09aab7e699
This reduces the number of class template instantiations needed for code using tuples, by reusing _Nth_type in tuple_element and specializing tuple_size_v for tuple, pair and array (and const-qualified versions of them). Also define the _Nth_type primary template as a complete type (but with no nested 'type' member). This avoids "invalid use of incomplete type" errors for out-of-range specializations of tuple_element. Those errors would probably be confusing and unhelpful for users. We already have a user-friendly static assert in tuple_element itself. Also ensure that tuple_size_v is available whenever tuple_size is (as proposed by LWG 3387). We already do that for tuple_element_t. libstdc++-v3/ChangeLog: * include/bits/stl_pair.h (tuple_size_v): Define partial specializations for std::pair. * include/bits/utility.h (_Nth_type): Move definition here and define primary template. (tuple_size_v): Move definition here. * include/std/array (tuple_size_v): Define partial specializations for std::array. * include/std/tuple (tuple_size_v): Move primary template to <bits/utility.h>. Define partial specializations for std::tuple. (tuple_element): Change definition to use _Nth_type. * include/std/variant (_Nth_type): Move to <bits/utility.h>. (variant_alternative, variant): Adjust qualification of _Nth_type. * testsuite/20_util/tuple/element_access/get_neg.cc: Prune additional errors from _Nth_type.
502 lines
14 KiB
C++
502 lines
14 KiB
C++
// <array> -*- C++ -*-
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// Copyright (C) 2007-2021 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file include/array
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* This is a Standard C++ Library header.
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*/
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#ifndef _GLIBCXX_ARRAY
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#define _GLIBCXX_ARRAY 1
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#pragma GCC system_header
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#if __cplusplus < 201103L
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# include <bits/c++0x_warning.h>
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#else
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#include <compare>
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#include <initializer_list>
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#include <type_traits>
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#include <bits/functexcept.h>
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#include <bits/stl_algobase.h>
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#include <bits/range_access.h> // std::begin, std::end etc.
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#include <bits/utility.h> // std::index_sequence, std::tuple_size
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#include <debug/assertions.h>
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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template<typename _Tp, std::size_t _Nm>
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struct __array_traits
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{
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typedef _Tp _Type[_Nm];
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typedef __is_swappable<_Tp> _Is_swappable;
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typedef __is_nothrow_swappable<_Tp> _Is_nothrow_swappable;
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static constexpr _Tp&
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_S_ref(const _Type& __t, std::size_t __n) noexcept
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{ return const_cast<_Tp&>(__t[__n]); }
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static constexpr _Tp*
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_S_ptr(const _Type& __t) noexcept
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{ return const_cast<_Tp*>(__t); }
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};
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template<typename _Tp>
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struct __array_traits<_Tp, 0>
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{
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struct _Type { };
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typedef true_type _Is_swappable;
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typedef true_type _Is_nothrow_swappable;
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static constexpr _Tp&
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_S_ref(const _Type&, std::size_t) noexcept
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{ return *static_cast<_Tp*>(nullptr); }
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static constexpr _Tp*
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_S_ptr(const _Type&) noexcept
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{ return nullptr; }
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};
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/**
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* @brief A standard container for storing a fixed size sequence of elements.
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*
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* @ingroup sequences
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*
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* Meets the requirements of a <a href="tables.html#65">container</a>, a
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* <a href="tables.html#66">reversible container</a>, and a
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* <a href="tables.html#67">sequence</a>.
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*
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* Sets support random access iterators.
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*
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* @tparam Tp Type of element. Required to be a complete type.
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* @tparam Nm Number of elements.
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*/
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template<typename _Tp, std::size_t _Nm>
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struct array
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{
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typedef _Tp value_type;
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typedef value_type* pointer;
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typedef const value_type* const_pointer;
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typedef value_type& reference;
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typedef const value_type& const_reference;
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typedef value_type* iterator;
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typedef const value_type* const_iterator;
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typedef std::size_t size_type;
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typedef std::ptrdiff_t difference_type;
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typedef std::reverse_iterator<iterator> reverse_iterator;
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typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
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// Support for zero-sized arrays mandatory.
