Dear Mr. Keep,
I believe 7z to be much better than the ones you described as it has better compression although I haven't look at zip and tar and compression methods that deeply. I've always judged compression by how small it gets my files.  The way you judge it seems to be more interesting.
Lester L. Martin II
Daniel Keep Wrote:

> 
> 
> Lester Martin wrote:
> > Lester Martin Wrote:
> > Dear Mr. Miller,
> > I have gotten DFL to finally work with tango. After I have everything working in C# i'll rewrite it with tango and dfl.
> > 
> > Does anyone know of a good zip compression library for D or is this integrated into tango in an easy to use way like example below.
> > FastZip fz = new FastZip(file);
> > fz.unzipTo(ftuzt);
> > fz.setNewZip(file2);
> > fz.compressDirToCurZip(dir);
> > 
> > Those method names may very as long as such functionality is provided.
> > 
> 
> I've got the beginnings of a Zip archive implementation for Tango lying around, but it's been held up by various things.  There's little doubt that Tango will have Zip support fairly soon (and by "fairly soon" I mean by around the end of the year.)
> 
> <rant>
> 
> Incidentally, Zip is a complete bastard of a format to support.  The format document is horribly written, disjointed, confusing, incomplete and the format itself hasn't so much evolved as *congealed* over time.
> 
> For instance: there's something like four different places the list of files in an archive can appear, and just to make things fun, the format spec doesn't say *anything* about which one to trust.
> 
> Of course, tar isn't much better; that one has *multiple* incompatible standards; half of the time, there's no reliable way to tell them apart, either.
> 
> I haven't had the heart to even try looking at 7z yet...
> 
> </rant>
> 
> 	-- Daniel

Lester L. Martin II wrote:
> Dear Mr. Keep,
> I believe 7z to be much better than the ones you described as it has better compression although I haven't look at zip and tar and compression methods that deeply. I've always judged compression by how small it gets my files.  The way you judge it seems to be more interesting.
> Lester L. Martin II
> Daniel Keep Wrote:
> 

While 7z is a great compression format, (de)compressing is much slower than the zlib codec. Furthermore, 7z is LGPL and zlib has a BSD style license. tar doesn't do compression by itself, it's for archiving only.

Lutger wrote:
> Lester L. Martin II wrote:
>> Dear Mr. Keep,
>> I believe 7z to be much better than the ones you described as it has
>> better compression although I haven't look at zip and tar and
>> compression methods that deeply. I've always judged compression by how
>> small it gets my files.  The way you judge it seems to be more
>> interesting.
>> Lester L. Martin II
>> Daniel Keep Wrote:
>>
> 
> While 7z is a great compression format, (de)compressing is much slower than the zlib codec. Furthermore, 7z is LGPL and zlib has a BSD style license. tar doesn't do compression by itself, it's for archiving only.

Well, I *did* say "Zip", "tar" and "7z" as opposed to "DEFLATE/zlib", "bzip2" and "LZMA".  I've noticed lots of people tend to confuse archive and compression formats.  :3

Incidentally, Tango now supports zlib (used by Zip and gzip) and bzip2
(used by, surprise, surprise, bzip2) as compression filters.

<rant id="second">

Now, I am aware that LZMA appears to be a generally better compression algorithm, but the reason I haven't tried adding support for it yet is because there doesn't appear to be a single "liblzma" available. There's the official SDK which is written in C++ with lots of Windows-specific code (which obviously makes it difficult to use), and then there's a portable, independent implementation.

But, joy of joys, they're not compatible with each other.  *sigh*

As for 7z itself, from what I can tell, the archives themselves are some kind of object-tree.  Frankly, that scares the hell out of me.  :|

Honestly, I've been tempted on more than one occasion to just write a *simple* archive format for Tango.  Of course, no one else would support it, which would kinda defeat the purpose...

Ok, bed time.

</rant>

	-- Daniel

Daniel Keep wrote:
> 
> Lutger wrote:
>> Lester L. Martin II wrote:
>>> Dear Mr. Keep,
>>> I believe 7z to be much better than the ones you described as it has
>>> better compression although I haven't look at zip and tar and
>>> compression methods that deeply. I've always judged compression by how
>>> small it gets my files.  The way you judge it seems to be more
>>> interesting.
>>> Lester L. Martin II
>>> Daniel Keep Wrote:
>>>
>> While 7z is a great compression format, (de)compressing is much slower
>> than the zlib codec. Furthermore, 7z is LGPL and zlib has a BSD style
>> license. tar doesn't do compression by itself, it's for archiving only.
> 
> Well, I *did* say "Zip", "tar" and "7z" as opposed to "DEFLATE/zlib",
> "bzip2" and "LZMA".  I've noticed lots of people tend to confuse archive
> and compression formats.  :3

I know, I meant to say that, talking about compression only, speed can be a criterium too.

...
> Honestly, I've been tempted on more than one occasion to just write a
> *simple* archive format for Tango.  Of course, no one else would support
> it, which would kinda defeat the purpose...

I'm not sure. It might still be useful if it would offer advantages above zip / tar / whatever.

Op Mon, 01 Oct 2007 02:53:08 +1000
schreef Daniel Keep <daniel.keep.lists@gmail.com>:

> Incidentally, Tango now supports zlib (used by Zip and gzip) and bzip2
> (used by, surprise, surprise, bzip2) as compression filters.

Actually, also both the .zip & .7z "containers" support bzip2 compression in their recent versions.   :)

> Now, I am aware that LZMA appears to be a generally better compression algorithm, but the reason I haven't tried adding support for it yet is because there doesn't appear to be a single "liblzma" available. There's the official SDK which is written in C++ with lots of Windows-specific code (which obviously makes it difficult to use), and then there's a portable, independent implementation.
> 
> But, joy of joys, they're not compatible with each other.  *sigh*

There's also p7zip, which seems to work?


-- 
JanC