[Interest] Replacing icudtXX.dll without rebuilding Qt?

[Elvis Stansvik]

2016-01-17 15:44 GMT+01:00 Konstantin Tokarev <annulen at yandex.ru>:
>
>
> 17.01.2016, 17:30, "Elvis Stansvik" <elvstone at gmail.com>:
>> 2016-01-17 14:48 GMT+01:00 Elvis Stansvik <elvstone at gmail.com>:
>>>  Hi all,
>>>
>>>  In an effort to cut down on the size of the standalone ZIP
>>>  distribution of my small command line tool [1] which only uses QtCore,
>>>  and which to my knowledge does not depend on any localization
>>>  features, I'd like to try replacing the icudtXX.dll that I currently
>>>  take from the Qt bin directory with a custom one built using the ICU
>>>  Data Library Customizer [2].
>>
>> I've slightly misunderstood how the ICU Data Library Customizer works.
>> I thought it would generate a icudtXX.dll, but it generates a .dat
>> file to be used in the compilation of ICU.
>>
>> So now that I know that I have to re-build ICU with this .dat file, my
>> question are:
>>
>> 1. Is it safe to replace the three icuXXXX.dll DLL files without also
>> re-building Qt, provided that I use the exact same ICU version,
>> compiled with the exact same compilation flags, but with a different
>> .dat file?
>
> You can rebuild ICU in a way that .dat file is loaded at runtime and you can do any customizations you like without messing with libraries. See documentation on ICU site.

Aha. I see. But if I re-build ICU in such a way, will I also need to
re-build Qt against the new ICU? Or can I use it as a drop-in
replacement, provided that I used the same version + compilation
flags, except for the one that enables run-time loading of the .dat
file?

Maybe John has already answered this in his answer. I'll answer him as well.

Thanks for the input.

Elvis

>
>>
>> 2. If so, which parts of the .dat file can I safely exclude with the
>> ICU Data Library Customizer? I don't think I need any of the features
>> which Qt uses ICU for, but are there some parts that must be included
>> for Qt to function at all?
>>
>> 3. Where can I find out how the ICU bundled with official Qt builds was built?
>>
>> Cheers,
>> Elvis
>>
>>>  My questions are:
>>>
>>>  1. Is this is safe to to replace icudtXX.dll without replacing the
>>>  other two ICU DLLs (icuinXX.dll and icuucXX.dll) and re-building the
>>>  Qt library itself?
>>>
>>>  2. Are the ICU build options / data config used for the ICU DLLs that
>>>  comes bundled with official Qt builds documented somewhere? I tried
>>>  looking in the `qtqa` repo, but found no ICU build scripts or similar
>>>  there. I know that Qt hosts some pre-built ICU version at [3]. Are
>>>  these the ones shipped with official Qt builds? If so, how were they
>>>  built?
>>>
>>>  I'm currently using MSVC on Appveyor to build my standalone ZIP, and
>>>  I'm using the official builds of Qt. I know I can completely cut out
>>>  the dependency on ICU by re-building Qt, but I'm looking for solution
>>>  where I don't have to do that.
>>>
>>>  If it's unsafe to replace icudtXX.dll without also re-building Qt,
>>>  I'll abandon the idea. If it's possible if I also replace the other
>>>  two ICU DLLs, then I'll consider it.
>>>
>>>  I know people don't really care if the size of a package is 4 MB or 11
>>>  MB, but it just feels a bit silly that 60% of the binaries in my
>>>  package are not really needed.
>>>
>>>  Thanks in advance.
>>>
>>>  Elvis
>>>
>>>  [1] https://github.com/estan/protoc-gen-doc
>>>  [2] http://apps.icu-project.org/datacustom/ICUData54.html
>>>  [3] http://download.qt.io/development_releases/prebuilt/icu/prebuilt/
>>
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>
> --
> Regards,
> Konstantin