[Python-Dev] The future of the wchar_t cache
22.10.18 16:24, Steve Dower ????:
> Yes, that's true. But "should reduce ... footprint" is also an
> optimisation that deserves a benchmark by that standard. Also, I'm
> proposing keeping the 'kind' as UCS-2 when the string is created from
> UCS-2 data that is likely to be used as UCS-2. We would not create the
> UCS-1 version in this case, so it's not the same as prefilling the
> cache, but it would cost a bit of memory in exchange for CPU. If slicing
> and concatentation between matching kinds also preserved the kind, a lot
> of path handling code could avoid back-and-forth conversions.
Oh, I afraid this will complicate the whole code of unicodeobject.c (and
several other files) a much and can introduce a lot of subtle bugs.
For example, when you search a UCS2 string in a UCS1 string, the current
code returns the result fast, because a UCS1 string can't contain codes
> 0xff, and a UCS2 string should contain codes > 0xff. And there are
many such assumptions.