[Oisf-devel] PDF and SWF file decompressor/parser

Giuseppe Longo giuseppe at glongo.it
Mon Aug 29 09:34:37 UTC 2016

Il giorno gio, 25/08/2016 alle 18.22 +0530, amit zala ha scritto:
> Hi,
> AFAIK, both pdf and swf use same decompression algorithms.
> So, Are you also writing parser for swf? "OR" based on initial few
> bytes (zws/fws) you are applying your decompression algorithms?

I'm writing new file decompression API that permits to decompress
only flash files currently.

What I do is to look the first 3 bytes to determine which
compression algorithm is used, then doing decompression with
zlib and libzma for CWS and ZWS respectively.

> I am asking this because, In snort they have file decompression code
> and they use it for both pdf & swf.
> They parse few bytes in swf to determine which decompression algo is
> being used.
> In Pdf, with the help of /filter object they determine which
> decompression algo is used.

In that way shouldn't be difficult to implement decompression methods
for pdf.

> Thanks
> Amit


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