std::string message()

in demo_example/asio/asio/impl/error_code.ipp [45:107]

• 63 lines of code
• 20 McCabe index (conditional complexity)

  std::string message(int value) const
  {
#if defined(ASIO_WINDOWS_RUNTIME) || defined(ASIO_WINDOWS_APP)
    std::wstring wmsg(128, wchar_t());
    for (;;)
    {
      DWORD wlength = ::FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM
          | FORMAT_MESSAGE_IGNORE_INSERTS, 0, value,
          MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
          &wmsg[0], static_cast<DWORD>(wmsg.size()), 0);
      if (wlength == 0 && ::GetLastError() == ERROR_INSUFFICIENT_BUFFER)
      {
        wmsg.resize(wmsg.size() + wmsg.size() / 2);
        continue;
      }
      if (wlength && wmsg[wlength - 1] == '\n')
        --wlength;
      if (wlength && wmsg[wlength - 1] == '\r')
        --wlength;
      if (wlength)
      {
        std::string msg(wlength * 2, char());
        int length = ::WideCharToMultiByte(CP_ACP, 0,
            wmsg.c_str(), static_cast<int>(wlength),
            &msg[0], static_cast<int>(wlength * 2), 0, 0);
        if (length <= 0)
          return "asio.system error";
        msg.resize(static_cast<std::size_t>(length));
        return msg;
      }
      else
        return "asio.system error";
    }
#elif defined(ASIO_WINDOWS) || defined(__CYGWIN__)
    char* msg = 0;
    DWORD length = ::FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER
        | FORMAT_MESSAGE_FROM_SYSTEM
        | FORMAT_MESSAGE_IGNORE_INSERTS, 0, value,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (char*)&msg, 0, 0);
    detail::local_free_on_block_exit local_free_obj(msg);
    if (length && msg[length - 1] == '\n')
      msg[--length] = '\0';
    if (length && msg[length - 1] == '\r')
      msg[--length] = '\0';
    if (length)
      return msg;
    else
      return "asio.system error";
#else // defined(ASIO_WINDOWS_DESKTOP) || defined(__CYGWIN__)
#if !defined(__sun)
    if (value == ECANCELED)
      return "Operation aborted.";
#endif // !defined(__sun)
#if defined(__sun) || defined(__QNX__) || defined(__SYMBIAN32__)
    using namespace std;
    return strerror(value);
#else
    char buf[256] = "";
    using namespace std;
    return strerror_result(strerror_r(value, buf, sizeof(buf)), buf);
#endif
#endif // defined(ASIO_WINDOWS_DESKTOP) || defined(__CYGWIN__)
  }