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 <type_traits>
40 #include <ext/numeric_traits.h>
42 namespace std
_GLIBCXX_VISIBILITY(default)
44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
48 template<unsigned _Base
, char _Dig
>
51 template<unsigned _Base
>
52 struct _Digit
<_Base
, '0'> : integral_constant
<unsigned, 0>
54 using __valid
= true_type
;
57 template<unsigned _Base
>
58 struct _Digit
<_Base
, '1'> : integral_constant
<unsigned, 1>
60 using __valid
= true_type
;
63 template<unsigned _Base
, unsigned _Val
>
64 struct _Digit_impl
: integral_constant
<unsigned, _Val
>
66 static_assert(_Base
> _Val
, "invalid digit");
67 using __valid
= true_type
;
70 template<unsigned _Base
>
71 struct _Digit
<_Base
, '2'> : _Digit_impl
<_Base
, 2>
74 template<unsigned _Base
>
75 struct _Digit
<_Base
, '3'> : _Digit_impl
<_Base
, 3>
78 template<unsigned _Base
>
79 struct _Digit
<_Base
, '4'> : _Digit_impl
<_Base
, 4>
82 template<unsigned _Base
>
83 struct _Digit
<_Base
, '5'> : _Digit_impl
<_Base
, 5>
86 template<unsigned _Base
>
87 struct _Digit
<_Base
, '6'> : _Digit_impl
<_Base
, 6>
90 template<unsigned _Base
>
91 struct _Digit
<_Base
, '7'> : _Digit_impl
<_Base
, 7>
94 template<unsigned _Base
>
95 struct _Digit
<_Base
, '8'> : _Digit_impl
<_Base
, 8>
98 template<unsigned _Base
>
99 struct _Digit
<_Base
, '9'> : _Digit_impl
<_Base
, 9>
102 template<unsigned _Base
>
103 struct _Digit
<_Base
, 'a'> : _Digit_impl
<_Base
, 0xa>
106 template<unsigned _Base
>
107 struct _Digit
<_Base
, 'A'> : _Digit_impl
<_Base
, 0xa>
110 template<unsigned _Base
>
111 struct _Digit
<_Base
, 'b'> : _Digit_impl
<_Base
, 0xb>
114 template<unsigned _Base
>
115 struct _Digit
<_Base
, 'B'> : _Digit_impl
<_Base
, 0xb>
118 template<unsigned _Base
>
119 struct _Digit
<_Base
, 'c'> : _Digit_impl
<_Base
, 0xc>
122 template<unsigned _Base
>
123 struct _Digit
<_Base
, 'C'> : _Digit_impl
<_Base
, 0xc>
126 template<unsigned _Base
>
127 struct _Digit
<_Base
, 'd'> : _Digit_impl
<_Base
, 0xd>
130 template<unsigned _Base
>
131 struct _Digit
<_Base
, 'D'> : _Digit_impl
<_Base
, 0xd>
134 template<unsigned _Base
>
135 struct _Digit
<_Base
, 'e'> : _Digit_impl
<_Base
, 0xe>
138 template<unsigned _Base
>
139 struct _Digit
<_Base
, 'E'> : _Digit_impl
<_Base
, 0xe>
142 template<unsigned _Base
>
143 struct _Digit
<_Base
, 'f'> : _Digit_impl
<_Base
, 0xf>
146 template<unsigned _Base
>
147 struct _Digit
<_Base
, 'F'> : _Digit_impl
<_Base
, 0xf>
151 template<unsigned _Base
>
152 struct _Digit
<_Base
, '\''> : integral_constant
<unsigned, 0>
154 using __valid
= false_type
;
157 //------------------------------------------------------------------------------
159 template<unsigned long long _Val
>
160 using __ull_constant
= integral_constant
<unsigned long long, _Val
>;
162 template<unsigned _Base
, char _Dig
, char... _Digs
>
165 using __next
= typename _Power_help
<_Base
, _Digs
...>::type
;
166 using __valid_digit
= typename _Digit
<_Base
, _Dig
>::__valid
;
168 = __ull_constant
<__next::value
* (__valid_digit
{} ? _Base
: 1ULL)>;
