id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
8572,iosteams indirect_streambuf::init_put_area should seek if data has been read from the get buffer,Alan Birtles <alan.birtles@…>,Jonathan Turkanis,"The following code with std::fstream prints 0x1801 but with boost::iostream prints 0x2000:
{{{
  boost::iostreams::stream< boost::iostreams::file > ios( boost::iostreams::file( ""test.dat"", std::ios_base::binary | std::ios_base::in | std::ios_base::out | std::ios_base::trunc ), 0x800 );
  //std::fstream ios( ""test.dat"", std::ios_base::binary | std::ios_base::in | std::ios_base::out | std::ios_base::trunc );
  char buffer[ 0x2000 ];
  ios.write( buffer, 0x2000 );
  ios.seekg( -0x1000, std::ios_base::cur );
  ios.get();
  ios.write( buffer, 0x800 );
  std::cout << std::hex << ios.tellp() << std::endl;
  std::cout << std::hex << ios.tellg() << std::endl;
}}}

I believe the problem lies in indirect_streambuf::init_put_area. The current implementation is:

{{{
    if (shared_buffer() && gptr() != 0)
        setg(0, 0, 0);
    if (output_buffered())
        setp(out().begin(), out().end());
    else
        setp(0, 0);
}}}

I think it should be:
{{{
    if (shared_buffer() && gptr() != 0)
    {
        obj().seek(gptr()-egptr(), BOOST_IOS::cur, BOOST_IOS::in, next_);
        setg(0, 0, 0);
    }
    if (output_buffered())
        setp(out().begin(), out().end());
    else
        setp(0, 0);
}}}
",Bugs,new,To Be Determined,iostreams,Boost 1.53.0,Problem,,,