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typedef __array_traits<_Tp, _Nm> _AT_Type;
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typename _AT_Type::_Type _M_elems;
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// No explicit construct/copy/destroy for aggregate type.
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// DR 776.
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_GLIBCXX20_CONSTEXPR void
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fill(const value_type& __u)
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{ std::fill_n(begin(), size(), __u); }
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_GLIBCXX20_CONSTEXPR void
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swap(array& __other)
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noexcept(_AT_Type::_Is_nothrow_swappable::value)
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{ std::swap_ranges(begin(), end(), __other.begin()); }
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// Iterators.
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR iterator
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begin() noexcept
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{ return iterator(data()); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_iterator
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begin() const noexcept
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{ return const_iterator(data()); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR iterator
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end() noexcept
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{ return iterator(data() + _Nm); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_iterator
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end() const noexcept
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{ return const_iterator(data() + _Nm); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR reverse_iterator
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rbegin() noexcept
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{ return reverse_iterator(end()); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_reverse_iterator
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rbegin() const noexcept
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{ return const_reverse_iterator(end()); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR reverse_iterator
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rend() noexcept
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{ return reverse_iterator(begin()); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_reverse_iterator
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rend() const noexcept
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{ return const_reverse_iterator(begin()); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_iterator
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cbegin() const noexcept
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{ return const_iterator(data()); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_iterator
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cend() const noexcept
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{ return const_iterator(data() + _Nm); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_reverse_iterator
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crbegin() const noexcept
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{ return const_reverse_iterator(end()); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_reverse_iterator
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crend() const noexcept
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{ return const_reverse_iterator(begin()); }
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// Capacity.
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[[__nodiscard__]]
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constexpr size_type
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size() const noexcept { return _Nm; }
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[[__nodiscard__]]
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constexpr size_type
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max_size() const noexcept { return _Nm; }
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[[__nodiscard__]]
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constexpr bool
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empty() const noexcept { return size() == 0; }
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// Element access.
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR reference
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operator[](size_type __n) noexcept
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{
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__glibcxx_requires_subscript(__n);
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return _AT_Type::_S_ref(_M_elems, __n);
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}
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[[__nodiscard__]]
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constexpr const_reference
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operator[](size_type __n) const noexcept
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{
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#if __cplusplus >= 201402L
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__glibcxx_requires_subscript(__n);
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#endif
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return _AT_Type::_S_ref(_M_elems, __n);
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}
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_GLIBCXX17_CONSTEXPR reference
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at(size_type __n)
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{
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if (__n >= _Nm)
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std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
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">= _Nm (which is %zu)"),
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__n, _Nm);
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return _AT_Type::_S_ref(_M_elems, __n);
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}
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constexpr const_reference
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at(size_type __n) const
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{
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// Result of conditional expression must be an lvalue so use
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// boolean ? lvalue : (throw-expr, lvalue)
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return __n < _Nm ? _AT_Type::_S_ref(_M_elems, __n)
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: (std::__throw_out_of_range_fmt(__N("array::at: __n (which is %zu) "
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">= _Nm (which is %zu)"),
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__n, _Nm),
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_AT_Type::_S_ref(_M_elems, 0));
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}
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR reference
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front() noexcept
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{
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__glibcxx_requires_nonempty();
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return *begin();
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}
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[[__nodiscard__]]
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constexpr const_reference
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front() const noexcept
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{
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#if __cplusplus >= 201402L
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__glibcxx_requires_nonempty();
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#endif
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return _AT_Type::_S_ref(_M_elems, 0);
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}
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR reference
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back() noexcept
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{
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__glibcxx_requires_nonempty();
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return _Nm ? *(end() - 1) : *end();
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}
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[[__nodiscard__]]
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constexpr const_reference
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back() const noexcept
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{
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#if __cplusplus >= 201402L
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__glibcxx_requires_nonempty();
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#endif
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return _Nm ? _AT_Type::_S_ref(_M_elems, _Nm - 1)
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: _AT_Type::_S_ref(_M_elems, 0);
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}
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR pointer
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data() noexcept
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{ return _AT_Type::_S_ptr(_M_elems); }
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[[__nodiscard__]]
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_GLIBCXX17_CONSTEXPR const_pointer
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data() const noexcept
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{ return _AT_Type::_S_ptr(_M_elems); }
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};
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#if __cpp_deduction_guides >= 201606
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template<typename _Tp, typename... _Up>
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array(_Tp, _Up...)
