[英]Boost gzip how to output compressed string as text
我在這里使用 boost gzip 示例代碼。 我正在嘗試壓縮一個簡單的字符串測試,並期待壓縮字符串H4sIAAAAAAAACitJLS4BAAx+f9gEAAAA如此在線壓縮器所示
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;
}
但是,當我打印出轉換結果時,我會得到像 +I- 這樣的垃圾值。 ~
我知道這是一個有效的轉換,因為解壓值返回了正確的字符串。 但是我需要字符串的格式是人類可讀的,即H4sIAAAAAAAACitJLS4BAAx+f9gEAAAA 。
如何將代碼修改為 output 人類可讀文本?
謝謝
動機
垃圾格式與我將發送壓縮文本的 JSON 庫不兼容。
示例站點完全沒有提到他們還 base64 編碼結果:
base64 -d <<< 'H4sIAAAAAAAACitJLS4BAAx+f9gEAAAA' | gunzip -
打印:
test
簡而言之,您還需要這樣做:
#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;
}
印刷
H4sIAAAAAAAC/ytJLS4BAAx+f9gEAAAA
test
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