1 // Components for compile-time parsing of numbers -*- C++ -*-
3 // Copyright (C) 2013-2021 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
25 /** @file bits/parse_numbers.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{chrono}
30 #ifndef _GLIBCXX_PARSE_NUMBERS_H
31 #define _GLIBCXX_PARSE_NUMBERS_H 1
33 #pragma GCC system_header
35 // From n3642.pdf except I added binary literals and digit separator '\''.
37 #if __cplusplus >= 201402L
39 #include <ext/numeric_traits.h>
41 namespace std
_GLIBCXX_VISIBILITY(default)
43 _GLIBCXX_BEGIN_NAMESPACE_VERSION
47 template<unsigned _Base
, char _Dig
>
50 template<unsigned _Base
>
51 struct _Digit
<_Base
, '0'> : integral_constant
<unsigned, 0>
53 using __valid
= true_type
;
56 template<unsigned _Base
>
57 struct _Digit
<_Base
, '1'> : integral_constant
<unsigned, 1>
59 using __valid
= true_type
;
62 template<unsigned _Base
, unsigned _Val
>
63 struct _Digit_impl
: integral_constant
<unsigned, _Val
>
65 static_assert(_Base
> _Val
, "invalid digit");
66 using __valid
= true_type
;
69 template<unsigned _Base
>
70 struct _Digit
<_Base
, '2'> : _Digit_impl
<_Base
, 2>
73 template<unsigned _Base
>
74 struct _Digit
<_Base
, '3'> : _Digit_impl
<_Base
, 3>
77 template<unsigned _Base
>
78 struct _Digit
<_Base
, '4'> : _Digit_impl
<_Base
, 4>
81 template<unsigned _Base
>
82 struct _Digit
<_Base
, '5'> : _Digit_impl
<_Base
, 5>
85 template<unsigned _Base
>
86 struct _Digit
<_Base
, '6'> : _Digit_impl
<_Base
, 6>
89 template<unsigned _Base
>
90 struct _Digit
<_Base
, '7'> : _Digit_impl
<_Base
, 7>
93 template<unsigned _Base
>
94 struct _Digit
<_Base
, '8'> : _Digit_impl
<_Base
, 8>
97 template<unsigned _Base
>
98 struct _Digit
<_Base
, '9'> : _Digit_impl
<_Base
, 9>
101 template<unsigned _Base
>
102 struct _Digit
<_Base
, 'a'> : _Digit_impl
<_Base
, 0xa>
105 template<unsigned _Base
>
106 struct _Digit
<_Base
, 'A'> : _Digit_impl
<_Base
, 0xa>
109 template<unsigned _Base
>
110 struct _Digit
<_Base
, 'b'> : _Digit_impl
<_Base
, 0xb>
113 template<unsigned _Base
>
114 struct _Digit
<_Base
, 'B'> : _Digit_impl
<_Base
, 0xb>
117 template<unsigned _Base
>
118 struct _Digit
<_Base
, 'c'> : _Digit_impl
<_Base
, 0xc>
121 template<unsigned _Base
>
122 struct _Digit
<_Base
, 'C'> : _Digit_impl
<_Base
, 0xc>
125 template<unsigned _Base
>
126 struct _Digit
<_Base
, 'd'> : _Digit_impl
<_Base
, 0xd>
129 template<unsigned _Base
>
130 struct _Digit
<_Base
, 'D'> : _Digit_impl
<_Base
, 0xd>
133 template<unsigned _Base
>
134 struct _Digit
<_Base
, 'e'> : _Digit_impl
<_Base
, 0xe>
137 template<unsigned _Base
>
138 struct _Digit
<_Base
, 'E'> : _Digit_impl
<_Base
, 0xe>
141 template<unsigned _Base
>
142 struct _Digit
<_Base
, 'f'> : _Digit_impl
<_Base
, 0xf>
145 template<unsigned _Base
>
146 struct _Digit
<_Base
, 'F'> : _Digit_impl
<_Base
, 0xf>
150 template<unsigned _Base
>
151 struct _Digit
<_Base
, '\''> : integral_constant
<unsigned, 0>
153 using __valid
= false_type
;
156 //------------------------------------------------------------------------------
158 template<unsigned long long _Val
>
159 using __ull_constant
= integral_constant
<unsigned long long, _Val
>;
161 template<unsigned _Base
, char _Dig
, char... _Digs
>
164 using __next
