Optimization of a c++ matrix/bitmap class
- by Andrew
I am searching a 2D matrix (or bitmap) class which is flexible but also fast element access. The contents A flexible class should allow you to choose dimensions during runtime, and would look something like this (simplified):
class Matrix
{
public:
Matrix(int w, int h) :
data(new int[x*y]), width(w) {}
void SetElement(int x, int y, int val)
{
data[x+y*width] = val;
}
// ...
private: // symbols
int width;
int* data;
};
A faster often proposed solution using templates is (simplified):
template <int W, int H>
class TMatrix {
TMatrix() data(new int[W*H]) {}
void SetElement(int x, int y, int val)
{
data[x+y*W] = val;
}
private:
int* data;
};
This is faster as the width can be "inlined" in the code. The first solution does not do this. However this is not very flexible anymore, as you can't change the size anymore at runtime.
So my question is:
Is there a possibility to tell the compiler to generate faster code (like when using the template solution), when the size in the code is fixed and generate flexible code when its runtime dependend?
I tried to achieve this by writing "const" where ever possible. I tried it with gcc and VS2005, but no success. This kind of optimization would be useful for many other similar cases.
