3 // Copyright (C) 2007-2024 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 include/array
26 * This is a Standard C++ Library header.
29 #ifndef _GLIBCXX_ARRAY
30 #define _GLIBCXX_ARRAY 1
32 #pragma GCC system_header
34 #if __cplusplus < 201103L
35 # include <bits/c++0x_warning.h>
39 #include <initializer_list>
41 #include <type_traits>
42 #include <bits/functexcept.h>
43 #include <bits/stl_algobase.h>
44 #include <bits/range_access.h> // std::begin, std::end etc.
45 #include <bits/utility.h> // std::index_sequence, std::tuple_size
46 #include <debug/assertions.h>
48 #define __glibcxx_want_array_constexpr
49 #define __glibcxx_want_freestanding_array
50 #define __glibcxx_want_nonmember_container_access
51 #define __glibcxx_want_to_array
52 #include <bits/version.h>
54 namespace std _GLIBCXX_VISIBILITY(default)
56 _GLIBCXX_BEGIN_NAMESPACE_VERSION
58 template<typename _Tp, size_t _Nm>
61 using _Type = _Tp[_Nm];
62 using _Is_swappable = __is_swappable<_Tp>;
63 using _Is_nothrow_swappable = __is_nothrow_swappable<_Tp>;
66 template<typename _Tp>
67 struct __array_traits<_Tp, 0>
69 // Empty type used instead of _Tp[0] for std::array<_Tp, 0>.
72 // Indexing is undefined.
73 __attribute__((__always_inline__,__noreturn__))
74 _Tp& operator[](size_t) const noexcept { __builtin_trap(); }
76 // Conversion to a pointer produces a null pointer.
77 __attribute__((__always_inline__))
78 constexpr explicit operator _Tp*() const noexcept { return nullptr; }
81 using _Is_swappable = true_type;
82 using _Is_nothrow_swappable = true_type;
86 * @brief A standard container for storing a fixed size sequence of elements.
90 * Meets the requirements of a <a href="tables.html#65">container</a>, a
91 * <a href="tables.html#66">reversible container</a>, and a
92 * <a href="tables.html#67">sequence</a>.
94 * Sets support random access iterators.
96 * @tparam Tp Type of element. Required to be a complete type.
97 * @tparam Nm Number of elements.
99 template<typename _Tp, std::size_t _Nm>
102 typedef _Tp value_type;
103 typedef value_type* pointer;
104 typedef const value_type* const_pointer;
105 typedef value_type& reference;
106 typedef const value_type& const_reference;
107 typedef value_type* iterator;
108 typedef const value_type* const_iterator;
109 typedef std::size_t size_type;
110 typedef std::ptrdiff_t difference_type;
111 typedef std::reverse_iterator<iterator> reverse_iterator;
112 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
114 // Support for zero-sized arrays mandatory.
115 typename __array_traits<_Tp, _Nm>::_Type _M_elems;
117 // No explicit construct/copy/destroy for aggregate type.
120 _GLIBCXX20_CONSTEXPR void
121 fill(const value_type& __u)
122 { std::fill_n(begin(), size(), __u); }
124 _GLIBCXX20_CONSTEXPR void
126 noexcept(__array_traits<_Tp, _Nm>::_Is_nothrow_swappable::value)
127 { std::swap_ranges(begin(), end(), __other.begin()); }
130 [[__gnu__::__const__, __nodiscard__]]
131 _GLIBCXX17_CONSTEXPR iterator
133 { return iterator(data()); }
136 _GLIBCXX17_CONSTEXPR const_iterator
137 begin() const noexcept
138 { return const_iterator(data()); }
140 [[__gnu__::__const__, __nodiscard__]]
141 _GLIBCXX17_CONSTEXPR iterator
143 { return iterator(data() + _Nm); }
146 _GLIBCXX17_CONSTEXPR const_iterator
148 { return const_iterator(data() + _Nm); }
150 [[__gnu__::__const__, __nodiscard__]]
151 _GLIBCXX17_CONSTEXPR reverse_iterator
153 { return reverse_iterator(end()); }
156 _GLIBCXX17_CONSTEXPR const_reverse_iterator
157 rbegin() const noexcept
158 { return const_reverse_iterator(end()); }
160 [[__gnu__::__const__, __nodiscard__]]
161 _GLIBCXX17_CONSTEXPR reverse_iterator
163 { return reverse_iterator(begin()); }
166 _GLIBCXX17_CONSTEXPR const_reverse_iterator
167 rend() const noexcept
168 { return const_reverse_iterator(begin()); }
171 _GLIBCXX17_CONSTEXPR const_iterator
172 cbegin() const noexcept
173 { return const_iterator(data()); }
176 _GLIBCXX17_CONSTEXPR const_iterator
177 cend() const noexcept
