cell.h

#ifndef CELL_H
#define CELL_H

class Cell {
public:
    enum class CellState : unsigned char {
        Closed,
        Opened,
        MarkedAsBomb,
        MarkedAsQuestion
    };
    inline bool isMine() const
    {
        return data & 1;
    }
    inline unsigned char minesAround() const
    {
        return data >> 1 & 0b1111;
    }
    inline CellState cellState() const
    {
        return CellState(data >> 5 & 0b11);
    }
    inline void setMine(bool value = true)
    {
        if (value)
            data |= 1;
        else
            data = data >> 1 << 1;
    }
    inline void setMinesAround(unsigned char value)
    {
        data &= ~0b11110;
        value <<= 1;
        data |= value;
    }
    inline void setCellState(CellState state)
    {
        unsigned char value = static_cast<unsigned char>(state);
        data &= ~0b1100000;
        value <<= 5;
        data |= value;
    }

private:
    // CellState state; // 2 bits
    // char minesAround; // 4 bits
    // bool mine; // 1 bit
    // reserved cellState minesAround isMine
    // 0        00         0000         0
    unsigned char data = 0;
};

#endif // CELL_H