williamr@2: #ifndef BOOST_LEXICAL_CAST_INCLUDED
williamr@2: #define BOOST_LEXICAL_CAST_INCLUDED
williamr@2: 
williamr@2: // Boost lexical_cast.hpp header  -------------------------------------------//
williamr@2: //
williamr@2: // See http://www.boost.org for most recent version including documentation.
williamr@2: // See end of this header for rights and permissions.
williamr@2: //
williamr@2: // what:  lexical_cast custom keyword cast
williamr@2: // who:   contributed by Kevlin Henney,
williamr@2: //        enhanced with contributions from Terje Slettebų,
williamr@2: //        with additional fixes and suggestions from Gennaro Prota,
williamr@2: //        Beman Dawes, Dave Abrahams, Daryle Walker, Peter Dimov,
williamr@2: //        and other Boosters
williamr@2: // when:  November 2000, March 2003, June 2005
williamr@2: 
williamr@2: #include <cstddef>
williamr@2: #include <string>
williamr@2: #include <typeinfo>
williamr@2: #include <boost/config.hpp>
williamr@2: #include <boost/limits.hpp>
williamr@2: #include <boost/throw_exception.hpp>
williamr@2: #include <boost/type_traits/is_pointer.hpp>
williamr@2: 
williamr@2: #ifdef BOOST_NO_STRINGSTREAM
williamr@2: #include <strstream>
williamr@2: #else
williamr@2: #include <sstream>
williamr@2: #endif
williamr@2: 
williamr@2: #if defined(BOOST_NO_STRINGSTREAM) || \
williamr@2:     defined(BOOST_NO_STD_WSTRING) || \
williamr@2:     defined(BOOST_NO_STD_LOCALE) 
williamr@2: #define DISABLE_WIDE_CHAR_SUPPORT
williamr@2: #endif
williamr@2: 
williamr@2: namespace boost
williamr@2: {
williamr@2:     // exception used to indicate runtime lexical_cast failure
williamr@2:     class bad_lexical_cast : public std::bad_cast
williamr@2:     {
williamr@2:     public:
williamr@2:         bad_lexical_cast() :
williamr@2:         source(&typeid(void)), target(&typeid(void))
williamr@2:         {
williamr@2:         }
williamr@2:         bad_lexical_cast(
williamr@2:             const std::type_info &source_type,
williamr@2:             const std::type_info &target_type) :
williamr@2:             source(&source_type), target(&target_type)
williamr@2:         {
williamr@2:         }
williamr@2:         const std::type_info &source_type() const
williamr@2:         {
williamr@2:             return *source;
williamr@2:         }
williamr@2:         const std::type_info &target_type() const
williamr@2:         {
williamr@2:             return *target;
williamr@2:         }
williamr@2:         virtual const char *what() const throw()
williamr@2:         {
williamr@2:             return "bad lexical cast: "
williamr@2:                    "source type value could not be interpreted as target";
williamr@2:         }
williamr@2:         virtual ~bad_lexical_cast() throw()
williamr@2:         {
williamr@2:         }
williamr@2:     private:
williamr@2:         const std::type_info *source;
williamr@2:         const std::type_info *target;
williamr@2:     };
williamr@2: 
williamr@2:     namespace detail // selectors for choosing stream character type
williamr@2:     {
williamr@2:         template<typename Type>
williamr@2:         struct stream_char
williamr@2:         {
williamr@2:             typedef char type;
williamr@2:         };
williamr@2: 
williamr@2:         #ifndef DISABLE_WIDE_CHAR_SUPPORT
williamr@2: #if !defined(BOOST_NO_INTRINSIC_WCHAR_T)
williamr@2:         template<>
williamr@2:         struct stream_char<wchar_t>
williamr@2:         {
williamr@2:             typedef wchar_t type;
williamr@2:         };
williamr@2: #endif
williamr@2: 
williamr@2:         template<>
williamr@2:         struct stream_char<wchar_t *>
williamr@2:         {
williamr@2:             typedef wchar_t type;
williamr@2:         };
williamr@2: 
williamr@2:         template<>
williamr@2:         struct stream_char<const wchar_t *>
williamr@2:         {
williamr@2:             typedef wchar_t type;
williamr@2:         };
williamr@2: 
williamr@2:         template<>
williamr@2:         struct stream_char<std::wstring>
williamr@2:         {
williamr@2:             typedef wchar_t type;
williamr@2:         };
williamr@2:         #endif
williamr@2: 
williamr@2:         template<typename TargetChar, typename SourceChar>
williamr@2:         struct widest_char
williamr@2:         {
williamr@2:             typedef TargetChar type;
williamr@2:         };
williamr@2: 
williamr@2:         template<>
williamr@2:         struct widest_char<char, wchar_t>
williamr@2:         {
williamr@2:             typedef wchar_t type;
williamr@2:         };
williamr@2:     }
williamr@2:     
williamr@2:     namespace detail // stream wrapper for handling lexical conversions
williamr@2:     {
williamr@2:         template<typename Target, typename Source>
williamr@2:         class lexical_stream
williamr@2:         {
williamr@2:         private:
williamr@2:             typedef typename widest_char<
williamr@2:                 typename stream_char<Target>::type,
williamr@2:                 typename stream_char<Source>::type>::type char_type;
williamr@2: 
williamr@2:         public:
williamr@2:             lexical_stream()
williamr@2:             {
williamr@2:                 stream.unsetf(std::ios::skipws);
williamr@2: 
williamr@2:                 if(std::numeric_limits<Target>::is_specialized)
williamr@2:                     stream.precision(std::numeric_limits<Target>::digits10 + 1);
williamr@2:                 else if(std::numeric_limits<Source>::is_specialized)
williamr@2:                     stream.precision(std::numeric_limits<Source>::digits10 + 1);
williamr@2:             }
williamr@2:             ~lexical_stream()
williamr@2:             {
williamr@2:                 #if defined(BOOST_NO_STRINGSTREAM)
williamr@2:                 stream.freeze(false);
williamr@2:                 #endif
williamr@2:             }
williamr@2:             bool operator<<(const Source &input)
williamr@2:             {
williamr@2:                 return !(stream << input).fail();
williamr@2:             }
williamr@2:             template<typename InputStreamable>
williamr@2:             bool operator>>(InputStreamable &output)
williamr@2:             {
williamr@2:                 return !is_pointer<InputStreamable>::value &&
williamr@2:                        stream >> output &&
williamr@2:                        stream.get() ==
williamr@2: #if defined(__GNUC__) && (__GNUC__<3) && defined(BOOST_NO_STD_WSTRING)
williamr@2: // GCC 2.9x lacks std::char_traits<>::eof().
