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// Iterators -*- C++ -*-
// Copyright (C) 2001-2022 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*
* Copyright (c) 1996-1998
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*/
/** @file bits/stl_iterator.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{iterator}
*
* This file implements reverse_iterator, back_insert_iterator,
* front_insert_iterator, insert_iterator, __normal_iterator, and their
* supporting functions and overloaded operators.
*/
#ifndef _STL_ITERATOR_H
#define _STL_ITERATOR_H 1
#include <bits/cpp_type_traits.h>
#include <bits/stl_iterator_base_types.h>
#include <ext/type_traits.h>
#include <bits/move.h>
#include <bits/ptr_traits.h>
#if __cplusplus >= 201103L
# include <type_traits>
#endif
#if __cplusplus > 201703L
# define __cpp_lib_array_constexpr 201811L
# define __cpp_lib_constexpr_iterator 201811L
#elif __cplusplus == 201703L
# define __cpp_lib_array_constexpr 201803L
#endif
#if __cplusplus >= 202002L
# include <compare>
# include <new>
# include <bits/exception_defines.h>
# include <bits/iterator_concepts.h>
# include <bits/stl_construct.h>
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @addtogroup iterators
* @{
*/
#if __cpp_lib_concepts
namespace __detail
{
// Weaken iterator_category _Cat to _Limit if it is derived from that,
// otherwise use _Otherwise.
template<typename _Cat, typename _Limit, typename _Otherwise = _Cat>
using __clamp_iter_cat
= __conditional_t<derived_from<_Cat, _Limit>, _Limit, _Otherwise>;
}
#endif
// Ignore warnings about std::iterator.
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
// 24.4.1 Reverse iterators
/**
* Bidirectional and random access iterators have corresponding reverse
* %iterator adaptors that iterate through the data structure in the
* opposite direction. They have the same signatures as the corresponding
* iterators. The fundamental relation between a reverse %iterator and its
* corresponding %iterator @c i is established by the identity:
* @code
* &*(reverse_iterator(i)) == &*(i - 1)
* @endcode
*
* <em>This mapping is dictated by the fact that while there is always a
* pointer past the end of an array, there might not be a valid pointer
* before the beginning of an array.</em> [24.4.1]/1,2
*
* Reverse iterators can be tricky and surprising at first. Their
* semantics make sense, however, and the trickiness is a side effect of
* the requirement that the iterators must be safe.
*/
template<typename _Iterator>
class reverse_iterator
: public iterator<typename iterator_traits<_Iterator>::iterator_category,
typename iterator_traits<_Iterator>::value_type,
typename iterator_traits<_Iterator>::difference_type,
typename iterator_traits<_Iterator>::pointer,
typename iterator_traits<_Iterator>::reference>
{
template<typename _Iter>
friend class reverse_iterator;
#if __cpp_lib_concepts
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3435. three_way_comparable_with<reverse_iterator<int*>, [...]>
template<typename _Iter>
static constexpr bool __convertible = !is_same_v<_Iter, _Iterator>
&& convertible_to<const _Iter&, _Iterator>;
#endif
protected:
_Iterator current;
typedef iterator_traits<_Iterator> __traits_type;
public:
typedef _Iterator iterator_type;
typedef typename __traits_type::pointer pointer;
#if ! __cpp_lib_concepts
typedef typename __traits_type::difference_type difference_type;
typedef typename __traits_type::reference reference;
#else
using iterator_concept
= __conditional_t<random_access_iterator<_Iterator>,
random_access_iterator_tag,
bidirectional_iterator_tag>;
using iterator_category
= __detail::__clamp_iter_cat<typename __traits_type::iterator_category,
random_access_iterator_tag>;
using value_type = iter_value_t<_Iterator>;
using difference_type = iter_difference_t<_Iterator>;
using reference = iter_reference_t<_Iterator>;
#endif
/**
* The default constructor value-initializes member @p current.
* If it is a pointer, that means it is zero-initialized.
*/
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 235 No specification of default ctor for reverse_iterator
// 1012. reverse_iterator default ctor should value initialize
_GLIBCXX17_CONSTEXPR
reverse_iterator()
_GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator()))
: current()
{ }
/**
* This %iterator will move in the opposite direction that @p x does.
*/
explicit _GLIBCXX17_CONSTEXPR
reverse_iterator(iterator_type __x)
_GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator(__x)))
: current(__x)
{ }
/**
* The copy constructor is normal.
*/
_GLIBCXX17_CONSTEXPR
reverse_iterator(const reverse_iterator& __x)
_GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator(__x.current)))
: current(__x.current)
{ }
#if __cplusplus >= 201103L
reverse_iterator& operator=(const reverse_iterator&) = default;
#endif
/**
* A %reverse_iterator across other types can be copied if the
* underlying %iterator can be converted to the type of @c current.
*/
template<typename _Iter>
#if __cpp_lib_concepts
requires __convertible<_Iter>
#endif
_GLIBCXX17_CONSTEXPR
reverse_iterator(const reverse_iterator<_Iter>& __x)
_GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator(__x.current)))
: current(__x.current)
{ }
#if __cplusplus >= 201103L
template<typename _Iter>
#if __cpp_lib_concepts
requires __convertible<_Iter>
&& assignable_from<_Iterator&, const _Iter&>
#endif
_GLIBCXX17_CONSTEXPR
reverse_iterator&
operator=(const reverse_iterator<_Iter>& __x)
_GLIBCXX_NOEXCEPT_IF(noexcept(current = __x.current))
{
current = __x.current;
return *this;
}
#endif
/**
* @return @c current, the %iterator used for underlying work.
*/
_GLIBCXX_NODISCARD
_GLIBCXX17_CONSTEXPR iterator_type
base() const
_GLIBCXX_NOEXCEPT_IF(noexcept(_Iterator(current)))
{ return current; }
/**
* @return A reference to the value at @c --current
*
* This requires that @c --current is dereferenceable.
*
* @warning This implementation requires that for an iterator of the
* underlying iterator type, @c x, a reference obtained by
* @c *x remains valid after @c x has been modified or
* destroyed. This is a bug: http://gcc.gnu.org/PR51823
*/
_GLIBCXX_NODISCARD
_GLIBCXX17_CONSTEXPR reference
operator*() const
{
_Iterator __tmp = current;
return *--__tmp;
}
/**
* @return A pointer to the value at @c --current
*
* This requires that @c --current is dereferenceable.
*/
_GLIBCXX_NODISCARD
_GLIBCXX17_CONSTEXPR pointer
operator->() const
#if __cplusplus > 201703L && __cpp_concepts >= 201907L
requires is_pointer_v<_Iterator>
|| requires(const _Iterator __i) { __i.operator->(); }
#endif
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 1052. operator-> should also support smart pointers
_Iterator __tmp = current;
--__tmp;
return _S_to_pointer(__tmp);
}
/**
* @return @c *this
*
* Decrements the underlying iterator.
*/
_GLIBCXX17_CONSTEXPR reverse_iterator&
operator++()
{
--current;
return *this;
}
/**
* @return The original value of @c *this
*
* Decrements the underlying iterator.
*/
_GLIBCXX17_CONSTEXPR reverse_iterator
operator++(int)
{
reverse_iterator __tmp = *this;
--current;
return __tmp;
}
/**
* @return @c *this
*
* Increments the underlying iterator.
*/
_GLIBCXX17_CONSTEXPR reverse_iterator&
operator--()
{
++current;
return *this;
}
/**
* @return A reverse_iterator with the previous value of @c *this
*
* Increments the underlying iterator.
*/
_GLIBCXX17_CONSTEXPR reverse_iterator
operator--(int)
{
reverse_iterator __tmp = *this;
++current;
return __tmp;
}
/**
* @return A reverse_iterator that refers to @c current - @a __n
*
* The underlying iterator must be a Random Access Iterator.
*/
_GLIBCXX_NODISCARD
_GLIBCXX17_CONSTEXPR reverse_iterator
operator+(difference_type __n) const
{ return reverse_iterator(current - __n); }
/**
* @return *this
*
* Moves the underlying iterator backwards @a __n steps.
* The underlying iterator must be a Random Access Iterator.
*/
_GLIBCXX17_CONSTEXPR reverse_iterator&
operator+=(difference_type __n)
{
current -= __n;
return *this;
}
/**
* @return A reverse_iterator that refers to @c current - @a __n
*
* The underlying iterator must be a Random Access Iterator.
*/
_GLIBCXX_NODISCARD
_GLIBCXX17_CONSTEXPR reverse_iterator
operator-(difference_type __n) const
{ return reverse_iterator(current + __n); }
/**
* @return *this
*
* Moves the underlying iterator forwards @a __n steps.
* The underlying iterator must be a Random Access Iterator.
*/
_GLIBCXX17_CONSTEXPR reverse_iterator&
operator-=(difference_type __n)
{
current += __n;
return *this;
}
/**
* @return The value at @c current - @a __n - 1
*
* The underlying iterator must be a Random Access Iterator.