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-> array<enable_if_t<(is_same_v<_Tp, _Up> && ...), _Tp>,
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1 + sizeof...(_Up)>;
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#endif
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// Array comparisons.
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template<typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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_GLIBCXX20_CONSTEXPR
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inline bool
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operator==(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
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{ return std::equal(__one.begin(), __one.end(), __two.begin()); }
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#if __cpp_lib_three_way_comparison && __cpp_lib_concepts
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template<typename _Tp, size_t _Nm>
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[[nodiscard]]
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constexpr __detail::__synth3way_t<_Tp>
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operator<=>(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
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{
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#ifdef __cpp_lib_is_constant_evaluated
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if constexpr (_Nm && __is_memcmp_ordered<_Tp>::__value)
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if (!std::is_constant_evaluated())
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{
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constexpr size_t __n = _Nm * sizeof(_Tp);
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return __builtin_memcmp(__a.data(), __b.data(), __n) <=> 0;
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}
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#endif
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for (size_t __i = 0; __i < _Nm; ++__i)
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{
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auto __c = __detail::__synth3way(__a[__i], __b[__i]);
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if (__c != 0)
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return __c;
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}
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return strong_ordering::equal;
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}
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#else
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template<typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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_GLIBCXX20_CONSTEXPR
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inline bool
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operator!=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
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{ return !(__one == __two); }
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template<typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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_GLIBCXX20_CONSTEXPR
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inline bool
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operator<(const array<_Tp, _Nm>& __a, const array<_Tp, _Nm>& __b)
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{
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return std::lexicographical_compare(__a.begin(), __a.end(),
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__b.begin(), __b.end());
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}
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template<typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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_GLIBCXX20_CONSTEXPR
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inline bool
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operator>(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
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{ return __two < __one; }
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template<typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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_GLIBCXX20_CONSTEXPR
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inline bool
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operator<=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
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{ return !(__one > __two); }
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template<typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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_GLIBCXX20_CONSTEXPR
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inline bool
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operator>=(const array<_Tp, _Nm>& __one, const array<_Tp, _Nm>& __two)
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{ return !(__one < __two); }
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#endif // three_way_comparison && concepts
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// Specialized algorithms.
