Chris@16: // ----------------------------------------------------------------------------
Chris@16: // Copyright (C) 2009 Sebastian Redl
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. 
Chris@16: // (See accompanying file LICENSE_1_0.txt or copy at 
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // For more information, see www.boost.org
Chris@16: // ----------------------------------------------------------------------------
Chris@16: 
Chris@16: #ifndef BOOST_PROPERTY_TREE_STREAM_TRANSLATOR_HPP_INCLUDED
Chris@16: #define BOOST_PROPERTY_TREE_STREAM_TRANSLATOR_HPP_INCLUDED
Chris@16: 
Chris@16: #include <boost/property_tree/ptree_fwd.hpp>
Chris@16: 
Chris@16: #include <boost/optional.hpp>
Chris@16: #include <boost/optional/optional_io.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: #include <boost/type_traits/decay.hpp>
Chris@16: #include <boost/type_traits/integral_constant.hpp>
Chris@16: #include <sstream>
Chris@16: #include <string>
Chris@16: #include <locale>
Chris@16: #include <limits>
Chris@16: 
Chris@16: namespace boost { namespace property_tree
Chris@16: {
Chris@16: 
Chris@16:     template <typename Ch, typename Traits, typename E, typename Enabler = void>
Chris@16:     struct customize_stream
Chris@16:     {
Chris@16:         static void insert(std::basic_ostream<Ch, Traits>& s, const E& e) {
Chris@16:             s << e;
Chris@16:         }
Chris@16:         static void extract(std::basic_istream<Ch, Traits>& s, E& e) {
Chris@16:             s >> e;
Chris@16:             if(!s.eof()) {
Chris@16:                 s >> std::ws;
Chris@16:             }
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     // No whitespace skipping for single characters.
Chris@16:     template <typename Ch, typename Traits>
Chris@16:     struct customize_stream<Ch, Traits, Ch, void>
Chris@16:     {
Chris@16:         static void insert(std::basic_ostream<Ch, Traits>& s, Ch e) {
Chris@16:             s << e;
Chris@16:         }
Chris@16:         static void extract(std::basic_istream<Ch, Traits>& s, Ch& e) {
Chris@16:             s.unsetf(std::ios_base::skipws);
Chris@16:             s >> e;
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     // Ugly workaround for numeric_traits that don't have members when not
Chris@16:     // specialized, e.g. MSVC.
Chris@16:     namespace detail
Chris@16:     {
Chris@16:         template <bool is_specialized>
Chris@16:         struct is_inexact_impl
Chris@16:         {
Chris@16:             template <typename T>
Chris@16:             struct test
Chris@16:             {
Chris@16:                 typedef boost::false_type type;
Chris@16:             };
Chris@16:         };
Chris@16:         template <>
Chris@16:         struct is_inexact_impl<true>
Chris@16:         {
Chris@16:             template <typename T>
Chris@16:             struct test
Chris@16:             {
Chris@16:               typedef boost::integral_constant<bool,
Chris@16:                   !std::numeric_limits<T>::is_exact> type;
Chris@16:             };
Chris@16:         };
Chris@16: 
Chris@16:         template <typename F>
Chris@16:         struct is_inexact
Chris@16:         {
Chris@16:             typedef typename boost::decay<F>::type decayed;
Chris@16:             typedef typename is_inexact_impl<
Chris@16:                 std::numeric_limits<decayed>::is_specialized
Chris@16:             >::BOOST_NESTED_TEMPLATE test<decayed>::type type;
Chris@16:             static const bool value = type::value;
Chris@16:         };
Chris@16:     }
Chris@16: 
Chris@16:     template <typename Ch, typename Traits, typename F>
Chris@16:     struct customize_stream<Ch, Traits, F,
Chris@16:         typename boost::enable_if< detail::is_inexact<F> >::type
Chris@16:     >
Chris@16:     {
Chris@16:         static void insert(std::basic_ostream<Ch, Traits>& s, const F& e) {
Chris@101: #ifndef BOOST_NO_CXX11_NUMERIC_LIMITS 
Chris@101:             s.precision(std::numeric_limits<F>::max_digits10); 
Chris@101: #else 
Chris@101:             s.precision(std::numeric_limits<F>::digits10 + 2); 
Chris@101: #endif 
Chris@16:             s << e;
Chris@16:         }
Chris@16:         static void extract(std::basic_istream<Ch, Traits>& s, F& e) {
Chris@16:             s >> e;
Chris@16:             if(!s.eof()) {
Chris@16:                 s >> std::ws;
Chris@16:             }
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Ch, typename Traits>
Chris@16:     struct customize_stream<Ch, Traits, bool, void>
Chris@16:     {
Chris@16:         static void insert(std::basic_ostream<Ch, Traits>& s, bool e) {
Chris@16:             s.setf(std::ios_base::boolalpha);
Chris@16:             s << e;
Chris@16:         }
Chris@16:         static void extract(std::basic_istream<Ch, Traits>& s, bool& e) {
Chris@16:             s >> e;
Chris@16:             if(s.fail()) {
Chris@16:                 // Try again in word form.