*/
_GLIBCXX_NODISCARD
_GLIBCXX17_CONSTEXPR reference
operator[](difference_type __n) const
{ return *(*this + __n); }
#if __cplusplus > 201703L && __cpp_lib_concepts
[[nodiscard]]
friend constexpr iter_rvalue_reference_t<_Iterator>
iter_move(const reverse_iterator& __i)
noexcept(is_nothrow_copy_constructible_v<_Iterator>
&& noexcept(ranges::iter_move(--std::declval<_Iterator&>())))
{
auto __tmp = __i.base();
return ranges::iter_move(--__tmp);
}
template<indirectly_swappable<_Iterator> _Iter2>
friend constexpr void
iter_swap(const reverse_iterator& __x,
const reverse_iterator<_Iter2>& __y)
noexcept(is_nothrow_copy_constructible_v<_Iterator>
&& is_nothrow_copy_constructible_v<_Iter2>
&& noexcept(ranges::iter_swap(--std::declval<_Iterator&>(),
--std::declval<_Iter2&>())))
{
auto __xtmp = __x.base();
auto __ytmp = __y.base();
ranges::iter_swap(--__xtmp, --__ytmp);
}
#endif
private:
template<typename _Tp>
static _GLIBCXX17_CONSTEXPR _Tp*
_S_to_pointer(_Tp* __p)
{ return __p; }
template<typename _Tp>
static _GLIBCXX17_CONSTEXPR pointer
_S_to_pointer(_Tp __t)
{ return __t.operator->(); }
};
///@{
/**
* @param __x A %reverse_iterator.
* @param __y A %reverse_iterator.
* @return A simple bool.
*
* Reverse iterators forward comparisons to their underlying base()
* iterators.
*
*/
#if __cplusplus <= 201703L || ! defined __cpp_lib_concepts
template<typename _Iterator>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator==(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
{ return __x.base() == __y.base(); }
template<typename _Iterator>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator<(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
{ return __y.base() < __x.base(); }
template<typename _Iterator>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator!=(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
{ return !(__x == __y); }
template<typename _Iterator>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator>(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
{ return __y < __x; }
template<typename _Iterator>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator<=(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
{ return !(__y < __x); }
template<typename _Iterator>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator>=(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
{ return !(__x < __y); }
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 280. Comparison of reverse_iterator to const reverse_iterator.
template<typename _IteratorL, typename _IteratorR>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator==(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
{ return __x.base() == __y.base(); }
template<typename _IteratorL, typename _IteratorR>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator<(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
{ return __x.base() > __y.base(); }
template<typename _IteratorL, typename _IteratorR>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator!=(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
{ return __x.base() != __y.base(); }
template<typename _IteratorL, typename _IteratorR>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator>(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
{ return __x.base() < __y.base(); }
template<typename _IteratorL, typename _IteratorR>
inline _GLIBCXX17_CONSTEXPR bool
operator<=(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
{ return __x.base() >= __y.base(); }
template<typename _IteratorL, typename _IteratorR>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR bool
operator>=(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
{ return __x.base() <= __y.base(); }
#else // C++20
template<typename _IteratorL, typename _IteratorR>
[[nodiscard]]
constexpr bool
operator==(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
requires requires { { __x.base() == __y.base() } -> convertible_to<bool>; }
{ return __x.base() == __y.base(); }
template<typename _IteratorL, typename _IteratorR>
[[nodiscard]]
constexpr bool
operator!=(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
requires requires { { __x.base() != __y.base() } -> convertible_to<bool>; }
{ return __x.base() != __y.base(); }
template<typename _IteratorL, typename _IteratorR>
[[nodiscard]]
constexpr bool
operator<(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
requires requires { { __x.base() > __y.base() } -> convertible_to<bool>; }
{ return __x.base() > __y.base(); }
template<typename _IteratorL, typename _IteratorR>
[[nodiscard]]
constexpr bool
operator>(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
requires requires { { __x.base() < __y.base() } -> convertible_to<bool>; }
{ return __x.base() < __y.base(); }
template<typename _IteratorL, typename _IteratorR>
[[nodiscard]]
constexpr bool
operator<=(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
requires requires { { __x.base() >= __y.base() } -> convertible_to<bool>; }
{ return __x.base() >= __y.base(); }
template<typename _IteratorL, typename _IteratorR>
[[nodiscard]]
constexpr bool
operator>=(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
requires requires { { __x.base() <= __y.base() } -> convertible_to<bool>; }
{ return __x.base() <= __y.base(); }
template<typename _IteratorL,
three_way_comparable_with<_IteratorL> _IteratorR>
[[nodiscard]]
constexpr compare_three_way_result_t<_IteratorL, _IteratorR>
operator<=>(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
{ return __y.base() <=> __x.base(); }
// Additional, non-standard overloads to avoid ambiguities with greedy,
// unconstrained overloads in associated namespaces.
template<typename _Iterator>
[[nodiscard]]
constexpr bool
operator==(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
requires requires { { __x.base() == __y.base() } -> convertible_to<bool>; }
{ return __x.base() == __y.base(); }
template<three_way_comparable _Iterator>
[[nodiscard]]
constexpr compare_three_way_result_t<_Iterator, _Iterator>
operator<=>(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
{ return __y.base() <=> __x.base(); }
#endif // C++20
///@}
#if __cplusplus < 201103L
template<typename _Iterator>
inline typename reverse_iterator<_Iterator>::difference_type
operator-(const reverse_iterator<_Iterator>& __x,
const reverse_iterator<_Iterator>& __y)
{ return __y.base() - __x.base(); }
template<typename _IteratorL, typename _IteratorR>
inline typename reverse_iterator<_IteratorL>::difference_type
operator-(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
{ return __y.base() - __x.base(); }
#else
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 685. reverse_iterator/move_iterator difference has invalid signatures
template<typename _IteratorL, typename _IteratorR>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR auto
operator-(const reverse_iterator<_IteratorL>& __x,
const reverse_iterator<_IteratorR>& __y)
-> decltype(__y.base() - __x.base())
{ return __y.base() - __x.base(); }
#endif
template<typename _Iterator>
_GLIBCXX_NODISCARD
inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Iterator>
operator+(typename reverse_iterator<_Iterator>::difference_type __n,
const reverse_iterator<_Iterator>& __x)
{ return reverse_iterator<_Iterator>(__x.base() - __n); }
#if __cplusplus >= 201103L
// Same as C++14 make_reverse_iterator but used in C++11 mode too.
template<typename _Iterator>
inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Iterator>
__make_reverse_iterator(_Iterator __i)
{ return reverse_iterator<_Iterator>(__i); }
# if __cplusplus >= 201402L
# define __cpp_lib_make_reverse_iterator 201402L
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 2285. make_reverse_iterator
/// Generator function for reverse_iterator.
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR reverse_iterator<_Iterator>
make_reverse_iterator(_Iterator __i)
{ return reverse_iterator<_Iterator>(__i); }
# if __cplusplus > 201703L && defined __cpp_lib_concepts
template<typename _Iterator1, typename _Iterator2>
requires (!sized_sentinel_for<_Iterator1, _Iterator2>)
inline constexpr bool
disable_sized_sentinel_for<reverse_iterator<_Iterator1>,
reverse_iterator<_Iterator2>> = true;
# endif // C++20
# endif // C++14
template<typename _Iterator>
_GLIBCXX20_CONSTEXPR
auto
__niter_base(reverse_iterator<_Iterator> __it)
-> decltype(__make_reverse_iterator(__niter_base(__it.base())))
{ return __make_reverse_iterator(__niter_base(__it.base())); }
template<typename _Iterator>
struct __is_move_iterator<reverse_iterator<_Iterator> >
: __is_move_iterator<_Iterator>
{ };
template<typename _Iterator>
_GLIBCXX20_CONSTEXPR
auto
__miter_base(reverse_iterator<_Iterator> __it)
-> decltype(__make_reverse_iterator(__miter_base(__it.base())))
{ return __make_reverse_iterator(__miter_base(__it.base())); }
#endif // C++11
// 24.4.2.2.1 back_insert_iterator
/**
* @brief Turns assignment into insertion.
*
* These are output iterators, constructed from a container-of-T.
* Assigning a T to the iterator appends it to the container using
* push_back.
*
* Tip: Using the back_inserter function to create these iterators can
* save typing.
*/
template<typename _Container>
class back_insert_iterator
: public iterator<output_iterator_tag, void, void, void, void>
{
protected:
_Container* container;
public:
/// A nested typedef for the type of whatever container you used.
typedef _Container container_type;
#if __cplusplus > 201703L
using difference_type = ptrdiff_t;
#endif
/// The only way to create this %iterator is with a container.
explicit _GLIBCXX20_CONSTEXPR
back_insert_iterator(_Container& __x)
: container(std::__addressof(__x)) { }
/**
* @param __value An instance of whatever type
* container_type::const_reference is; presumably a
* reference-to-const T for container<T>.