= typename _Power_help
<_Base
, _Digs
...>::type
;
165 using __valid_digit
= typename _Digit
<_Base
, _Dig
>::__valid
;
167 = __ull_constant
<__next::value
* (__valid_digit
{} ? _Base
: 1ULL)>;
170 template<unsigned _Base
, char _Dig
>
171 struct _Power_help
<_Base
, _Dig
>
173 using __valid_digit
= typename _Digit
<_Base
, _Dig
>::__valid
;
174 using type
= __ull_constant
<__valid_digit::value
>;
177 template<unsigned _Base
, char... _Digs
>
178 struct _Power
: _Power_help
<_Base
, _Digs
...>::type
181 template<unsigned _Base
>
182 struct _Power
<_Base
> : __ull_constant
<0>
185 //------------------------------------------------------------------------------
187 template<unsigned _Base
, unsigned long long _Pow
, char _Dig
, char... _Digs
>
190 using __digit
= _Digit
<_Base
, _Dig
>;
191 using __valid_digit
= typename
__digit::__valid
;
192 using __next
= _Number_help
<_Base
,
193 __valid_digit::value
? _Pow
/ _Base
: _Pow
,
195 using type
= __ull_constant
<_Pow
* __digit::value
+ __next::type::value
>;
196 static_assert((type::value
/ _Pow
) == __digit::value
,
197 "integer literal does not fit in unsigned long long");
200 // Skip past digit separators:
201 template<unsigned _Base
, unsigned long long _Pow
, char _Dig
, char..._Digs
>
202 struct _Number_help
<_Base
, _Pow
, '\'', _Dig
, _Digs
...>
203 : _Number_help
<_Base
, _Pow
, _Dig
, _Digs
...>
206 // Terminating case for recursion:
207 template<unsigned _Base
, char _Dig
>
208 struct _Number_help
<_Base
, 1ULL, _Dig
>
210 using type
= __ull_constant
<_Digit
<_Base
, _Dig
>::value
>;
213 template<unsigned _Base
, char... _Digs
>
215 : _Number_help
<_Base
, _Power
<_Base
, _Digs
...>::value
, _Digs
...>::type
218 template<unsigned _Base
>
219 struct _Number
<_Base
>
223 //------------------------------------------------------------------------------
225 template<char... _Digs
>
228 template<char... _Digs
>
229 struct _Parse_int
<'0', 'b', _Digs
...>
230 : _Number
<2U, _Digs
...>::type
233 template<char... _Digs
>
234 struct _Parse_int
<'0', 'B', _Digs
...>
235 : _Number
<2U, _Digs
...>::type
238 template<char... _Digs
>
239 struct _Parse_int
<'0', 'x', _Digs
...>
240 : _Number
<16U, _Digs
...>::type
243 template<char... _Digs
>
244 struct _Parse_int
<'0', 'X', _Digs
...>
245 : _Number
<16U, _Digs
...>::type
248 template<char... _Digs
>
249 struct _Parse_int
<'0', _Digs
...>
250 : _Number
<8U, _Digs
...>::type
253 template<char... _Digs
>
255 : _Number
<10U, _Digs
...>::type
258 } // namespace __parse_int
261 namespace __select_int
263 template<unsigned long long _Val
, typename
... _Ints
>
264 struct _Select_int_base
;
266 template<unsigned long long _Val
, typename _IntType
, typename
... _Ints
>
267 struct _Select_int_base
<_Val
, _IntType
, _Ints
...>
268 : conditional_t
<(_Val
<= __gnu_cxx::__int_traits
<_IntType
>::__max
),
269 integral_constant
<_IntType
, (_IntType
)_Val
>,
270 _Select_int_base
<_Val
, _Ints
...>>
273 template<unsigned long long _Val
>
274 struct _Select_int_base
<_Val
>
277 template<char... _Digs
>
278 using _Select_int
= typename _Select_int_base
<
279 __parse_int::_Parse_int
<_Digs
...>::value
,
287 } // namespace __select_int
289 _GLIBCXX_END_NAMESPACE_VERSION
294 #endif // _GLIBCXX_PARSE_NUMBERS_H