Chris@16:                 s.clear();
Chris@16:                 s.setf(std::ios_base::boolalpha);
Chris@16:                 s >> e;
Chris@16:             }
Chris@16:             if(!s.eof()) {
Chris@16:                 s >> std::ws;
Chris@16:             }
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Ch, typename Traits>
Chris@16:     struct customize_stream<Ch, Traits, signed char, void>
Chris@16:     {
Chris@16:         static void insert(std::basic_ostream<Ch, Traits>& s, signed char e) {
Chris@16:             s << (int)e;
Chris@16:         }
Chris@16:         static void extract(std::basic_istream<Ch, Traits>& s, signed char& e) {
Chris@16:             int i;
Chris@16:             s >> i;
Chris@16:             // out of range?
Chris@16:             if(i > (std::numeric_limits<signed char>::max)() ||
Chris@16:                 i < (std::numeric_limits<signed char>::min)())
Chris@16:             {
Chris@16:                 s.clear(); // guarantees eof to be unset
Chris@101:                 e = 0;
Chris@101:                 s.setstate(std::ios_base::badbit);
Chris@16:                 return;
Chris@16:             }
Chris@16:             e = (signed char)i;
Chris@16:             if(!s.eof()) {
Chris@16:                 s >> std::ws;
Chris@16:             }
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Ch, typename Traits>
Chris@16:     struct customize_stream<Ch, Traits, unsigned char, void>
Chris@16:     {
Chris@16:         static void insert(std::basic_ostream<Ch, Traits>& s, unsigned char e) {
Chris@16:             s << (unsigned)e;
Chris@16:         }
Chris@16:         static void extract(std::basic_istream<Ch,Traits>& s, unsigned char& e){
Chris@16:             unsigned i;
Chris@16:             s >> i;
Chris@16:             // out of range?
Chris@16:             if(i > (std::numeric_limits<unsigned char>::max)()) {
Chris@16:                 s.clear(); // guarantees eof to be unset
Chris@101:                 e = 0;
Chris@101:                 s.setstate(std::ios_base::badbit);
Chris@16:                 return;
Chris@16:             }
Chris@16:             e = (unsigned char)i;
Chris@16:             if(!s.eof()) {
Chris@16:                 s >> std::ws;
Chris@16:             }
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     /// Implementation of Translator that uses the stream overloads.
Chris@16:     template <typename Ch, typename Traits, typename Alloc, typename E>
Chris@16:     class stream_translator
Chris@16:     {
Chris@16:         typedef customize_stream<Ch, Traits, E> customized;
Chris@16:     public:
Chris@16:         typedef std::basic_string<Ch, Traits, Alloc> internal_type;
Chris@16:         typedef E external_type;
Chris@16: 
Chris@16:         explicit stream_translator(std::locale loc = std::locale())
Chris@16:             : m_loc(loc)
Chris@16:         {}
Chris@16: 
Chris@16:         boost::optional<E> get_value(const internal_type &v) {
Chris@16:             std::basic_istringstream<Ch, Traits, Alloc> iss(v);
Chris@16:             iss.imbue(m_loc);
Chris@16:             E e;
Chris@16:             customized::extract(iss, e);
Chris@16:             if(iss.fail() || iss.bad() || iss.get() != Traits::eof()) {
Chris@16:                 return boost::optional<E>();
Chris@16:             }
Chris@16:             return e;
Chris@16:         }
Chris@16:         boost::optional<internal_type> put_value(const E &v) {
Chris@16:             std::basic_ostringstream<Ch, Traits, Alloc> oss;
Chris@16:             oss.imbue(m_loc);
Chris@16:             customized::insert(oss, v);
Chris@16:             if(oss) {
Chris@16:                 return oss.str();
Chris@16:             }
Chris@16:             return boost::optional<internal_type>();
Chris@16:         }
Chris@16: 
Chris@16:     private:
Chris@16:         std::locale m_loc;
Chris@16:     };
Chris@16: 
Chris@16:     // This is the default translator when basic_string is the internal type.
Chris@16:     // Unless the external type is also basic_string, in which case
Chris@16:     // id_translator takes over.
Chris@16:     template <typename Ch, typename Traits, typename Alloc, typename E>
Chris@16:     struct translator_between<std::basic_string<Ch, Traits, Alloc>, E>
Chris@16:     {
Chris@16:         typedef stream_translator<Ch, Traits, Alloc, E> type;
Chris@16:     };
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif