libstdc++
array
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1 // <array> -*- C++ -*-
2 
3 // Copyright (C) 2007-2020 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 /** @file include/array
26  * This is a Standard C++ Library header.
27  */
28 
29 #ifndef _GLIBCXX_ARRAY
30 #define _GLIBCXX_ARRAY 1
31 
32 #pragma GCC system_header
33 
34 #if __cplusplus < 201103L
35 # include <bits/c++0x_warning.h>
36 #else
37 
38 #include <utility>
39 #include <bits/functexcept.h>
40 #include <bits/stl_algobase.h>
41 #include <bits/range_access.h>
42 
43 namespace std _GLIBCXX_VISIBILITY(default)
44 {
45 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
46 
47  template<typename _Tp, std::size_t _Nm>
48  struct __array_traits
49  {
50  typedef _Tp _Type[_Nm];
51  typedef __is_swappable<_Tp> _Is_swappable;
52  typedef __is_nothrow_swappable<_Tp> _Is_nothrow_swappable;
53 
54  static constexpr _Tp&
55  _S_ref(const _Type& __t, std::size_t __n) noexcept
56  { return const_cast<_Tp&>(__t[__n]); }
57 
58  static constexpr _Tp*
59  _S_ptr(const _Type& __t) noexcept
60  { return const_cast<_Tp*>(__t); }
61  };
62 
63  template<typename _Tp>
64  struct __array_traits<_Tp, 0>
65  {
66  struct _Type { };
67  typedef true_type _Is_swappable;
68  typedef true_type _Is_nothrow_swappable;
69 
70  static constexpr _Tp&
71  _S_ref(const _Type&, std::size_t) noexcept
72  { return *static_cast<_Tp*>(nullptr); }
73 
74  static constexpr _Tp*
75  _S_ptr(const _Type&) noexcept
76  { return nullptr; }
77  };
78 
79  /**
80  * @brief A standard container for storing a fixed size sequence of elements.
81  *
82  * @ingroup sequences
83  *
84  * Meets the requirements of a <a href="tables.html#65">container</a>, a
85  * <a href="tables.html#66">reversible container</a>, and a
86  * <a href="tables.html#67">sequence</a>.
87  *
88  * Sets support random access iterators.
89  *
90  * @tparam Tp Type of element. Required to be a complete type.
91  * @tparam Nm Number of elements.
92  */
93  template<typename _Tp, std::size_t _Nm>
94  struct array
95  {
96  typedef _Tp value_type;
97  typedef value_type* pointer;
98  typedef const value_type* const_pointer;
99  typedef value_type& reference;
100  typedef const value_type& const_reference;
101  typedef value_type* iterator;
102  typedef const value_type* const_iterator;
103  typedef std::size_t size_type;
104  typedef std::ptrdiff_t difference_type;
105  typedef std::reverse_iterator<iterator> reverse_iterator;
106  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
107 
108  // Support for zero-sized arrays mandatory.
109  typedef _GLIBCXX_STD_C::__array_traits<_Tp, _Nm> _AT_Type;
110  typename _AT_Type::_Type _M_elems;
111 
112  // No explicit construct/copy/destroy for aggregate type.
113 
114  // DR 776.
115  _GLIBCXX20_CONSTEXPR void
116  fill(const value_type& __u)
117  { std::fill_n(begin(), size(), __u); }
118 
119  _GLIBCXX20_CONSTEXPR void
120  swap(array& __other)
121  noexcept(_AT_Type::_Is_nothrow_swappable::value)
122  { std::swap_ranges(begin(), end(), __other.begin()); }
123 
124  // Iterators.
