ceph/src/boost/boost/lexical_cast/try_lexical_convert.hpp

   1 // Copyright Kevlin Henney, 2000-2005.
   2 // Copyright Alexander Nasonov, 2006-2010.
   3 // Copyright Antony Polukhin, 2011-2020.
   4 //
   5 // Distributed under the Boost Software License, Version 1.0. (See
   6 // accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8 //
   9 // what:  lexical_cast custom keyword cast
  10 // who:   contributed by Kevlin Henney,
  11 //        enhanced with contributions from Terje Slettebo,
  12 //        with additional fixes and suggestions from Gennaro Prota,
  13 //        Beman Dawes, Dave Abrahams, Daryle Walker, Peter Dimov,
  14 //        Alexander Nasonov, Antony Polukhin, Justin Viiret, Michael Hofmann,
  15 //        Cheng Yang, Matthew Bradbury, David W. Birdsall, Pavel Korzh and other Boosters
  16 // when:  November 2000, March 2003, June 2005, June 2006, March 2011 - 2014
  17
  18 #ifndef BOOST_LEXICAL_CAST_TRY_LEXICAL_CONVERT_HPP
  19 #define BOOST_LEXICAL_CAST_TRY_LEXICAL_CONVERT_HPP
  20
  21 #include <boost/config.hpp>
  22 #ifdef BOOST_HAS_PRAGMA_ONCE
  23 #   pragma once
  24 #endif
  25
  26 #if defined(__clang__) || (defined(__GNUC__) && \
  27     !(defined(__INTEL_COMPILER) || defined(__ICL) || defined(__ICC) || defined(__ECC)) && \
  28     (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))
  29 #pragma GCC diagnostic push
  30 #pragma GCC diagnostic ignored "-Wuninitialized"
  31 #pragma GCC diagnostic ignored "-Wsign-conversion"
  32 #endif
  33
  34
  35 #include <string>
  36 #include <boost/type_traits/is_integral.hpp>
  37 #include <boost/type_traits/type_identity.hpp>
  38 #include <boost/type_traits/conditional.hpp>
  39 #include <boost/type_traits/is_same.hpp>
  40 #include <boost/type_traits/is_arithmetic.hpp>
  41
  42 #include <boost/lexical_cast/detail/is_character.hpp>
  43 #include <boost/lexical_cast/detail/converter_numeric.hpp>
  44 #include <boost/lexical_cast/detail/converter_lexical.hpp>
  45
  46 #include <boost/range/iterator_range_core.hpp>
  47 #include <boost/container/container_fwd.hpp>
  48
  49 namespace boost {
  50     namespace detail
  51     {
  52         template<typename T>
  53         struct is_stdstring
  54             : boost::false_type
  55         {};
  56
  57         template<typename CharT, typename Traits, typename Alloc>
  58         struct is_stdstring< std::basic_string<CharT, Traits, Alloc> >
  59             : boost::true_type
  60         {};
  61
  62         // Sun Studio has problem with partial specialization of templates differing only in namespace.
  63         // We workaround that by making `is_booststring` trait, instead of specializing `is_stdstring` for `boost::container::basic_string`.
  64         template<typename T>
  65         struct is_booststring
  66             : boost::false_type
  67         {};
  68
  69         template<typename CharT, typename Traits, typename Alloc>
  70         struct is_booststring< boost::container::basic_string<CharT, Traits, Alloc> >
  71             : boost::true_type
  72         {};
  73
  74         template<typename Target, typename Source>
  75         struct is_arithmetic_and_not_xchars
  76         {
  77             typedef boost::integral_constant<
  78                 bool,
  79                 !(boost::detail::is_character<Target>::value) &&
  80                     !(boost::detail::is_character<Source>::value) &&
  81                     boost::is_arithmetic<Source>::value &&
  82                     boost::is_arithmetic<Target>::value
  83                 > type;
  84
  85             BOOST_STATIC_CONSTANT(bool, value = (
  86                 type::value
  87             ));
  88         };
  89
  90         /*
  91          * is_xchar_to_xchar<Target, Source>::value is true,
  92          * Target and Souce are char types of the same size 1 (char, signed char, unsigned char).
  93          */
  94         template<typename Target, typename Source>
  95         struct is_xchar_to_xchar
  96         {
  97             typedef boost::integral_constant<
  98                 bool,
  99                 sizeof(Source) == sizeof(Target) &&
 100                      sizeof(Source) == sizeof(char) &&
 101                      boost::detail::is_character<Target>::value &&
 102                      boost::detail::is_character<Source>::value
 103                 > type;
 104
 105             BOOST_STATIC_CONSTANT(bool, value = (
 106                 type::value
 107             ));
 108         };
 109
 110         template<typename Target, typename Source>
 111         struct is_char_array_to_stdstring
 112             : boost::false_type
 113         {};
 114
 115         template<typename CharT, typename Traits, typename Alloc>
 116         struct is_char_array_to_stdstring< std::basic_string<CharT, Traits, Alloc>, CharT* >
 117             : boost::true_type
 118         {};
 119
 120         template<typename CharT, typename Traits, typename Alloc>
 121         struct is_char_array_to_stdstring< std::basic_string<CharT, Traits, Alloc>, const CharT* >
 122             : boost::true_type
 123         {};
 124
 125         // Sun Studio has problem with partial specialization of templates differing only in namespace.
