Re: [PATCH v3 1/5] Copy utf-7 module to modified-utf-7

[Florian Weimer <fweimer@redhat.com>]

* Max Gautier via Libc-alpha:

> When I initially looked at utf-7.c, the use of the _tab arrays with
> magic values and the subsequent shifting didn't make a lot of sense to
> me, which is why I modified them like this for utf-7-imap. If they are
> in the same file, it's probably better to use the same method.
> So do you see any benefits to keeping the old method ?

I think the old method was an optimization in the long-gone times when
memory access was relatively fast compared to computation.

GCC has also improved since: it can use shifts and bit lookups to
combine comparisons against multiple constants into one check.

> Testing directly for the actual characters seems a lot more readable to
> me, is shorter, and can be mapped to the RFC definition.

Agreed.

>> You could remove the UTF7_ENCODE_OPTIONAL_CHARS from the existing UTF-7
>> codec in a first, separate patch.
>
> Do you mean I should modify the utf-7 conversion to not encode the
> optional chars ?  That would change the result of utf-7 conversions,
> wouldn't it ? I'm not opposed to it, but isn't that going to break
> things ?

Sorry, I meant to remove the constructs that enable this type of
compile-time configurability.  That is, remove the macro, but do not
change the generated code.

Thanks,
Florian
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