Hi I did an old work with Huffman compression. You can see an example here : http://thomas-pfeiffer.info/files/huffman/
So if it might be interessting for you, mail me to have the source file :) ++ 2006/2/3, David Rorex <[EMAIL PROTECTED]>: > There's a lot of talk about compression in flash/AS2 here: > http://www.quasimondo.com/archives/000572.php > > In particular is this post: > > Posted by: Grant Cox on October 19, 2005 08:35 AM > > > > > > > Well, I've largely completed the 64bit float packing class and the LZW > class (modified from Ash's > http://www.razorberry.com/blog/archives/2004/08/22/lzw-compression-methods-in-as2/ > ). > > > > The packing works well (it's tighter than a Base64 string), and it is fast > enough (the unpacking on PHP is a bit slow), and, as it preserves the bytes > correctly it is worthwhile to use LZW, particularly on images with > gradients/flat colours. > > > > I have provided both Actionscript and PHP classes, for packing/unpacking > both bytes and multibytes into a 64bit float, and for > compressing/uncompressing to LZW. > > > > You can download the Pack64Float classes from > www.ensogroup.com.au/grant/pack64float.zip > > > > and the LZW classes from > www.ensogroup.com.au/grant/LZW.zip > > the pack64float is only usefull for sending to php via amfphp, but lzw > could work in your case. the only problem is it outputs in binary (values > 0-255), not all of which are valid characters for URLs. so you may have to > do some further encoding (like base64 or something), and that may increase > the size by as much or more than it was compressed by. > > good luck > -David R > > > On 2/3/06, Henrik Lindahl <[EMAIL PROTECTED]> wrote: > > Thanks, I'll have a look at that. > > And yes, I am generating *long* urls. I serialize the application state > > into a long string that is sent to the browser as the hash part of an > > url. The idea is to be able to bookmark the app. state (and it actually > > works well right now with urls around 1500 chars). > > There is no real 1000 char limit, but probably a 2000 one - I've been > > told IE has a 2K limit. > > Right now the serialized state is about 2400 chars, but I imagine it'll > > grow when more requirements are added:). > > If using a backend was an option I wouldn't have to do it this way, but > > unfortunately it is not. The app has to be able to run from any server, > > even locally. > > > > Cheers > > /Henrik > > > > > > > > Martin Wood wrote: > > > i dont know of any actual implementations, but it sounds like it might > be a good > > > candidate for Huffman coding. Its not too difficult to implement. :) > > > > > > here's a good page here explaining how it works : > > > > > > http://www.cs.duke.edu/csed/poop/huff/info/ > > > > > > and here is a page here with python code : > > > > > > > http://gumuz.looze.net/wordpress/index.php/archives/2004/11/25/huffman-encoding/ > > > > > > as to whether you can actually achieve that level of compression really > depends > > > on your input. If you absolutely must get to 25% of the input size you > might > > > need to consider something a bit more hardcore :) > > > > > > What concerns me is are you really going to generate a 1000 character > url? or > > > are the numbers just for demonstration purposes? > > > > > > thanks, > > > > > > Martin > > > > > > > > > Henrik Lindahl wrote: > > > > > >>Hi, > > >>I wonder if anyone knows of symmetric string compression librarys for > AS. > > >>What I'm looking for is functions to compress a string of about 4000 > > >>characters to something like 1000 and then be able to recreate the > > >>original string. A symmetric String codec?;) > > >> > > >>Can this be done efficiently in AS2? > > >> > > >>Oh, and the encoded string must be displayable in a web browsers url;) > > >> > > >>Cheers > > >>/Henrik > > >> > > >> > > >> > > >>_______________________________________________ > > >>osflash mailing list > > >>[email protected] > > >> > http://osflash.org/mailman/listinfo/osflash_osflash.org > > >> > > > > > > > > > > _______________________________________________ > > osflash mailing list > > [email protected] > > http://osflash.org/mailman/listinfo/osflash_osflash.org > > > > > _______________________________________________ > osflash mailing list > [email protected] > http://osflash.org/mailman/listinfo/osflash_osflash.org > > > _______________________________________________ osflash mailing list [email protected] http://osflash.org/mailman/listinfo/osflash_osflash.org
