Re: [Boost-users] [serialization]Nans and infinity in wide xml archive

Subject: Re: [Boost-users] [serialization]Nans and infinity in wide xml archive
From: Robert Ramey (ramey_at_[hidden])
Date: 2017-07-04 15:04:33

On 7/4/17 2:48 AM, Elizabeta via Boost-users wrote:
> Hi Robert
> I did template specialization of basic_text_iprimitive::load for double, and
> it works with visual studio 2010 compiler. Do you see something problematic
> with this code
> 
> namespace boost {
>      namespace archive {
>          template<> template<>
>          void basic_text_iprimitive< std::basic_istream<wchar_t,
> std::char_traits&lt;wchar_t>> >::load<double>(double& t)
>          {
>              if (!is.fail())
>              {
>                  std::wstring s;
>                  getline(is, s, L'<');
>                  is.putback(L'<');
> 
>                  int index = s.find(L"IND");
>                  if (index != -1)
>                  {
>                      t = std::numeric_limits<double>::quiet_NaN();
>                      return;
>                  }
> 
>                  index = s.find(L"NAN");
>                  if (index != -1)
>                  {
>                      t = std::numeric_limits<double>::quiet_NaN();
>                      return;
>                  }
> 
>                  index = s.find(L"INF");
>                  if (index != -1)
>                  {
>                      t = std::numeric_limits<double>::infinity();
>                      return;
>                  }
> 
>                  t = std::stod(s);
>                  return;
>              }
> 
>              boost::serialization::throw_exception(
>                  archive_exception(archive_exception::input_stream_error)
>                  );
>          }
> }
> }

Hmmm - very clever.  I have to say the specialization of just one member 
function is something that would never have occurred to me.

I would wonder though.  I'm not sure that the Nan literals are standard. 
  I also don't trust them to be portable.  Also to me it's a problem 
with stream i/o rather than serialization itself.  So my instinct would 
have been to maybe make a custom manipulator or something like that. But 
still, you've got a solution which looks like it will work well for your 
needs so good luck with this.

Robert Ramey