ceph/src/boost/libs/optional/include/boost/optional/optional_io.hpp

   1 // Copyright (C) 2005, Fernando Luis Cacciola Carballal.
   2 //
   3 // Use, modification, and distribution is subject to the Boost Software
   4 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // See http://www.boost.org/libs/optional for documentation.
   8 //
   9 // You are welcome to contact the author at:
  10 //  fernando_cacciola@hotmail.com
  11 //
  12 #ifndef BOOST_OPTIONAL_OPTIONAL_IO_FLC_19NOV2002_HPP
  13 #define BOOST_OPTIONAL_OPTIONAL_IO_FLC_19NOV2002_HPP
  14
  15 #include <istream>
  16 #include <ostream>
  17
  18 #include "boost/none.hpp"
  19 #include "boost/optional/optional.hpp"
  20
  21
  22 namespace boost
  23 {
  24
  25 template<class CharType, class CharTrait>
  26 inline
  27 std::basic_ostream<CharType, CharTrait>&
  28 operator<<(std::basic_ostream<CharType, CharTrait>& out, none_t)
  29 {
  30   if (out.good())
  31   {
  32     out << "--";
  33   }
  34
  35   return out;
  36 }
  37
  38 template<class CharType, class CharTrait, class T>
  39 inline
  40 std::basic_ostream<CharType, CharTrait>&
  41 operator<<(std::basic_ostream<CharType, CharTrait>& out, optional<T> const& v)
  42 {
  43   if (out.good())
  44   {
  45     if (!v)
  46          out << "--" ;
  47     else out << ' ' << *v ;
  48   }
  49
  50   return out;
  51 }
  52
  53 template<class CharType, class CharTrait, class T>
  54 inline
  55 std::basic_istream<CharType, CharTrait>&
  56 operator>>(std::basic_istream<CharType, CharTrait>& in, optional<T>& v)
  57 {
  58   if (in.good())
  59   {
  60     int d = in.get();
  61     if (d == ' ')
  62     {
  63       T x;
  64       in >> x;
  65 #ifndef  BOOST_OPTIONAL_DETAIL_NO_RVALUE_REFERENCES
  66       v = boost::move(x);
  67 #else
  68       v = x;
  69 #endif
  70     }
  71     else
  72     {
  73       if (d == '-')
  74       {
  75         d = in.get();
  76
  77         if (d == '-')
  78         {
  79           v = none;
  80           return in;
  81         }
  82       }
  83
  84       in.setstate( std::ios::failbit );
  85     }
  86   }
  87
  88   return in;
  89 }
  90
  91 } // namespace boost
  92
  93 #endif
  94