williamr@2: // We use BOOST_NO_STD_WSTRING to filter out STLport and libstdc++-v3
williamr@2: // configurations, which do provide std::char_traits<>::eof().
williamr@2:     
williamr@2:                            EOF;
williamr@2: #else
williamr@2:                            std::char_traits<char_type>::eof();
williamr@2: #endif
williamr@2:             }
williamr@2:             bool operator>>(std::string &output)
williamr@2:             {
williamr@2:                 #if defined(BOOST_NO_STRINGSTREAM)
williamr@2:                 stream << '\0';
williamr@2:                 #endif
williamr@2:                 output = stream.str();
williamr@2:                 return true;
williamr@2:             }
williamr@2:             #ifndef DISABLE_WIDE_CHAR_SUPPORT
williamr@2:             bool operator>>(std::wstring &output)
williamr@2:             {
williamr@2:                 output = stream.str();
williamr@2:                 return true;
williamr@2:             }
williamr@2:             #endif
williamr@2:         private:
williamr@2:             #if defined(BOOST_NO_STRINGSTREAM)
williamr@2:             std::strstream stream;
williamr@2:             #elif defined(BOOST_NO_STD_LOCALE)
williamr@2:             std::stringstream stream;
williamr@2:             #else
williamr@2:             std::basic_stringstream<char_type> stream;
williamr@2:             #endif
williamr@2:         };
williamr@2:     }
williamr@2: 
williamr@2:     #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2: 
williamr@2:     // call-by-const reference version
williamr@2: 
williamr@2:     namespace detail
williamr@2:     {
williamr@2:         template<class T>
williamr@2:         struct array_to_pointer_decay
williamr@2:         {
williamr@2:             typedef T type;
williamr@2:         };
williamr@2: 
williamr@2:         template<class T, std::size_t N>
williamr@2:         struct array_to_pointer_decay<T[N]>
williamr@2:         {
williamr@2:             typedef const T * type;
williamr@2:         };
williamr@2:     }
williamr@2: 
williamr@2:     template<typename Target, typename Source>
williamr@2:     Target lexical_cast(const Source &arg)
williamr@2:     {
williamr@2:         typedef typename detail::array_to_pointer_decay<Source>::type NewSource;
williamr@2: 
williamr@2:         detail::lexical_stream<Target, NewSource> interpreter;
williamr@2:         Target result;
williamr@2: 
williamr@2:         if(!(interpreter << arg && interpreter >> result))
williamr@2:             throw_exception(bad_lexical_cast(typeid(NewSource), typeid(Target)));
williamr@2:         return result;
williamr@2:     }
williamr@2: 
williamr@2:     #else
williamr@2: 
williamr@2:     // call-by-value fallback version (deprecated)
williamr@2: 
williamr@2:     template<typename Target, typename Source>
williamr@2:     Target lexical_cast(Source arg)
williamr@2:     {
williamr@2:         detail::lexical_stream<Target, Source> interpreter;
williamr@2:         Target result;
williamr@2: 
williamr@2:         if(!(interpreter << arg && interpreter >> result))
williamr@2:             throw_exception(bad_lexical_cast(typeid(Source), typeid(Target)));
williamr@2:         return result;
williamr@2:     }
williamr@2: 
williamr@2:     #endif
williamr@2: }
williamr@2: 
williamr@2: // Copyright Kevlin Henney, 2000-2005. All rights reserved.
williamr@2: //
williamr@2: // Distributed under the Boost Software License, Version 1.0. (See
williamr@2: // accompanying file LICENSE_1_0.txt or copy at
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: 
williamr@2: #undef DISABLE_WIDE_CHAR_SUPPORT
williamr@2: #endif