microsoft
/
STL
зеркало из https://github.com/microsoft/STL.git
1
0
Форкнуть 0
Код Задачи Пакеты Проекты Релизы Вики Активность
STL/stl/inc/xutility

5846 строки
224 KiB
C++
Исходник Ответственный История

// xutility internal header
// Copyright (c) Microsoft Corporation.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#pragma once
#ifndef _XUTILITY_
#define _XUTILITY_
#include <yvals.h>
#if _STL_COMPILER_PREPROCESSOR
#include <climits>
#include <cstdlib>
#include <cstring>
#include <utility>
#pragma pack(push, _CRT_PACKING)
#pragma warning(push, _STL_WARNING_LEVEL)
#pragma warning(disable : _STL_DISABLED_WARNINGS)
_STL_DISABLE_CLANG_WARNINGS
#pragma push_macro("new")
#undef new
#if (defined(_M_IX86) || defined(_M_X64)) && !defined(_M_CEE_PURE) && !defined(_M_HYBRID)
#define _USE_STD_VECTOR_ALGORITHMS 1
#else
#define _USE_STD_VECTOR_ALGORITHMS 0
#endif
#if _USE_STD_VECTOR_ALGORITHMS
_EXTERN_C
// The "noalias" attribute tells the compiler optimizer that pointers going into these hand-vectorized algorithms
// won't be stored beyond the lifetime of the function, and that the function will only reference arrays denoted by
// those pointers. The optimizer also assumes in that case that a pointer parameter is not returned to the caller via
// the return value, so functions using "noalias" must usually return void. This attribute is valuable because these
// functions are in native code objects that the compiler cannot analyze. In the absence of the noalias attribute, the
// compiler has to assume that the denoted arrays are "globally address taken", and that any later calls to
// unanalyzable routines may modify those arrays.
__declspec(noalias) void __cdecl __std_reverse_trivially_swappable_1(void* _First, void* _Last) noexcept;
__declspec(noalias) void __cdecl __std_reverse_trivially_swappable_2(void* _First, void* _Last) noexcept;
__declspec(noalias) void __cdecl __std_reverse_trivially_swappable_4(void* _First, void* _Last) noexcept;
__declspec(noalias) void __cdecl __std_reverse_trivially_swappable_8(void* _First, void* _Last) noexcept;
__declspec(noalias) void __cdecl __std_swap_ranges_trivially_swappable_noalias(
void* _First1, void* _Last1, void* _First2) noexcept;
_END_EXTERN_C
#endif // _USE_STD_VECTOR_ALGORITHMS
_STD_BEGIN
// FUNCTION TEMPLATE _Bit_cast
template <class _To, class _From,
enable_if_t<conjunction_v<bool_constant<sizeof(_To) == sizeof(_From)>, is_trivially_copyable<_To>,
is_trivially_copyable<_From>>,
int> = 0>
#ifdef __CUDACC__
_NODISCARD _To _Bit_cast(const _From& _Val) noexcept {
_To _To_obj; // assumes default-init
_CSTD memcpy(_STD addressof(_To_obj), _STD addressof(_Val), sizeof(_To));
return _To_obj;
}
#else // ^^^ workaround ^^^ / vvv no workaround vvv
_NODISCARD constexpr _To _Bit_cast(const _From& _Val) noexcept {
return __builtin_bit_cast(_To, _Val);
}
#endif // ^^^ no workaround ^^^
// STRUCT TEMPLATE _Get_first_parameter
template <class _Ty>
struct _Get_first_parameter;
template <template <class, class...> class _Ty, class _First, class... _Rest>
struct _Get_first_parameter<_Ty<_First, _Rest...>> { // given _Ty<_First, _Rest...>, extract _First
using type = _First;
};
// STRUCT TEMPLATE _Replace_first_parameter
template <class _Newfirst, class _Ty>
struct _Replace_first_parameter;
template <class _Newfirst, template <class, class...> class _Ty, class _First, class... _Rest>
struct _Replace_first_parameter<_Newfirst, _Ty<_First, _Rest...>> { // given _Ty<_First, _Rest...>, replace _First
using type = _Ty<_Newfirst, _Rest...>;
};
// STRUCT TEMPLATE _Get_element_type
template <class _Ty, class = void>
struct _Get_element_type {
using type = typename _Get_first_parameter<_Ty>::type;
};
template <class _Ty>
struct _Get_element_type<_Ty, void_t<typename _Ty::element_type>> {
using type = typename _Ty::element_type;
};
// STRUCT TEMPLATE _Get_ptr_difference_type
template <class _Ty, class = void>
struct _Get_ptr_difference_type {
using type = ptrdiff_t;
};
template <class _Ty>
struct _Get_ptr_difference_type<_Ty, void_t<typename _Ty::difference_type>> {
using type = typename _Ty::difference_type;
};
// STRUCT TEMPLATE _Get_rebind_alias
template <class _Ty, class _Other, class = void>
struct _Get_rebind_alias {
using type = typename _Replace_first_parameter<_Other, _Ty>::type;
};
template <class _Ty, class _Other>
struct _Get_rebind_alias<_Ty, _Other, void_t<typename _Ty::template rebind<_Other>>> {
using type = typename _Ty::template rebind<_Other>;
};
// STRUCT TEMPLATE pointer_traits
template <class _Ty>
struct pointer_traits {
using pointer = _Ty;
using element_type = typename _Get_element_type<_Ty>::type;
using difference_type = typename _Get_ptr_difference_type<_Ty>::type;
template <class _Other>
using rebind = typename _Get_rebind_alias<_Ty, _Other>::type;
using _Reftype = conditional_t<is_void_v<element_type>, char, element_type>&;
_NODISCARD static pointer pointer_to(_Reftype _Val) noexcept(noexcept(_Ty::pointer_to(_Val))) /* strengthened */ {
return _Ty::pointer_to(_Val);
}
};
template <class _Ty>
struct pointer_traits<_Ty*> {
using pointer = _Ty*;
using element_type = _Ty;
using difference_type = ptrdiff_t;
template <class _Other>
using rebind = _Other*;
using _Reftype = conditional_t<is_void_v<_Ty>, char, _Ty>&;
_NODISCARD static _CONSTEXPR20 pointer pointer_to(_Reftype _Val) noexcept {
return _STD addressof(_Val);
}
};
#if _HAS_CXX20
// FUNCTION TEMPLATE to_address
template <class _Ty, class = void>
inline constexpr bool _Has_to_address_v = false; // determines whether _Ptr has pointer_traits<_Ptr>::to_address(p)
template <class _Ty>
inline constexpr bool
_Has_to_address_v<_Ty, void_t<decltype(pointer_traits<_Ty>::to_address(_STD declval<const _Ty&>()))>> = true;
template <class _Ty>
_NODISCARD constexpr _Ty* to_address(_Ty* const _Val) noexcept {
static_assert(!is_function_v<_Ty>,
"N4810 20.10.4 [pointer.conversion]/2: The program is ill-formed if T is a function type.");
return _Val;
}
template <class _Ptr>
_NODISCARD constexpr auto to_address(const _Ptr& _Val) noexcept {
if constexpr (_Has_to_address_v<_Ptr>) {
return pointer_traits<_Ptr>::to_address(_Val);
} else {
return _STD to_address(_Val.operator->()); // plain pointer overload must come first
}
}
// STRUCT identity
struct identity {
template <class _Ty>
_NODISCARD constexpr _Ty&& operator()(_Ty&& _Left) const noexcept {
return _STD forward<_Ty>(_Left);
}
using is_transparent = int;
};
#endif // _HAS_CXX20
// FUNCTION TEMPLATE _Pass_fn
// TRANSITION, VSO-386225
template <class _Fx>
struct _Ref_fn { // pass function object by value as a reference
template <class... _Args>
constexpr decltype(auto) operator()(_Args&&... _Vals) { // forward function call operator
return _Fn(_STD forward<_Args>(_Vals)...);
}
_Fx& _Fn;
};
template <class _Fn>
_INLINE_VAR constexpr bool
_Pass_functor_by_value_v = sizeof(_Fn) <= sizeof(void*)
&& conjunction_v<is_trivially_copy_constructible<_Fn>, is_trivially_destructible<_Fn>>;
template <class _Fn, enable_if_t<_Pass_functor_by_value_v<_Fn>, int> = 0> // TRANSITION, if constexpr
constexpr _Fn _Pass_fn(_Fn _Val) { // pass functor by value
return _Val;
}
template <class _Fn, enable_if_t<!_Pass_functor_by_value_v<_Fn>, int> = 0>
constexpr _Ref_fn<_Fn> _Pass_fn(_Fn& _Val) { // pass functor by "reference"
return {_Val};
}
// STRUCT _Unused_parameter
struct _Unused_parameter { // generic unused parameter struct
constexpr _Unused_parameter() noexcept = default;
template <class _Ty>
constexpr _Unused_parameter(_Ty&&) noexcept {}
};
// ALIAS _Any_tag
using _Any_tag = _Unused_parameter; // generic fallback/default/"other" target for tag dispatch
// ALIAS TEMPLATE _Algorithm_int_t
template <class _Ty>
using _Algorithm_int_t = conditional_t<is_integral_v<_Ty>, _Ty, ptrdiff_t>;
// ITERATOR STUFF (from <iterator>)
// ITERATOR TAGS (from <iterator>)
struct input_iterator_tag {};
struct output_iterator_tag {};
struct forward_iterator_tag : input_iterator_tag {};
struct bidirectional_iterator_tag : forward_iterator_tag {};
struct random_access_iterator_tag : bidirectional_iterator_tag {};
#ifdef __cpp_lib_concepts
struct contiguous_iterator_tag : random_access_iterator_tag {};
// ALIAS TEMPLATE _With_reference
template <class _Ty>
using _With_reference = _Ty&;
// CONCEPT _Can_reference
// clang-format off
template <class _Ty>
concept _Can_reference = requires { typename _With_reference<_Ty>; };
// CONCEPT _Dereferenceable
template <class _Ty>
concept _Dereferenceable = requires(_Ty& __t) {
{ *__t } -> _Can_reference;
};
// clang-format on
// CONCEPT _Has_member_iterator_concept
template <class _Ty>
concept _Has_member_iterator_concept = requires {
typename _Ty::iterator_concept;
};
// CONCEPT _Has_member_iterator_category
template <class _Ty>
concept _Has_member_iterator_category = requires {
typename _Ty::iterator_category;
};
// CONCEPT _Has_member_value_type
template <class _Ty>
concept _Has_member_value_type = requires {
typename _Ty::value_type;
};
// CONCEPT _Has_member_element_type
template <class _Ty>
concept _Has_member_element_type = requires {
typename _Ty::element_type;
};
// CONCEPT _Has_member_difference_type
template <class _Ty>
concept _Has_member_difference_type = requires {
typename _Ty::difference_type;
};
// CONCEPT _Has_member_pointer
template <class _Ty>
concept _Has_member_pointer = requires {
typename _Ty::pointer;
};
// CONCEPT _Has_member_reference
template <class _Ty>
concept _Has_member_reference = requires {
typename _Ty::reference;
};
// STRUCT TEMPLATE incrementable_traits
template <class>
struct incrementable_traits {};
// clang-format off
template <class _Ty>
