mfc字符转码

std::wstring UTF8ToUnicode(const std::string& utf8string)

 {
  int widesize = ::MultiByteToWideChar(CP_UTF8, , utf8string.c_str(), -, NULL, );
  if (widesize == ERROR_NO_UNICODE_TRANSLATION)
  {
   throw std::exception("Invalid UTF-8 sequence.");
  }
  if (widesize == )
  {
   throw std::exception("Error in conversion.");
  }
  std::vector<wchar_t> resultstring(widesize);
  int convresult = ::MultiByteToWideChar(CP_UTF8, , utf8string.c_str(), -, &resultstring[], widesize);
  if (convresult != widesize)
  {
   throw std::exception("La falla!");
  }
  return std::wstring(&resultstring[]);
 }

std::string WideByteToAcsi(std::wstring& wstrcode)

 {
  int asciisize = ::WideCharToMultiByte(CP_OEMCP, , wstrcode.c_str(), -, NULL, , NULL, NULL);
  if (asciisize == ERROR_NO_UNICODE_TRANSLATION)
  {
   throw std::exception("Invalid UTF-8 sequence.");
  }
  if (asciisize == )
  {
   throw std::exception("Error in conversion.");
  }
  std::vector<char> resultstring(asciisize);
  int convresult = ::WideCharToMultiByte(CP_OEMCP, , wstrcode.c_str(), -, &resultstring[], asciisize, NULL, NULL);
  if (convresult != asciisize)
  {
   throw std::exception("La falla!");
  }
  return std::string(&resultstring[]);
 }

std::string UTF8ToASCII(std::string& strUtf8Code)

{
 std::string strRet("");
 //先把 utf8 转为 unicode  
 std::wstring wstr = UTF8ToUnicode(strUtf8Code);
 //最后把 unicode 转为 ascii  
 strRet = WideByteToAcsi(wstr);
 return strRet;
}

std::string ASCIIToUTF8(std::string& strASCIICode)

 {
  std::string strOutUTF8 = "";
  WCHAR * str1;
  int n = MultiByteToWideChar(CP_ACP, , strASCIICode.c_str(), -, NULL, );
  str1 = new WCHAR[n];
  MultiByteToWideChar(CP_ACP, , strASCIICode.c_str(), -, str1, n);
  n = WideCharToMultiByte(CP_UTF8, , str1, -, NULL, , NULL, NULL);
  char * str2 = new char[n];
  WideCharToMultiByte(CP_UTF8, , str1, -, str2, n, NULL, NULL);
  strOutUTF8 = str2;
  delete[]str1;
  str1 = NULL;
  delete[]str2;
  str2 = NULL;
  return strOutUTF8;
 }

//!!为了减少字符串的拷贝，改为使用shared_array，性能升级

#include <boost/shared_array.hpp>

#define CHAR_EMPTY_ARR_PTR boost::shared_array<char>(new char[1]{'\0'})
#define WCHAR_EMPTY_ARR_PTR boost::shared_array<wchar_t>(new wchar_t[1]{L'\0'})

boost::shared_array<char> UTF8ToASCII(std::string& strUtf8Code)

 {
  return std::move(UTF8ToASCII(strUtf8Code.c_str()));
 }

boost::shared_array<char> UTF8ToASCII(const char* ch, int nLen /*= -1*/)

 {
  //先把 utf8 转为 unicode  
  auto wstr = UTF8ToUnicode(ch, nLen);
  //最后把 unicode 转为 ascii  
  return std::move(WideByteToAcsi(wstr.get()));
 }

boost::shared_array<char> ASCIIToUTF8(std::string& strASCIICode)

 {
  return std::move(ASCIIToUTF8(strASCIICode.c_str()));
 }

boost::shared_array<char> ASCIIToUTF8(const char* ch, int nLen/* = -1*/)

 {
  int n = MultiByteToWideChar(CP_ACP, , ch, nLen, NULL, );
  if ( == n)
  {
   return CHAR_EMPTY_ARR_PTR;
  }
  boost::shared_array<wchar_t> ptrWtArr(new wchar_t[n]{ L'\0' });
  if ( == MultiByteToWideChar(CP_ACP, , ch, nLen, ptrWtArr.get(), n))
  {
   return CHAR_EMPTY_ARR_PTR;
  }
  n = WideCharToMultiByte(CP_UTF8, , ptrWtArr.get(), -, NULL, , NULL, NULL);
  if ( == n)
  {
   return CHAR_EMPTY_ARR_PTR;
  }
  boost::shared_array<char> ptrArr(new char[n]{ '\0' });
  if ( == WideCharToMultiByte(CP_UTF8, , ptrWtArr.get(), -, ptrArr.get(), n, NULL, NULL))
  {
   return CHAR_EMPTY_ARR_PTR;
  }
  return std::move(ptrArr);
 }

boost::shared_array<wchar_t> UTF8ToUnicode(const char* ch, int nLen /*= -1*/)

 {
  int widesize = ::MultiByteToWideChar(CP_UTF8, , ch, nLen, NULL, );
  if ( == widesize)
  {
   return WCHAR_EMPTY_ARR_PTR;
  }
  boost::shared_array<wchar_t> ptrWtArr(new wchar_t[widesize]{ L'\0' });
  int convresult = ::MultiByteToWideChar(CP_UTF8, , ch, nLen, ptrWtArr.get(), widesize);
  if ( == convresult)
  {
   return WCHAR_EMPTY_ARR_PTR;
  }
  return std::move(ptrWtArr);
 }
 boost::shared_array<char> DPC::WideByteToAcsi(std::wstring& wstrcode)
 {
  return std::move(WideByteToAcsi(wstrcode.c_str()));
 }

boost::shared_array<char> WideByteToAcsi(const wchar_t* wch, int nLen /*= -1*/)

 {
  int asciisize = ::WideCharToMultiByte(CP_OEMCP, , wch, nLen, NULL, , NULL, NULL);
  if ( == asciisize)
  {
   return CHAR_EMPTY_ARR_PTR;
  }
  boost::shared_array<char> ptrArr(new char[asciisize + ]{'\0'});
  int convresult = ::WideCharToMultiByte(CP_OEMCP, , wch, nLen, ptrArr.get(), asciisize, NULL, NULL);
  if ( == convresult)
  {
   return CHAR_EMPTY_ARR_PTR;
  }
  return std::move(ptrArr);
 }