 126         // We workaround that by making `is_char_array_to_booststring` trait, instead of specializing `is_char_array_to_stdstring` for `boost::container::basic_string`.
 127         template<typename Target, typename Source>
 128         struct is_char_array_to_booststring
 129             : boost::false_type
 130         {};
 131
 132         template<typename CharT, typename Traits, typename Alloc>
 133         struct is_char_array_to_booststring< boost::container::basic_string<CharT, Traits, Alloc>, CharT* >
 134             : boost::true_type
 135         {};
 136
 137         template<typename CharT, typename Traits, typename Alloc>
 138         struct is_char_array_to_booststring< boost::container::basic_string<CharT, Traits, Alloc>, const CharT* >
 139             : boost::true_type
 140         {};
 141
 142         template <typename Target, typename Source>
 143         struct copy_converter_impl
 144         {
 145 // MSVC fail to forward an array (DevDiv#555157 "SILENT BAD CODEGEN triggered by perfect forwarding",
 146 // fixed in 2013 RTM).
 147 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && (!defined(BOOST_MSVC) || BOOST_MSVC >= 1800)
 148             template <class T>
 149             static inline bool try_convert(T&& arg, Target& result) {
 150                 result = static_cast<T&&>(arg); // eqaul to `result = std::forward<T>(arg);`
 151                 return true;
 152             }
 153 #else
 154             static inline bool try_convert(const Source& arg, Target& result) {
 155                 result = arg;
 156                 return true;
 157             }
 158 #endif
 159         };
 160     }
 161
 162     namespace conversion { namespace detail {
 163
 164         template <typename Target, typename Source>
 165         inline bool try_lexical_convert(const Source& arg, Target& result)
 166         {
 167             typedef BOOST_DEDUCED_TYPENAME boost::detail::array_to_pointer_decay<Source>::type src;
 168
 169             typedef boost::integral_constant<
 170                 bool,
 171                 boost::detail::is_xchar_to_xchar<Target, src >::value ||
 172                 boost::detail::is_char_array_to_stdstring<Target, src >::value ||
 173                 boost::detail::is_char_array_to_booststring<Target, src >::value ||
 174                 (
 175                      boost::is_same<Target, src >::value &&
 176                      (boost::detail::is_stdstring<Target >::value || boost::detail::is_booststring<Target >::value)
 177                 ) ||
 178                 (
 179                      boost::is_same<Target, src >::value &&
 180                      boost::detail::is_character<Target >::value
 181                 )
 182             > shall_we_copy_t;
 183
 184             typedef boost::detail::is_arithmetic_and_not_xchars<Target, src >
 185                 shall_we_copy_with_dynamic_check_t;
 186
 187             // We do evaluate second `if_` lazily to avoid unnecessary instantiations
 188             // of `shall_we_copy_with_dynamic_check_t` and improve compilation times.
 189             typedef BOOST_DEDUCED_TYPENAME boost::conditional<
 190                 shall_we_copy_t::value,
 191                 boost::type_identity<boost::detail::copy_converter_impl<Target, src > >,
 192                 boost::conditional<
 193                      shall_we_copy_with_dynamic_check_t::value,
 194                      boost::detail::dynamic_num_converter_impl<Target, src >,
 195                      boost::detail::lexical_converter_impl<Target, src >
 196                 >
 197             >::type caster_type_lazy;
 198
 199             typedef BOOST_DEDUCED_TYPENAME caster_type_lazy::type caster_type;
 200
 201             return caster_type::try_convert(arg, result);
 202         }
 203
 204         template <typename Target, typename CharacterT>
 205         inline bool try_lexical_convert(const CharacterT* chars, std::size_t count, Target& result)
 206         {
 207             BOOST_STATIC_ASSERT_MSG(
 208                 boost::detail::is_character<CharacterT>::value,
 209                 "This overload of try_lexical_convert is meant to be used only with arrays of characters."
 210             );
 211             return ::boost::conversion::detail::try_lexical_convert(
 212                 ::boost::iterator_range<const CharacterT*>(chars, chars + count), result
 213             );
 214         }
 215
 216     }} // namespace conversion::detail
 217
 218     namespace conversion {
 219         // ADL barrier
 220         using ::boost::conversion::detail::try_lexical_convert;
 221     }
 222
 223 } // namespace boost
 224
 225 #if defined(__clang__) || (defined(__GNUC__) && \
 226     !(defined(__INTEL_COMPILER) || defined(__ICL) || defined(__ICC) || defined(__ECC)) && \
 227     (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))
 228 #pragma GCC diagnostic pop
 229 #endif
 230
 231 #endif // BOOST_LEXICAL_CAST_TRY_LEXICAL_CONVERT_HPP
 232