requires is_object_v<_Ty>
struct incrementable_traits<_Ty*> {
using difference_type = ptrdiff_t;
};
// clang-format on
template <class _Ty>
struct incrementable_traits<const _Ty> : incrementable_traits<_Ty> {};
template <_Has_member_difference_type _Ty>
struct incrementable_traits<_Ty> {
using difference_type = typename _Ty::difference_type;
};
// clang-format off
template <class _Ty>
concept _Can_difference = requires(const _Ty& __a, const _Ty& __b) {
{ __a - __b } -> integral;
};
template <class _Ty>
requires (!_Has_member_difference_type<_Ty> && _Can_difference<_Ty>)
struct incrementable_traits<_Ty> {
using difference_type = make_signed_t<decltype(_STD declval<_Ty>() - _STD declval<_Ty>())>;
};
// clang-format on
// ALIAS TEMPLATE iter_difference_t
template <class _Ty>
concept _Is_from_primary = _Same_impl<typename _Ty::_From_primary, _Ty>;
template <class>
struct iterator_traits;
template <class _Ty>
using iter_difference_t = typename conditional_t<_Is_from_primary<iterator_traits<remove_cvref_t<_Ty>>>,
incrementable_traits<remove_cvref_t<_Ty>>, iterator_traits<remove_cvref_t<_Ty>>>::difference_type;
// STRUCT TEMPLATE indirectly_readable_traits
template <class>
struct _Cond_value_type {};
// clang-format off
template <class _Ty>
requires is_object_v<_Ty>
struct _Cond_value_type<_Ty> {
using value_type = remove_cv_t<_Ty>;
};
// clang-format on
template <class>
struct indirectly_readable_traits {};
template <class _Ty>
struct indirectly_readable_traits<_Ty*> : _Cond_value_type<_Ty> {};
// clang-format off
template <class _Ty>
requires is_array_v<_Ty>
struct indirectly_readable_traits<_Ty> {
using value_type = remove_cv_t<remove_extent_t<_Ty>>;
};
// clang-format on
template <class _Ty>
struct indirectly_readable_traits<const _Ty> : indirectly_readable_traits<_Ty> {};
template <_Has_member_value_type _Ty>
struct indirectly_readable_traits<_Ty> : _Cond_value_type<typename _Ty::value_type> {};
template <_Has_member_element_type _Ty>
struct indirectly_readable_traits<_Ty> : _Cond_value_type<typename _Ty::element_type> {};
// ALIAS TEMPLATE iter_value_t
template <class _Ty>
using iter_value_t = typename conditional_t<_Is_from_primary<iterator_traits<remove_cvref_t<_Ty>>>,
indirectly_readable_traits<remove_cvref_t<_Ty>>, iterator_traits<remove_cvref_t<_Ty>>>::value_type;
// ALIAS TEMPLATE iter_reference_t
template <_Dereferenceable _Ty>
using iter_reference_t = decltype(*_STD declval<_Ty&>());
// STRUCT TEMPLATE _Iterator_traits_base
template <class>
struct _Iterator_traits_base {};
// clang-format off
template <class _It>
concept _Has_iter_types = _Has_member_difference_type<_It> && _Has_member_value_type<_It> && _Has_member_reference<_It>
&& _Has_member_iterator_category<_It>;
// clang-format on
template <bool _Has_member_typedef>
struct _Old_iter_traits_pointer {
template <class _It>
using _Apply = typename _It::pointer;
};
template <>
struct _Old_iter_traits_pointer<false> {
template <class>
using _Apply = void;
};
template <_Has_iter_types _It>
struct _Iterator_traits_base<_It> {
using iterator_category = typename _It::iterator_category;
using difference_type = typename _It::difference_type;
using value_type = typename _It::value_type;
using pointer = typename _Old_iter_traits_pointer<_Has_member_pointer<_It>>::template _Apply<_It>;
using reference = typename _It::reference;
};
template <bool _Has_member_typedef>
struct _Iter_traits_difference {
template <class _It>
using _Apply = typename incrementable_traits<_It>::difference_type;
};
template <>
struct _Iter_traits_difference<false> {
template <class>
using _Apply = void;
};
// clang-format off
template <class _It>
concept _Cpp17_iterator = // per LWG-3420
requires(_It __i) {
{ *__i } -> _Can_reference;
{ ++__i } -> same_as<_It&>;
{ *__i++ } -> _Can_reference;
}
&& copyable<_It>;
template <class _It>
concept _Cpp17_input_iterator = _Cpp17_iterator<_It>
&& equality_comparable<_It>
&& _Has_member_difference_type<incrementable_traits<_It>>
&& _Has_member_value_type<indirectly_readable_traits<_It>>
&& requires(_It __i) {
typename common_reference_t<iter_reference_t<_It>&&, typename indirectly_readable_traits<_It>::value_type&>;
typename common_reference_t<decltype(*__i++)&&, typename indirectly_readable_traits<_It>::value_type&>;
requires signed_integral<typename incrementable_traits<_It>::difference_type>;
};
#if 1 // TRANSITION, VSO-1002863
template <class _Ty>
using _Member_iterator_category = typename _Ty::iterator_category;
#endif // TRANSITION, VSO-1002863
template <class _It>
requires (!_Has_iter_types<_It> && _Cpp17_iterator<_It> && !_Cpp17_input_iterator<_It>
// Implements the proposed resolution of LWG-3283:
#if 1 // TRANSITION, VSO-1002863
&& (!requires { typename _It::iterator_category; }
|| derived_from<_Member_iterator_category<_It>, output_iterator_tag>))
#else // ^^^ workaround / no workaround vvv
&& (!requires { typename _It::iterator_category; }
|| derived_from<typename _It::iterator_category, output_iterator_tag>))
#endif // TRANSITION, VSO-1002863
struct _Iterator_traits_base<_It> {
using iterator_category = output_iterator_tag;
using difference_type =
typename _Iter_traits_difference<_Has_member_difference_type<incrementable_traits<_It>>>::template _Apply<_It>;
using value_type = void;
using pointer = void;
using reference = void;
};
// clang-format on
enum class _Itraits_pointer_strategy { _Use_void, _Use_member, _Use_decltype };
template <_Itraits_pointer_strategy>
struct _Iter_traits_pointer;
template <>
struct _Iter_traits_pointer<_Itraits_pointer_strategy::_Use_void> {
template <class>
using _Apply = void;
};
template <>
struct _Iter_traits_pointer<_Itraits_pointer_strategy::_Use_member> {
template <class _It>
using _Apply = typename _It::pointer;
};
template <>
struct _Iter_traits_pointer<_Itraits_pointer_strategy::_Use_decltype> {
template <class _It>
using _Apply = decltype(_STD declval<_It&>().operator->());
};
template <class _Ty>
concept _Has_op_arrow = requires(_Ty&& __t) {
static_cast<_Ty&&>(__t).operator->();
};
template <bool _Has_member_typedef>
struct _Iter_traits_reference {
template <class _It>
using _Apply = typename _It::reference;
};
template <>
struct _Iter_traits_reference<false> {
template <class _It>
using _Apply = iter_reference_t<_It>;
};
template <bool _Is_random>
struct _Iter_traits_category4 {
using type = random_access_iterator_tag;
};
template <>
struct _Iter_traits_category4<false> {
using type = bidirectional_iterator_tag;
};
// clang-format off
template <class _It>
concept _Cpp17_random_delta = totally_ordered<_It>
&& requires(_It __i, typename incrementable_traits<_It>::difference_type __n) {
{ __i += __n } -> same_as<_It&>;
{ __i -= __n } -> same_as<_It&>;
{ __i + __n } -> same_as<_It>;
{ __n + __i } -> same_as<_It>;
{ __i - __n } -> same_as<_It>;
{ __i - __i } -> same_as<decltype(__n)>;
{ __i[__n] } -> convertible_to<iter_reference_t<_It>>;
};
// clang-format on
template <bool _Is_bidi>
struct _Iter_traits_category3 {
template <class _It>
using _Apply = typename _Iter_traits_category4<_Cpp17_random_delta<_It>>::type;
};
template <>
struct _Iter_traits_category3<false> {
template <class>
using _Apply = forward_iterator_tag;
};
// clang-format off
template <class _It>
concept _Cpp17_bidi_delta = requires(_It __i) {
{ --__i } -> same_as<_It&>;
{ __i-- } -> convertible_to<const _It&>;
requires same_as<decltype(*__i--), iter_reference_t<_It>>;
};
// clang-format on
template <bool _Is_forward>
struct _Iter_traits_category2 {
template <class _It>
using _Apply = typename _Iter_traits_category3<_Cpp17_bidi_delta<_It>>::template _Apply<_It>;
};
template <>
struct _Iter_traits_category2<false> {
template <class>
using _Apply = input_iterator_tag;
};
// clang-format off
template <class _It>
concept _Cpp17_forward_delta = constructible_from<_It> && is_lvalue_reference_v<iter_reference_t<_It>>
&& same_as<remove_cvref_t<iter_reference_t<_It>>, typename indirectly_readable_traits<_It>::value_type>
&& requires(_It __i) {
{ __i++ } -> convertible_to<const _It&>;
requires same_as<decltype(*__i++), iter_reference_t<_It>>;
};
// clang-format on
template <bool _Has_member_typedef>
struct _Iter_traits_category {
template <class _It>
using _Apply = typename _It::iterator_category;
};
template <>
struct _Iter_traits_category<false> {
template <class _It>
using _Apply = typename _Iter_traits_category2<_Cpp17_forward_delta<_It>>::template _Apply<_It>;
};
// clang-format off
template <class _It>
requires (!_Has_iter_types<_It> && _Cpp17_input_iterator<_It>)
struct _Iterator_traits_base<_It> {
using iterator_category = typename _Iter_traits_category<_Has_member_iterator_category<_It>>::template _Apply<_It>;
using difference_type = typename incrementable_traits<_It>::difference_type;
using value_type = typename indirectly_readable_traits<_It>::value_type;
using pointer = typename _Iter_traits_pointer<(
_Has_member_pointer<_It> ? _Itraits_pointer_strategy::_Use_member
: _Has_op_arrow<_It&> ? _Itraits_pointer_strategy::_Use_decltype
: _Itraits_pointer_strategy::_Use_void)>::template _Apply<_It>;
using reference = typename _Iter_traits_reference<_Has_member_reference<_It>>::template _Apply<_It>;
};
// clang-format on
// STRUCT TEMPLATE iterator_traits
template <class _Ty>
struct iterator_traits : _Iterator_traits_base<_Ty> {
using _From_primary = iterator_traits;
};
// clang-format off
template <class _Ty>
requires is_object_v<_Ty>
struct iterator_traits<_Ty*> {
using iterator_concept = contiguous_iterator_tag;
using iterator_category = random_access_iterator_tag;
using value_type = remove_cv_t<_Ty>;
using difference_type = ptrdiff_t;
