[fpc-pascal] streaming file from zip into my app
dhkblaszyk at zeelandnet.nl
Sat Dec 1 10:04:29 CET 2007
Marc Santhoff wrote:
> Am Freitag, den 30.11.2007, 23:09 +0200 schrieb Graeme Geldenhuys:
>> On 30/11/2007, Marc Santhoff <M.Santhoff at t-online.de> wrote:
>>> But I still have questions about the code. Do I understand correctly
>>> that Graeme contributed the de-/compression code but it still has to get
>>> integrated and used by the component?
>> We used the zlib (de)compression units from the tiOPF project. We
>> simply removed the references to other tiOPF units - it was pretty
>> stand-alone already so was easy. So yes, what's left is to integrate
>> that code into the TZipFile component and do some tests. The
>> (de)compression code has already been well unit tested in tiOPF, so we
>> know that part works perfectly. As I stated earlier, I have also
>> found a Object Pascal implementation of 7zip which I would like to add
>> to both TZipFile and tiOPF - I still need to double check the
>> licensing though.
> I'm remembering slowly, zlib is for handling gzip format, pkzip format
> is still missing. And 7zip, does it have it's own format or is this used
> for the common ".zip"-files?
Both gzip and zip support DEFLATE compression. The main difference
between the two is that gzip internally ias a solid archive and zip not.
This enables the use of the zip format as a "filesystem" without
requiring to inflate the entire archive.
7zip uses LZMA compression which is also supported by the zipfile format.
> If I would want to complete the component, I'd try to use and maybe add
> something to the unit I've already found in packages/extra/unzip. At
> least the compression routines should do.
Wherever you will start it will boil down to implement the zlib
compression / decompression (inflate / deflate) algorithms.
> fpc-pascal maillist - fpc-pascal at lists.freepascal.org
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