uint value comparison for a 32 layer system (GameDev)

//Derived from the example
void Foo(uint num)
{
  switch(num)
  {
    case 0:
    // No toggles active
    break;
    case 1:
    // First toggle is active
    break;
    case 3:
    // First and Second toggle are active
    break;
    case 7:
    // First, second and third toggles are active
    break;
    case 15:
    // 1st, 2nd, 3rd, 4th toggles are active
    break;
    case 31:
    // 1st, 2nd, 3rd, 4th, 5th toggles are active
    break;
    //etc.
  }
}