Who wants to change the world? | The Coffeehouse

W3bbo
The Master of Baiters

...well, the world of software dev.

Right now there's no implementation of 7zip for the managed world. There is a C# port of the LZMA algorithm for compressing streams but it isn't 7z compatible and has pitiful performance (6 min to compress 80MB when 7z does it in 30 seconds). The only alternatives include P/Invoking to the 7z DLLs or using ShellExecute.

7z is under a pretty liberal licensing scheme and is begging for a port over to C#. I can't do it all myself as it's a fairly large undertaking, I imagine a team of two or three people would be great, especially if you're a student like me who doesn't have much to do over the summer holiday until October.

I propose putting it on CodePlex and doing all dev there. Who'se with me?

This would also be my first true "team" software dev exercise; to anyone who might be interested: I can deflate my ego where necessary, I'm after a nice managed 7z library first, fame and glory second.

brian.shapiro
things go on as always

I'd be interested in the design-side of things if anyone is ever interested in creating an actual compression/decompression application.

CannotResolveSymbol
{insert caption here}

In reply to brian.shapiro

#Jun 12th @ 11:55 AM

I'm interested... I'll IM you if you're still on after I get done @ work.

spivonious

I'm interested...Let me know what I can do. Email is paistss at hotmail dot com.

TommyCarlier
I want my scalps!

I might be interested. Mail me on:
string.Format( CultureInfo.InvariantCulture, "{0}.{1}@telenet.{2}", myFirstName, myLastName, Belgium.CountryCode);

figuerres
???

In reply to TommyCarlier

#Jun 12th @ 12:33 PM

"I might be interested. Mail me on string.Format(CultureInfo.InvariantCulture, "{0}.{1}@telenet.{2}", myFirstName, myLastName, Belgium.CountryCode);"

neat way to make it hard to web-scrape ....

TommyCarlier
I want my scalps!

In reply to figuerres

#Jun 12th @ 12:37 PM

It's also a test to see if W3bbo is worthy Wink

“But choose wisely, for while the true Grail will bring you life, the false Grail will take it from you.”

W3bbo
The Master of Baiters

In reply to TommyCarlier

#Jun 12th @ 12:46 PM

Symbol "Belgium" undefined Smiley

stevo_
Human after all

In reply to W3bbo

#Jun 12th @ 1:09 PM

Symbol? phht- been that long? Tongue Out

Dan

Love this idea, we'll pimp it out on This Week on Channel 9 next week to see if you can get more volunteers.

MasterPie
I'm white because I smelt an onion

I'll gladly sacrifice a line of code for your endeavors W3bbo! Tongue Out

littleguru
<3 Seattle

I thought 7zip provides a SDK that allows you to code against it in C#. At least there's a link for that on the website...

longzheng

In reply to littleguru

#Jun 13th @ 1:27 AM

http://www.7-zip.org/sdk.html

LZMA is the default and general compression method of 7z format in the 7-Zip program. LZMA provides a high compression ratio and very fast decompression, so it is very suitable for embedded applications. For example, it can be used for ROM (firmware) compressing.

LZMA SDK includes:

C++ source code of LZMA Encoder and Decoder
ANSI-C compatible source code for LZMA decompression with example
C# source code for LZMA compression and decompression
Java source code for LZMA compression and decompression
Compiled file->file LZMA compression/decompression program for the Windows operating system

Dr Herbie
Horses for courses

I don't have much spare time to give, but I'm willing and able to help out in a minor role (review and test, perhaps?).

Herbie

W3bbo
The Master of Baiters

In reply to littleguru

#Jun 13th @ 1:27 AM

As I said, the C# implementation is just the LZMA compression algorithm, not the whole 7z library, and it's very inefficient.

stevo_
Human after all

In reply to W3bbo

#Jun 13th @ 2:57 AM

What does the rest of the 7z library do then? surely the c# lzma impl atm just isn't well optimized?

ZippyV
Fired Up

In reply to W3bbo

#Jun 13th @ 2:57 AM

When you have created the Codeplex project, post the link here and I'll sign up.

W3bbo
The Master of Baiters

In reply to stevo_

#Jun 13th @ 3:46 AM

Archive management, for one thing; it also uses a different LZMA algorithm implementation (in addition to also supporting PPMd and BZip algos). The C# LZMA implementation is a straight port of the C version which is just as slow.

Ion Todirel
buuu

"save the cheerleader save the world" huh? Smiley

vesuvius
Das Glasperlenspiel

According to Vance Morrison unzipping/zipping is one of those easily parallelisable events. If you use the Task Parallel Library, unzipping on a Core 2 takes half the time, quad core 1/4 and so on so you may want to use that.

Dr Herbie
Horses for courses

In reply to vesuvius

#Jun 13th @ 7:23 AM

Ooh, now that sounds like a feature!

Herbie

CannotResolveSymbol
{insert caption here}

In reply to stevo_

#Jun 13th @ 3:46 AM

Compress 7z files... the LZMA library only implements the LZMA algorithm, not the rest of the 7zip format (e.g. archives with multiple files, etc.)

Bass
www.spreadfirefox.com/5years/

If you implement it using Mono.SIMD it will be very very fast (at least on Mono). Smiley

longnightmoon
crop_circles

Sounds like fun. I'm kind of busy, but I might be able to squeeze in a few cycles.

stevo_
Human after all

In reply to CannotResolveSymbol

#Jun 13th @ 10:02 AM

My point was.. making the rest of the 7z library wouldn't somehow make it faster.. the core problem is that somebody needs to build a good perf lzma impl for c#.. which to me would indicate requirement for a little more arrangment than asking a couple of people on what isn't really a serious developers forum.