using pointer = _Ty*;
using reference = _Ty&;
};
// clang-format on
// CUSTOMIZATION POINT OBJECT iter_move
namespace ranges {
// STRUCT TEMPLATE _Choice_t
template <class _Ty>
struct _Choice_t {
_Ty _Strategy = _Ty{};
bool _No_throw = false;
};
namespace _Iter_move {
void iter_move(); // Block unqualified name lookup
// clang-format off
template <class _Ty>
concept _Has_ADL = _Has_class_or_enum_type<_Ty> && requires(_Ty&& __t) {
iter_move(static_cast<_Ty&&>(__t));
};
template <class _Ty>
concept _Can_deref = requires(_Ty&& __t) {
*static_cast<_Ty&&>(__t);
};
class _Cpo {
private:
enum class _St { _None, _Custom, _Fallback };
template <class _Ty>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
if constexpr (_Has_ADL<_Ty>) {
return {_St::_Custom, noexcept(iter_move(_STD declval<_Ty>()))};
} else if constexpr (_Can_deref<_Ty>) {
return {_St::_Fallback, noexcept(*_STD declval<_Ty>())};
} else {
return {_St::_None};
}
}
template <class _Ty>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty>();
public:
template <class _Ty>
requires (_Choice<_Ty>._Strategy != _St::_None)
_NODISCARD constexpr decltype(auto) operator()(_Ty&& _Val) const noexcept(_Choice<_Ty>._No_throw) {
if constexpr (_Choice<_Ty>._Strategy == _St::_Custom) {
return iter_move(static_cast<_Ty&&>(_Val));
} else if constexpr (_Choice<_Ty>._Strategy == _St::_Fallback) {
using _Ref = decltype(*static_cast<_Ty&&>(_Val));
if constexpr (is_lvalue_reference_v<_Ref>) {
return _STD move(*static_cast<_Ty&&>(_Val));
} else {
return *static_cast<_Ty&&>(_Val);
}
} else {
static_assert(_Always_false<_Ty>, "should be unreachable");
}
}
};
// clang-format on
} // namespace _Iter_move
inline namespace _Cpos {
inline constexpr _Iter_move::_Cpo iter_move;
}
} // namespace ranges
// iter_swap defined below since it depends on indirectly_movable_storable
// ALIAS TEMPLATE iter_rvalue_reference_t
// clang-format off
template <class _Ty>
requires _Dereferenceable<_Ty> && requires(_Ty& __t) {
{ _RANGES iter_move(__t) } -> _Can_reference;
}
using iter_rvalue_reference_t = decltype(_RANGES iter_move(_STD declval<_Ty&>()));
// CONCEPT indirectly_readable
template <class _It>
concept _Indirectly_readable_impl = requires(const _It __i) {
typename iter_value_t<_It>;
typename iter_reference_t<_It>;
typename iter_rvalue_reference_t<_It>;
{ *__i } -> same_as<iter_reference_t<_It>>;
{ _RANGES iter_move(__i) } -> same_as<iter_rvalue_reference_t<_It>>;
} && common_reference_with<iter_reference_t<_It>&&, iter_value_t<_It>&>
&& common_reference_with<iter_reference_t<_It>&&, iter_rvalue_reference_t<_It>&&>
&& common_reference_with<iter_rvalue_reference_t<_It>&&, const iter_value_t<_It>&>;
template <class _It>
concept indirectly_readable = _Indirectly_readable_impl<remove_cvref_t<_It>>;
// clang-format on
// ALIAS TEMPLATE iter_common_reference_t
template <indirectly_readable _Ty>
using iter_common_reference_t = common_reference_t<iter_reference_t<_Ty>, iter_value_t<_Ty>&>;
// CONCEPT indirectly_writable
template <class _It, class _Ty>
concept indirectly_writable = requires(_It&& __i, _Ty&& __t) {
*__i = static_cast<_Ty&&>(__t);
*static_cast<_It&&>(__i) = static_cast<_Ty&&>(__t);
const_cast<const iter_reference_t<_It>&&>(*__i) = static_cast<_Ty&&>(__t);
const_cast<const iter_reference_t<_It>&&>(*static_cast<_It&&>(__i)) = static_cast<_Ty&&>(__t);
};
// CONCEPT weakly_incrementable
// clang-format off
template <class _Ty>
concept weakly_incrementable = default_initializable<_Ty> && movable<_Ty> && requires(_Ty __i) {
typename iter_difference_t<_Ty>;
requires signed_integral<iter_difference_t<_Ty>>;
{ ++__i } -> same_as<_Ty&>;
__i++;
};
// ALIAS TEMPLATE _Make_unsigned_like_t
template <class _Ty>
using _Make_unsigned_like_t = make_unsigned_t<_Ty>;
// CONCEPT incrementable
template <class _Ty>
concept incrementable = regular<_Ty> && weakly_incrementable<_Ty> && requires(_Ty __t) {
{ __t++ } -> same_as<_Ty>;
};
// CONCEPT input_or_output_iterator
template <class _It>
concept input_or_output_iterator = requires(_It __i) {
{ *__i } -> _Can_reference;
requires weakly_incrementable<_It>;
};
// CONCEPT sentinel_for
template <class _Se, class _It>
concept sentinel_for = semiregular<_Se>
&& input_or_output_iterator<_It>
&& _Weakly_equality_comparable_with<_Se, _It>;
// clang-format on
// VARIABLE TEMPLATE disable_sized_sentinel_for
template <class _Se, class _It>
inline constexpr bool disable_sized_sentinel_for = false;
// CONCEPT sized_sentinel_for
// clang-format off
template <class _Se, class _It>
concept sized_sentinel_for = sentinel_for<_Se, _It>
&& !disable_sized_sentinel_for<remove_cv_t<_Se>, remove_cv_t<_It>>
&& requires(const _It& __i, const _Se& __s) {
{ __s - __i } -> same_as<iter_difference_t<_It>>;
{ __i - __s } -> same_as<iter_difference_t<_It>>;
};
// clang-format on
// ALIAS TEMPLATE _Iter_concept
template <class _It, bool _NotSpec = _Is_from_primary<iterator_traits<_It>>>
struct _Iter_concept_impl {};
// clang-format off
template <class _It>
requires _Has_member_iterator_concept<iterator_traits<_It>>
struct _Iter_concept_impl<_It, false> {
using type = typename iterator_traits<_It>::iterator_concept;
};
template <class _It>
requires (!_Has_member_iterator_concept<iterator_traits<_It>>
&& _Has_member_iterator_category<iterator_traits<_It>>)
struct _Iter_concept_impl<_It, false> {
using type = typename iterator_traits<_It>::iterator_category;
};
// clang-format on
template <class _It>
struct _Iter_concept_impl<_It, true> {
using type = random_access_iterator_tag;
};
template <_Has_member_iterator_concept _It>
struct _Iter_concept_impl<_It, true> {
using type = typename _It::iterator_concept;
};
// clang-format off
template <class _It>
requires(!_Has_member_iterator_concept<_It> && _Has_member_iterator_category<_It>)
struct _Iter_concept_impl<_It, true> {
using type = typename _It::iterator_category;
};
// clang-format on
template <class _It>
using _Iter_concept = typename _Iter_concept_impl<_It>::type;
// clang-format off
// CONCEPT input_iterator
template <class _It>
concept input_iterator = input_or_output_iterator<_It> && indirectly_readable<_It>
&& requires { typename _Iter_concept<_It>; }
&& derived_from<_Iter_concept<_It>, input_iterator_tag>;
// CONCEPT output_iterator
template <class _It, class _Ty>
concept output_iterator = input_or_output_iterator<_It> && indirectly_writable<_It, _Ty>
&& requires(_It __i, _Ty&& __t) {
*__i++ = static_cast<_Ty&&>(__t);
};
// CONCEPT forward_iterator
template <class _It>
concept forward_iterator = input_iterator<_It> && derived_from<_Iter_concept<_It>, forward_iterator_tag>
&& incrementable<_It> && sentinel_for<_It, _It>;
// CONCEPT bidirectional_iterator
template <class _It>
concept bidirectional_iterator = forward_iterator<_It> && derived_from<_Iter_concept<_It>, bidirectional_iterator_tag>
&& requires(_It __i) {
{ --__i } -> same_as<_It&>;
{ __i-- } -> same_as<_It>;
};
// CONCEPT random_access_iterator
template <class _It>
concept random_access_iterator = bidirectional_iterator<_It>
&& derived_from<_Iter_concept<_It>, random_access_iterator_tag> && totally_ordered<_It>
&& sized_sentinel_for<_It, _It> && requires(_It __i, const _It __j, const iter_difference_t<_It> __n) {
{ __i += __n } -> same_as<_It&>;
{ __j + __n } -> same_as<_It>;
{ __n + __j } -> same_as<_It>;
{ __i -= __n } -> same_as<_It&>;
{ __j - __n } -> same_as<_It>;
{ __j[__n] } -> same_as<iter_reference_t<_It>>;
};
// CONCEPT contiguous_iterator
template <class _It>
concept contiguous_iterator = random_access_iterator<_It>
&& derived_from<_Iter_concept<_It>, contiguous_iterator_tag>
&& is_lvalue_reference_v<iter_reference_t<_It>>
&& same_as<iter_value_t<_It>, remove_cvref_t<iter_reference_t<_It>>>
&& requires(const _It& __i) {
{ _STD to_address(__i) } -> same_as<add_pointer_t<iter_reference_t<_It>>>;
};
// CONCEPT indirectly_unary_invocable
template <class _Fn, class _It>
concept indirectly_unary_invocable = indirectly_readable<_It>
&& copy_constructible<_Fn>
&& invocable<_Fn&, iter_value_t<_It>&>
&& invocable<_Fn&, iter_reference_t<_It>>
&& invocable<_Fn&, iter_common_reference_t<_It>>
&& common_reference_with<
invoke_result_t<_Fn&, iter_value_t<_It>&>,
invoke_result_t<_Fn&, iter_reference_t<_It>>>;
// CONCEPT indirectly_regular_unary_invocable
template <class _Fn, class _It>
concept indirectly_regular_unary_invocable = indirectly_readable<_It>
&& copy_constructible<_Fn>
&& regular_invocable<_Fn&, iter_value_t<_It>&>
&& regular_invocable<_Fn&, iter_reference_t<_It>>
&& regular_invocable<_Fn&, iter_common_reference_t<_It>>
&& common_reference_with<
invoke_result_t<_Fn&, iter_value_t<_It>&>,
invoke_result_t<_Fn&, iter_reference_t<_It>>>;
// CONCEPT indirect_unary_predicate
template <class _Fn, class _It>
concept indirect_unary_predicate = indirectly_readable<_It>
&& copy_constructible<_Fn>
&& predicate<_Fn&, iter_value_t<_It>&>
&& predicate<_Fn&, iter_reference_t<_It>>
&& predicate<_Fn&, iter_common_reference_t<_It>>;
// CONCEPT indirect_binary_predicate
template <class _Fn, class _It1, class _It2>
concept indirect_binary_predicate = indirectly_readable<_It1>
&& indirectly_readable<_It2>
&& copy_constructible<_Fn>
&& predicate<_Fn&, iter_value_t<_It1>&, iter_value_t<_It2>&>
&& predicate<_Fn&, iter_value_t<_It1>&, iter_reference_t<_It2>>
&& predicate<_Fn&, iter_reference_t<_It1>, iter_value_t<_It2>&>
&& predicate<_Fn&, iter_reference_t<_It1>, iter_reference_t<_It2>>
&& predicate<_Fn&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
// ALIAS TEMPLATE indirect_result_t
template <class _Fn, class... _Its>
requires (indirectly_readable<_Its> && ...)
