The code basically wants to get the last element of equal_range(id).
The problem is that backwards iteration on QHash is very expensive,
because it's implemented as forward search with wrap-around at bucket
end.
So it was implementing its own equal_range with look-ahead. The
problem is that it compared each key in the equal_range twice: once in
the if, and once more in the following while iteration.
I expect to see this kind of algorithm more as we move away from the
fake bidirectionalism of QHash, so I decided to implement it in a
generic way. We can copy it somewhere else when we find more users.
Change-Id: I7951652107ab897f6a456035f02e0339835e078d
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
2e5b8032a2