171 template<unsigned _Base
, char _Dig
>
172 struct _Power_help
<_Base
, _Dig
>
174 using __valid_digit
= typename _Digit
<_Base
, _Dig
>::__valid
;
175 using type
= __ull_constant
<__valid_digit::value
>;
178 template<unsigned _Base
, char... _Digs
>
179 struct _Power
: _Power_help
<_Base
, _Digs
...>::type
182 template<unsigned _Base
>
183 struct _Power
<_Base
> : __ull_constant
<0>
186 //------------------------------------------------------------------------------
188 template<unsigned _Base
, unsigned long long _Pow
, char _Dig
, char... _Digs
>
191 using __digit
= _Digit
<_Base
, _Dig
>;
192 using __valid_digit
= typename
__digit::__valid
;
193 using __next
= _Number_help
<_Base
,
194 __valid_digit::value
? _Pow
/ _Base
: _Pow
,
196 using type
= __ull_constant
<_Pow
* __digit::value
+ __next::type::value
>;
197 static_assert((type::value
/ _Pow
) == __digit::value
,
198 "integer literal does not fit in unsigned long long");
201 // Skip past digit separators:
202 template<unsigned _Base
, unsigned long long _Pow
, char _Dig
, char..._Digs
>
203 struct _Number_help
<_Base
, _Pow
, '\'', _Dig
, _Digs
...>
204 : _Number_help
<_Base
, _Pow
, _Dig
, _Digs
...>
207 // Terminating case for recursion:
208 template<unsigned _Base
, char _Dig
>
209 struct _Number_help
<_Base
, 1ULL, _Dig
>
211 using type
= __ull_constant
<_Digit
<_Base
, _Dig
>::value
>;
214 template<unsigned _Base
, char... _Digs
>
216 : _Number_help
<_Base
, _Power
<_Base
, _Digs
...>::value
, _Digs
...>::type
219 template<unsigned _Base
>
220 struct _Number
<_Base
>
224 //------------------------------------------------------------------------------
226 template<char... _Digs
>
229 template<char... _Digs
>
230 struct _Parse_int
<'0', 'b', _Digs
...>
231 : _Number
<2U, _Digs
...>::type
234 template<char... _Digs
>
235 struct _Parse_int
<'0', 'B', _Digs
...>
236 : _Number
<2U, _Digs
...>::type
239 template<char... _Digs
>
240 struct _Parse_int
<'0', 'x', _Digs
...>
241 : _Number
<16U, _Digs
...>::type
244 template<char... _Digs
>
245 struct _Parse_int
<'0', 'X', _Digs
...>
246 : _Number
<16U, _Digs
...>::type
249 template<char... _Digs
>
250 struct _Parse_int
<'0', _Digs
...>
251 : _Number
<8U, _Digs
...>::type
254 template<char... _Digs
>
256 : _Number
<10U, _Digs
...>::type
259 } // namespace __parse_int
262 namespace __select_int
264 template<unsigned long long _Val
, typename
... _Ints
>
265 struct _Select_int_base
;
267 template<unsigned long long _Val
, typename _IntType
, typename
... _Ints
>
268 struct _Select_int_base
<_Val
, _IntType
, _Ints
...>
269 : conditional_t
<(_Val
<= __gnu_cxx::__int_traits
<_IntType
>::__max
),
270 integral_constant
<_IntType
, (_IntType
)_Val
>,
271 _Select_int_base
<_Val
, _Ints
...>>
274 template<unsigned long long _Val
>
275 struct _Select_int_base
<_Val
>
278 template<char... _Digs
>
279 using _Select_int
= typename _Select_int_base
<
280 __parse_int::_Parse_int
<_Digs
...>::value
,
288 } // namespace __select_int
290 _GLIBCXX_END_NAMESPACE_VERSION
295 #endif // _GLIBCXX_PARSE_NUMBERS_H