125  _GLIBCXX17_CONSTEXPR iterator
126  begin() noexcept
127  { return iterator(data()); }
128 
129  _GLIBCXX17_CONSTEXPR const_iterator
130  begin() const noexcept
131  { return const_iterator(data()); }
132 
133  _GLIBCXX17_CONSTEXPR iterator
134  end() noexcept
135  { return iterator(data() + _Nm); }
136 
137  _GLIBCXX17_CONSTEXPR const_iterator
138  end() const noexcept
139  { return const_iterator(data() + _Nm); }
140 
141  _GLIBCXX17_CONSTEXPR reverse_iterator
142  rbegin() noexcept
143  { return reverse_iterator(end()); }
144 
145  _GLIBCXX17_CONSTEXPR const_reverse_iterator
146  rbegin() const noexcept
147  { return const_reverse_iterator(end()); }
148 
149  _GLIBCXX17_CONSTEXPR reverse_iterator
150  rend() noexcept
151  { return reverse_iterator(begin()); }
152 
153  _GLIBCXX17_CONSTEXPR const_reverse_iterator
154  rend() const noexcept
155  { return const_reverse_iterator(begin()); }
156 
157  _GLIBCXX17_CONSTEXPR const_iterator
158  cbegin() const noexcept
159  { return const_iterator(data()); }
160 
161  _GLIBCXX17_CONSTEXPR const_iterator
162  cend() const noexcept
163  { return const_iterator(data() + _Nm); }
164 
165  _GLIBCXX17_CONSTEXPR const_reverse_iterator
166  crbegin() const noexcept
167  { return const_reverse_iterator(end()); }
168 
169  _GLIBCXX17_CONSTEXPR const_reverse_iterator
170  crend() const noexcept
171  { return const_reverse_iterator(begin()); }
172 
173  // Capacity.
174  constexpr size_type
175  size() const noexcept { return _Nm; }
176 
177  constexpr size_type
178  max_size() const noexcept { return _Nm; }
179 
180  _GLIBCXX_NODISCARD constexpr bool
181  empty() const noexcept { return size() == 0; }
182 
183  // Element access.
184  _GLIBCXX17_CONSTEXPR reference
185  operator[](size_type __n) noexcept
186  { return _AT_Type::_S_ref(_M_elems, __n); }
187 
188  constexpr const_reference
189  operator[](size_type __n) const noexcept
190  { return _AT_Type::_S_ref(_M_elems, __n); }
191 
192  _GLIBCXX17_CONSTEXPR reference
193  at(size_type __n)
194  {
195  if (__n >= _Nm)
196  std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
197  ">= _Nm (which is %zu)"),
198  __n, _Nm);
199  return _AT_Type::_S_ref(_M_elems, __n);
200  }
201 
202  constexpr const_reference
203  at(size_type __n) const
204  {
205  // Result of conditional expression must be an lvalue so use
206  // boolean ? lvalue : (throw-expr, lvalue)
207  return __n < _Nm ? _AT_Type::_S_ref(_M_elems, __n)
208  : (std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
209  ">= _Nm (which is %zu)"),
210  __n, _Nm),
211  _AT_Type::_S_ref(_M_elems, 0));
212  }
213 
214  _GLIBCXX17_CONSTEXPR reference
215  front() noexcept
216  { return *begin(); }
217 
218  constexpr const_reference
219  front() const noexcept
220  { return _AT_Type::_S_ref(_M_elems, 0); }
221 
222  _GLIBCXX17_CONSTEXPR reference
223  back() noexcept
224  { return _Nm ? *(end() - 1) : *end(); }
225 
226  constexpr const_reference
227  back() const noexcept
228  {
229  return _Nm ? _AT_Type::_S_ref(_M_elems, _Nm - 1)
230  : _AT_Type::_S_ref(_M_elems, 0);
231  }
232 
233  _GLIBCXX17_CONSTEXPR pointer
234  data() noexcept
235  { return _AT_Type::_S_ptr(_M_elems); }
236 
237  _GLIBCXX17_CONSTEXPR const_pointer
238  data() const noexcept
239  { return _AT_Type::_S_ptr(_M_elems); }
240  };
241 
242 #if __cpp_deduction_guides >= 201606
243  template<typename _Tp, typename... _Up>
244  array(_Tp, _Up...)
