On 07/07/2014 13:14, Jonathan Wakely wrote:
On 7 July 2014 12:08, Tobias Grosser wrote:
The number of elements in these maps is most likely between 3-10.
Then std::map is the wrong solution.
The overhead of dereferencing all the pointers while walking through a
std::map will be higher than the savings you get from logarithmic
lookup.
For ten elements a linear search of a std::vector will probably be
quicker than lookup in a std::map. A binary search of a sorted vector
(which needs no pointer-chasing because it uses random-access
iterators) will definitely be faster.
Very good point. On the other side, we still want to hide this behind a
map-like interface. So starting with a std::map may be a good thing.
To tune this later we can introduce a specialized vector_map. Such a
vector_map may not even want to use a std::vector, but a vector class
that stores its data in stack memory.
Cheers,
Tobias