&& invocable<_Fn, iter_reference_t<_Its>...>
using indirect_result_t = invoke_result_t<_Fn, iter_reference_t<_Its>...>;
// clang-format on
// STRUCT TEMPLATE projected
#pragma warning(push)
#pragma warning(disable : 5046) // '%s': Symbol involving type with internal linkage not defined
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wundefined-internal" // function '%s' has internal linkage but is not defined
#endif // __clang__
template <indirectly_readable _It, indirectly_regular_unary_invocable<_It> _Proj>
struct projected {
using value_type = remove_cvref_t<indirect_result_t<_Proj&, _It>>;
indirect_result_t<_Proj&, _It> operator*() const;
};
#ifdef __clang__
#pragma clang diagnostic pop
#endif // __clang__
#pragma warning(pop)
template <weakly_incrementable _It, class _Proj>
struct incrementable_traits<projected<_It, _Proj>> {
using difference_type = iter_difference_t<_It>;
};
// clang-format off
// CONCEPT indirectly_movable
template <class _In, class _Out>
concept indirectly_movable = indirectly_readable<_In> && indirectly_writable<_Out, iter_rvalue_reference_t<_In>>;
// CONCEPT indirectly_movable_storable
template <class _In, class _Out>
concept indirectly_movable_storable = indirectly_movable<_In, _Out>
&& indirectly_writable<_Out, iter_value_t<_In>>
&& movable<iter_value_t<_In>>
&& constructible_from<iter_value_t<_In>, iter_rvalue_reference_t<_In>>
&& assignable_from<iter_value_t<_In>&, iter_rvalue_reference_t<_In>>;
// CONCEPT indirectly_copyable
template <class _In, class _Out>
concept indirectly_copyable = indirectly_readable<_In> && indirectly_writable<_Out, iter_reference_t<_In>>;
// clang-format on
// CUSTOMIZATION POINT OBJECT iter_swap
namespace ranges {
namespace _Iter_swap {
template <class _Ty1, class _Ty2>
void iter_swap(_Ty1, _Ty2) = delete;
// clang-format off
template <class _Ty1, class _Ty2>
concept _Has_ADL = (_Has_class_or_enum_type<_Ty1> || _Has_class_or_enum_type<_Ty2>)
&& requires(_Ty1&& __t1, _Ty2&& __t2) {
iter_swap(static_cast<_Ty1&&>(__t1), static_cast<_Ty2&&>(__t2));
};
template <class _Ty1, class _Ty2>
concept _Can_swap_references = indirectly_readable<remove_reference_t<_Ty1>>
&& indirectly_readable<remove_reference_t<_Ty2>>
&& swappable_with<iter_reference_t<_Ty1>, iter_reference_t<_Ty2>>;
// clang-format on
template <class _Xty, class _Yty>
_NODISCARD constexpr iter_value_t<remove_reference_t<_Xty>> _Iter_exchange_move(
_Xty&& _XVal, _Yty&& _YVal) noexcept(noexcept(iter_value_t<remove_reference_t<_Xty>>(iter_move(_XVal)))) {
iter_value_t<remove_reference_t<_Xty>> _Tmp(iter_move(_XVal));
*_XVal = iter_move(_YVal);
return _Tmp;
}
class _Cpo {
private:
enum class _St { _None, _Custom, _Swap, _Exchange };
// clang-format off
template <class _Ty1, class _Ty2>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
if constexpr (_Has_ADL<_Ty1, _Ty2>) {
return {_St::_Custom, noexcept(iter_swap(_STD declval<_Ty1>(), _STD declval<_Ty2>()))};
} else if constexpr (_Can_swap_references<_Ty1, _Ty2>) {
return {_St::_Swap, noexcept(_RANGES swap(*_STD declval<_Ty1>(), *_STD declval<_Ty2>()))};
} else if constexpr (indirectly_movable_storable<remove_reference_t<_Ty1>, remove_reference_t<_Ty2>>
&& indirectly_movable_storable<remove_reference_t<_Ty2>, remove_reference_t<_Ty1>>) {
constexpr auto _Nothrow = noexcept(
*_STD declval<_Ty1>() = _Iter_exchange_move(_STD declval<_Ty1>(), _STD declval<_Ty2>()));
return {_St::_Exchange, _Nothrow};
} else {
return {_St::_None};
}
}
template <class _Ty1, class _Ty2>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty1, _Ty2>();
public:
template <class _Ty1, class _Ty2>
requires (_Choice<_Ty1, _Ty2>._Strategy != _St::_None)
constexpr void operator()(_Ty1&& _Val1, _Ty2&& _Val2) const noexcept(_Choice<_Ty1, _Ty2>._No_throw) {
if constexpr (_Choice<_Ty1, _Ty2>._Strategy == _St::_Custom) {
iter_swap(static_cast<_Ty1&&>(_Val1), static_cast<_Ty2&&>(_Val2));
} else if constexpr (_Choice<_Ty1, _Ty2>._Strategy == _St::_Swap) {
_RANGES swap(*static_cast<_Ty1&&>(_Val1), *static_cast<_Ty2&&>(_Val2));
} else if constexpr (_Choice<_Ty1, _Ty2>._Strategy == _St::_Exchange) {
*static_cast<_Ty1&&>(_Val1) =
_Iter_exchange_move(static_cast<_Ty1&&>(_Val1), static_cast<_Ty2&&>(_Val2));
} else {
static_assert(_Always_false<_Ty1>, "should be unreachable");
}
}
// clang-format on
};
} // namespace _Iter_swap
inline namespace _Cpos {
inline constexpr _Iter_swap::_Cpo iter_swap;
}
} // namespace ranges
// clang-format off
// CONCEPT indirectly_swappable
template <class _It1, class _It2 = _It1>
concept indirectly_swappable = indirectly_readable<_It1> && indirectly_readable<_It2>
&& requires(const _It1 __i1, const _It2 __i2) {
_RANGES iter_swap(__i1, __i1);
_RANGES iter_swap(__i2, __i2);
_RANGES iter_swap(__i1, __i2);
_RANGES iter_swap(__i2, __i1);
};
// CONCEPT indirectly_comparable
template <class _It1, class _It2, class _Rel, class _Proj1 = identity, class _Proj2 = identity>
concept indirectly_comparable =
indirect_binary_predicate<_Rel,
projected<_It1, _Proj1>,
projected<_It2, _Proj2>>;
// clang-format on
// ALIAS TEMPLATE _Iter_ref_t
template <class _Iter>
using _Iter_ref_t = iter_reference_t<_Iter>;
// ALIAS TEMPLATE _Iter_value_t
template <class _Iter>
using _Iter_value_t = iter_value_t<_Iter>;
// ALIAS TEMPLATE _Iter_diff_t
template <class _Iter>
using _Iter_diff_t = iter_difference_t<_Iter>;
#else // ^^^ __cpp_lib_concepts / !__cpp_lib_concepts vvv
// STRUCT TEMPLATE iterator_traits
template <class, class = void>
struct _Iterator_traits_base {}; // empty for non-iterators
template <class _Iter>
struct _Iterator_traits_base<_Iter,
void_t<typename _Iter::iterator_category, typename _Iter::value_type, typename _Iter::difference_type,
typename _Iter::pointer, typename _Iter::reference>> {
// defined if _Iter::* types exist
using iterator_category = typename _Iter::iterator_category;
using value_type = typename _Iter::value_type;
using difference_type = typename _Iter::difference_type;
using pointer = typename _Iter::pointer;
using reference = typename _Iter::reference;
};
template <class _Ty, bool = is_object_v<_Ty>>
struct _Iterator_traits_pointer_base { // iterator properties for pointers to object
using iterator_category = random_access_iterator_tag;
using value_type = remove_cv_t<_Ty>;
using difference_type = ptrdiff_t;
using pointer = _Ty*;
using reference = _Ty&;
};
template <class _Ty>
struct _Iterator_traits_pointer_base<_Ty, false> {}; // iterator non-properties for pointers to non-object
template <class _Iter>
struct iterator_traits : _Iterator_traits_base<_Iter> {}; // get traits from iterator _Iter, if possible
template <class _Ty>
struct iterator_traits<_Ty*> : _Iterator_traits_pointer_base<_Ty> {}; // get traits from pointer, if possible
// ALIAS TEMPLATE _Iter_ref_t
template <class _Iter>
using _Iter_ref_t = typename iterator_traits<_Iter>::reference;
// ALIAS TEMPLATE _Iter_value_t
template <class _Iter>
using _Iter_value_t = typename iterator_traits<_Iter>::value_type;
// ALIAS TEMPLATE _Iter_diff_t
template <class _Iter>
using _Iter_diff_t = typename iterator_traits<_Iter>::difference_type;
#endif // __cpp_lib_concepts
// ALIAS TEMPLATE _Common_diff_t
template <class... _Iters>
using _Common_diff_t = common_type_t<_Iter_diff_t<_Iters>...>;
// ALIAS TEMPLATE _Iter_cat_t
template <class _Iter>
using _Iter_cat_t = typename iterator_traits<_Iter>::iterator_category;
// VARIABLE TEMPLATE _Is_iterator_v
template <class _Ty, class = void>
_INLINE_VAR constexpr bool _Is_iterator_v = false;
template <class _Ty>
_INLINE_VAR constexpr bool _Is_iterator_v<_Ty, void_t<_Iter_cat_t<_Ty>>> = true;
// TRAIT _Is_iterator
template <class _Ty>
struct _Is_iterator : bool_constant<_Is_iterator_v<_Ty>> {};
// VARIABLE TEMPLATE _Is_input_iter_v
template <class _Iter>
_INLINE_VAR constexpr bool _Is_input_iter_v = is_convertible_v<_Iter_cat_t<_Iter>, input_iterator_tag>;
// VARIABLE TEMPLATE _Is_fwd_iter_v
template <class _Iter>
_INLINE_VAR constexpr bool _Is_fwd_iter_v = is_convertible_v<_Iter_cat_t<_Iter>, forward_iterator_tag>;
// VARIABLE TEMPLATE _Is_bidi_iter_v
template <class _Iter>
_INLINE_VAR constexpr bool _Is_bidi_iter_v = is_convertible_v<_Iter_cat_t<_Iter>, bidirectional_iterator_tag>;
// VARIABLE TEMPLATE _Is_random_iter_v
template <class _Iter>
_INLINE_VAR constexpr bool _Is_random_iter_v = is_convertible_v<_Iter_cat_t<_Iter>, random_access_iterator_tag>;
// STRUCT TEMPLATE _Is_checked_helper
template <class, class = void>
struct _Is_checked_helper {}; // default definition, no longer used, retained due to pseudo-documentation
// FUNCTION TEMPLATE _Adl_verify_range
#if _ITERATOR_DEBUG_LEVEL != 0
template <class _Ty>
constexpr void _Verify_range(const _Ty* const _First, const _Ty* const _Last) noexcept {
// special case range verification for pointers
_STL_VERIFY(_First <= _Last, "transposed pointer range");
}
#endif // _ITERATOR_DEBUG_LEVEL != 0
template <class _Iter, class = void>
_INLINE_VAR constexpr bool _Allow_inheriting_unwrap_v = true;
template <class _Iter>
_INLINE_VAR constexpr bool _Allow_inheriting_unwrap_v<_Iter, void_t<typename _Iter::_Prevent_inheriting_unwrap>> =
is_same_v<_Iter, typename _Iter::_Prevent_inheriting_unwrap>;
template <class _Iter, class _Sentinel = _Iter, class = void>
_INLINE_VAR constexpr bool _Range_verifiable_v = false;
template <class _Iter, class _Sentinel>
_INLINE_VAR constexpr bool _Range_verifiable_v<_Iter, _Sentinel,
void_t<decltype(_Verify_range(_STD declval<const _Iter&>(), _STD declval<const _Sentinel&>()))>> =
_Allow_inheriting_unwrap_v<_Iter>;
#if _HAS_IF_CONSTEXPR
template <class _Iter, class _Sentinel>
constexpr void _Adl_verify_range(const _Iter& _First, const _Sentinel& _Last) {
// check that [_First, _Last) forms an iterator range
if constexpr (_Range_verifiable_v<_Iter, _Sentinel>) {
_Verify_range(_First, _Last);
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _Iter, class _Sentinel>
constexpr void _Adl_verify_range1(const _Iter& _First, const _Sentinel& _Last, true_type) {
// check that [_First, _Last) forms an iterator range
_Verify_range(_First, _Last);
}
template <class _Iter, class _Sentinel>
constexpr void _Adl_verify_range1(const _Iter&, const _Sentinel&, false_type) {
// (don't) check that [_First, _Last) forms an iterator range
}
template <class _Iter, class _Sentinel>
