OpenCV-style Matrix Class

1#include <cstddef>
2#include <memory>
3 
4class Mat {
5public:
6  int rows;
7  int cols;
8  int type;
9  unsigned char* data;
10 
11private:
12  std::shared_ptr<unsigned char[]> dataPtr;
13  size_t step;
14 
15public:
16  Mat() : rows(0), cols(0), type(0), data(nullptr), step(0) {}
17  
18  Mat(int _rows, int _cols, int _type)
19    : rows(_rows), cols(_cols), type(_type) {
20    size_t elemSize = (type & 7) + 1;
21    step = cols * elemSize;
22    dataPtr = std::make_shared<unsigned char[]>(rows * step);
23    data = dataPtr.get();
24  }
25 
26  bool empty() const { return data == nullptr; }
27  size_t total() const { return static_cast<size_t>(rows) * cols; }
28 
29  Mat clone() const {
30    Mat m(rows, cols, type);
31    std::copy(data, data + rows * step, m.data);
32    return m;
33  }
34 
35  template<typename T>
36  T& at(int row, int col) {
37    return reinterpret_cast<T*>(data + row * step)[col];
38  }
39};