Re: [Boost-users] [Iostreams] Zlib compression sometimes creates corrupt data on OSX

Subject: Re: [Boost-users] [Iostreams] Zlib compression sometimes creates corrupt data on OSX
From: Jeff Flinn (jeffrey.flinn_at_[hidden])
Date: 2013-10-02 13:50:06

On 10/2/2013 11:07 AM, Michael Jung wrote:
> Hello,
>
> I’m having the following problem with my program: If I save data on OSX
> using a boost::iostreams::filtering_ostream with a
> boost::iostreams::zlib_compressor() the resulting file is sometimes
> corrupted.
>
> The following example code reproduces the problem:
>
> #include <fstream>
> #include <iostream>
> #include <vector>
> #include <boost/iostreams/filtering_stream.hpp>
> #include <boost/iostreams/filter/zlib.hpp>
>
> int main(int argc, char** argv)
> {
>    if (argc != 2) return 1;
>    std::ifstream file(argv[1]);

Maybe add: , std::ios_base::binary

>    if (file)
>    {
>      file.seekg(0, std::ios::end);
>      std::streampos length = file.tellg();
>      file.seekg(0, std::ios::beg);
>
>      std::vector<char> buffer1(length);
>      std::vector<char> buffer2(length);
>
>      file.read(&buffer1[0], length);
>
>      {
>        std::ofstream ofs("test.dat", std::ios_base::binary);
>        boost::iostreams::filtering_ostream fos;
>        fos.push(boost::iostreams::zlib_compressor());
>        fos.push(ofs);
>
>        fos.write(&buffer1[0], length);
>      }
>      {
>        std::ifstream ifs("test.dat", std::ios_base::binary);
>        boost::iostreams::filtering_istream fis;
>        fis.push(boost::iostreams::zlib_decompressor());
>        fis.push(ifs);
>
>        fis.read(&buffer2[0], length);
>      }
>
>      std::cout << (buffer1 == buffer2 ? "equal" : "not equal")
>              << std::endl;
>    }
> }

otherwise search the mailing list for a thread from back in July 2013:

"[iostreams] How can I use the Stream Insertion operator (<<) with a 
filtering_streambuf?"

Jeff