178 { return const_iterator(data() + _Nm); }
181 _GLIBCXX17_CONSTEXPR const_reverse_iterator
182 crbegin() const noexcept
183 { return const_reverse_iterator(end()); }
186 _GLIBCXX17_CONSTEXPR const_reverse_iterator
187 crend() const noexcept
188 { return const_reverse_iterator(begin()); }
191 [[__nodiscard__, __gnu__::__const__, __gnu__::__always_inline__]]
193 size() const noexcept { return _Nm; }
195 [[__nodiscard__, __gnu__::__const__, __gnu__::__always_inline__]]
197 max_size() const noexcept { return _Nm; }
199 [[__nodiscard__, __gnu__::__const__, __gnu__::__always_inline__]]
201 empty() const noexcept { return size() == 0; }
205 _GLIBCXX17_CONSTEXPR reference
206 operator[](size_type __n) noexcept
208 __glibcxx_requires_subscript(__n);
209 return _M_elems[__n];
213 constexpr const_reference
214 operator[](size_type __n) const noexcept
216 #if __cplusplus >= 201402L
217 __glibcxx_requires_subscript(__n);
219 return _M_elems[__n];
222 _GLIBCXX17_CONSTEXPR reference
226 std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
227 ">= _Nm (which is %zu)"),
229 return _M_elems[__n];
232 constexpr const_reference
233 at(size_type __n) const
235 // Result of conditional expression must be an lvalue so use
236 // boolean ? lvalue : (throw-expr, lvalue)
237 return __n < _Nm ? _M_elems[__n]
238 : (std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
239 ">= _Nm (which is %zu)"),
245 _GLIBCXX17_CONSTEXPR reference
248 __glibcxx_requires_nonempty();
249 return _M_elems[(size_type)0];
253 constexpr const_reference
254 front() const noexcept
256 #if __cplusplus >= 201402L
257 __glibcxx_requires_nonempty();
259 return _M_elems[(size_type)0];
263 _GLIBCXX17_CONSTEXPR reference
266 __glibcxx_requires_nonempty();
267 return _M_elems[_Nm - 1];
271 constexpr const_reference
272 back() const noexcept
274 #if __cplusplus >= 201402L
275 __glibcxx_requires_nonempty();
277 return _M_elems[_Nm - 1];
280 [[__nodiscard__, __gnu__::__const__, __gnu__::__always_inline__]]
281 _GLIBCXX17_CONSTEXPR pointer
283 { return static_cast<pointer>(_M_elems); }
286 _GLIBCXX17_CONSTEXPR const_pointer
287 data() const noexcept
288 { return static_cast<const_pointer>(_M_elems); }
291 #if __cpp_deduction_guides >= 201606
292 template<typename _Tp, typename... _Up>
294 -> array<enable_if_t<(is_same_v<_Tp, _Up> && ...), _Tp>,
298 // Array comparisons.
299 template<typename _Tp, std::size_t _Nm>
303 operator==(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
304 { return std::equal(__one.begin(), __one.end(), __two.begin()); }
306 #if __cpp_lib_three_way_comparison // C++ >= 20 && lib_concepts
307 template<typename _Tp, size_t _Nm>
309 constexpr __detail::__synth3way_t<_Tp>
310 operator<=>(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
312 if constexpr (_Nm && __is_memcmp_ordered<_Tp>::__value)
313 if (!std::__is_constant_evaluated())
315 constexpr size_t __n = _Nm * sizeof(_Tp);
316 return __builtin_memcmp(__a.data(), __b.data(), __n) <=> 0;
319 for (size_t __i = 0; __i < _Nm; ++__i)
321 auto __c = __detail::__synth3way(__a[__i], __b[__i]);
325 return strong_ordering::equal;
328 template<typename _Tp, std::size_t _Nm>
332 operator!=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
333 { return !(__one == __two); }
335 template<typename _Tp, std::size_t _Nm>
339 operator<(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
341 return std::lexicographical_compare(__a.begin(), __a.end(),
342 __b.begin(), __b.end());
345 template<typename _Tp, std::size_t _Nm>
349 operator>(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
350 { return __two < __one; }
352 template<typename _Tp, std::size_t _Nm>
356 operator<=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
357 { return !(__one > __two); }
359 template<typename _Tp, std::size_t _Nm>
363 operator>=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
364 { return !(__one < __two); }
365 #endif // three_way_comparison && concepts
367 // Specialized algorithms.
