[SDL] Re: BeOS and SDL

[Mattias Engdegård]

>> My only question, how fast is inheritance compared to a switch?
>
>Inheritance is faster than a switch, usually. Inheritance works like
>function pointers, there is a small overhead, but the decision-making is
>all done at once (when the object is created).

Most modern CPUs do a fair job on predicting branches, but most do not
at all as well in the indirect function call prediction business.
(Most tests I've done confirm this.)

When you compare a switch to a virtual function call (which is basically
a indirect function call + the cost of fetching the pointer from the vtbl),
it depends on what code is emitted for the switch, how many branches etc.

Compilers often emit branch trees and/or jump tables for switches,
depending on the number and distribution of the case labels.
So the right answer is the one you don't want: "It depends" :-)