constexpr void _Adl_verify_range(const _Iter& _First, const _Sentinel& _Last) {
// check that [_First, _Last) forms an iterator range
_Adl_verify_range1(_First, _Last, bool_constant<_Range_verifiable_v<_Iter, _Sentinel>>{});
}
#endif // _HAS_IF_CONSTEXPR
// FUNCTION TEMPLATE _Get_unwrapped
template <class _Iter, class = void>
_INLINE_VAR constexpr bool _Unwrappable_v = false;
template <class _Iter>
_INLINE_VAR constexpr bool _Unwrappable_v<_Iter,
void_t<decltype(_STD declval<_Remove_cvref_t<_Iter>&>()._Seek_to(_STD declval<_Iter>()._Unwrapped()))>> =
_Allow_inheriting_unwrap_v<_Remove_cvref_t<_Iter>>;
#if _HAS_IF_CONSTEXPR
template <class _Iter>
_NODISCARD constexpr decltype(auto) _Get_unwrapped(_Iter&& _It) {
// unwrap an iterator previously subjected to _Adl_verify_range or otherwise validated
if constexpr (is_pointer_v<decay_t<_Iter>>) { // special-case pointers and arrays
return _It + 0;
} else if constexpr (_Unwrappable_v<_Iter>) {
return static_cast<_Iter&&>(_It)._Unwrapped();
} else {
return static_cast<_Iter&&>(_It);
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _Iter, enable_if_t<_Unwrappable_v<_Iter>, int> = 0>
_NODISCARD constexpr decltype(auto) _Get_unwrapped(_Iter&& _It) {
// unwrap an iterator previously subjected to _Adl_verify_range or otherwise validated
return static_cast<_Iter&&>(_It)._Unwrapped();
}
template <class _Iter, enable_if_t<!_Unwrappable_v<_Iter>, int> = 0>
_NODISCARD constexpr _Iter&& _Get_unwrapped(_Iter&& _It) {
// (don't) unwrap an iterator previously subjected to _Adl_verify_range or otherwise validated
return static_cast<_Iter&&>(_It);
}
template <class _Ty>
_NODISCARD constexpr _Ty* _Get_unwrapped(_Ty* const _Ptr) { // special case already-unwrapped pointers
return _Ptr;
}
#endif // _HAS_IF_CONSTEXPR
template <class _Iter>
using _Unwrapped_t = _Remove_cvref_t<decltype(_Get_unwrapped(_STD declval<_Iter>()))>;
// FUNCTION TEMPLATE _Get_unwrapped_unverified
template <class _Iter, class = bool>
_INLINE_VAR constexpr bool _Do_unwrap_when_unverified_v = false;
template <class _Iter>
_INLINE_VAR constexpr bool
_Do_unwrap_when_unverified_v<_Iter, decltype(static_cast<bool>(_Iter::_Unwrap_when_unverified))> =
static_cast<bool>(_Iter::_Unwrap_when_unverified);
template <class _Iter>
_INLINE_VAR constexpr bool _Unwrappable_for_unverified_v =
_Unwrappable_v<_Iter>&& _Do_unwrap_when_unverified_v<_Remove_cvref_t<_Iter>>;
#if _HAS_IF_CONSTEXPR
template <class _Iter>
_NODISCARD constexpr decltype(auto) _Get_unwrapped_unverified(_Iter&& _It) {
// unwrap an iterator not previously subjected to _Adl_verify_range
if constexpr (is_pointer_v<decay_t<_Iter>>) { // special-case pointers and arrays
return _It + 0;
} else if constexpr (_Unwrappable_for_unverified_v<_Iter>) {
return static_cast<_Iter&&>(_It)._Unwrapped();
} else {
return static_cast<_Iter&&>(_It);
}
}
#else // ^^^_HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _Iter, enable_if_t<_Unwrappable_for_unverified_v<_Iter>, int> = 0>
_NODISCARD constexpr decltype(auto) _Get_unwrapped_unverified(_Iter&& _It) {
// unwrap an iterator not previously subjected to _Adl_verify_range
return static_cast<_Iter&&>(_It)._Unwrapped();
}
template <class _Iter, enable_if_t<!_Unwrappable_for_unverified_v<_Iter>, int> = 0>
_NODISCARD constexpr _Iter&& _Get_unwrapped_unverified(_Iter&& _It) {
// (don't) unwrap an iterator not previously subjected to _Adl_verify_range
return static_cast<_Iter&&>(_It);
}
template <class _Ty>
_NODISCARD constexpr _Ty* _Get_unwrapped_unverified(_Ty* const _Ptr) { // special case already-unwrapped pointers
return _Ptr;
}
#endif // _HAS_IF_CONSTEXPR
template <class _Iter>
using _Unwrapped_unverified_t = _Remove_cvref_t<decltype(_Get_unwrapped_unverified(_STD declval<_Iter>()))>;
// FUNCTION TEMPLATE _Get_unwrapped_n
struct _Distance_unknown {
constexpr _Distance_unknown operator-() const noexcept {
return {};
}
};
template <class _Diff>
_INLINE_VAR constexpr auto _Max_possible_v = _Diff{static_cast<make_unsigned_t<_Diff>>(-1) >> 1};
template <class _Diff>
_INLINE_VAR constexpr auto _Min_possible_v = _Diff{-_Max_possible_v<_Diff> - 1};
template <class _Iter, class = void>
_INLINE_VAR constexpr bool _Offset_verifiable_v = false;
template <class _Iter>
_INLINE_VAR constexpr bool
_Offset_verifiable_v<_Iter, void_t<decltype(_STD declval<const _Iter&>()._Verify_offset(_Iter_diff_t<_Iter>{}))>> =
true;
template <class _Iter>
_INLINE_VAR constexpr bool _Unwrappable_for_offset_v =
_Unwrappable_v<_Iter>&& _Offset_verifiable_v<_Remove_cvref_t<_Iter>>;
#if _HAS_IF_CONSTEXPR
template <class _Iter, class _Diff>
_NODISCARD constexpr decltype(auto) _Get_unwrapped_n(_Iter&& _It, const _Diff _Off) {
if constexpr (is_pointer_v<decay_t<_Iter>>) {
return _It + 0;
} else if constexpr (_Unwrappable_for_offset_v<_Iter> && is_integral_v<_Diff>) {
// ask an iterator to assert that the iterator moved _Off positions is valid, and unwrap
using _IDiff = _Iter_diff_t<_Remove_cvref_t<_Iter>>;
using _CDiff = common_type_t<_Diff, _IDiff>;
const auto _COff = static_cast<_CDiff>(_Off);
_STL_ASSERT(_COff <= static_cast<_CDiff>(_Max_possible_v<_IDiff>)
&& (is_unsigned_v<_Diff> || static_cast<_CDiff>(_Min_possible_v<_IDiff>) <= _COff),
"integer overflow");
(void) _COff;
_It._Verify_offset(static_cast<_IDiff>(_Off));
return static_cast<_Iter&&>(_It)._Unwrapped();
} else if constexpr (_Unwrappable_for_unverified_v<_Iter>) {
// iterator doesn't support offset-based asserts, or offset unknown; defer to unverified unwrap
return static_cast<_Iter&&>(_It)._Unwrapped();
} else {
// pass through iterator that doesn't participate in checking
return static_cast<_Iter&&>(_It);
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _Iter, class _Diff, enable_if_t<_Unwrappable_for_offset_v<_Iter> && is_integral_v<_Diff>, int> = 0>
_NODISCARD constexpr decltype(auto) _Get_unwrapped_n(_Iter&& _It, const _Diff _Off) {
// ask an iterator to assert that the iterator moved _Off positions is valid, and unwrap
using _IDiff = _Iter_diff_t<_Remove_cvref_t<_Iter>>;
using _CDiff = common_type_t<_Diff, _IDiff>;
const auto _COff = static_cast<_CDiff>(_Off);
_STL_ASSERT(_COff <= static_cast<_CDiff>(_Max_possible_v<_IDiff>)
&& (is_unsigned_v<_Diff> || static_cast<_CDiff>(_Min_possible_v<_IDiff>) <= _COff),
"integer overflow");
(void) _COff;
_It._Verify_offset(static_cast<_IDiff>(_Off));
return static_cast<_Iter&&>(_It)._Unwrapped();
}
template <class _Iter, class _Diff,
enable_if_t<
_Unwrappable_for_unverified_v<_Iter> //
&& ((!_Unwrappable_for_offset_v<_Iter> && is_integral_v<_Diff>) || is_same_v<_Diff, _Distance_unknown>),
int> = 0>
_NODISCARD constexpr decltype(auto) _Get_unwrapped_n(_Iter&& _It, _Diff) {
// iterator doesn't support offset-based asserts, or offset unknown; defer to unverified unwrap
return static_cast<_Iter&&>(_It)._Unwrapped();
}
template <class _Iter, class _Diff,
enable_if_t<
!_Unwrappable_for_unverified_v<_Iter> //
&& ((!_Unwrappable_for_offset_v<_Iter> && is_integral_v<_Diff>) || is_same_v<_Diff, _Distance_unknown>),
int> = 0>
_NODISCARD constexpr _Iter&& _Get_unwrapped_n(_Iter&& _It, _Diff) {
// pass through iterator that doesn't participate in checking
return static_cast<_Iter&&>(_It);
}
template <class _Ty, class _Diff, enable_if_t<is_same_v<_Diff, _Distance_unknown> || is_integral_v<_Diff>, int> = 0>
_NODISCARD constexpr _Ty* _Get_unwrapped_n(_Ty* const _Src, _Diff) {
return _Src;
}
#endif // _HAS_IF_CONSTEXPR
template <class _Iter>
using _Unwrapped_n_t =
_Remove_cvref_t<decltype(_Get_unwrapped_n(_STD declval<_Iter>(), _Iter_diff_t<_Remove_cvref_t<_Iter>>{}))>;
// FUNCTION TEMPLATE _Seek_wrapped
template <class _Iter, class _UIter, class = void>
_INLINE_VAR constexpr bool _Wrapped_seekable_v = false;
template <class _Iter, class _UIter>
_INLINE_VAR constexpr bool
_Wrapped_seekable_v<_Iter, _UIter, void_t<decltype(_STD declval<_Iter&>()._Seek_to(_STD declval<_UIter>()))>> =
true;
#if _HAS_IF_CONSTEXPR
template <class _Iter, class _UIter>
constexpr void _Seek_wrapped(_Iter& _It, _UIter&& _UIt) {
if constexpr (_Wrapped_seekable_v<_Iter, _UIter>) {
_It._Seek_to(static_cast<_UIter&&>(_UIt));
} else {
_It = static_cast<_UIter&&>(_UIt);
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _Iter, class _UIter, enable_if_t<_Wrapped_seekable_v<_Iter, _UIter>, int> = 0>
constexpr void _Seek_wrapped(_Iter& _It, _UIter&& _UIt) {
_It._Seek_to(static_cast<_UIter&&>(_UIt));
}
template <class _Iter, class _UIter, enable_if_t<!_Wrapped_seekable_v<_Iter, _UIter>, int> = 0>
constexpr void _Seek_wrapped(_Iter& _It, _UIter&& _UIt) {
_It = static_cast<_UIter&&>(_UIt);
}
template <class _Ty>
constexpr void _Seek_wrapped(_Ty*& _It, _Ty* const _UIt) {
_It = _UIt;
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
// STRUCT TEMPLATE _Is_allocator
template <class _Ty, class = void>
struct _Is_allocator : false_type { // selected when _Ty can't possibly be an allocator
};
template <class _Ty>
struct _Is_allocator<_Ty, void_t<typename _Ty::value_type, decltype(_STD declval<_Ty&>().deallocate(
_STD declval<_Ty&>().allocate(size_t{1}), size_t{1}))>>
: true_type { // selected when _Ty resembles an allocator, N4687 26.2.1 [container.requirements.general]/17
};
// ALIAS TEMPLATES FOR DEDUCTION GUIDES, N4687 26.4.1 [associative.general]/2
template <class _Iter>
using _Guide_key_t = remove_const_t<typename iterator_traits<_Iter>::value_type::first_type>;
template <class _Iter>
using _Guide_val_t = typename iterator_traits<_Iter>::value_type::second_type;
template <class _Iter>
using _Guide_pair_t = pair<add_const_t<typename iterator_traits<_Iter>::value_type::first_type>,
typename iterator_traits<_Iter>::value_type::second_type>;
// STRUCT TEMPLATE is_execution_policy
template <class _Ty>
struct is_execution_policy : false_type {};
template <class _Ty>
inline constexpr bool is_execution_policy_v = is_execution_policy<_Ty>::value;
// ALIAS TEMPLATE _Enable_if_execution_policy_t
// Note: The noexcept specifiers on all parallel algorithm overloads enforce termination as per
// N4713 23.19.4 [execpol.seq]/2, 23.19.5 [execpol.par]/2, and 23.19.6 [execpol.parunseq]/2
template <class _ExPo>
using _Enable_if_execution_policy_t = typename remove_reference_t<_ExPo>::_Standard_execution_policy;
#define _REQUIRE_PARALLEL_ITERATOR(_Iter) \
static_assert(_Is_fwd_iter_v<_Iter>, "Parallel algorithms require forward iterators or stronger.")
