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- // Copyright Kevlin Henney, 2000-2005.
- // Copyright Alexander Nasonov, 2006-2010.
- // Copyright Antony Polukhin, 2011-2021.
- //
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- //
- // what: lexical_cast custom keyword cast
- // who: contributed by Kevlin Henney,
- // enhanced with contributions from Terje Slettebo,
- // with additional fixes and suggestions from Gennaro Prota,
- // Beman Dawes, Dave Abrahams, Daryle Walker, Peter Dimov,
- // Alexander Nasonov, Antony Polukhin, Justin Viiret, Michael Hofmann,
- // Cheng Yang, Matthew Bradbury, David W. Birdsall, Pavel Korzh and other Boosters
- // when: November 2000, March 2003, June 2005, June 2006, March 2011 - 2014
- #ifndef BOOST_LEXICAL_CAST_LEXICAL_CAST_OLD_HPP
- #define BOOST_LEXICAL_CAST_LEXICAL_CAST_OLD_HPP
- #include <boost/config.hpp>
- #ifdef BOOST_HAS_PRAGMA_ONCE
- # pragma once
- #endif
- #if defined(BOOST_NO_STRINGSTREAM) || defined(BOOST_NO_STD_WSTRING)
- #define BOOST_LCAST_NO_WCHAR_T
- #endif
- #include <climits>
- #include <cstddef>
- #include <string>
- #include <cstring>
- #include <cstdio>
- #include <boost/limits.hpp>
- #include <boost/type_traits/is_pointer.hpp>
- #include <boost/static_assert.hpp>
- #include <boost/detail/lcast_precision.hpp>
- #include <boost/detail/workaround.hpp>
- #ifdef BOOST_NO_STRINGSTREAM
- #include <strstream>
- #else
- #include <sstream>
- #endif
- #include <boost/lexical_cast/bad_lexical_cast.hpp>
- #include <boost/lexical_cast/detail/widest_char.hpp>
- namespace boost {
- namespace detail
- {
- // selectors for choosing stream character type
- template<typename Type>
- struct stream_char
- {
- typedef char type;
- };
- #ifndef BOOST_LCAST_NO_WCHAR_T
- #ifndef BOOST_NO_INTRINSIC_WCHAR_T
- template<>
- struct stream_char<wchar_t>
- {
- typedef wchar_t type;
- };
- #endif
- template<>
- struct stream_char<wchar_t *>
- {
- typedef wchar_t type;
- };
- template<>
- struct stream_char<const wchar_t *>
- {
- typedef wchar_t type;
- };
- template<>
- struct stream_char<std::wstring>
- {
- typedef wchar_t type;
- };
- #endif
- // stream wrapper for handling lexical conversions
- template<typename Target, typename Source, typename Traits>
- class lexical_stream
- {
- private:
- typedef typename widest_char<
- typename stream_char<Target>::type,
- typename stream_char<Source>::type>::type char_type;
- typedef Traits traits_type;
- public:
- lexical_stream(char_type* = 0, char_type* = 0)
- {
- stream.unsetf(std::ios::skipws);
- lcast_set_precision(stream, static_cast<Source*>(0), static_cast<Target*>(0) );
- }
- ~lexical_stream()
- {
- #if defined(BOOST_NO_STRINGSTREAM)
- stream.freeze(false);
- #endif
- }
- bool operator<<(const Source &input)
- {
- return !(stream << input).fail();
- }
- template<typename InputStreamable>
- bool operator>>(InputStreamable &output)
- {
- return !is_pointer<InputStreamable>::value &&
- stream >> output &&
- stream.get() == traits_type::eof();
- }
- bool operator>>(std::string &output)
- {
- #if defined(BOOST_NO_STRINGSTREAM)
- stream << '\0';
- #endif
- stream.str().swap(output);
- return true;
- }
- #ifndef BOOST_LCAST_NO_WCHAR_T
- bool operator>>(std::wstring &output)
- {
- stream.str().swap(output);
- return true;
- }
- #endif
- private:
- #if defined(BOOST_NO_STRINGSTREAM)
- std::strstream stream;
- #elif defined(BOOST_NO_STD_LOCALE)
- std::stringstream stream;
- #else
- std::basic_stringstream<char_type,traits_type> stream;
- #endif
- };
- }
- // call-by-value fallback version (deprecated)
- template<typename Target, typename Source>
- Target lexical_cast(Source arg)
- {
- typedef typename detail::widest_char<
- BOOST_DEDUCED_TYPENAME detail::stream_char<Target>::type
- , BOOST_DEDUCED_TYPENAME detail::stream_char<Source>::type
- >::type char_type;
- typedef std::char_traits<char_type> traits;
- detail::lexical_stream<Target, Source, traits> interpreter;
- Target result;
- if(!(interpreter << arg && interpreter >> result))
- boost::conversion::detail::throw_bad_cast<Source, Target>();
- return result;
- }
- } // namespace boost
- #undef BOOST_LCAST_NO_WCHAR_T
- #endif // BOOST_LEXICAL_CAST_LEXICAL_CAST_OLD_HPP
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