#include <iostream>
#include <cstring>

#define USING_MEMSET 1

class pixmap {
    // this section is, by default, private
public:
    virtual void clear() = 0;
    virtual void set_pixel(unsigned int x, unsigned int y, int value) = 0;
    virtual int get_pixel(unsigned int x, unsigned int y) const = 0;
    virtual unsigned int get_width() const = 0;
    virtual unsigned int get_height() const = 0;
    virtual size_t get_memory_size() const = 0;
    virtual void print_name(std::ostream & output) const;

    pixmap(const char * n): name(n) {};
    virtual ~pixmap() {};

protected:
    const char * name;
};

void pixmap::print_name(std::ostream & output) const {
    output << name << std::endl;
}

class ascii_pixmap : public pixmap { // class ascii_pixmap extends pixmap
public:
    ascii_pixmap(unsigned int width, unsigned int height);
    virtual ~ascii_pixmap();

    virtual void clear();
    virtual void set_pixel(unsigned int x, unsigned int y, int value);
    virtual int get_pixel(unsigned int x, unsigned int y) const;
    virtual unsigned int get_width() const;
    virtual unsigned int get_height() const;
    virtual size_t get_memory_size() const;

    void set_background(char c) { bg = c; }
    void set_foreground(char c) { fg = c; }
    char get_background() const { return bg; }
    char get_foreground() const { return fg; }

private:
    unsigned int width;
    unsigned int height;
    char * data;
    char fg;
    char bg;
};

ascii_pixmap::ascii_pixmap(unsigned int w, unsigned int h)
    : pixmap("ascii"), width(w), height(h), fg('*'), bg(' ') {
    data = new char[width*height]; // WARNING: check allocation
    std::cout << "ascii_pixmap::ascii_pixmap() called." << std::endl;
}

ascii_pixmap::~ascii_pixmap() {
    delete (data);
    std::cout << "ascii_pixmap::~ascii_pixmap() called." << std::endl;
}

void ascii_pixmap::clear() {
#if USING_MEMSET
    memset(data, bg, width*height);
#else
    for (int i = 0; i < width*height; ++i)
	data[i] = bg;
#endif
}

void ascii_pixmap::set_pixel(unsigned int x, unsigned int y, int value) {
    data[x + y*width] = value;
}

int ascii_pixmap::get_pixel(unsigned int x, unsigned int y) const {
    return data[x + y*width];
}

unsigned int ascii_pixmap::get_width() const {
    return width;
}

unsigned int ascii_pixmap::get_height() const {
    return height;
}

size_t ascii_pixmap::get_memory_size() const {
    return width*height;
}

ascii_pixmap & operator |= (ascii_pixmap & a, const ascii_pixmap & b) {
    int w = (a.get_width() < b.get_width()) ? a.get_width() : b.get_width();
    int h = (a.get_height() < b.get_height()) ? a.get_height() : b.get_height();
    for (int x = 0; x < w; ++x)
	for (int y = 0; y < h; ++y)
	    if (b.get_pixel(x, y))
		a.set_pixel(x,y,1);
	
    return a;
}

int main() {
    pixmap * p;
    ascii_pixmap * ap;

    ap = new ascii_pixmap(100, 200);
    p = ap;

    std::cout << "my name is: ";
    ap->print_name(std::cout);

    ascii_pixmap aa(200, 300);

    aa |= *ap;

    delete(p);
    return 0;
}