvpsu;    // also works, as operator = is used, but still need type

// this line does not work!
// as the = assignment is redirected into a copy of the struct, not the template
HVPSUControl->a = 1; // this line

那么，有没有办法让上面的这一行起作用？

编辑: 比如，我希望“这一行”像在模板类中一样作为一个“集合”执行。

编辑: 1. 直接内联赋值给构成模板的结构体成员 的。
2. 使该分配通过模板访问器。

这样我就不必在作业上这样做了:-

// HVPSUControl is predefined and used many times.
_HVPSUControl hvpsu;
hvpsu.a = 1;
HVPSUControl.set(hvpsu);

我想做

HVPSUControl.a = 1; // or 
HVPSUControl->a = 1; // or ?

在线工作:

如果(HVPSUControl->a)

Answer 1

您可以从模板结构派生，而不是覆盖“->”和“=”运算符。

template <class T> class TCVmeAccess : public CBase, public T {
    public:
        TCVmeAccess(int address);

        T get();
        // T *operator->();
        unsigned long asLong();

        bool set(T);
        // void operator->(T);
        // void operator=(T);

    private :
        int Address;
};

HVPSUControl.a = 1; // and use this for setting a bitfield.

编辑:如果你想使用自定义赋值运算符，你应该在 HVPSUControl 中声明它，或者甚至是它的基类，如果你有更多类似控件的结构的话。

struct _HVPSUControl
{
    int a: 1; // 0
    int b: 1; // 1
    int c: 1; // 2
    int d: 1; // 3
    int NotUsed : 28; // 31-4
    void operator = (int x);
};

或

struct _HVPSUBase {
    void operator = (int x);
}
struct _HVPSUControl: public _HVPSUBase
{
    int a: 1; // 0
    int b: 1; // 1
    int c: 1; // 2
    int d: 1; // 3
    int NotUsed : 28; // 31-4
};