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
43namespace 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
411namespace 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
452