#endif // _HAS_CXX17
// FUNCTION TEMPLATE _Idl_distance
#if _HAS_IF_CONSTEXPR
template <class _Checked, class _Iter>
_NODISCARD constexpr auto _Idl_distance(const _Iter& _First, const _Iter& _Last) {
// tries to get the distance between _First and _Last if they are random-access iterators
if constexpr (_Is_random_iter_v<_Iter>) {
return static_cast<_Iter_diff_t<_Checked>>(_Last - _First);
} else {
return _Distance_unknown{};
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _Checked, class _Iter>
_NODISCARD constexpr _Distance_unknown _Idl_distance1(const _Iter&, const _Iter&, input_iterator_tag) {
// _Idl_distance for non-random-access iterators
return {};
}
template <class _Checked, class _Iter>
_NODISCARD constexpr _Iter_diff_t<_Checked> _Idl_distance1(
const _Iter& _First, const _Iter& _Last, random_access_iterator_tag) {
// _Idl_distance for random-access iterators
return static_cast<_Iter_diff_t<_Checked>>(_Last - _First);
}
template <class _Checked, class _Iter>
_NODISCARD constexpr auto _Idl_distance(const _Iter& _First, const _Iter& _Last) {
// tries to get the distance between _First and _Last if they are random-access iterators
return _Idl_distance1<_Checked>(_First, _Last, _Iter_cat_t<_Iter>());
}
#endif // _HAS_IF_CONSTEXPR
// STRUCT TEMPLATE _Unwrap_enum AND ALIAS
template <class _Elem, bool _Is_enum = is_enum_v<_Elem>>
struct _Unwrap_enum { // if _Elem is an enum, gets its underlying type; otherwise leaves _Elem unchanged
using type = underlying_type_t<_Elem>;
};
template <class _Elem>
struct _Unwrap_enum<_Elem, false> { // passthrough non-enum type
using type = _Elem;
};
template <class _Elem>
using _Unwrap_enum_t = typename _Unwrap_enum<_Elem>::type;
// DEBUG TESTING MACROS
#if _ITERATOR_DEBUG_LEVEL < 2
#define _DEBUG_LT_PRED(pred, x, y) static_cast<bool>(pred(x, y))
#define _DEBUG_ORDER_UNWRAPPED(first, last, pred)
#define _DEBUG_ORDER_SET_UNWRAPPED(otherIter, first, last, pred)
#else // _ITERATOR_DEBUG_LEVEL < 2
#define _DEBUG_LT_PRED(pred, x, y) _Debug_lt_pred(pred, x, y)
#define _DEBUG_ORDER_UNWRAPPED(first, last, pred) _Debug_order_unchecked(first, last, pred)
#define _DEBUG_ORDER_SET_UNWRAPPED(otherIter, first, last, pred) \
_Debug_order_set_unchecked<otherIter>(first, last, pred)
// FUNCTION TEMPLATE _Debug_lt_pred
template <class _Pr, class _Ty1, class _Ty2,
enable_if_t<is_same_v<_Remove_cvref_t<_Ty1>, _Remove_cvref_t<_Ty2>>, int> = 0>
constexpr bool _Debug_lt_pred(_Pr&& _Pred, _Ty1&& _Left, _Ty2&& _Right) noexcept(
noexcept(_Pred(_Left, _Right)) && noexcept(_Pred(_Right, _Left))) {
// test if _Pred(_Left, _Right) and _Pred is strict weak ordering, when the arguments are the cv-same-type
const auto _Result = static_cast<bool>(_Pred(_Left, _Right));
if (_Result) {
_STL_VERIFY(!_Pred(_Right, _Left), "invalid comparator");
}
return _Result;
}
template <class _Pr, class _Ty1, class _Ty2,
enable_if_t<!is_same_v<_Remove_cvref_t<_Ty1>, _Remove_cvref_t<_Ty2>>, int> = 0>
constexpr bool _Debug_lt_pred(_Pr&& _Pred, _Ty1&& _Left, _Ty2&& _Right) noexcept(noexcept(_Pred(_Left, _Right))) {
// test if _Pred(_Left, _Right); no debug checks as the types differ
return static_cast<bool>(_Pred(_Left, _Right));
}
// FUNCTION TEMPLATE _Debug_order_unchecked
#if _HAS_IF_CONSTEXPR
template <class _InIt, class _Sentinel, class _Pr>
constexpr void _Debug_order_unchecked(_InIt _First, _Sentinel _Last, _Pr&& _Pred) {
// test if range is ordered by predicate
if constexpr (_Is_fwd_iter_v<_InIt>) {
if (_First != _Last) {
for (auto _Next = _First; ++_Next != _Last; _First = _Next) {
_STL_VERIFY(!static_cast<bool>(_Pred(*_Next, *_First)), "sequence not ordered");
}
}
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _InIt, class _Sentinel, class _Pr>
constexpr void _Debug_order_unchecked2(_InIt, _Sentinel, _Pr&, input_iterator_tag) {
// (don't) test if range is ordered by predicate, input iterators
}
template <class _FwdIt, class _Sentinel, class _Pr>
constexpr void _Debug_order_unchecked2(_FwdIt _First, _Sentinel _Last, _Pr& _Pred, forward_iterator_tag) {
// test if range is ordered by predicate, forward iterators
if (_First != _Last) {
for (_FwdIt _Next = _First; ++_Next != _Last; _First = _Next) {
_STL_VERIFY(!static_cast<bool>(_Pred(*_Next, *_First)), "sequence not ordered");
}
}
}
template <class _InIt, class _Sentinel, class _Pr>
constexpr void _Debug_order_unchecked(_InIt _First, _Sentinel _Last, _Pr&& _Pred) {
// test if range is ordered by predicate
_Debug_order_unchecked2(_First, _Last, _Pred, _Iter_cat_t<_InIt>());
}
#endif // _HAS_IF_CONSTEXPR
// FUNCTION TEMPLATE _Debug_order_set_unchecked
#if _HAS_IF_CONSTEXPR
template <class _OtherIt, class _InIt, class _Pr>
constexpr void _Debug_order_set_unchecked(_InIt _First, _InIt _Last, _Pr&& _Pred) {
// test if range is ordered by predicate
if constexpr (is_same_v<_Iter_value_t<_OtherIt>, _Iter_value_t<_InIt>> && _Is_fwd_iter_v<_InIt>) {
_Debug_order_unchecked(_First, _Last, _Pred);
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <size_t _Value>
struct _Priority_tag : _Priority_tag<_Value - 1> { // priority tag for tag dispatch
explicit _Priority_tag() = default;
};
template <>
struct _Priority_tag<0> { // base case priority tag for tag dispatch
explicit _Priority_tag() = default;
};
template <class _InIt, class _Pr>
void _Debug_order_set_unchecked2(_InIt, _InIt, _Pr&, input_iterator_tag,
_Priority_tag<0>) { // (don't) test if range is ordered by predicate, input iterators or different types
}
template <class _FwdIt, class _Pr>
constexpr void _Debug_order_set_unchecked2(
_FwdIt _First, _FwdIt _Last, _Pr& _Pred, forward_iterator_tag, _Priority_tag<1>) {
// test if range is ordered by predicate, forward iterators and same types
_Debug_order_unchecked2(_First, _Last, _Pred, forward_iterator_tag{});
}
template <class _OtherIt, class _InIt, class _Pr>
constexpr void _Debug_order_set_unchecked(_InIt _First, _InIt _Last, _Pr&& _Pred) {
// test if range is ordered by predicate
_Debug_order_set_unchecked2(_First, _Last, _Pred, _Iter_cat_t<_InIt>(),
_Priority_tag<is_same_v<_Iter_value_t<_OtherIt>, _Iter_value_t<_InIt>>>());
}
#endif // _HAS_IF_CONSTEXPR
#endif // _ITERATOR_DEBUG_LEVEL < 2
// MORE ITERATOR STUFF (from <iterator>)
// FUNCTION TEMPLATE advance
#if _HAS_IF_CONSTEXPR
template <class _InIt, class _Diff>
_CONSTEXPR17 void advance(_InIt& _Where, _Diff _Off) { // increment iterator by offset
if constexpr (_Is_random_iter_v<_InIt>) {
_Where += _Off;
} else {
if constexpr (is_signed_v<_Diff> && !_Is_bidi_iter_v<_InIt>) {
_STL_ASSERT(_Off >= 0, "negative advance of non-bidirectional iterator");
}
auto&& _UWhere = _Get_unwrapped_n(_STD move(_Where), _Off);
constexpr bool _Need_rewrap = !is_reference_v<decltype(_Get_unwrapped_n(_STD move(_Where), _Off))>;
if constexpr (is_signed_v<_Diff> && _Is_bidi_iter_v<_InIt>) {
for (; _Off < 0; ++_Off) {
--_UWhere;
}
}
for (; 0 < _Off; --_Off) {
++_UWhere;
}
if constexpr (_Need_rewrap) {
_Seek_wrapped(_Where, _STD move(_UWhere));
}
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _InIt, class _Diff>
_CONSTEXPR17 void _Advance1(_InIt& _Where, _Diff _Off, input_iterator_tag) {
// increment iterator by offset, input iterators
_STL_ASSERT(_Off >= 0, "negative advance of non-bidirectional iterator");
auto&& _UWhere = _Get_unwrapped_n(_STD move(_Where), _Off);
constexpr bool _Need_rewrap = !is_reference_v<decltype(_Get_unwrapped_n(_STD move(_Where), _Off))>;
for (; 0 < _Off; --_Off) {
++_UWhere;
}
if (_Need_rewrap) {
_Seek_wrapped(_Where, _STD move(_UWhere));
}
}
template <class _BidIt, class _Diff>
_CONSTEXPR17 void _Advance1(_BidIt& _Where, _Diff _Off, bidirectional_iterator_tag) {
// increment iterator by offset, bidirectional iterators
auto&& _UWhere = _Get_unwrapped_n(_STD move(_Where), _Off);
constexpr bool _Need_rewrap = !is_reference_v<decltype(_Get_unwrapped_n(_STD move(_Where), _Off))>;
for (; 0 < _Off; --_Off) {
++_UWhere;
}
for (; _Off < 0; ++_Off) {
--_UWhere;
}
if (_Need_rewrap) {
_Seek_wrapped(_Where, _STD move(_UWhere));
}
}
template <class _RanIt, class _Diff>
_CONSTEXPR17 void _Advance1(_RanIt& _Where, _Diff _Off, random_access_iterator_tag) {
// increment iterator by offset, random-access iterators
_Where += _Off;
}
template <class _InIt, class _Diff>
_CONSTEXPR17 void advance(_InIt& _Where, _Diff _Off) {
// increment iterator by offset, arbitrary iterators
// we remove_const_t before _Iter_cat_t for better diagnostics if the user passes an iterator that is const
_Advance1(_Where, _Off, _Iter_cat_t<remove_const_t<_InIt>>());
}
#endif // _HAS_IF_CONSTEXPR
// FUNCTION TEMPLATE distance
#if _HAS_IF_CONSTEXPR
template <class _InIt>
_NODISCARD _CONSTEXPR17 _Iter_diff_t<_InIt> distance(_InIt _First, _InIt _Last) {
if constexpr (_Is_random_iter_v<_InIt>) {
return _Last - _First; // assume the iterator will do debug checking
} else {
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
_Iter_diff_t<_InIt> _Off = 0;
for (; _UFirst != _ULast; ++_UFirst) {
++_Off;
}
return _Off;
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _InIt>
_CONSTEXPR17 _Iter_diff_t<_InIt> _Distance1(_InIt _First, _InIt _Last, input_iterator_tag) {
// return distance between iterators; input
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
_Iter_diff_t<_InIt> _Off = 0;
for (; _UFirst != _ULast; ++_UFirst) {
++_Off;
}
return _Off;
}
template <class _RanIt>
_CONSTEXPR17 _Iter_diff_t<_RanIt> _Distance1(_RanIt _First, _RanIt _Last, random_access_iterator_tag) {
// return distance between iterators; random-access
return _Last - _First;
}
template <class _InIt>
_NODISCARD _CONSTEXPR17 _Iter_diff_t<_InIt> distance(_InIt _First, _InIt _Last) {
return _Distance1(_First, _Last, _Iter_cat_t<_InIt>());
}
#endif // _HAS_IF_CONSTEXPR
// FUNCTION TEMPLATE _Next_iter
template <class _InIt>
constexpr _InIt _Next_iter(_InIt _First) { // increment iterator
return ++_First;
}
// FUNCTION TEMPLATE next
template <class _InIt>
_NODISCARD _CONSTEXPR17 _InIt next(_InIt _First, _Iter_diff_t<_InIt> _Off = 1) { // increment iterator
static_assert(_Is_input_iter_v<_InIt>, "next requires input iterator");
_STD advance(_First, _Off);
return _First;
}
// FUNCTION TEMPLATE _Prev_iter
template <class _BidIt>