* @return This %iterator, for chained operations.
*
* This kind of %iterator doesn't really have a @a position in the
* container (you can think of the position as being permanently at
* the end, if you like). Assigning a value to the %iterator will
* always append the value to the end of the container.
*/
#if __cplusplus < 201103L
back_insert_iterator&
operator=(typename _Container::const_reference __value)
{
container->push_back(__value);
return *this;
}
#else
_GLIBCXX20_CONSTEXPR
back_insert_iterator&
operator=(const typename _Container::value_type& __value)
{
container->push_back(__value);
return *this;
}
_GLIBCXX20_CONSTEXPR
back_insert_iterator&
operator=(typename _Container::value_type&& __value)
{
container->push_back(std::move(__value));
return *this;
}
#endif
/// Simply returns *this.
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
back_insert_iterator&
operator*()
{ return *this; }
/// Simply returns *this. (This %iterator does not @a move.)
_GLIBCXX20_CONSTEXPR
back_insert_iterator&
operator++()
{ return *this; }
/// Simply returns *this. (This %iterator does not @a move.)
_GLIBCXX20_CONSTEXPR
back_insert_iterator
operator++(int)
{ return *this; }
};
/**
* @param __x A container of arbitrary type.
* @return An instance of back_insert_iterator working on @p __x.
*
* This wrapper function helps in creating back_insert_iterator instances.
* Typing the name of the %iterator requires knowing the precise full
* type of the container, which can be tedious and impedes generic
* programming. Using this function lets you take advantage of automatic
* template parameter deduction, making the compiler match the correct
* types for you.
*/
template<typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline back_insert_iterator<_Container>
back_inserter(_Container& __x)
{ return back_insert_iterator<_Container>(__x); }
/**
* @brief Turns assignment into insertion.
*
* These are output iterators, constructed from a container-of-T.
* Assigning a T to the iterator prepends it to the container using
* push_front.
*
* Tip: Using the front_inserter function to create these iterators can
* save typing.
*/
template<typename _Container>
class front_insert_iterator
: public iterator<output_iterator_tag, void, void, void, void>
{
protected:
_Container* container;
public:
/// A nested typedef for the type of whatever container you used.
typedef _Container container_type;
#if __cplusplus > 201703L
using difference_type = ptrdiff_t;
#endif
/// The only way to create this %iterator is with a container.
explicit _GLIBCXX20_CONSTEXPR
front_insert_iterator(_Container& __x)
: container(std::__addressof(__x)) { }
/**
* @param __value An instance of whatever type
* container_type::const_reference is; presumably a
* reference-to-const T for container<T>.
* @return This %iterator, for chained operations.
*
* This kind of %iterator doesn't really have a @a position in the
* container (you can think of the position as being permanently at
* the front, if you like). Assigning a value to the %iterator will
* always prepend the value to the front of the container.
*/
#if __cplusplus < 201103L
front_insert_iterator&
operator=(typename _Container::const_reference __value)
{
container->push_front(__value);
return *this;
}
#else
_GLIBCXX20_CONSTEXPR
front_insert_iterator&
operator=(const typename _Container::value_type& __value)
{
container->push_front(__value);
return *this;
}
_GLIBCXX20_CONSTEXPR
front_insert_iterator&
operator=(typename _Container::value_type&& __value)
{
container->push_front(std::move(__value));
return *this;
}
#endif
/// Simply returns *this.
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
front_insert_iterator&
operator*()
{ return *this; }
/// Simply returns *this. (This %iterator does not @a move.)
_GLIBCXX20_CONSTEXPR
front_insert_iterator&
operator++()
{ return *this; }
/// Simply returns *this. (This %iterator does not @a move.)
_GLIBCXX20_CONSTEXPR
front_insert_iterator
operator++(int)
{ return *this; }
};
/**
* @param __x A container of arbitrary type.
* @return An instance of front_insert_iterator working on @p x.
*
* This wrapper function helps in creating front_insert_iterator instances.
* Typing the name of the %iterator requires knowing the precise full
* type of the container, which can be tedious and impedes generic
* programming. Using this function lets you take advantage of automatic
* template parameter deduction, making the compiler match the correct
* types for you.
*/
template<typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline front_insert_iterator<_Container>
front_inserter(_Container& __x)
{ return front_insert_iterator<_Container>(__x); }
/**
* @brief Turns assignment into insertion.
*
* These are output iterators, constructed from a container-of-T.
* Assigning a T to the iterator inserts it in the container at the
* %iterator's position, rather than overwriting the value at that
* position.
*
* (Sequences will actually insert a @e copy of the value before the
* %iterator's position.)
*
* Tip: Using the inserter function to create these iterators can
* save typing.
*/
template<typename _Container>
class insert_iterator
: public iterator<output_iterator_tag, void, void, void, void>
{
#if __cplusplus > 201703L && defined __cpp_lib_concepts
using _Iter = std::__detail::__range_iter_t<_Container>;
#else
typedef typename _Container::iterator _Iter;
#endif
protected:
_Container* container;
_Iter iter;
public:
/// A nested typedef for the type of whatever container you used.
typedef _Container container_type;
#if __cplusplus > 201703L && defined __cpp_lib_concepts
using difference_type = ptrdiff_t;
#endif
/**
* The only way to create this %iterator is with a container and an
* initial position (a normal %iterator into the container).
*/
_GLIBCXX20_CONSTEXPR
insert_iterator(_Container& __x, _Iter __i)
: container(std::__addressof(__x)), iter(__i) {}
/**
* @param __value An instance of whatever type
* container_type::const_reference is; presumably a
* reference-to-const T for container<T>.
* @return This %iterator, for chained operations.
*
* This kind of %iterator maintains its own position in the
* container. Assigning a value to the %iterator will insert the
* value into the container at the place before the %iterator.
*
* The position is maintained such that subsequent assignments will
* insert values immediately after one another. For example,
* @code
* // vector v contains A and Z
*
* insert_iterator i (v, ++v.begin());
* i = 1;
* i = 2;
* i = 3;
*
* // vector v contains A, 1, 2, 3, and Z
* @endcode
*/
#if __cplusplus < 201103L
insert_iterator&
operator=(typename _Container::const_reference __value)
{
iter = container->insert(iter, __value);
++iter;
return *this;
}
#else
_GLIBCXX20_CONSTEXPR
insert_iterator&
operator=(const typename _Container::value_type& __value)
{
iter = container->insert(iter, __value);
++iter;
return *this;
}
_GLIBCXX20_CONSTEXPR
insert_iterator&
operator=(typename _Container::value_type&& __value)
{
iter = container->insert(iter, std::move(__value));
++iter;
return *this;
}
#endif
/// Simply returns *this.
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
insert_iterator&
operator*()
{ return *this; }
/// Simply returns *this. (This %iterator does not @a move.)
_GLIBCXX20_CONSTEXPR
insert_iterator&
operator++()
{ return *this; }
/// Simply returns *this. (This %iterator does not @a move.)
_GLIBCXX20_CONSTEXPR
insert_iterator&
operator++(int)
{ return *this; }
};
#pragma GCC diagnostic pop
/**
* @param __x A container of arbitrary type.
* @param __i An iterator into the container.
* @return An instance of insert_iterator working on @p __x.
*
* This wrapper function helps in creating insert_iterator instances.
* Typing the name of the %iterator requires knowing the precise full
* type of the container, which can be tedious and impedes generic
* programming. Using this function lets you take advantage of automatic
* template parameter deduction, making the compiler match the correct
* types for you.
*/
#if __cplusplus > 201703L && defined __cpp_lib_concepts
template<typename _Container>
[[nodiscard]]
constexpr insert_iterator<_Container>
inserter(_Container& __x, std::__detail::__range_iter_t<_Container> __i)
{ return insert_iterator<_Container>(__x, __i); }
#else
template<typename _Container>
_GLIBCXX_NODISCARD
inline insert_iterator<_Container>
inserter(_Container& __x, typename _Container::iterator __i)
{ return insert_iterator<_Container>(__x, __i); }
#endif
/// @} group iterators
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
// This iterator adapter is @a normal in the sense that it does not
// change the semantics of any of the operators of its iterator
// parameter. Its primary purpose is to convert an iterator that is
// not a class, e.g. a pointer, into an iterator that is a class.