245  -> array<enable_if_t<(is_same_v<_Tp, _Up> && ...), _Tp>,
246  1 + sizeof...(_Up)>;
247 #endif
248 
249  // Array comparisons.
250  template<typename _Tp, std::size_t _Nm>
251  _GLIBCXX20_CONSTEXPR
252  inline bool
253  operator==(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
254  { return std::equal(__one.begin(), __one.end(), __two.begin()); }
255 
256 #if __cpp_lib_three_way_comparison && __cpp_lib_concepts
257  template<typename _Tp, size_t _Nm>
258  constexpr __detail::__synth3way_t<_Tp>
259  operator<=>(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
260  {
261 #ifdef __cpp_lib_is_constant_evaluated
262  if constexpr (_Nm && __is_memcmp_ordered<_Tp>::__value)
263  if (!std::is_constant_evaluated())
264  {
265  constexpr size_t __n = _Nm * sizeof(_Tp);
266  return __builtin_memcmp(__a.data(), __b.data(), __n) <=> 0;
267  }
268 #endif
269 
270  for (size_t __i = 0; __i < _Nm; ++__i)
271  {
272  auto __c = __detail::__synth3way(__a[__i], __b[__i]);
273  if (__c != 0)
274  return __c;
275  }
276  return strong_ordering::equal;
277  }
278 #else
279  template<typename _Tp, std::size_t _Nm>
280  _GLIBCXX20_CONSTEXPR
281  inline bool
282  operator!=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
283  { return !(__one == __two); }
284 
285  template<typename _Tp, std::size_t _Nm>
286  _GLIBCXX20_CONSTEXPR
287  inline bool
288  operator<(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
289  {
290  return std::lexicographical_compare(__a.begin(), __a.end(),
291  __b.begin(), __b.end());
292  }
293 
294  template<typename _Tp, std::size_t _Nm>
295  _GLIBCXX20_CONSTEXPR
296  inline bool
297  operator>(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
298  { return __two < __one; }
299 
300  template<typename _Tp, std::size_t _Nm>
301  _GLIBCXX20_CONSTEXPR
302  inline bool
303  operator<=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
304  { return !(__one > __two); }
305 
306  template<typename _Tp, std::size_t _Nm>
307  _GLIBCXX20_CONSTEXPR
308  inline bool
309  operator>=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
310  { return !(__one < __two); }
311 #endif // three_way_comparison && concepts
312 
313  // Specialized algorithms.
314  template<typename _Tp, std::size_t _Nm>
315  _GLIBCXX20_CONSTEXPR
316  inline
317 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
318  // Constrained free swap overload, see p0185r1
319  typename enable_if<
320  _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::_Is_swappable::value
321  >::type
322 #else
323  void
324 #endif
325  swap(array<_Tp, _Nm>& __one, array<_Tp, _Nm>& __two)
326  noexcept(noexcept(__one.swap(__two)))
327  { __one.swap(__two); }
328 
329 #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
330  template<typename _Tp, std::size_t _Nm>
331  typename enable_if<
332  !_GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::_Is_swappable::value>::type
333  swap(array<_Tp, _Nm>&, array<_Tp, _Nm>&) = delete;
334 #endif
335 
336  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
337  constexpr _Tp&
338  get(array<_Tp, _Nm>& __arr) noexcept
339  {
340  static_assert(_Int < _Nm, "array index is within bounds");
341  return _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::
342  _S_ref(__arr._M_elems, _Int);
343  }
344 
345  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
