[Development] QHash for Qt 6

[Giuseppe D'Angelo]

Il 20/12/19 09:23, Lars Knoll ha scritto:
> The result was that QHash has clear weaknesses compared to other implementations. It uses too much memory and certainly isn’t the fastest implementation. But std::unordered_map is just as bad, so there’s no point in using that to implement QHash.

Just to be devil's advocate, there is... As much as it's fun and 
everything implementing a container, just using std::unordered_map would 
have minimal effort on our side ("someone else's problem", and it's not 
even a random 3rd party, but a mandatory prerequisite for building Qt), 
and we can put in our API move-conversion between QHash / 
std::unordered_map.

I stopped thinking that Qt should provide "special" data structures (and 
for sure we should kill any QHash/QMap usage in our APIs); QHash can be 
as bad (or as good) as std::unordered_map, and if people need something 
more tailored for their use cases, there's plenty of 3rd parties to 
choose from. Or is there a political agenda here trying to promove QHash 
usage? :-)

Is the plan to also have QMap be backed by an hybrid solution 
(array-backed, etc.), or std::map, or something else?

My 2 c,

-- 
Giuseppe D'Angelo | giuseppe.dangelo at kdab.com | Senior Software Engineer
KDAB (France) S.A.S., a KDAB Group company
Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
KDAB - The Qt, C++ and OpenGL Experts

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