Optimal basic_string<>::append

[Paolo Carlini]

Hi again,

sorry Ryszard :(

my previous counterexample was flawed: if this != &__str and moreover this
is not shared, __k1 and __k2 *cannot* point inside it !!

Therefore, I think now that your approach is sound. It should spare the
call to reserve anytime this != &__str and could make a sequence of append
faster (notice, however, the the reserve istself, now that the allocation
policy is exponential, does not really reallocates such frequently)

If you manage to prepare and test a patch vs the current mainline it could
be discussed by the list. I could do this for you but not now: I'm hard at
work on other member functions (replace itself, in particular).

Thanks,
Paolo.