Handling Huge Multidimensional Arrays in C++

Question

I\'m designing a game in C++ similar to Minecraft that holds an enormous amount of terrain data in memory. In general, I want to store an array in memory that is [5][4][5][50][

Answer 1

Here's something that works and can be built upon without the boost dependency. One downside is it removes use of [][][] style of referencing elements, but it's a small cost and can be added.

template
class Matrix {
    unsigned char* _data;
    const size_t _depth;
    const size_t _cols;
    const size_t _rows;
public:
    Matrix(const size_t& depth, const size_t& rows, const size_t& cols):
        _depth(depth),
        _rows(rows), 
        _cols(cols) {
        _data = new unsigned char [depth * rows * cols * sizeof(T)];
    }
    ~Matrix() {
        delete[] _data;
    }
    T& at(const size_t& depthIndex, const size_t& rowIndex, const size_t& colIndex) const {
        return *reinterpret_cast(_data + ((((depthIndex * _cols + colIndex) * _rows) + rowIndex) * sizeof(T)));
    }
    const size_t& getDepth() const {
        return _depth;
    }
    const size_t& getRows() const {
        return _rows;
    }
    const size_t& getCols() const {
        return _cols;
    }
};

int _tmain(int argc, _TCHAR* argv[])
{
    Matrix block(50, 50, 50);
    size_t d, r, c;
    for (d = 0; d < block.getDepth(); d++) {
        for (r = 0; r < block.getRows(); r++) {
            for (c = 0; c < block.getCols(); c++) {
                block.at(d, r, c) = d * 10000000 + r * 10000 + c;
            }
        }
    }
    for (d = 0; d < block.getDepth(); d++) {
        for (r = 0; r < block.getRows(); r++) {
            for (c = 0; c < block.getCols(); c++) {
                assert(block.at(d, r, c) == d * 10000000 + r * 10000 + c);
            }
        }
    }
return 0;
}