[Boost-users] boost::iostreams de/compress data from memory question.

20 Apr 2007

      Hi!
Is there anyone know how to use boost::iostreams to de/compress data from 
memory ?
...
From file the code bellow works well:
#include <fstream>
#include <iostream>
#include <boost/iostreams/filtering_streambuf.hpp>
#include <boost/iostreams/copy.hpp>
#include <boost/iostreams/filter/gzip.hpp>

namespace io = boost::iostreams;

int main()
{
        using namespace std;

        ifstream file("hello.gz", ios_base::in | ios_base::binary);
        io::filtering_streambuf<io::input> in;
        in.push(io::gzip_decompressor());
        in.push(file);
        io::copy(in, cout);
}

But if I changed ifstream into istringstream like this:
#include <fstream>
#include <sstream>
#include <boost/iostreams/filtering_stream.hpp>
//#include <boost/iostreams/copy.hpp>
#include <boost/iostreams/filter/gzip.hpp>

namespace io = boost::iostreams;

int main() 
{
	using namespace std;

	ifstream file("hello.gz", ios_base::in | ios_base::binary);
	io::filtering_istream in;
	in.push(io::gzip_decompressor());
	in.push(file);

	//std::ostringstream ostr;

	//io::copy (in, ostr);

	//std::string stir = ostr.str ();
	std::string stir;

	in >> stir;

	//ofstream ofs("output.gz", ios_base::out | ios_base::binary);
	ostringstream ostr;
	io::filtering_ostream out;
	out.push (io::gzip_compressor());
	out.push (ostr);

	out << stir;

	stir= out.str();
}

the std::string stir always NULL when I want to get the data after compress.

Sorry for my bad English..
I am a Chinese.

[Boost-users] boost::iostreams de/compress data from memory question.

CPPer