// The _Container parameter exists solely so that different containers
// using this template can instantiate different types, even if the
// _Iterator parameter is the same.
template<typename _Iterator, typename _Container>
class __normal_iterator
{
protected:
_Iterator _M_current;
typedef std::iterator_traits<_Iterator> __traits_type;
#if __cplusplus >= 201103L
template<typename _Iter>
using __convertible_from
= std::__enable_if_t<std::is_convertible<_Iter, _Iterator>::value>;
#endif
public:
typedef _Iterator iterator_type;
typedef typename __traits_type::iterator_category iterator_category;
typedef typename __traits_type::value_type value_type;
typedef typename __traits_type::difference_type difference_type;
typedef typename __traits_type::reference reference;
typedef typename __traits_type::pointer pointer;
#if __cplusplus > 201703L && __cpp_lib_concepts
using iterator_concept = std::__detail::__iter_concept<_Iterator>;
#endif
_GLIBCXX_CONSTEXPR __normal_iterator() _GLIBCXX_NOEXCEPT
: _M_current(_Iterator()) { }
explicit _GLIBCXX20_CONSTEXPR
__normal_iterator(const _Iterator& __i) _GLIBCXX_NOEXCEPT
: _M_current(__i) { }
// Allow iterator to const_iterator conversion
#if __cplusplus >= 201103L
template<typename _Iter, typename = __convertible_from<_Iter>>
_GLIBCXX20_CONSTEXPR
__normal_iterator(const __normal_iterator<_Iter, _Container>& __i)
noexcept
#else
// N.B. _Container::pointer is not actually in container requirements,
// but is present in std::vector and std::basic_string.
template<typename _Iter>
__normal_iterator(const __normal_iterator<_Iter,
typename __enable_if<
(std::__are_same<_Iter, typename _Container::pointer>::__value),
_Container>::__type>& __i)
#endif
: _M_current(__i.base()) { }
// Forward iterator requirements
_GLIBCXX20_CONSTEXPR
reference
operator*() const _GLIBCXX_NOEXCEPT
{ return *_M_current; }
_GLIBCXX20_CONSTEXPR
pointer
operator->() const _GLIBCXX_NOEXCEPT
{ return _M_current; }
_GLIBCXX20_CONSTEXPR
__normal_iterator&
operator++() _GLIBCXX_NOEXCEPT
{
++_M_current;
return *this;
}
_GLIBCXX20_CONSTEXPR
__normal_iterator
operator++(int) _GLIBCXX_NOEXCEPT
{ return __normal_iterator(_M_current++); }
// Bidirectional iterator requirements
_GLIBCXX20_CONSTEXPR
__normal_iterator&
operator--() _GLIBCXX_NOEXCEPT
{
--_M_current;
return *this;
}
_GLIBCXX20_CONSTEXPR
__normal_iterator
operator--(int) _GLIBCXX_NOEXCEPT
{ return __normal_iterator(_M_current--); }
// Random access iterator requirements
_GLIBCXX20_CONSTEXPR
reference
operator[](difference_type __n) const _GLIBCXX_NOEXCEPT
{ return _M_current[__n]; }
_GLIBCXX20_CONSTEXPR
__normal_iterator&
operator+=(difference_type __n) _GLIBCXX_NOEXCEPT
{ _M_current += __n; return *this; }
_GLIBCXX20_CONSTEXPR
__normal_iterator
operator+(difference_type __n) const _GLIBCXX_NOEXCEPT
{ return __normal_iterator(_M_current + __n); }
_GLIBCXX20_CONSTEXPR
__normal_iterator&
operator-=(difference_type __n) _GLIBCXX_NOEXCEPT
{ _M_current -= __n; return *this; }
_GLIBCXX20_CONSTEXPR
__normal_iterator
operator-(difference_type __n) const _GLIBCXX_NOEXCEPT
{ return __normal_iterator(_M_current - __n); }
_GLIBCXX20_CONSTEXPR
const _Iterator&
base() const _GLIBCXX_NOEXCEPT
{ return _M_current; }
};
// Note: In what follows, the left- and right-hand-side iterators are
// allowed to vary in types (conceptually in cv-qualification) so that
// comparison between cv-qualified and non-cv-qualified iterators be
// valid. However, the greedy and unfriendly operators in std::rel_ops
// will make overload resolution ambiguous (when in scope) if we don't
// provide overloads whose operands are of the same type. Can someone
// remind me what generic programming is about? -- Gaby
#if __cpp_lib_three_way_comparison
template<typename _IteratorL, typename _IteratorR, typename _Container>
[[nodiscard]]
constexpr bool
operator==(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
noexcept(noexcept(__lhs.base() == __rhs.base()))
requires requires {
{ __lhs.base() == __rhs.base() } -> std::convertible_to<bool>;
}
{ return __lhs.base() == __rhs.base(); }
template<typename _IteratorL, typename _IteratorR, typename _Container>
[[nodiscard]]
constexpr std::__detail::__synth3way_t<_IteratorR, _IteratorL>
operator<=>(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
noexcept(noexcept(std::__detail::__synth3way(__lhs.base(), __rhs.base())))
{ return std::__detail::__synth3way(__lhs.base(), __rhs.base()); }
template<typename _Iterator, typename _Container>
[[nodiscard]]
constexpr bool
operator==(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
noexcept(noexcept(__lhs.base() == __rhs.base()))
requires requires {
{ __lhs.base() == __rhs.base() } -> std::convertible_to<bool>;
}
{ return __lhs.base() == __rhs.base(); }
template<typename _Iterator, typename _Container>
[[nodiscard]]
constexpr std::__detail::__synth3way_t<_Iterator>
operator<=>(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
noexcept(noexcept(std::__detail::__synth3way(__lhs.base(), __rhs.base())))
{ return std::__detail::__synth3way(__lhs.base(), __rhs.base()); }
#else
// Forward iterator requirements
template<typename _IteratorL, typename _IteratorR, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline bool
operator==(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() == __rhs.base(); }
template<typename _Iterator, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline bool
operator==(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() == __rhs.base(); }
template<typename _IteratorL, typename _IteratorR, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline bool
operator!=(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() != __rhs.base(); }
template<typename _Iterator, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline bool
operator!=(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() != __rhs.base(); }
// Random access iterator requirements
template<typename _IteratorL, typename _IteratorR, typename _Container>
_GLIBCXX_NODISCARD
inline bool
operator<(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() < __rhs.base(); }
template<typename _Iterator, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline bool
operator<(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() < __rhs.base(); }
template<typename _IteratorL, typename _IteratorR, typename _Container>
_GLIBCXX_NODISCARD
inline bool
operator>(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() > __rhs.base(); }
template<typename _Iterator, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline bool
operator>(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() > __rhs.base(); }
template<typename _IteratorL, typename _IteratorR, typename _Container>
_GLIBCXX_NODISCARD
inline bool
operator<=(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() <= __rhs.base(); }
template<typename _Iterator, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline bool
operator<=(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() <= __rhs.base(); }
template<typename _IteratorL, typename _IteratorR, typename _Container>
_GLIBCXX_NODISCARD
inline bool
operator>=(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() >= __rhs.base(); }
template<typename _Iterator, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline bool
operator>=(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() >= __rhs.base(); }
#endif // three-way comparison
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// According to the resolution of DR179 not only the various comparison
// operators but also operator- must accept mixed iterator/const_iterator
// parameters.
template<typename _IteratorL, typename _IteratorR, typename _Container>
#if __cplusplus >= 201103L
// DR 685.
[[__nodiscard__]] _GLIBCXX20_CONSTEXPR
inline auto
operator-(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs) noexcept
-> decltype(__lhs.base() - __rhs.base())
#else
inline typename __normal_iterator<_IteratorL, _Container>::difference_type
operator-(const __normal_iterator<_IteratorL, _Container>& __lhs,
const __normal_iterator<_IteratorR, _Container>& __rhs)
#endif
{ return __lhs.base() - __rhs.base(); }
template<typename _Iterator, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline typename __normal_iterator<_Iterator, _Container>::difference_type
operator-(const __normal_iterator<_Iterator, _Container>& __lhs,
const __normal_iterator<_Iterator, _Container>& __rhs)
_GLIBCXX_NOEXCEPT
{ return __lhs.base() - __rhs.base(); }
template<typename _Iterator, typename _Container>
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
inline __normal_iterator<_Iterator, _Container>
operator+(typename __normal_iterator<_Iterator, _Container>::difference_type
__n, const __normal_iterator<_Iterator, _Container>& __i)
_GLIBCXX_NOEXCEPT
{ return __normal_iterator<_Iterator, _Container>(__i.base() + __n); }
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Iterator, typename _Container>
_GLIBCXX20_CONSTEXPR
_Iterator
__niter_base(__gnu_cxx::__normal_iterator<_Iterator, _Container> __it)
_GLIBCXX_NOEXCEPT_IF(std::is_nothrow_copy_constructible<_Iterator>::value)
{ return __it.base(); }
#if __cplusplus >= 201103L
#if __cplusplus <= 201703L
// Need to overload __to_address because the pointer_traits primary template
// will deduce element_type of __normal_iterator<T*, C> as T* rather than T.