constexpr _BidIt _Prev_iter(_BidIt _First) { // decrement iterator
return --_First;
}
// FUNCTION TEMPLATE prev
template <class _BidIt>
_NODISCARD _CONSTEXPR17 _BidIt prev(_BidIt _First, _Iter_diff_t<_BidIt> _Off = 1) { // decrement iterator
static_assert(_Is_bidi_iter_v<_BidIt>, "prev requires bidirectional iterator");
_STD advance(_First, -_Off);
return _First;
}
// CLASS TEMPLATE reverse_iterator
#if !_HAS_IF_CONSTEXPR
template <class _Iter>
_NODISCARD constexpr _Iter _Operator_arrow(true_type, _Iter _Target) {
return _Target;
}
template <class _Iter>
_NODISCARD constexpr decltype(auto) _Operator_arrow(false_type, _Iter& _Target) {
return _Target.operator->();
}
#endif // !_HAS_IF_CONSTEXPR
template <class _BidIt>
class reverse_iterator {
public:
using iterator_type = _BidIt;
#ifdef __cpp_lib_concepts
using iterator_concept =
conditional_t<random_access_iterator<_BidIt>, random_access_iterator_tag, bidirectional_iterator_tag>;
using iterator_category = conditional_t<derived_from<_Iter_cat_t<_BidIt>, random_access_iterator_tag>,
random_access_iterator_tag, _Iter_cat_t<_BidIt>>;
#else // ^^^ __cpp_lib_concepts / !__cpp_lib_concepts vvv
using iterator_category = _Iter_cat_t<_BidIt>;
#endif // __cpp_lib_concepts
using value_type = _Iter_value_t<_BidIt>;
using difference_type = _Iter_diff_t<_BidIt>;
using pointer = typename iterator_traits<_BidIt>::pointer;
using reference = _Iter_ref_t<_BidIt>;
template <class>
friend class reverse_iterator;
_CONSTEXPR17 reverse_iterator() = default;
_CONSTEXPR17 explicit reverse_iterator(_BidIt _Right) noexcept(
is_nothrow_move_constructible_v<_BidIt>) // strengthened
: current(_STD move(_Right)) {}
// clang-format off
template <class _Other>
#ifdef __cpp_lib_concepts
// Per LWG-3435
requires (!is_same_v<_Other, _BidIt>) && convertible_to<const _Other&, _BidIt>
#endif // __cpp_lib_concepts
_CONSTEXPR17 reverse_iterator(const reverse_iterator<_Other>& _Right) noexcept(
is_nothrow_constructible_v<_BidIt, const _Other&>) // strengthened
: current(_Right.current) {}
template <class _Other>
#ifdef __cpp_lib_concepts
// Per LWG-3435
requires (!is_same_v<_Other, _BidIt>) && convertible_to<const _Other&, _BidIt>
&& assignable_from<_BidIt&, const _Other&>
#endif // __cpp_lib_concepts
_CONSTEXPR17 reverse_iterator& operator=(const reverse_iterator<_Other>& _Right) {
current = _Right.current;
return *this;
}
// clang-format on
_NODISCARD _CONSTEXPR17 _BidIt base() const {
return current;
}
_NODISCARD _CONSTEXPR17 reference operator*() const {
_BidIt _Tmp = current;
return *--_Tmp;
}
#ifdef __cpp_lib_concepts
_NODISCARD constexpr pointer operator->() const
requires(is_pointer_v<_BidIt> || requires(const _BidIt __i) { __i.operator->(); }) {
_BidIt _Tmp = current;
--_Tmp;
if constexpr (is_pointer_v<_BidIt>) {
return _Tmp;
} else {
return _Tmp.operator->();
}
}
#else // ^^^ __cpp_lib_concepts / !__cpp_lib_concepts vvv
_NODISCARD _CONSTEXPR17 pointer operator->() const {
_BidIt _Tmp = current;
--_Tmp;
#if _HAS_IF_CONSTEXPR
if constexpr (is_pointer_v<_BidIt>) {
return _Tmp;
} else {
return _Tmp.operator->();
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
return _Operator_arrow(is_pointer<_BidIt>{}, _Tmp);
#endif // _HAS_IF_CONSTEXPR
}
#endif // __cpp_lib_concepts
_CONSTEXPR17 reverse_iterator& operator++() {
--current;
return *this;
}
_CONSTEXPR17 reverse_iterator operator++(int) {
reverse_iterator _Tmp = *this;
--current;
return _Tmp;
}
_CONSTEXPR17 reverse_iterator& operator--() {
++current;
return *this;
}
_CONSTEXPR17 reverse_iterator operator--(int) {
reverse_iterator _Tmp = *this;
++current;
return _Tmp;
}
_NODISCARD _CONSTEXPR17 reverse_iterator operator+(const difference_type _Off) const {
return reverse_iterator(current - _Off);
}
_CONSTEXPR17 reverse_iterator& operator+=(const difference_type _Off) {
current -= _Off;
return *this;
}
_NODISCARD _CONSTEXPR17 reverse_iterator operator-(const difference_type _Off) const {
return reverse_iterator(current + _Off);
}
_CONSTEXPR17 reverse_iterator& operator-=(const difference_type _Off) {
current += _Off;
return *this;
}
_NODISCARD _CONSTEXPR17 reference operator[](const difference_type _Off) const {
return current[static_cast<difference_type>(-_Off - 1)];
}
#ifdef __cpp_lib_concepts
_NODISCARD friend constexpr iter_rvalue_reference_t<_BidIt> iter_move(const reverse_iterator& _It) noexcept(
is_nothrow_copy_constructible_v<_BidIt>&& noexcept(_RANGES iter_move(--_STD declval<_BidIt&>()))) {
auto _Tmp = _It.current;
--_Tmp;
return _RANGES iter_move(_Tmp);
}
template <indirectly_swappable<_BidIt> _BidIt2>
friend constexpr void iter_swap(const reverse_iterator& _Left, const reverse_iterator<_BidIt2>& _Right) noexcept(
is_nothrow_copy_constructible_v<_BidIt>&& is_nothrow_copy_constructible_v<_BidIt2>&& noexcept(
_RANGES iter_swap(--_STD declval<_BidIt&>(), --_STD declval<_BidIt2&>()))) {
auto _LTmp = _Left.current;
auto _RTmp = _Right.base();
--_LTmp;
--_RTmp;
_RANGES iter_swap(_LTmp, _RTmp);
}
#endif // __cpp_lib_concepts
using _Prevent_inheriting_unwrap = reverse_iterator;
template <class _BidIt2, enable_if_t<_Range_verifiable_v<_BidIt, _BidIt2>, int> = 0>
friend constexpr void _Verify_range(const reverse_iterator& _First, const reverse_iterator<_BidIt2>& _Last) {
_Verify_range(_Last._Get_current(), _First.current); // note reversed parameters
}
template <class _BidIt2 = _BidIt, enable_if_t<_Offset_verifiable_v<_BidIt2>, int> = 0>
constexpr void _Verify_offset(const difference_type _Off) const {
_STL_VERIFY(_Off != _Min_possible_v<difference_type>, "integer overflow");
current._Verify_offset(-_Off);
}
template <class _BidIt2 = _BidIt, enable_if_t<_Unwrappable_v<const _BidIt2&>, int> = 0>
_NODISCARD constexpr reverse_iterator<_Unwrapped_t<const _BidIt2&>> _Unwrapped() const {
return static_cast<reverse_iterator<_Unwrapped_t<const _BidIt2&>>>(current._Unwrapped());
}
static constexpr bool _Unwrap_when_unverified = _Do_unwrap_when_unverified_v<_BidIt>;
template <class _Src, enable_if_t<_Wrapped_seekable_v<_BidIt, const _Src&>, int> = 0>
constexpr void _Seek_to(const reverse_iterator<_Src>& _It) {
current._Seek_to(_It.current);
}
_NODISCARD constexpr const _BidIt& _Get_current() const noexcept {
return current;
}
protected:
_BidIt current{};
};
#ifdef __cpp_lib_concepts
template <class _From, class _To>
concept _Implicitly_convertible_to = is_convertible_v<_From, _To>;
#endif // __cpp_lib_concepts
template <class _BidIt1, class _BidIt2>
_NODISCARD _CONSTEXPR17 bool operator==(const reverse_iterator<_BidIt1>& _Left, const reverse_iterator<_BidIt2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Left._Get_current() == _Right._Get_current() } -> _Implicitly_convertible_to<bool>;
}
// clang-format on
#endif // __cpp_lib_concepts
{ return _Left._Get_current() == _Right._Get_current(); }
template <class _BidIt1, class _BidIt2>
_NODISCARD _CONSTEXPR17 bool operator!=(const reverse_iterator<_BidIt1>& _Left, const reverse_iterator<_BidIt2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Left._Get_current() != _Right._Get_current() } -> _Implicitly_convertible_to<bool>;
}
// clang-format on
#endif // __cpp_lib_concepts
{ return _Left._Get_current() != _Right._Get_current(); }
template <class _BidIt1, class _BidIt2>
_NODISCARD _CONSTEXPR17 bool operator<(const reverse_iterator<_BidIt1>& _Left, const reverse_iterator<_BidIt2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Left._Get_current() > _Right._Get_current() } -> _Implicitly_convertible_to<bool>;
}
// clang-format on
#endif // __cpp_lib_concepts
{ return _Left._Get_current() > _Right._Get_current(); }
template <class _BidIt1, class _BidIt2>
_NODISCARD _CONSTEXPR17 bool operator>(const reverse_iterator<_BidIt1>& _Left, const reverse_iterator<_BidIt2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Left._Get_current() < _Right._Get_current() } -> _Implicitly_convertible_to<bool>;
}
// clang-format on
#endif // __cpp_lib_concepts
{ return _Left._Get_current() < _Right._Get_current(); }
template <class _BidIt1, class _BidIt2>
_NODISCARD _CONSTEXPR17 bool operator<=(const reverse_iterator<_BidIt1>& _Left, const reverse_iterator<_BidIt2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Left._Get_current() >= _Right._Get_current() } -> _Implicitly_convertible_to<bool>;
}
// clang-format on
#endif // __cpp_lib_concepts
{ return _Left._Get_current() >= _Right._Get_current(); }
template <class _BidIt1, class _BidIt2>
_NODISCARD _CONSTEXPR17 bool operator>=(const reverse_iterator<_BidIt1>& _Left, const reverse_iterator<_BidIt2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Left._Get_current() <= _Right._Get_current() } -> _Implicitly_convertible_to<bool>;
}
// clang-format on
#endif // __cpp_lib_concepts
{ return _Left._Get_current() <= _Right._Get_current(); }
#if defined(__cpp_impl_three_way_comparison) && defined(__cpp_lib_concepts)
template <class _BidIt1, three_way_comparable_with<_BidIt1> _BidIt2>
_NODISCARD constexpr compare_three_way_result_t<_BidIt1, _BidIt2> operator<=>(
const reverse_iterator<_BidIt1>& _Left, const reverse_iterator<_BidIt2>& _Right) {
return _Right._Get_current() <=> _Left._Get_current();
}
#endif // defined(__cpp_impl_three_way_comparison) && defined(__cpp_lib_concepts)
template <class _BidIt1, class _BidIt2>
_NODISCARD _CONSTEXPR17 auto operator-(const reverse_iterator<_BidIt1>& _Left, const reverse_iterator<_BidIt2>& _Right)
-> decltype(_Right._Get_current() - _Left._Get_current()) {
return _Right._Get_current() - _Left._Get_current();
}
template <class _BidIt>
_NODISCARD _CONSTEXPR17 reverse_iterator<_BidIt> operator+(
typename reverse_iterator<_BidIt>::difference_type _Off, const reverse_iterator<_BidIt>& _Right) {
return _Right + _Off;
}
// FUNCTION TEMPLATE make_reverse_iterator
template <class _BidIt>
_NODISCARD _CONSTEXPR17 reverse_iterator<_BidIt> make_reverse_iterator(_BidIt _Iter) noexcept(
is_nothrow_move_constructible_v<_BidIt>) /* strengthened */ {
return reverse_iterator<_BidIt>(_STD move(_Iter));
}
#ifdef __cpp_lib_concepts
// clang-format off
template <class _BidIt1, class _BidIt2>
requires (!sized_sentinel_for<_BidIt1, _BidIt2>)
