Boost gzip how to output compressed string as text - c++

Question

I'm using boost gzip example code here.
I am attempting to compress a simple string test and am expecting the compressed string H4sIAAAAAAAACitJLS4BAAx+f9gEAAAA as shown in this online compressor
static std::string compress(const std::string& data)
{
namespace bio = boost::iostreams;
std::stringstream compressed;
std::stringstream origin(data);
bio::filtering_streambuf<bio::input> out;
out.push(bio::gzip_compressor(bio::gzip_params(bio::gzip::best_compression)));
out.push(origin);
bio::copy(out, compressed);
return compressed.str();
}
int main(int argc, char* argv[]){
std::cout << compress("text") << std::endl;
// prints out garabage
return 0;
}
However when I print out the result of the conversion I get garbage values like +I-. ~
I know that it's a valid conversion because the decompression value returns the correct string. However I need the format of the string to be human readable i.e. H4sIAAAAAAAACitJLS4BAAx+f9gEAAAA.
How can I modify the code to output human readable text?
Thanks
Motivation
The garbage format is not compatible with my JSON library where I will send the compressed text through.

Answer 1

The example site completely fails to mention they also base64 encode the result:
base64 -d <<< 'H4sIAAAAAAAACitJLS4BAAx+f9gEAAAA' | gunzip -
Prints:
test
In short, you need to also do that:
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#include <boost/iostreams/copy.hpp>
#include <boost/iostreams/filter/gzip.hpp>
#include <boost/iostreams/filtering_streambuf.hpp>
#include <iostream>
#include <sstream>
#include <boost/archive/iterators/binary_from_base64.hpp>
#include <boost/archive/iterators/base64_from_binary.hpp>
#include <boost/archive/iterators/transform_width.hpp>
std::string decode64(std::string const& val)
{
using namespace boost::archive::iterators;
return {
transform_width<binary_from_base64<std::string::const_iterator>, 8, 6>{
std::begin(val)},
{std::end(val)},
};
}
std::string encode64(std::string const& val)
{
using namespace boost::archive::iterators;
std::string r{
base64_from_binary<transform_width<std::string::const_iterator, 6, 8>>{
std::begin(val)},
{std::end(val)},
};
return r.append((3 - val.size() % 3) % 3, '=');
}
static std::string compress(const std::string& data)
{
namespace bio = boost::iostreams;
std::istringstream origin(data);
bio::filtering_istreambuf in;
in.push(
bio::gzip_compressor(bio::gzip_params(bio::gzip::best_compression)));
in.push(origin);
std::ostringstream compressed;
bio::copy(in, compressed);
return compressed.str();
}
static std::string decompress(const std::string& data)
{
namespace bio = boost::iostreams;
std::istringstream compressed(data);
bio::filtering_istreambuf in;
in.push(bio::gzip_decompressor());
in.push(compressed);
std::ostringstream origin;
bio::copy(in, origin);
return origin.str();
}
int main() {
auto msg = encode64(compress("test"));
std::cout << msg << std::endl;
std::cout << decompress(decode64(msg)) << std::endl;
}
Prints
H4sIAAAAAAAC/ytJLS4BAAx+f9gEAAAA
test