template<typename _Iterator, typename _Container>
constexpr auto
__to_address(const __gnu_cxx::__normal_iterator<_Iterator,
_Container>& __it) noexcept
-> decltype(std::__to_address(__it.base()))
{ return std::__to_address(__it.base()); }
#endif
/**
* @addtogroup iterators
* @{
*/
#if __cplusplus > 201703L && __cpp_lib_concepts
template<semiregular _Sent>
class move_sentinel
{
public:
constexpr
move_sentinel()
noexcept(is_nothrow_default_constructible_v<_Sent>)
: _M_last() { }
constexpr explicit
move_sentinel(_Sent __s)
noexcept(is_nothrow_move_constructible_v<_Sent>)
: _M_last(std::move(__s)) { }
template<typename _S2> requires convertible_to<const _S2&, _Sent>
constexpr
move_sentinel(const move_sentinel<_S2>& __s)
noexcept(is_nothrow_constructible_v<_Sent, const _S2&>)
: _M_last(__s.base())
{ }
template<typename _S2> requires assignable_from<_Sent&, const _S2&>
constexpr move_sentinel&
operator=(const move_sentinel<_S2>& __s)
noexcept(is_nothrow_assignable_v<_Sent, const _S2&>)
{
_M_last = __s.base();
return *this;
}
[[nodiscard]]
constexpr _Sent
base() const
noexcept(is_nothrow_copy_constructible_v<_Sent>)
{ return _M_last; }
private:
_Sent _M_last;
};
#endif // C++20
namespace __detail
{
#if __cplusplus > 201703L && __cpp_lib_concepts
template<typename _Iterator>
struct __move_iter_cat
{ };
template<typename _Iterator>
requires requires { typename iterator_traits<_Iterator>::iterator_category; }
struct __move_iter_cat<_Iterator>
{
using iterator_category
= __clamp_iter_cat<typename iterator_traits<_Iterator>::iterator_category,
random_access_iterator_tag>;
};
#endif
}
// 24.4.3 Move iterators
/**
* Class template move_iterator is an iterator adapter with the same
* behavior as the underlying iterator except that its dereference
* operator implicitly converts the value returned by the underlying
* iterator's dereference operator to an rvalue reference. Some
* generic algorithms can be called with move iterators to replace
* copying with moving.
*/
template<typename _Iterator>
class move_iterator
#if __cplusplus > 201703L && __cpp_lib_concepts
: public __detail::__move_iter_cat<_Iterator>
#endif
{
_Iterator _M_current;
using __traits_type = iterator_traits<_Iterator>;
#if ! (__cplusplus > 201703L && __cpp_lib_concepts)
using __base_ref = typename __traits_type::reference;
#endif
template<typename _Iter2>
friend class move_iterator;
#if __cpp_lib_concepts
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3435. three_way_comparable_with<reverse_iterator<int*>, [...]>
template<typename _Iter2>
static constexpr bool __convertible = !is_same_v<_Iter2, _Iterator>
&& convertible_to<const _Iter2&, _Iterator>;
#endif
#if __cplusplus > 201703L && __cpp_lib_concepts
static auto
_S_iter_concept()
{
if constexpr (random_access_iterator<_Iterator>)
return random_access_iterator_tag{};
else if constexpr (bidirectional_iterator<_Iterator>)
return bidirectional_iterator_tag{};
else if constexpr (forward_iterator<_Iterator>)
return forward_iterator_tag{};
else
return input_iterator_tag{};
}
#endif
public:
using iterator_type = _Iterator;
#if __cplusplus > 201703L && __cpp_lib_concepts
// This is P2520R0, a C++23 change, but we treat it as a DR against C++20.
# define __cpp_lib_move_iterator_concept 202207L
using iterator_concept = decltype(_S_iter_concept());
// iterator_category defined in __move_iter_cat
using value_type = iter_value_t<_Iterator>;
using difference_type = iter_difference_t<_Iterator>;
using pointer = _Iterator;
using reference = iter_rvalue_reference_t<_Iterator>;
#else
typedef typename __traits_type::iterator_category iterator_category;
typedef typename __traits_type::value_type value_type;
typedef typename __traits_type::difference_type difference_type;
// NB: DR 680.
typedef _Iterator pointer;
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 2106. move_iterator wrapping iterators returning prvalues
using reference
= __conditional_t<is_reference<__base_ref>::value,
typename remove_reference<__base_ref>::type&&,
__base_ref>;
#endif
_GLIBCXX17_CONSTEXPR
move_iterator()
: _M_current() { }
explicit _GLIBCXX17_CONSTEXPR
move_iterator(iterator_type __i)
: _M_current(std::move(__i)) { }
template<typename _Iter>
#if __cpp_lib_concepts
requires __convertible<_Iter>
#endif
_GLIBCXX17_CONSTEXPR
move_iterator(const move_iterator<_Iter>& __i)
: _M_current(__i._M_current) { }
template<typename _Iter>
#if __cpp_lib_concepts
requires __convertible<_Iter>
&& assignable_from<_Iterator&, const _Iter&>
#endif
_GLIBCXX17_CONSTEXPR
move_iterator& operator=(const move_iterator<_Iter>& __i)
{
_M_current = __i._M_current;
return *this;
}
#if __cplusplus <= 201703L
[[__nodiscard__]]
_GLIBCXX17_CONSTEXPR iterator_type
base() const
{ return _M_current; }
#else
[[nodiscard]]
constexpr const iterator_type&
base() const & noexcept
{ return _M_current; }
[[nodiscard]]
constexpr iterator_type
base() &&
{ return std::move(_M_current); }
#endif
[[__nodiscard__]]
_GLIBCXX17_CONSTEXPR reference
operator*() const
#if __cplusplus > 201703L && __cpp_lib_concepts
{ return ranges::iter_move(_M_current); }
#else
{ return static_cast<reference>(*_M_current); }
#endif
[[__nodiscard__]]
_GLIBCXX17_CONSTEXPR pointer
operator->() const
{ return _M_current; }
_GLIBCXX17_CONSTEXPR move_iterator&
operator++()
{
++_M_current;
return *this;
}
_GLIBCXX17_CONSTEXPR move_iterator
operator++(int)
{
move_iterator __tmp = *this;
++_M_current;
return __tmp;
}
#if __cpp_lib_concepts
constexpr void
operator++(int) requires (!forward_iterator<_Iterator>)
{ ++_M_current; }
#endif
_GLIBCXX17_CONSTEXPR move_iterator&
operator--()
{
--_M_current;
return *this;
}
_GLIBCXX17_CONSTEXPR move_iterator
operator--(int)
{
move_iterator __tmp = *this;
--_M_current;
return __tmp;
}
[[__nodiscard__]]
_GLIBCXX17_CONSTEXPR move_iterator
operator+(difference_type __n) const
{ return move_iterator(_M_current + __n); }
_GLIBCXX17_CONSTEXPR move_iterator&
operator+=(difference_type __n)
{
_M_current += __n;
return *this;
}
[[__nodiscard__]]
_GLIBCXX17_CONSTEXPR move_iterator
operator-(difference_type __n) const
{ return move_iterator(_M_current - __n); }
_GLIBCXX17_CONSTEXPR move_iterator&
operator-=(difference_type __n)
{
_M_current -= __n;
return *this;
}
[[__nodiscard__]]
_GLIBCXX17_CONSTEXPR reference
operator[](difference_type __n) const
#if __cplusplus > 201703L && __cpp_lib_concepts
{ return ranges::iter_move(_M_current + __n); }
#else
{ return std::move(_M_current[__n]); }
#endif
#if __cplusplus > 201703L && __cpp_lib_concepts
template<sentinel_for<_Iterator> _Sent>
[[nodiscard]]
friend constexpr bool
operator==(const move_iterator& __x, const move_sentinel<_Sent>& __y)
{ return __x.base() == __y.base(); }
template<sized_sentinel_for<_Iterator> _Sent>
[[nodiscard]]
friend constexpr iter_difference_t<_Iterator>
operator-(const move_sentinel<_Sent>& __x, const move_iterator& __y)
{ return __x.base() - __y.base(); }
template<sized_sentinel_for<_Iterator> _Sent>
[[nodiscard]]
friend constexpr iter_difference_t<_Iterator>
operator-(const move_iterator& __x, const move_sentinel<_Sent>& __y)
{ return __x.base() - __y.base(); }
[[nodiscard]]
friend constexpr iter_rvalue_reference_t<_Iterator>
iter_move(const move_iterator& __i)
noexcept(noexcept(ranges::iter_move(__i._M_current)))
{ return ranges::iter_move(__i._M_current); }
template<indirectly_swappable<_Iterator> _Iter2>
friend constexpr void
iter_swap(const move_iterator& __x, const move_iterator<_Iter2>& __y)
noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
{ return ranges::iter_swap(__x._M_current, __y._M_current); }
#endif // C++20
};
template<typename _IteratorL, typename _IteratorR>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator==(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
#if __cplusplus > 201703L && __cpp_lib_concepts
requires requires { { __x.base() == __y.base() } -> convertible_to<bool>; }
#endif
{ return __x.base() == __y.base(); }
#if __cpp_lib_three_way_comparison
template<typename _IteratorL,
three_way_comparable_with<_IteratorL> _IteratorR>
[[__nodiscard__]]
constexpr compare_three_way_result_t<_IteratorL, _IteratorR>
operator<=>(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
{ return __x.base() <=> __y.base(); }
#else
template<typename _IteratorL, typename _IteratorR>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator!=(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
{ return !(__x == __y); }
#endif
template<typename _IteratorL, typename _IteratorR>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator<(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
#if __cplusplus > 201703L && __cpp_lib_concepts
requires requires { { __x.base() < __y.base() } -> convertible_to<bool>; }
#endif
{ return __x.base() < __y.base(); }
template<typename _IteratorL, typename _IteratorR>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator<=(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
#if __cplusplus > 201703L && __cpp_lib_concepts
requires requires { { __y.base() < __x.base() } -> convertible_to<bool>; }
#endif
{ return !(__y < __x); }
template<typename _IteratorL, typename _IteratorR>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator>(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
#if __cplusplus > 201703L && __cpp_lib_concepts
requires requires { { __y.base() < __x.base() } -> convertible_to<bool>; }
#endif
{ return __y < __x; }
template<typename _IteratorL, typename _IteratorR>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator>=(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
#if __cplusplus > 201703L && __cpp_lib_concepts
requires requires { { __x.base() < __y.base() } -> convertible_to<bool>; }
#endif
{ return !(__x < __y); }
// Note: See __normal_iterator operators note from Gaby to understand
// why we have these extra overloads for some move_iterator operators.