346  constexpr _Tp&&
347  get(array<_Tp, _Nm>&& __arr) noexcept
348  {
349  static_assert(_Int < _Nm, "array index is within bounds");
350  return std::move(_GLIBCXX_STD_C::get<_Int>(__arr));
351  }
352 
353  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
354  constexpr const _Tp&
355  get(const array<_Tp, _Nm>& __arr) noexcept
356  {
357  static_assert(_Int < _Nm, "array index is within bounds");
358  return _GLIBCXX_STD_C::__array_traits<_Tp, _Nm>::
359  _S_ref(__arr._M_elems, _Int);
360  }
361 
362  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
363  constexpr const _Tp&&
364  get(const array<_Tp, _Nm>&& __arr) noexcept
365  {
366  static_assert(_Int < _Nm, "array index is within bounds");
367  return std::move(_GLIBCXX_STD_C::get<_Int>(__arr));
368  }
369 
370 #if __cplusplus > 201703L
371 #define __cpp_lib_to_array 201907L
372 
373  template<bool _Move = false, typename _Tp, size_t... _Idx>
374  constexpr array<remove_cv_t<_Tp>, sizeof...(_Idx)>
375  __to_array(_Tp (&__a)[sizeof...(_Idx)], index_sequence<_Idx...>)
376  {
377  if constexpr (_Move)
378  return {{std::move(__a[_Idx])...}};
379  else
380  return {{__a[_Idx]...}};
381  }
382 
383  template<typename _Tp, size_t _Nm>
384  constexpr array<remove_cv_t<_Tp>, _Nm>
385  to_array(_Tp (&__a)[_Nm])
386  noexcept(is_nothrow_constructible_v<_Tp, _Tp&>)
387  {
388  static_assert(!is_array_v<_Tp>);
389  static_assert(is_constructible_v<_Tp, _Tp&>);
390  if constexpr (is_constructible_v<_Tp, _Tp&>)
391  return _GLIBCXX_STD_C::__to_array(__a, make_index_sequence<_Nm>{});
392  __builtin_unreachable(); // FIXME: see PR c++/91388
393  }
394 
395  template<typename _Tp, size_t _Nm>
396  constexpr array<remove_cv_t<_Tp>, _Nm>
397  to_array(_Tp (&&__a)[_Nm])
398  noexcept(is_nothrow_move_constructible_v<_Tp>)
399  {
400  static_assert(!is_array_v<_Tp>);
401  static_assert(is_move_constructible_v<_Tp>);
402  if constexpr (is_move_constructible_v<_Tp>)
403  return _GLIBCXX_STD_C::__to_array<1>(__a, make_index_sequence<_Nm>{});
404  __builtin_unreachable(); // FIXME: see PR c++/91388
405  }
406 #endif // C++20
407 
408 _GLIBCXX_END_NAMESPACE_CONTAINER
409 } // namespace std
410 
411 namespace std _GLIBCXX_VISIBILITY(default)
412 {
413 _GLIBCXX_BEGIN_NAMESPACE_VERSION
414 
415  // Tuple interface to class template array.
416 
417  /// tuple_size
418  template<typename _Tp>
419  struct tuple_size;
420 
421  /// Partial specialization for std::array
422  template<typename _Tp, std::size_t _Nm>
423  struct tuple_size<_GLIBCXX_STD_C::array<_Tp, _Nm>>
424  : public integral_constant<std::size_t, _Nm> { };
425 
426  /// tuple_element
427  template<std::size_t _Int, typename _Tp>
428  struct tuple_element;
429 
430  /// Partial specialization for std::array
431  template<std::size_t _Int, typename _Tp, std::size_t _Nm>
432  struct tuple_element<_Int, _GLIBCXX_STD_C::array<_Tp, _Nm>>
433  {
434  static_assert(_Int < _Nm, "index is out of bounds");
435  typedef _Tp type;
436  };
437 
438  template<typename _Tp, std::size_t _Nm>
439  struct __is_tuple_like_impl<_GLIBCXX_STD_C::array<_Tp, _Nm>> : true_type
440  { };
441 
442 _GLIBCXX_END_NAMESPACE_VERSION
443 } // namespace std
444 
445 #ifdef _GLIBCXX_DEBUG
446 # include <debug/array>
447 #endif
448 
449 #endif // C++11
450 
451 #endif // _GLIBCXX_ARRAY