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1 : // Copyright Kevlin Henney, 2000-2005.
2 : // Copyright Alexander Nasonov, 2006-2010.
3 : // Copyright Antony Polukhin, 2011-2019.
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 0 : static inline bool try_convert(T&& arg, Target& result) {
150 0 : 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 895905 : 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 895905 : 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 :
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