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator==(const move_iterator<_Iterator>& __x,
const move_iterator<_Iterator>& __y)
{ return __x.base() == __y.base(); }
#if __cpp_lib_three_way_comparison
template<three_way_comparable _Iterator>
[[__nodiscard__]]
constexpr compare_three_way_result_t<_Iterator>
operator<=>(const move_iterator<_Iterator>& __x,
const move_iterator<_Iterator>& __y)
{ return __x.base() <=> __y.base(); }
#else
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator!=(const move_iterator<_Iterator>& __x,
const move_iterator<_Iterator>& __y)
{ return !(__x == __y); }
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator<(const move_iterator<_Iterator>& __x,
const move_iterator<_Iterator>& __y)
{ return __x.base() < __y.base(); }
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator<=(const move_iterator<_Iterator>& __x,
const move_iterator<_Iterator>& __y)
{ return !(__y < __x); }
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator>(const move_iterator<_Iterator>& __x,
const move_iterator<_Iterator>& __y)
{ return __y < __x; }
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR bool
operator>=(const move_iterator<_Iterator>& __x,
const move_iterator<_Iterator>& __y)
{ return !(__x < __y); }
#endif // ! C++20
// DR 685.
template<typename _IteratorL, typename _IteratorR>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR auto
operator-(const move_iterator<_IteratorL>& __x,
const move_iterator<_IteratorR>& __y)
-> decltype(__x.base() - __y.base())
{ return __x.base() - __y.base(); }
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR move_iterator<_Iterator>
operator+(typename move_iterator<_Iterator>::difference_type __n,
const move_iterator<_Iterator>& __x)
{ return __x + __n; }
template<typename _Iterator>
[[__nodiscard__]]
inline _GLIBCXX17_CONSTEXPR move_iterator<_Iterator>
make_move_iterator(_Iterator __i)
{ return move_iterator<_Iterator>(std::move(__i)); }
template<typename _Iterator, typename _ReturnType
= __conditional_t<__move_if_noexcept_cond
<typename iterator_traits<_Iterator>::value_type>::value,
_Iterator, move_iterator<_Iterator>>>
inline _GLIBCXX17_CONSTEXPR _ReturnType
__make_move_if_noexcept_iterator(_Iterator __i)
{ return _ReturnType(__i); }
// Overload for pointers that matches std::move_if_noexcept more closely,
// returning a constant iterator when we don't want to move.
template<typename _Tp, typename _ReturnType
= __conditional_t<__move_if_noexcept_cond<_Tp>::value,
const _Tp*, move_iterator<_Tp*>>>
inline _GLIBCXX17_CONSTEXPR _ReturnType
__make_move_if_noexcept_iterator(_Tp* __i)
{ return _ReturnType(__i); }
#if __cplusplus > 201703L && __cpp_lib_concepts
// [iterators.common] Common iterators
namespace __detail
{
template<typename _It>
concept __common_iter_has_arrow = indirectly_readable<const _It>
&& (requires(const _It& __it) { __it.operator->(); }
|| is_reference_v<iter_reference_t<_It>>
|| constructible_from<iter_value_t<_It>, iter_reference_t<_It>>);
template<typename _It>
concept __common_iter_use_postfix_proxy
= (!requires (_It& __i) { { *__i++ } -> __can_reference; })
&& constructible_from<iter_value_t<_It>, iter_reference_t<_It>>
&& move_constructible<iter_value_t<_It>>;
} // namespace __detail
/// An iterator/sentinel adaptor for representing a non-common range.
template<input_or_output_iterator _It, sentinel_for<_It> _Sent>
requires (!same_as<_It, _Sent>) && copyable<_It>
class common_iterator
{
template<typename _Tp, typename _Up>
static constexpr bool
_S_noexcept1()
{
if constexpr (is_trivially_default_constructible_v<_Tp>)
return is_nothrow_assignable_v<_Tp&, _Up>;
else
return is_nothrow_constructible_v<_Tp, _Up>;
}
template<typename _It2, typename _Sent2>
static constexpr bool
_S_noexcept()
{ return _S_noexcept1<_It, _It2>() && _S_noexcept1<_Sent, _Sent2>(); }
class __arrow_proxy
{
iter_value_t<_It> _M_keep;
constexpr
__arrow_proxy(iter_reference_t<_It>&& __x)
: _M_keep(std::move(__x)) { }
friend class common_iterator;
public:
constexpr const iter_value_t<_It>*
operator->() const noexcept
{ return std::__addressof(_M_keep); }
};
class __postfix_proxy
{
iter_value_t<_It> _M_keep;
constexpr
__postfix_proxy(iter_reference_t<_It>&& __x)
: _M_keep(std::forward<iter_reference_t<_It>>(__x)) { }
friend class common_iterator;
public:
constexpr const iter_value_t<_It>&
operator*() const noexcept
{ return _M_keep; }
};
public:
constexpr
common_iterator()
noexcept(is_nothrow_default_constructible_v<_It>)
requires default_initializable<_It>
: _M_it(), _M_index(0)
{ }
constexpr
common_iterator(_It __i)
noexcept(is_nothrow_move_constructible_v<_It>)
: _M_it(std::move(__i)), _M_index(0)
{ }
constexpr
common_iterator(_Sent __s)
noexcept(is_nothrow_move_constructible_v<_Sent>)
: _M_sent(std::move(__s)), _M_index(1)
{ }
template<typename _It2, typename _Sent2>
requires convertible_to<const _It2&, _It>
&& convertible_to<const _Sent2&, _Sent>
constexpr
common_iterator(const common_iterator<_It2, _Sent2>& __x)
noexcept(_S_noexcept<const _It2&, const _Sent2&>())
: _M_valueless(), _M_index(__x._M_index)
{
__glibcxx_assert(__x._M_has_value());
if (_M_index == 0)
{
if constexpr (is_trivially_default_constructible_v<_It>)
_M_it = std::move(__x._M_it);
else
std::construct_at(std::__addressof(_M_it), __x._M_it);
}
else if (_M_index == 1)
{
if constexpr (is_trivially_default_constructible_v<_Sent>)
_M_sent = std::move(__x._M_sent);
else
std::construct_at(std::__addressof(_M_sent), __x._M_sent);
}
}
constexpr
common_iterator(const common_iterator& __x)
noexcept(_S_noexcept<const _It&, const _Sent&>())
: _M_valueless(), _M_index(__x._M_index)
{
if (_M_index == 0)
{
if constexpr (is_trivially_default_constructible_v<_It>)
_M_it = __x._M_it;
else
std::construct_at(std::__addressof(_M_it), __x._M_it);
}
else if (_M_index == 1)
{
if constexpr (is_trivially_default_constructible_v<_Sent>)
_M_sent = __x._M_sent;
else
std::construct_at(std::__addressof(_M_sent), __x._M_sent);
}
}
constexpr
common_iterator(common_iterator&& __x)
noexcept(_S_noexcept<_It, _Sent>())
: _M_valueless(), _M_index(__x._M_index)
{
if (_M_index == 0)
{
if constexpr (is_trivially_default_constructible_v<_It>)
_M_it = std::move(__x._M_it);
else
std::construct_at(std::__addressof(_M_it), std::move(__x._M_it));
}
else if (_M_index == 1)
{
if constexpr (is_trivially_default_constructible_v<_Sent>)
_M_sent = std::move(__x._M_sent);
else
std::construct_at(std::__addressof(_M_sent),
std::move(__x._M_sent));
}
}
constexpr common_iterator&
operator=(const common_iterator&) = default;
constexpr common_iterator&
operator=(const common_iterator& __x)
noexcept(is_nothrow_copy_assignable_v<_It>
&& is_nothrow_copy_assignable_v<_Sent>
&& is_nothrow_copy_constructible_v<_It>
&& is_nothrow_copy_constructible_v<_Sent>)
requires (!is_trivially_copy_assignable_v<_It>
|| !is_trivially_copy_assignable_v<_Sent>)
{
_M_assign(__x);
return *this;
}
constexpr common_iterator&
operator=(common_iterator&&) = default;
constexpr common_iterator&
operator=(common_iterator&& __x)
noexcept(is_nothrow_move_assignable_v<_It>
&& is_nothrow_move_assignable_v<_Sent>
