Re: [Boost-users] [iostreams] Problem with gzip_decompressor

Subject: Re: [Boost-users] [iostreams] Problem with gzip_decompressor
From: Pfligersdorffer, Christian (Christian.Pfligersdorffer_at_[hidden])
Date: 2010-11-11 06:49:21

Hi Chenwj,

boost-users-bounces_at_[hidden] on Wednesday, November 10, 2010 9:43
AM:

> Dear all,
> 
>   Some compressed data was stored in a vector<char> buf
> (don't know if it's a right way to store compressed data). I
> used the "buf" as a source, and tried to add a
> gzip_decompressor to restore those data. I have tried the
> following approach, but it doesn't work.
> 
>   vector<char> buf;
> 
>   /* fill in the buf */
> 
>   namespace io = boost::iostreams;
>   io::filtering_istream in(boost::make_iterator_range(buf));
>   in.push(io::gzip_decompressor());
> 
> What I got is an exception,
> 
>   terminate called after throwing an instance of
> 
> 'boost::exception_detail::clone_impl<boost::exception_detail::
>   error_info_injector <std::logic_error>>'
>   what():  chain complete
>   Aborted
> 
>   How can I compose a source which comes from a container,
> and add a gzip_decompressor to the source? Thanks in advance.
> 
> Regards,
> chenwj

it seems to me that "chain complete" is a very precise complaint. To use
the filtering_istream you have to reverse natural order and push the
source last. Simply try

io::filtering_istream in;
in.push(io::gzip_decompressor());
in.push(boost::make_iterator_range(buf));

Hope that helps,

-- 
Christian Pfligersdorffer
Software Engineering
http://www.eos.info