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DelphiZlib 0.2.99

Yes, this is version 0.2.99. It doesn't mean this component is not usable, it means that I'm not sure if I like it the way it works now. Until I release version 1.0.0 some property's could change (Of course I will keep the newer versions backwards compatible for a while.)

Please read the legal notes at the end of this file.

DelphiZlib is based on the zlib 1.1.2 general purpose data compression library. The original Zlib library can be found on http://www.info-zip.org/pub/infozip/zlib/ The Pascal implementation I used is by Jacques Nomssi Nzali. Because he did such a great job, writing this component was easy. I changed only a few bytes in the original code in order to avoid some compilation-warnings.

I did only include the files I needed for this component. Some of them I changed a bit. For the complete and original PASZLIB-code I refer to: http://www.tu-chemnitz.de/~nomssi/paszlib.html Read also paszlib.txt, which is in fact the original readme.txt by Jacques Nomssi Nzali and contains more information. [And yes, I copied some lines from this file]

The untar-code is based on extar 1.0 made by TapirSoft Gisbert W.Selke (feb 1990). The untar code is a quick implementation that might not work correctly will all tar-files.
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The components

The components can be used after installing it the normal way in Delphi 4. Someone told me it also works for Delphi 5 and I guess it will also work for Delphi 3 and would appreciate when somebody can mail me if it indeed works. Please ignore the compiler hints. I did not yet clean up or optimize the code.

To install (Delphi 4):
Just unpack the zip-file into a directory where you want to keep your components. Then choose [File],[Open] and select the file 'DelphiZlib.dpk'. In the new window you should choose [install]. The component will be placed under [samples]

After installing the component you will need to tell Delphi where it can find the files that belong to it. Go to [Tools], [Environment Options], [Library], [Library Path]. Add the following paths here:

  • The path where Delphi can find DelphiZlib.dpk ($PATH)
  • $PATH\Zlib
  • $PATH\Other
If somebody knows how I can set this automatic, please let me know.

Important if you are upgrading: Please remove the old component completely before you install the new one. Make sure there are no old files left. Delphi (at least for me) is not always rebuilding components in a correct way.
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Interface

TGzip
TCrc32
TAdler32
TUnTar
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Versions

0.2.99:
  • Added TUnTar
  • Bug-fix in TGzip.gzip. This bug could cause wrong header information in the gzip-ed file. This bug appeared in version 0.2.1
  • Small bug-fix in error-message TGzip.gunzip
0.2.2:
  • Small bug-fix in getGzipHeader
0.2.1:
  • TGzip: Removed path-information from FileSource when storing in gzip-header.
0.2.0:
  • Implemented basic header-functionality to TGzip
  • Fixed bug in TGzip.gunzip
0.1.0: 
  • Added TCrc32
  • Added TAdler32
  • Fixed returning error-value from TGzip
  • Added OnProgress-event to TGzip
  • Added delphizlib.pkg package
  • Renamed project from DelphiGzip to DelphiZlib
0.0.0:
  • First public release
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And in the future..

Unfortunately I don't have much time at the moment, so don't expect me to fully develop this component into a new WinZip. When I'll have more time I'll start writing a TZip component also based on the Zlib library. Please let me know if I should add or change something.

But first I'll finish the TUnTar component. I'll try to make it in such a way that gzipped tar-files can be extracted more efficient.
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Legal issues

Copyright (C) 2000 by Vincent Nikkelen

   This software is provided 'as-is', without any express or implied
   warranty. In no event will the author be held liable for any damages
   arising from the use of this software.

   Permission is granted to anyone to use this software for any purpose,
   including commercial applications, and to alter it and redistribute
   it freely, subject to the following restrictions:

   1. The origin of this software must not be misrepresented; you must
      not claim that you wrote the original software. If you use this
      software in a product, an acknowledgment in the product
      documentation would be appreciated but is not required.
   2. Altered source versions must be plainly marked as such, and must
      not be misrepresented as being the original software.
   3. This notice may not be removed or altered from any source
      distribution.

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FAQ:

  • How can I add multiple files to 1 gzip file?
    You can't. Gzip only compresses 1 file. If you want to compress more files to a single file use e.g. zip.
  • What is the best way to de-install your component?
    I don't know if this is the best way, but this is the way I do it: Remove the directory where you installed the component, including all .dcu and .bpl files. Start Delphi and when Delphi asks if it should try to load the component next time you start, answer no. This way you're sure there are no old files around when you want to upgrade the component. (Don't forget to remove the library paths if you want to get rid of this component for ever.)
  • The component does not work, will you implement function x-y-z, how can I...?
    Please check my web-site if there is not a newer version. Some Delphi sites are distributing an old version of my component (Sorry for that, but I have no influence on that except changing the license which I don't want to do.) If this does not solve your question, mail me. Sometimes it will take some time before I react, but I definitely will answer you.

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Download:

DelphiZlib home-page: http://www.gewis.win.tue.nl/info/delphizlib/
Download DelphiZlib: http://www.gewis.win.tue.nl/info/delphizlib/delphizlib.zip (120 kb)
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Vincent Nikkelen (vincent@caesar.elte.hu) Januari 01, 2001