&& is_nothrow_move_constructible_v<_It>
&& is_nothrow_move_constructible_v<_Sent>)
requires (!is_trivially_move_assignable_v<_It>
|| !is_trivially_move_assignable_v<_Sent>)
{
_M_assign(std::move(__x));
return *this;
}
template<typename _It2, typename _Sent2>
requires convertible_to<const _It2&, _It>
&& convertible_to<const _Sent2&, _Sent>
&& assignable_from<_It&, const _It2&>
&& assignable_from<_Sent&, const _Sent2&>
constexpr common_iterator&
operator=(const common_iterator<_It2, _Sent2>& __x)
noexcept(is_nothrow_constructible_v<_It, const _It2&>
&& is_nothrow_constructible_v<_Sent, const _Sent2&>
&& is_nothrow_assignable_v<_It&, const _It2&>
&& is_nothrow_assignable_v<_Sent&, const _Sent2&>)
{
__glibcxx_assert(__x._M_has_value());
_M_assign(__x);
return *this;
}
constexpr
~common_iterator()
{
if (_M_index == 0)
_M_it.~_It();
else if (_M_index == 1)
_M_sent.~_Sent();
}
[[nodiscard]]
constexpr decltype(auto)
operator*()
{
__glibcxx_assert(_M_index == 0);
return *_M_it;
}
[[nodiscard]]
constexpr decltype(auto)
operator*() const requires __detail::__dereferenceable<const _It>
{
__glibcxx_assert(_M_index == 0);
return *_M_it;
}
[[nodiscard]]
constexpr auto
operator->() const requires __detail::__common_iter_has_arrow<_It>
{
__glibcxx_assert(_M_index == 0);
if constexpr (is_pointer_v<_It> || requires { _M_it.operator->(); })
return _M_it;
else if constexpr (is_reference_v<iter_reference_t<_It>>)
{
auto&& __tmp = *_M_it;
return std::__addressof(__tmp);
}
else
return __arrow_proxy{*_M_it};
}
constexpr common_iterator&
operator++()
{
__glibcxx_assert(_M_index == 0);
++_M_it;
return *this;
}
constexpr decltype(auto)
operator++(int)
{
__glibcxx_assert(_M_index == 0);
if constexpr (forward_iterator<_It>)
{
common_iterator __tmp = *this;
++*this;
return __tmp;
}
else if constexpr (!__detail::__common_iter_use_postfix_proxy<_It>)
return _M_it++;
else
{
__postfix_proxy __p(**this);
++*this;
return __p;
}
}
template<typename _It2, sentinel_for<_It> _Sent2>
requires sentinel_for<_Sent, _It2>
friend constexpr bool
operator== [[nodiscard]] (const common_iterator& __x,
const common_iterator<_It2, _Sent2>& __y)
{
switch(__x._M_index << 2 | __y._M_index)
{
case 0b0000:
case 0b0101:
return true;
case 0b0001:
return __x._M_it == __y._M_sent;
case 0b0100:
return __x._M_sent == __y._M_it;
default:
__glibcxx_assert(__x._M_has_value());
__glibcxx_assert(__y._M_has_value());
__builtin_unreachable();
}
}
template<typename _It2, sentinel_for<_It> _Sent2>
requires sentinel_for<_Sent, _It2> && equality_comparable_with<_It, _It2>
friend constexpr bool
operator== [[nodiscard]] (const common_iterator& __x,
const common_iterator<_It2, _Sent2>& __y)
{
switch(__x._M_index << 2 | __y._M_index)
{
case 0b0101:
return true;
case 0b0000:
return __x._M_it == __y._M_it;
case 0b0001:
return __x._M_it == __y._M_sent;
case 0b0100:
return __x._M_sent == __y._M_it;
default:
__glibcxx_assert(__x._M_has_value());
__glibcxx_assert(__y._M_has_value());
__builtin_unreachable();
}
}
template<sized_sentinel_for<_It> _It2, sized_sentinel_for<_It> _Sent2>
requires sized_sentinel_for<_Sent, _It2>
friend constexpr iter_difference_t<_It2>
operator- [[nodiscard]] (const common_iterator& __x,
const common_iterator<_It2, _Sent2>& __y)
{
switch(__x._M_index << 2 | __y._M_index)
{
case 0b0101:
return 0;
case 0b0000:
return __x._M_it - __y._M_it;
case 0b0001:
return __x._M_it - __y._M_sent;
case 0b0100:
return __x._M_sent - __y._M_it;
default:
__glibcxx_assert(__x._M_has_value());
__glibcxx_assert(__y._M_has_value());
__builtin_unreachable();
}
}
[[nodiscard]]
friend constexpr iter_rvalue_reference_t<_It>
iter_move(const common_iterator& __i)
noexcept(noexcept(ranges::iter_move(std::declval<const _It&>())))
requires input_iterator<_It>
{
__glibcxx_assert(__i._M_index == 0);
return ranges::iter_move(__i._M_it);
}
template<indirectly_swappable<_It> _It2, typename _Sent2>
friend constexpr void
iter_swap(const common_iterator& __x,
const common_iterator<_It2, _Sent2>& __y)
noexcept(noexcept(ranges::iter_swap(std::declval<const _It&>(),
std::declval<const _It2&>())))
{
__glibcxx_assert(__x._M_index == 0);
__glibcxx_assert(__y._M_index == 0);
return ranges::iter_swap(__x._M_it, __y._M_it);
}
private:
template<input_or_output_iterator _It2, sentinel_for<_It2> _Sent2>
requires (!same_as<_It2, _Sent2>) && copyable<_It2>
friend class common_iterator;
constexpr bool
_M_has_value() const noexcept { return _M_index != _S_valueless; }
template<typename _CIt>
constexpr void
_M_assign(_CIt&& __x)
{
if (_M_index == __x._M_index)
{
if (_M_index == 0)
_M_it = std::forward<_CIt>(__x)._M_it;
else if (_M_index == 1)
_M_sent = std::forward<_CIt>(__x)._M_sent;
}
else
{
if (_M_index == 0)
_M_it.~_It();
else if (_M_index == 1)
_M_sent.~_Sent();
_M_index = _S_valueless;
if (__x._M_index == 0)
std::construct_at(std::__addressof(_M_it),
std::forward<_CIt>(__x)._M_it);
else if (__x._M_index == 1)
std::construct_at(std::__addressof(_M_sent),
std::forward<_CIt>(__x)._M_sent);
_M_index = __x._M_index;
}
}
union
{
_It _M_it;
_Sent _M_sent;
unsigned char _M_valueless;
};
unsigned char _M_index; // 0 == _M_it, 1 == _M_sent, 2 == valueless
static constexpr unsigned char _S_valueless{2};
};
template<typename _It, typename _Sent>
struct incrementable_traits<common_iterator<_It, _Sent>>
{
using difference_type = iter_difference_t<_It>;
};
template<input_iterator _It, typename _Sent>
struct iterator_traits<common_iterator<_It, _Sent>>
{
private:
template<typename _Iter>
struct __ptr
{
using type = void;
};
template<typename _Iter>
requires __detail::__common_iter_has_arrow<_Iter>
struct __ptr<_Iter>
{
using _CIter = common_iterator<_Iter, _Sent>;
using type = decltype(std::declval<const _CIter&>().operator->());
};
static auto
_S_iter_cat()
{
using _Traits = iterator_traits<_It>;
if constexpr (requires { requires derived_from<typename _Traits::iterator_category,
forward_iterator_tag>; })
return forward_iterator_tag{};
else
return input_iterator_tag{};
}
public:
using iterator_concept = __conditional_t<forward_iterator<_It>,
forward_iterator_tag,
input_iterator_tag>;
using iterator_category = decltype(_S_iter_cat());
using value_type = iter_value_t<_It>;
using difference_type = iter_difference_t<_It>;
using pointer = typename __ptr<_It>::type;
using reference = iter_reference_t<_It>;
};
// [iterators.counted] Counted iterators
namespace __detail
{
template<typename _It>
struct __counted_iter_value_type
{ };
template<indirectly_readable _It>
struct __counted_iter_value_type<_It>
{ using value_type = iter_value_t<_It>; };
template<typename _It>
struct __counted_iter_concept
{ };
template<typename _It>
requires requires { typename _It::iterator_concept; }
struct __counted_iter_concept<_It>
{ using iterator_concept = typename _It::iterator_concept; };
template<typename _It>
struct __counted_iter_cat
{ };
template<typename _It>
requires requires { typename _It::iterator_category; }
struct __counted_iter_cat<_It>
{ using iterator_category = typename _It::iterator_category; };
}
/// An iterator adaptor that keeps track of the distance to the end.
