[pclasses-devel] IOFilters / ZLibIOFilter

[Christian P. <cp...@se...>]

Hi !

I've finished the IOFilter architecture!

Description:
IOFilters are proxies which will be called by IODevice's to serve the actual 
I/O requests. The default implementation of IOFilter directly calls the real 
I/O methods (_read, _write, _....).

Note:
IOFilters work on any type of IODevice. however I/O filters may change the 
return value of IODevice::isSeekable(). Therefore you cannot rely on 
assumptions like "Files are always seekable".


ZLibIOFilter
-----------

Description:
an IOFilter that compresses/decompresses IODevice's on the fly. 

Note:
seek(), peek() is not supported.
size() incorrectly returns the compressed size instead of the uncompressed 
size.

Since this is a "raw" zlib deflate stream I/O filter it cannot be directly 
used to decompress/compress gzip files.
Processing gzip files require an additional header and a trailer 
(http://www.faqs.org/rfcs/rfc1952.html).

Maybe we should also add an GZipIOFilter ?
or if it isn't possible a GZipFile() ? 


Greetings,

Christian