Re: Implicit and Explicit Template Instantiation

Hi there,

Template, once again... Nice topic but a bit tricky to code.

My problem is the following:

I have to video parser which retrieve image frames. The pixel values can
be unsigned char (8 bit) or unsigned short (16 bit).

I've got a templated frame:

template <class T>
class Frame {
    Frame(int height, int width) {
        data = new T[height * width]
    }
    T * data;
}

I've got my readers:

class Video16bit : public Frame<unsigned char> {
    Video16bit : Frame(20,20) {
        // whatever
    }
}

class Video16bit : public Frame<unsigned short> {
    Video16bit : Frame(20,20) {
        // whatever
    }
}

This one seems to compile fine. Everything goes wrong when I try to
process these videos.

I would like to create a class which can take either of the videos but I
got lost...

class Processor {
public:
    Processor();
    LoadData(Frame<T> * data);
protected:
    Frame<T> * mydata;
}

My main would look like (the two videos should be usable):

int main(void) {
    Video16bit * vid = new Video16bit();
    // Video8bit * vid = new Video8bit();
    Processor * pro = new Processor();
    pro->LoadData(vid);
    delete whatever is required;
}

The problem is that the creation of my processor depends on the type of
template and ... I dunno how to pass it cleanly. My current solution is
to template the Processor as well. However, I could make a mistake of
type: I would like the T of the processor defined by the loaded video...

Does it make sense?

Another way to see it would be: can I do a
Processor<vid->getType()> * pro = new Processor();