Linux C++ 乱码字符转换问题 GBK转UTF8

本例来源于CSDN的另一篇博客，但并非是复读机。原博客使用char类型作为输入，需要传递src_len和dst_len，用起来比较难受。本文使用std::string做了封装，不需要传递src_len和dst_len，代价就是在函数中动态分配了2src_len的空间。

#include <iostream>
#include <string>
#include <string.h>
#include <stdlib.h>
#include <iconv.h>
#include <fstream>

using namespace std;

bool encoding_convert(std::string const& src_str, std::string& dst_str, 
  std::string const& src_encoding, std::string const& dst_encoding)
{
  iconv_t cd;
  std::size_t src_len = src_str.size();
  std::size_t dst_len = src_len * 2;
  dst_str.resize(dst_len);
  cd = iconv_open(dst_encoding.c_str(), src_encoding.c_str());
  if (cd == 0)
  	return false;
  char* src_data = (char*)(src_str.data());
  char* dst_data = (char*)(dst_str.data());
  std::size_t left_len {dst_len};
  if (iconv(cd, &src_data, &src_len, &dst_data, &left_len) == -1)
  	return false;
  iconv_close(cd);
  dst_str.resize(dst_len-left_len);
  return true;
}

char const* GBK = "gbk";
char const* UTF8 = "utf8";

#define GBK_2_UTF8(src_str, dst_str) encoding_convert(src_str, dst_str, GBK, UTF8)
#define UTF8_2_GBK(src_str, dst_str) encoding_convert(src_str, dst_str, UTF8, GBK)


int main(int argc, char* argv[]) {
  std::string src = "\xc4\xe3\xba\xc3";
  std::string dst;
  std::fstream ofs("./result.txt", std::ios::out);
  
  GBK_2_UTF8(src, dst);
  std::cout << "Source GBK string：" << src << std::endl;
  std::cout << "Result UTF8 String: " << dst << std::endl;
  ofs << dst << std::endl;
  std::cout << "========================================" << std::endl;
  std::cout << std::endl;
  std::cout << std::endl;
  
  std::string src1 = "你好，小黄鸡，小黄鸭，小黄狗";
  std::string dst1;
  UTF8_2_GBK(src1, dst1);
  std::string res;
  GBK_2_UTF8(dst1, res);

  ofs << res << std::endl;
  ofs.close();

  std::cout << "Source UTF-8 string:" << src1 << std::endl;
  std::cout << "Result GBK string:" << dst1 << std::endl;
  std::cout << "Result UTF-8 string:" << res << std::endl;
  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.6)
project(chat_room)

add_definitions(-std=c++14)


find_package(Boost REQUIRED COMPONENTS
  system
  filesystem
  serialization
  program_options
  thread
  )

include_directories(${Boost_INCLUDE_DIRS})

file( GLOB APP_SOURCES ${CMAKE_CURRENT_SOURCE_DIR}/*.cpp ${CMAKE_CURRENT_SOURCE_DIR}/*.h)
foreach( sourcefile ${APP_SOURCES} )
      file(RELATIVE_PATH filename ${CMAKE_CURRENT_SOURCE_DIR} ${sourcefile})
  if( "${filename}" STREQUAL "main.cpp")
      string(REPLACE ".cpp" "" file ${filename})
      add_executable(${file}  ${APP_SOURCES})
      target_link_libraries(${file} ${Boost_LIBRARIES})
      target_link_libraries(${file} pthread)
  endif()
endforeach( sourcefile ${APP_SOURCES})

程序输出如下，

result.txt文件内容如下，