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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_TRY_LEXICAL_CONVERT_HPP
- #define BOOST_LEXICAL_CAST_TRY_LEXICAL_CONVERT_HPP
- #include <boost/config.hpp>
- #ifdef BOOST_HAS_PRAGMA_ONCE
- # pragma once
- #endif
- #if defined(__clang__) || (defined(__GNUC__) && \
- !(defined(__INTEL_COMPILER) || defined(__ICL) || defined(__ICC) || defined(__ECC)) && \
- (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))
- #pragma GCC diagnostic push
- #pragma GCC diagnostic ignored "-Wuninitialized"
- #pragma GCC diagnostic ignored "-Wsign-conversion"
- #endif
- #include <string>
- #include <boost/type_traits/is_integral.hpp>
- #include <boost/type_traits/type_identity.hpp>
- #include <boost/type_traits/conditional.hpp>
- #include <boost/type_traits/is_same.hpp>
- #include <boost/type_traits/is_arithmetic.hpp>
- #include <boost/lexical_cast/detail/is_character.hpp>
- #include <boost/lexical_cast/detail/converter_numeric.hpp>
- #include <boost/lexical_cast/detail/converter_lexical.hpp>
- #include <boost/range/iterator_range_core.hpp>
- #include <boost/container/container_fwd.hpp>
- namespace boost {
- namespace detail
- {
- template<typename T>
- struct is_stdstring
- : boost::false_type
- {};
- template<typename CharT, typename Traits, typename Alloc>
- struct is_stdstring< std::basic_string<CharT, Traits, Alloc> >
- : boost::true_type
- {};
- // Sun Studio has problem with partial specialization of templates differing only in namespace.
- // We workaround that by making `is_booststring` trait, instead of specializing `is_stdstring` for `boost::container::basic_string`.
- template<typename T>
- struct is_booststring
- : boost::false_type
- {};
- template<typename CharT, typename Traits, typename Alloc>
- struct is_booststring< boost::container::basic_string<CharT, Traits, Alloc> >
- : boost::true_type
- {};
- template<typename Target, typename Source>
- struct is_arithmetic_and_not_xchars
- {
- typedef boost::integral_constant<
- bool,
- !(boost::detail::is_character<Target>::value) &&
- !(boost::detail::is_character<Source>::value) &&
- boost::is_arithmetic<Source>::value &&
- boost::is_arithmetic<Target>::value
- > type;
- BOOST_STATIC_CONSTANT(bool, value = (
- type::value
- ));
- };
- /*
- * is_xchar_to_xchar<Target, Source>::value is true,
- * Target and Souce are char types of the same size 1 (char, signed char, unsigned char).
- */
- template<typename Target, typename Source>
- struct is_xchar_to_xchar
- {
- typedef boost::integral_constant<
- bool,
- sizeof(Source) == sizeof(Target) &&
- sizeof(Source) == sizeof(char) &&
- boost::detail::is_character<Target>::value &&
- boost::detail::is_character<Source>::value
- > type;
- BOOST_STATIC_CONSTANT(bool, value = (
- type::value
- ));
- };
- template<typename Target, typename Source>
- struct is_char_array_to_stdstring
- : boost::false_type
- {};
- template<typename CharT, typename Traits, typename Alloc>
- struct is_char_array_to_stdstring< std::basic_string<CharT, Traits, Alloc>, CharT* >
- : boost::true_type
- {};
- template<typename CharT, typename Traits, typename Alloc>
- struct is_char_array_to_stdstring< std::basic_string<CharT, Traits, Alloc>, const CharT* >
- : boost::true_type
- {};
- // Sun Studio has problem with partial specialization of templates differing only in namespace.
- // We workaround that by making `is_char_array_to_booststring` trait, instead of specializing `is_char_array_to_stdstring` for `boost::container::basic_string`.
- template<typename Target, typename Source>
- struct is_char_array_to_booststring
- : boost::false_type
- {};
- template<typename CharT, typename Traits, typename Alloc>
- struct is_char_array_to_booststring< boost::container::basic_string<CharT, Traits, Alloc>, CharT* >
- : boost::true_type
- {};
- template<typename CharT, typename Traits, typename Alloc>
- struct is_char_array_to_booststring< boost::container::basic_string<CharT, Traits, Alloc>, const CharT* >
- : boost::true_type
- {};
- template <typename Target, typename Source>
- struct copy_converter_impl
- {
- // MSVC fail to forward an array (DevDiv#555157 "SILENT BAD CODEGEN triggered by perfect forwarding",
- // fixed in 2013 RTM).
- #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && (!defined(BOOST_MSVC) || BOOST_MSVC >= 1800)
- template <class T>
- static inline bool try_convert(T&& arg, Target& result) {
- result = static_cast<T&&>(arg); // eqaul to `result = std::forward<T>(arg);`
- return true;
- }
- #else
- static inline bool try_convert(const Source& arg, Target& result) {
- result = arg;
- return true;
- }
- #endif
- };
- }
- namespace conversion { namespace detail {
- template <typename Target, typename Source>
- inline bool try_lexical_convert(const Source& arg, Target& result)
- {
- typedef BOOST_DEDUCED_TYPENAME boost::detail::array_to_pointer_decay<Source>::type src;
- typedef boost::integral_constant<
- bool,
- boost::detail::is_xchar_to_xchar<Target, src >::value ||
- boost::detail::is_char_array_to_stdstring<Target, src >::value ||
- boost::detail::is_char_array_to_booststring<Target, src >::value ||
- (
- boost::is_same<Target, src >::value &&
- (boost::detail::is_stdstring<Target >::value || boost::detail::is_booststring<Target >::value)
- ) ||
- (
- boost::is_same<Target, src >::value &&
- boost::detail::is_character<Target >::value
- )
- > shall_we_copy_t;
- typedef boost::detail::is_arithmetic_and_not_xchars<Target, src >
- shall_we_copy_with_dynamic_check_t;
- // We do evaluate second `if_` lazily to avoid unnecessary instantiations
- // of `shall_we_copy_with_dynamic_check_t` and improve compilation times.
- typedef BOOST_DEDUCED_TYPENAME boost::conditional<
- shall_we_copy_t::value,
- boost::type_identity<boost::detail::copy_converter_impl<Target, src > >,
- boost::conditional<
- shall_we_copy_with_dynamic_check_t::value,
- boost::detail::dynamic_num_converter_impl<Target, src >,
- boost::detail::lexical_converter_impl<Target, src >
- >
- >::type caster_type_lazy;
- typedef BOOST_DEDUCED_TYPENAME caster_type_lazy::type caster_type;
- return caster_type::try_convert(arg, result);
- }
- template <typename Target, typename CharacterT>
- inline bool try_lexical_convert(const CharacterT* chars, std::size_t count, Target& result)
- {
- BOOST_STATIC_ASSERT_MSG(
- boost::detail::is_character<CharacterT>::value,
- "This overload of try_lexical_convert is meant to be used only with arrays of characters."
- );
- return ::boost::conversion::detail::try_lexical_convert(
- ::boost::iterator_range<const CharacterT*>(chars, chars + count), result
- );
- }
- }} // namespace conversion::detail
- namespace conversion {
- // ADL barrier
- using ::boost::conversion::detail::try_lexical_convert;
- }
- } // namespace boost
- #if defined(__clang__) || (defined(__GNUC__) && \
- !(defined(__INTEL_COMPILER) || defined(__ICL) || defined(__ICC) || defined(__ECC)) && \
- (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))
- #pragma GCC diagnostic pop
- #endif
- #endif // BOOST_LEXICAL_CAST_TRY_LEXICAL_CONVERT_HPP
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