368 template<typename _Tp, std::size_t _Nm>
371 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
372 // Constrained free swap overload, see p0185r1
373 __enable_if_t<__array_traits<_Tp, _Nm>::_Is_swappable::value>
377 swap(array<_Tp, _Nm>& __one, array<_Tp, _Nm>& __two)
378 noexcept(noexcept(__one.swap(__two)))
379 { __one.swap(__two); }
381 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
382 template<typename _Tp, std::size_t _Nm>
383 __enable_if_t<!__array_traits<_Tp, _Nm>::_Is_swappable::value>
384 swap(array<_Tp, _Nm>&, array<_Tp, _Nm>&) = delete;
387 template<std::size_t _Int, typename _Tp, std::size_t _Nm>
390 get(array<_Tp, _Nm>& __arr) noexcept
392 static_assert(_Int < _Nm, "array index is within bounds");
393 return __arr._M_elems[_Int];
396 template<std::size_t _Int, typename _Tp, std::size_t _Nm>
399 get(array<_Tp, _Nm>&& __arr) noexcept
401 static_assert(_Int < _Nm, "array index is within bounds");
402 return std::move(std::get<_Int>(__arr));
405 template<std::size_t _Int, typename _Tp, std::size_t _Nm>
408 get(const array<_Tp, _Nm>& __arr) noexcept
410 static_assert(_Int < _Nm, "array index is within bounds");
411 return __arr._M_elems[_Int];
414 template<std::size_t _Int, typename _Tp, std::size_t _Nm>
416 constexpr const _Tp&&
417 get(const array<_Tp, _Nm>&& __arr) noexcept
419 static_assert(_Int < _Nm, "array index is within bounds");
420 return std::move(std::get<_Int>(__arr));
423 #ifdef __cpp_lib_to_array // C++ >= 20 && __cpp_generic_lambdas >= 201707L
424 template<typename _Tp, size_t _Nm>
426 constexpr array<remove_cv_t<_Tp>, _Nm>
427 to_array(_Tp (&__a)[_Nm])
428 noexcept(is_nothrow_constructible_v<_Tp, _Tp&>)
430 static_assert(!is_array_v<_Tp>);
431 static_assert(is_constructible_v<_Tp, _Tp&>);
432 if constexpr (is_constructible_v<_Tp, _Tp&>)
434 if constexpr (is_trivially_copyable_v<_Tp>
435 && is_trivially_default_constructible_v<_Tp>
436 && is_copy_assignable_v<_Tp>)
438 array<remove_cv_t<_Tp>, _Nm> __arr;
439 if (!__is_constant_evaluated() && _Nm != 0)
440 __builtin_memcpy((void*)__arr.data(), (void*)__a, sizeof(__a));
442 for (size_t __i = 0; __i < _Nm; ++__i)
443 __arr._M_elems[__i] = __a[__i];
447 return [&__a]<size_t... _Idx>(index_sequence<_Idx...>) {
448 return array<remove_cv_t<_Tp>, _Nm>{{ __a[_Idx]... }};
449 }(make_index_sequence<_Nm>{});
452 __builtin_unreachable(); // FIXME: see PR c++/91388
455 template<typename _Tp, size_t _Nm>
457 constexpr array<remove_cv_t<_Tp>, _Nm>
458 to_array(_Tp (&&__a)[_Nm])
459 noexcept(is_nothrow_move_constructible_v<_Tp>)
461 static_assert(!is_array_v<_Tp>);
462 static_assert(is_move_constructible_v<_Tp>);
463 if constexpr (is_move_constructible_v<_Tp>)
465 if constexpr (is_trivially_copyable_v<_Tp>
466 && is_trivially_default_constructible_v<_Tp>
467 && is_copy_assignable_v<_Tp>)
469 array<remove_cv_t<_Tp>, _Nm> __arr;
470 if (!__is_constant_evaluated() && _Nm != 0)
471 __builtin_memcpy((void*)__arr.data(), (void*)__a, sizeof(__a));
473 for (size_t __i = 0; __i < _Nm; ++__i)
474 __arr._M_elems[__i] = __a[__i];
478 return [&__a]<size_t... _Idx>(index_sequence<_Idx...>) {
479 return array<remove_cv_t<_Tp>, _Nm>{{ std::move(__a[_Idx])... }};
480 }(make_index_sequence<_Nm>{});
483 __builtin_unreachable(); // FIXME: see PR c++/91388
485 #endif // __cpp_lib_to_array
487 // Tuple interface to class template array.
489 /// Partial specialization for std::array
490 template<typename _Tp, size_t _Nm>
491 struct tuple_size<array<_Tp, _Nm>>
492 : public integral_constant<size_t, _Nm> { };
494 /// Partial specialization for std::array
495 template<size_t _Ind, typename _Tp, size_t _Nm>
496 struct tuple_element<_Ind, array<_Tp, _Nm>>
498 static_assert(_Ind < _Nm, "array index is in range");
502 #if __cplusplus >= 201703L
503 template<typename _Tp, size_t _Nm>
504 inline constexpr size_t tuple_size_v<array<_Tp, _Nm>> = _Nm;
506 template<typename _Tp, size_t _Nm>
507 inline constexpr size_t tuple_size_v<const array<_Tp, _Nm>> = _Nm;
510 template<typename _Tp, size_t _Nm>
511 struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type
514 _GLIBCXX_END_NAMESPACE_VERSION
519 #endif // _GLIBCXX_ARRAY