1 // <utility> -*- C++ -*- 2 3 // Copyright (C) 2001-2024 Free Software Foundation, Inc. 4 // 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) 9 // any later version. 10 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. 15 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. 19 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/>. 24 25 /* 26 * 27 * Copyright (c) 1994 28 * Hewlett-Packard Company 29 * 30 * Permission to use, copy, modify, distribute and sell this software 31 * and its documentation for any purpose is hereby granted without fee, 32 * provided that the above copyright notice appear in all copies and 33 * that both that copyright notice and this permission notice appear 34 * in supporting documentation. Hewlett-Packard Company makes no 35 * representations about the suitability of this software for any 36 * purpose. It is provided "as is" without express or implied warranty. 37 * 38 * 39 * Copyright (c) 1996,1997 40 * Silicon Graphics Computer Systems, Inc. 41 * 42 * Permission to use, copy, modify, distribute and sell this software 43 * and its documentation for any purpose is hereby granted without fee, 44 * provided that the above copyright notice appear in all copies and 45 * that both that copyright notice and this permission notice appear 46 * in supporting documentation. Silicon Graphics makes no 47 * representations about the suitability of this software for any 48 * purpose. It is provided "as is" without express or implied warranty. 49 */ 50 51 /** @file include/utility 52 * This is a Standard C++ Library header. 53 */ 54 55 #ifndef _GLIBCXX_UTILITY 56 #define _GLIBCXX_UTILITY 1 57 58 #pragma GCC system_header 59 60 /** 61 * @defgroup utilities Utilities 62 * 63 * Basic function and class templates used with the rest of the library. 64 * Includes pair, swap, forward/move helpers, declval, integer_sequence. 65 */ 66 67 #include <bits/c++config.h> 68 #include <bits/stl_relops.h> 69 #include <bits/stl_pair.h> 70 71 #if __cplusplus >= 201103L 72 73 #include <initializer_list> 74 #include <type_traits> 75 #include <bits/move.h> 76 #include <bits/utility.h> 77 78 #if __cplusplus >= 202002L 79 #include <ext/numeric_traits.h> // __is_standard_integer, __int_traits 80 #endif 81 82 #define __glibcxx_want_addressof_constexpr 83 #define __glibcxx_want_as_const 84 #define __glibcxx_want_constexpr_algorithms 85 #define __glibcxx_want_constexpr_utility 86 #define __glibcxx_want_exchange_function 87 #define __glibcxx_want_forward_like 88 #define __glibcxx_want_integer_comparison_functions 89 #define __glibcxx_want_integer_sequence 90 #define __glibcxx_want_ranges_zip 91 #define __glibcxx_want_to_underlying 92 #define __glibcxx_want_tuple_element_t 93 #define __glibcxx_want_tuples_by_type 94 #define __glibcxx_want_unreachable 95 #define __glibcxx_want_tuple_like 96 #include <bits/version.h> 97 98 namespace std _GLIBCXX_VISIBILITY(default) 99 { 100 _GLIBCXX_BEGIN_NAMESPACE_VERSION 101 102 #ifdef __cpp_lib_exchange_function // C++ >= 14 103 /// Assign @p __new_val to @p __obj and return its previous value. 104 template <typename _Tp, typename _Up = _Tp> 105 _GLIBCXX20_CONSTEXPR 106 inline _Tp 107 exchange(_Tp& __obj, _Up&& __new_val) 108 noexcept(__and_<is_nothrow_move_constructible<_Tp>, 109 is_nothrow_assignable<_Tp&, _Up>>::value) 110 { return std::__exchange(__obj, std::forward<_Up>(__new_val)); } 111 #endif 112 113 #ifdef __cpp_lib_as_const // C++ >= 17 114 template<typename _Tp> 115 [[nodiscard]] 116 constexpr add_const_t<_Tp>& 117 as_const(_Tp& __t) noexcept 118 { return __t; } 119 120 template<typename _Tp> 121 void as_const(const _Tp&&) = delete; 122 #endif 123 124 #ifdef __cpp_lib_integer_comparison_functions // C++ >= 20 125 template<typename _Tp, typename _Up> 126 constexpr bool 127 cmp_equal(_Tp __t, _Up __u) noexcept 128 { 129 static_assert(__is_standard_integer<_Tp>::value); 130 static_assert(__is_standard_integer<_Up>::value); 131 132 if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>) 133 return __t == __u; 134 else if constexpr (is_signed_v<_Tp>) 135 return __t >= 0 && make_unsigned_t<_Tp>(__t) == __u; 136 else 137 return __u >= 0 && __t == make_unsigned_t<_Up>(__u); 138 } 139 140 template<typename _Tp, typename _Up> 141 constexpr bool 142 cmp_not_equal(_Tp __t, _Up __u) noexcept 143 { return !std::cmp_equal(__t, __u); } 144 145 template<typename _Tp, typename _Up> 146 constexpr bool 147 cmp_less(_Tp __t, _Up __u) noexcept 148 { 149 static_assert(__is_standard_integer<_Tp>::value); 150 static_assert(__is_standard_integer<_Up>::value); 151 152 if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>) 153 return __t < __u; 154 else if constexpr (is_signed_v<_Tp>) 155 return __t < 0 || make_unsigned_t<_Tp>(__t) < __u; 156 else 157 return __u >= 0 && __t < make_unsigned_t<_Up>(__u); 158 } 159 160 template<typename _Tp, typename _Up> 161 constexpr bool 162 cmp_greater(_Tp __t, _Up __u) noexcept 163 { return std::cmp_less(__u, __t); } 164 165 template<typename _Tp, typename _Up> 166 constexpr bool 167 cmp_less_equal(_Tp __t, _Up __u) noexcept 168 { return !std::cmp_less(__u, __t); } 169 170 template<typename _Tp, typename _Up> 171 constexpr bool 172 cmp_greater_equal(_Tp __t, _Up __u) noexcept 173 { return !std::cmp_less(__t, __u); } 174 175 template<typename _Res, typename _Tp> 176 constexpr bool 177 in_range(_Tp __t) noexcept 178 { 179 static_assert(__is_standard_integer<_Res>::value); 180 static_assert(__is_standard_integer<_Tp>::value); 181 using __gnu_cxx::__int_traits; 182 183 if constexpr (is_signed_v<_Tp> == is_signed_v<_Res>) 184 return __int_traits<_Res>::__min <= __t 185 && __t <= __int_traits<_Res>::__max; 186 else if constexpr (is_signed_v<_Tp>) 187 return __t >= 0 188 && make_unsigned_t<_Tp>(__t) <= __int_traits<_Res>::__max; 189 else 190 return __t <= make_unsigned_t<_Res>(__int_traits<_Res>::__max); 191 } 192 #endif // __cpp_lib_integer_comparison_functions 193 194 #ifdef __cpp_lib_to_underlying // C++ >= 23 195 /// Convert an object of enumeration type to its underlying type. 196 template<typename _Tp> 197 [[nodiscard]] 198 constexpr underlying_type_t<_Tp> 199 to_underlying(_Tp __value) noexcept 200 { return static_cast<underlying_type_t<_Tp>>(__value); } 201 #endif 202 203 #ifdef __cpp_lib_unreachable // C++ >= 23 204 /// Informs the compiler that program control flow never reaches this point. 205 /** 206 * Evaluating a call to this function results in undefined behaviour. 207 * This can be used as an assertion informing the compiler that certain 208 * conditions are impossible, for when the compiler is unable to determine 209 * that by itself. 210 * 211 * For example, it can be used to prevent warnings about reaching the 212 * end of a non-void function without returning. 213 * 214 * @since C++23 215 */ 216 [[noreturn,__gnu__::__always_inline__]] 217 inline void 218 unreachable() 219 { 220 #ifdef _GLIBCXX_DEBUG 221 std::__glibcxx_assert_fail(nullptr, 0, "std::unreachable()", nullptr); 222 #elif defined _GLIBCXX_ASSERTIONS 223 __builtin_trap(); 224 #else 225 __builtin_unreachable(); 226 #endif 227 } 228 #endif 229 230 _GLIBCXX_END_NAMESPACE_VERSION 231 } // namespace 232 233 #endif 234 235 #endif /* _GLIBCXX_UTILITY */ 236
Indexes created Thu Oct 01 00:25:45 UTC 2026