CodeSquid
24th December 2001 18:57 UTC
BICOM compression
While searching for compression libraries I've found BICOM, a bijective compressor. Here's the URL: http://www3.sympatico.ca/mtimmerm/bicom/bicom.html
In most cases it compresses better than zlib.
Best of all: BICOM does not create any overhead since it is bijective (it is headerless)
Quote from the website:
If you consider compression to be an important first step before encryption, because it minimizes redundancy in the plaintext, then you can appreciate this bijective quality, because bijectivity implies that the compression adds no known plaintext to its output
Bicom is open source and free to use for noncommercial purposes.
Can anyone try implement bicom in nsis? I don't have enough time to test it myself.
spanky
25th December 2001 20:36 UTC
wow, looks quite impressive.
I took a quick look and it seems to be creating larger files. (took a 400k file and after compression it grew to 1.3MB) It's also very slow. (about 3 mins for a 5MB file)
I'm sure in some cases this can pay off. It would be neat to see this implmented into NSIS.
spanky
25th December 2001 21:11 UTC
I took a different file and ran some tests with it.
--------------------------------------------------
Original size: 2,316 KB
File type: executable
For Zip and UPX I used the best compression available.
Original exe > zip: 448 KB
Original exe > rar: 389 KB
Original exe > bicom: 403 KB
(and for fun) Original exe > UPX: 397 KB
--------------------------------------------------
For those of you who are curious..
Original size: 2,316 KB
File type: UPX'd executable
UPX'd exe > zip: 378 KB
UPX'd exe > rar: 376 KB
UPX'd exe > bicom: 378 KB
Since RAR support is not available the second best option would be to go with BiCom, based on these results.
I'm sure there will be mixed results depending on which types of files are being tested. This is why it would be nice to see additional support in NSIS.
Maybe MakeNSIS.exe should compress each package several times and automatically decide which compression method is the best to use.
Koen van de Sande
25th December 2001 21:16 UTC
And how does it compare to NSIS-BZIP2?
As I'm not *that* impressed by BICOM. And is it open-source/GPL?
spanky
25th December 2001 23:10 UTC
"It is freely available and open source."
I'm happy with the compression rate but I'm not happy with its performance. It's way too slow. I'm afraid it might be too slow for most practical purposes.