template<input_or_output_iterator _It>
class counted_iterator
: public __detail::__counted_iter_value_type<_It>,
public __detail::__counted_iter_concept<_It>,
public __detail::__counted_iter_cat<_It>
{
public:
using iterator_type = _It;
// value_type defined in __counted_iter_value_type
using difference_type = iter_difference_t<_It>;
// iterator_concept defined in __counted_iter_concept
// iterator_category defined in __counted_iter_cat
constexpr counted_iterator() requires default_initializable<_It> = default;
constexpr
counted_iterator(_It __i, iter_difference_t<_It> __n)
: _M_current(std::move(__i)), _M_length(__n)
{ __glibcxx_assert(__n >= 0); }
template<typename _It2>
requires convertible_to<const _It2&, _It>
constexpr
counted_iterator(const counted_iterator<_It2>& __x)
: _M_current(__x._M_current), _M_length(__x._M_length)
{ }
template<typename _It2>
requires assignable_from<_It&, const _It2&>
constexpr counted_iterator&
operator=(const counted_iterator<_It2>& __x)
{
_M_current = __x._M_current;
_M_length = __x._M_length;
return *this;
}
[[nodiscard]]
constexpr const _It&
base() const & noexcept
{ return _M_current; }
[[nodiscard]]
constexpr _It
base() &&
noexcept(is_nothrow_move_constructible_v<_It>)
{ return std::move(_M_current); }
[[nodiscard]]
constexpr iter_difference_t<_It>
count() const noexcept { return _M_length; }
[[nodiscard]]
constexpr decltype(auto)
operator*()
noexcept(noexcept(*_M_current))
{
__glibcxx_assert( _M_length > 0 );
return *_M_current;
}
[[nodiscard]]
constexpr decltype(auto)
operator*() const
noexcept(noexcept(*_M_current))
requires __detail::__dereferenceable<const _It>
{
__glibcxx_assert( _M_length > 0 );
return *_M_current;
}
[[nodiscard]]
constexpr auto
operator->() const noexcept
requires contiguous_iterator<_It>
{ return std::to_address(_M_current); }
constexpr counted_iterator&
operator++()
{
__glibcxx_assert(_M_length > 0);
++_M_current;
--_M_length;
return *this;
}
constexpr decltype(auto)
operator++(int)
{
__glibcxx_assert(_M_length > 0);
--_M_length;
__try
{
return _M_current++;
} __catch(...) {
++_M_length;
__throw_exception_again;
}
}
constexpr counted_iterator
operator++(int) requires forward_iterator<_It>
{
auto __tmp = *this;
++*this;
return __tmp;
}
constexpr counted_iterator&
operator--() requires bidirectional_iterator<_It>
{
--_M_current;
++_M_length;
return *this;
}
constexpr counted_iterator
operator--(int) requires bidirectional_iterator<_It>
{
auto __tmp = *this;
--*this;
return __tmp;
}
[[nodiscard]]
constexpr counted_iterator
operator+(iter_difference_t<_It> __n) const
requires random_access_iterator<_It>
{ return counted_iterator(_M_current + __n, _M_length - __n); }
[[nodiscard]]
friend constexpr counted_iterator
operator+(iter_difference_t<_It> __n, const counted_iterator& __x)
requires random_access_iterator<_It>
{ return __x + __n; }
constexpr counted_iterator&
operator+=(iter_difference_t<_It> __n)
requires random_access_iterator<_It>
{
__glibcxx_assert(__n <= _M_length);
_M_current += __n;
_M_length -= __n;
return *this;
}
[[nodiscard]]
constexpr counted_iterator
operator-(iter_difference_t<_It> __n) const
requires random_access_iterator<_It>
{ return counted_iterator(_M_current - __n, _M_length + __n); }
template<common_with<_It> _It2>
[[nodiscard]]
friend constexpr iter_difference_t<_It2>
operator-(const counted_iterator& __x,
const counted_iterator<_It2>& __y)
{ return __y._M_length - __x._M_length; }
[[nodiscard]]
friend constexpr iter_difference_t<_It>
operator-(const counted_iterator& __x, default_sentinel_t)
{ return -__x._M_length; }
[[nodiscard]]
friend constexpr iter_difference_t<_It>
operator-(default_sentinel_t, const counted_iterator& __y)
{ return __y._M_length; }
constexpr counted_iterator&
operator-=(iter_difference_t<_It> __n)
requires random_access_iterator<_It>
{
__glibcxx_assert(-__n <= _M_length);
_M_current -= __n;
_M_length += __n;
return *this;
}
[[nodiscard]]
constexpr decltype(auto)
operator[](iter_difference_t<_It> __n) const
noexcept(noexcept(_M_current[__n]))
requires random_access_iterator<_It>
{
__glibcxx_assert(__n < _M_length);
return _M_current[__n];
}
template<common_with<_It> _It2>
[[nodiscard]]
friend constexpr bool
operator==(const counted_iterator& __x,
const counted_iterator<_It2>& __y)
{ return __x._M_length == __y._M_length; }
[[nodiscard]]
friend constexpr bool
operator==(const counted_iterator& __x, default_sentinel_t)
{ return __x._M_length == 0; }
template<common_with<_It> _It2>
[[nodiscard]]
friend constexpr strong_ordering
operator<=>(const counted_iterator& __x,
const counted_iterator<_It2>& __y)
{ return __y._M_length <=> __x._M_length; }
[[nodiscard]]
friend constexpr iter_rvalue_reference_t<_It>
iter_move(const counted_iterator& __i)
noexcept(noexcept(ranges::iter_move(__i._M_current)))
requires input_iterator<_It>
{
__glibcxx_assert( __i._M_length > 0 );
return ranges::iter_move(__i._M_current);
}
template<indirectly_swappable<_It> _It2>
friend constexpr void
iter_swap(const counted_iterator& __x,
const counted_iterator<_It2>& __y)
noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
{
__glibcxx_assert( __x._M_length > 0 && __y._M_length > 0 );
ranges::iter_swap(__x._M_current, __y._M_current);
}
private:
template<input_or_output_iterator _It2> friend class counted_iterator;
_It _M_current = _It();
iter_difference_t<_It> _M_length = 0;
};
template<input_iterator _It>
requires same_as<__detail::__iter_traits<_It>, iterator_traits<_It>>
struct iterator_traits<counted_iterator<_It>> : iterator_traits<_It>
{
using pointer = __conditional_t<contiguous_iterator<_It>,
add_pointer_t<iter_reference_t<_It>>,
void>;
};
#endif // C++20
/// @} group iterators
template<typename _Iterator>
_GLIBCXX20_CONSTEXPR
auto
__niter_base(move_iterator<_Iterator> __it)
-> decltype(make_move_iterator(__niter_base(__it.base())))
{ return make_move_iterator(__niter_base(__it.base())); }
template<typename _Iterator>
struct __is_move_iterator<move_iterator<_Iterator> >
{
enum { __value = 1 };
typedef __true_type __type;
};
template<typename _Iterator>
_GLIBCXX20_CONSTEXPR
auto
__miter_base(move_iterator<_Iterator> __it)
-> decltype(__miter_base(__it.base()))
{ return __miter_base(__it.base()); }
#define _GLIBCXX_MAKE_MOVE_ITERATOR(_Iter) std::make_move_iterator(_Iter)
#define _GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(_Iter) \
std::__make_move_if_noexcept_iterator(_Iter)
#else
#define _GLIBCXX_MAKE_MOVE_ITERATOR(_Iter) (_Iter)
#define _GLIBCXX_MAKE_MOVE_IF_NOEXCEPT_ITERATOR(_Iter) (_Iter)
#endif // C++11
#if __cpp_deduction_guides >= 201606
// These helper traits are used for deduction guides
// of associative containers.
template<typename _InputIterator>
using __iter_key_t = remove_const_t<
typename iterator_traits<_InputIterator>::value_type::first_type>;
template<typename _InputIterator>
using __iter_val_t =
typename iterator_traits<_InputIterator>::value_type::second_type;
template<typename _T1, typename _T2>
struct pair;
template<typename _InputIterator>
using __iter_to_alloc_t =
pair<add_const_t<__iter_key_t<_InputIterator>>,
__iter_val_t<_InputIterator>>;
#endif // __cpp_deduction_guides
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#ifdef _GLIBCXX_DEBUG
# include <debug/stl_iterator.h>
#endif
#endif
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