Re: GConverter commited

[Shaun McCance <shaunm gnome org>]

On Mon, 2009-11-23 at 16:30 +0100, Alexander Larsson wrote:
> I just commited GConverter to glib master (in gio). GConverter is a
> generic interface for streaming data conversion. Shipping with gio are
> converters based on iconv and zlib compression/decompression.
> 
> Additionally there is GConverterInputStream and GConverterOutputStream
> for doing the conversion automatically as part of reading or writing a
> file.
> 
> At the moment the compression support is just zlib, but theoretically it
> should be possible to make decompression a generic extensible thing so
> that extensions can ship other compression algorightms that are picked
> based on file sniffing. I'm not 100% sure this is all that useful
> though. And for compression its not quite possible since the exact
> parameters used for compressions vary for different compression
> algorithms.
> 
> Please check out this API and give comments on it. I think its pretty
> good, as we've talked about this a bit on irc over the years, but
> feedback is always good.

Thanks.  I threw together some decompressors for bzip2 and lzma.
I also cobbled together a quick magic decompressor that inspects
the first two bytes to determine what to do.  Code is here:

http://www.gnome.org/~shaunm/git/convert.git

I'll be using the bzip2 and lzma converters in Yelp.  I'm not
sure about the magic converter.  I might just throw it away and
go off the file name.  The magic detection is not suitable for
general use, though I think it's OKish for Yelp.  Although this
Debian bug report concerns me:

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=364260

Also, when putting together chains of streams when content may
or may not be encoded, I think it would be useful to have some
sort of NullConverter, i.e. a GConverter that doesn't change
anything.  Would anybody else find that useful?

Anyway, since I was one of the people wanting this, I thought
I'd share my first experiences with it.  I'm curious what other
people would like to do about GConverters for other compression
schemes.  The code is simple enough that I don't really mind
keeping it in Yelp.  But if other people are doing this stuff,
maybe we should talk about how to share code.

Thanks again,
Shaun