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template<typename _Tp, std::size_t _Nm>
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_GLIBCXX20_CONSTEXPR
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inline
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#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
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// Constrained free swap overload, see p0185r1
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typename enable_if<
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__array_traits<_Tp, _Nm>::_Is_swappable::value
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>::type
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#else
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void
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#endif
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swap(array<_Tp, _Nm>& __one, array<_Tp, _Nm>& __two)
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noexcept(noexcept(__one.swap(__two)))
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{ __one.swap(__two); }
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#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
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template<typename _Tp, std::size_t _Nm>
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typename enable_if<
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!__array_traits<_Tp, _Nm>::_Is_swappable::value>::type
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swap(array<_Tp, _Nm>&, array<_Tp, _Nm>&) = delete;
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#endif
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template<std::size_t _Int, typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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constexpr _Tp&
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get(array<_Tp, _Nm>& __arr) noexcept
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{
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static_assert(_Int < _Nm, "array index is within bounds");
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return __array_traits<_Tp, _Nm>::_S_ref(__arr._M_elems, _Int);
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}
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template<std::size_t _Int, typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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constexpr _Tp&&
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get(array<_Tp, _Nm>&& __arr) noexcept
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{
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static_assert(_Int < _Nm, "array index is within bounds");
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return std::move(std::get<_Int>(__arr));
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}
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template<std::size_t _Int, typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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constexpr const _Tp&
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get(const array<_Tp, _Nm>& __arr) noexcept
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{
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static_assert(_Int < _Nm, "array index is within bounds");
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return __array_traits<_Tp, _Nm>::_S_ref(__arr._M_elems, _Int);
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}
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template<std::size_t _Int, typename _Tp, std::size_t _Nm>
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[[__nodiscard__]]
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constexpr const _Tp&&
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get(const array<_Tp, _Nm>&& __arr) noexcept
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{
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static_assert(_Int < _Nm, "array index is within bounds");
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return std::move(std::get<_Int>(__arr));
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}
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#if __cplusplus > 201703L
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#define __cpp_lib_to_array 201907L
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template<bool _Move = false, typename _Tp, size_t... _Idx>
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constexpr array<remove_cv_t<_Tp>, sizeof...(_Idx)>
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__to_array(_Tp (&__a)[sizeof...(_Idx)], index_sequence<_Idx...>)
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{
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if constexpr (_Move)
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return {{std::move(__a[_Idx])...}};
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else
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return {{__a[_Idx]...}};
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}
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template<typename _Tp, size_t _Nm>
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[[nodiscard]]
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constexpr array<remove_cv_t<_Tp>, _Nm>
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to_array(_Tp (&__a)[_Nm])
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noexcept(is_nothrow_constructible_v<_Tp, _Tp&>)
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{
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static_assert(!is_array_v<_Tp>);
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static_assert(is_constructible_v<_Tp, _Tp&>);
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if constexpr (is_constructible_v<_Tp, _Tp&>)
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return __to_array(__a, make_index_sequence<_Nm>{});
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__builtin_unreachable(); // FIXME: see PR c++/91388
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}
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template<typename _Tp, size_t _Nm>
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[[nodiscard]]
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constexpr array<remove_cv_t<_Tp>, _Nm>
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to_array(_Tp (&&__a)[_Nm])
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noexcept(is_nothrow_move_constructible_v<_Tp>)
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{
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static_assert(!is_array_v<_Tp>);
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static_assert(is_move_constructible_v<_Tp>);
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if constexpr (is_move_constructible_v<_Tp>)
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return __to_array<1>(__a, make_index_sequence<_Nm>{});
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__builtin_unreachable(); // FIXME: see PR c++/91388
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}
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#endif // C++20
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// Tuple interface to class template array.
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/// Partial specialization for std::array
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template<typename _Tp, size_t _Nm>
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struct tuple_size<array<_Tp, _Nm>>
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: public integral_constant<size_t, _Nm> { };
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/// Partial specialization for std::array
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template<size_t _Ind, typename _Tp, size_t _Nm>
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struct tuple_element<_Ind, array<_Tp, _Nm>>
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{
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static_assert(_Ind < _Nm, "array index is in range");
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using type = _Tp;
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};
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#if __cplusplus >= 201703L
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template<typename _Tp, size_t _Nm>
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inline constexpr size_t tuple_size_v<array<_Tp, _Nm>> = _Nm;
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template<typename _Tp, size_t _Nm>
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inline constexpr size_t tuple_size_v<const array<_Tp, _Nm>> = _Nm;
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#endif
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template<typename _Tp, size_t _Nm>
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struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type
|
|
{ };
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|
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_GLIBCXX_END_NAMESPACE_VERSION
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|
} // namespace std
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#endif // C++11
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#endif // _GLIBCXX_ARRAY
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