inline constexpr bool disable_sized_sentinel_for<reverse_iterator<_BidIt1>, reverse_iterator<_BidIt2>> = true;
// clang-format on
#endif // __cpp_lib_concepts
// FUNCTION TEMPLATES begin AND end
template <class _Container>
_NODISCARD _CONSTEXPR17 auto begin(_Container& _Cont) -> decltype(_Cont.begin()) {
return _Cont.begin();
}
template <class _Container>
_NODISCARD _CONSTEXPR17 auto begin(const _Container& _Cont) -> decltype(_Cont.begin()) {
return _Cont.begin();
}
template <class _Container>
_NODISCARD _CONSTEXPR17 auto end(_Container& _Cont) -> decltype(_Cont.end()) {
return _Cont.end();
}
template <class _Container>
_NODISCARD _CONSTEXPR17 auto end(const _Container& _Cont) -> decltype(_Cont.end()) {
return _Cont.end();
}
template <class _Ty, size_t _Size>
_NODISCARD constexpr _Ty* begin(_Ty (&_Array)[_Size]) noexcept {
return _Array;
}
template <class _Ty, size_t _Size>
_NODISCARD constexpr _Ty* end(_Ty (&_Array)[_Size]) noexcept {
return _Array + _Size;
}
// FUNCTION TEMPLATES cbegin AND cend
template <class _Container>
_NODISCARD constexpr auto cbegin(const _Container& _Cont) noexcept(noexcept(_STD begin(_Cont)))
-> decltype(_STD begin(_Cont)) {
return _STD begin(_Cont);
}
template <class _Container>
_NODISCARD constexpr auto cend(const _Container& _Cont) noexcept(noexcept(_STD end(_Cont)))
-> decltype(_STD end(_Cont)) {
return _STD end(_Cont);
}
// FUNCTION TEMPLATES rbegin AND rend
template <class _Container>
_NODISCARD _CONSTEXPR17 auto rbegin(_Container& _Cont) -> decltype(_Cont.rbegin()) {
return _Cont.rbegin();
}
template <class _Container>
_NODISCARD _CONSTEXPR17 auto rbegin(const _Container& _Cont) -> decltype(_Cont.rbegin()) {
return _Cont.rbegin();
}
template <class _Container>
_NODISCARD _CONSTEXPR17 auto rend(_Container& _Cont) -> decltype(_Cont.rend()) {
return _Cont.rend();
}
template <class _Container>
_NODISCARD _CONSTEXPR17 auto rend(const _Container& _Cont) -> decltype(_Cont.rend()) {
return _Cont.rend();
}
template <class _Ty, size_t _Size>
_NODISCARD _CONSTEXPR17 reverse_iterator<_Ty*> rbegin(_Ty (&_Array)[_Size]) {
return reverse_iterator<_Ty*>(_Array + _Size);
}
template <class _Ty, size_t _Size>
_NODISCARD _CONSTEXPR17 reverse_iterator<_Ty*> rend(_Ty (&_Array)[_Size]) {
return reverse_iterator<_Ty*>(_Array);
}
template <class _Elem>
_NODISCARD _CONSTEXPR17 reverse_iterator<const _Elem*> rbegin(initializer_list<_Elem> _Ilist) {
return reverse_iterator<const _Elem*>(_Ilist.end());
}
template <class _Elem>
_NODISCARD _CONSTEXPR17 reverse_iterator<const _Elem*> rend(initializer_list<_Elem> _Ilist) {
return reverse_iterator<const _Elem*>(_Ilist.begin());
}
// FUNCTION TEMPLATES crbegin AND crend
template <class _Container>
_NODISCARD _CONSTEXPR17 auto crbegin(const _Container& _Cont) -> decltype(_STD rbegin(_Cont)) {
return _STD rbegin(_Cont);
}
template <class _Container>
_NODISCARD _CONSTEXPR17 auto crend(const _Container& _Cont) -> decltype(_STD rend(_Cont)) {
return _STD rend(_Cont);
}
template <class _Container>
_NODISCARD constexpr auto size(const _Container& _Cont) -> decltype(_Cont.size()) {
return _Cont.size();
}
template <class _Ty, size_t _Size>
_NODISCARD constexpr size_t size(const _Ty (&)[_Size]) noexcept {
return _Size;
}
#if _HAS_CXX20
// FUNCTION TEMPLATE ssize
template <class _Container>
_NODISCARD constexpr auto ssize(const _Container& _Cont)
-> common_type_t<ptrdiff_t, make_signed_t<decltype(_Cont.size())>> {
using _Common = common_type_t<ptrdiff_t, make_signed_t<decltype(_Cont.size())>>;
return static_cast<_Common>(_Cont.size());
}
template <class _Ty, ptrdiff_t _Size>
_NODISCARD constexpr ptrdiff_t ssize(const _Ty (&)[_Size]) noexcept {
return _Size;
}
#endif // _HAS_CXX20
template <class _Container>
_NODISCARD constexpr auto empty(const _Container& _Cont) -> decltype(_Cont.empty()) {
return _Cont.empty();
}
template <class _Ty, size_t _Size>
_NODISCARD constexpr bool empty(const _Ty (&)[_Size]) noexcept {
return false;
}
template <class _Elem>
_NODISCARD constexpr bool empty(initializer_list<_Elem> _Ilist) noexcept {
return _Ilist.size() == 0;
}
template <class _Container>
_NODISCARD constexpr auto data(_Container& _Cont) -> decltype(_Cont.data()) {
return _Cont.data();
}
template <class _Container>
_NODISCARD constexpr auto data(const _Container& _Cont) -> decltype(_Cont.data()) {
return _Cont.data();
}
template <class _Ty, size_t _Size>
_NODISCARD constexpr _Ty* data(_Ty (&_Array)[_Size]) noexcept {
return _Array;
}
template <class _Elem>
_NODISCARD constexpr const _Elem* data(initializer_list<_Elem> _Ilist) noexcept {
return _Ilist.begin();
}
#ifdef __cpp_lib_concepts
// FUNCTION TEMPLATE _Fake_decay_copy
template <class _Ty>
_NODISCARD _Ty _Fake_decay_copy(_Ty) noexcept;
// _Fake_decay_copy<T>(E):
// (1) has type T [decay_t<decltype((E))> if T is deduced],
// (2) is well-formed if and only if E is implicitly convertible to T and T is destructible, and
// (3) is non-throwing if and only if both conversion from decltype((E)) to T and destruction of T are non-throwing.
namespace ranges {
// VARIABLE TEMPLATE _Has_complete_elements
template <class>
inline constexpr bool _Has_complete_elements = false;
// clang-format off
template <class _Ty>
requires requires(_Ty& __t) { sizeof(__t[0]); }
inline constexpr bool _Has_complete_elements<_Ty> = true;
// clang-format on
// VARIABLE TEMPLATE ranges::enable_borrowed_range
template <class>
inline constexpr bool enable_borrowed_range = false;
template <class _Rng>
concept _Should_range_access = is_lvalue_reference_v<_Rng> || enable_borrowed_range<remove_cvref_t<_Rng>>;
// CUSTOMIZATION POINT OBJECT ranges::begin
namespace _Begin {
template <class _Ty>
void begin(_Ty&) = delete;
template <class _Ty>
void begin(const _Ty&) = delete;
// clang-format off
template <class _Ty>
concept _Has_member = requires(_Ty __t) {
{ _Fake_decay_copy(__t.begin()) } -> input_or_output_iterator;
};
template <class _Ty>
concept _Has_ADL = _Has_class_or_enum_type<_Ty> && requires(_Ty __t) {
{ _Fake_decay_copy(begin(__t)) } -> input_or_output_iterator;
};
// clang-format on
class _Cpo {
private:
enum class _St { _None, _Array, _Member, _Non_member };
template <class _Ty>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
_STL_INTERNAL_STATIC_ASSERT(is_lvalue_reference_v<_Ty>);
if constexpr (is_array_v<remove_reference_t<_Ty>>) {
static_assert(_Has_complete_elements<_Ty>,
"The range access customization point objects "
"std::ranges::begin, std::ranges::end, std::ranges::rbegin, std::ranges::rend, "
"and std::ranges::data do not accept arrays with incomplete element types.");
return {_St::_Array, true};
} else if constexpr (_Has_member<_Ty>) {
return {_St::_Member, noexcept(_Fake_decay_copy(_STD declval<_Ty>().begin()))};
} else if constexpr (_Has_ADL<_Ty>) {
return {_St::_Non_member, noexcept(_Fake_decay_copy(begin(_STD declval<_Ty>())))};
} else {
return {_St::_None};
}
}
template <class _Ty>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty>();
public:
// clang-format off
template <_Should_range_access _Ty>
requires (_Choice<_Ty&>._Strategy != _St::_None)
_NODISCARD constexpr auto operator()(_Ty&& _Val) const noexcept(_Choice<_Ty&>._No_throw) {
if constexpr (_Choice<_Ty&>._Strategy == _St::_Array) {
return _Val;
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Member) {
return _Val.begin();
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Non_member) {
return begin(_Val);
} else {
static_assert(_Always_false<_Ty>, "Should be unreachable");
}
}
// clang-format on
};
} // namespace _Begin
inline namespace _Cpos {
inline constexpr _Begin::_Cpo begin;
}
// ALIAS TEMPLATE ranges::iterator_t
template <class _Ty>
using iterator_t = decltype(_RANGES begin(_STD declval<_Ty&>()));
// CUSTOMIZATION POINT OBJECT ranges::end
namespace _End {
template <class _Ty>
void end(_Ty&) = delete;
template <class _Ty>
void end(const _Ty&) = delete;
// clang-format off
template <class _Ty>
concept _Has_member = requires(_Ty __t) {
{ _Fake_decay_copy(__t.end()) } -> sentinel_for<iterator_t<_Ty>>;
};
template <class _Ty>
concept _Has_ADL = _Has_class_or_enum_type<_Ty> && requires(_Ty __t) {
{ _Fake_decay_copy(end(__t)) } -> sentinel_for<iterator_t<_Ty>>;
};
// clang-format on
class _Cpo {
private:
enum class _St { _None, _Array, _Member, _Non_member };
template <class _Ty>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
_STL_INTERNAL_STATIC_ASSERT(is_lvalue_reference_v<_Ty>);
using _UnRef = remove_reference_t<_Ty>;
if constexpr (is_array_v<_UnRef>) {
static_assert(_Has_complete_elements<_UnRef>,
"The range access customization point objects "
"std::ranges::begin, std::ranges::end, std::ranges::rbegin, std::ranges::rend, "
"and std::ranges::data do not accept arrays with incomplete element types.");
if constexpr (extent_v<_UnRef> != 0) {
return {_St::_Array, true};
} else {
return {_St::_None};
}
} else if constexpr (_Has_member<_Ty>) {
return {_St::_Member, noexcept(_Fake_decay_copy(_STD declval<_Ty>().end()))};
} else if constexpr (_Has_ADL<_Ty>) {
return {_St::_Non_member, noexcept(_Fake_decay_copy(end(_STD declval<_Ty>())))};
} else {
return {_St::_None};
}
}
template <class _Ty>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty>();
public:
// clang-format off
template <_Should_range_access _Ty>
requires (_Choice<_Ty&>._Strategy != _St::_None)
_NODISCARD constexpr auto operator()(_Ty&& _Val) const noexcept(_Choice<_Ty&>._No_throw) {
if constexpr (_Choice<_Ty&>._Strategy == _St::_Array) {
// extent_v<remove_reference_t<_Ty&>> reuses specializations from _Choose
return _Val + extent_v<remove_reference_t<_Ty&>>;
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Member) {
return _Val.end();
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Non_member) {
return end(_Val);
} else {
static_assert(_Always_false<_Ty>, "should be unreachable");
}
}
// clang-format on
};
} // namespace _End
inline namespace _Cpos {
inline constexpr _End::_Cpo end;
}
// CONCEPT ranges::range
template <class _Rng>
concept range = requires(_Rng& __r) {
_RANGES begin(__r);
_RANGES end(__r);
};
// CONCEPT ranges::borrowed_range
// clang-format off
template <class _Rng>
concept borrowed_range = range<_Rng> && _Should_range_access<_Rng>;
// clang-format on
// ALIAS TEMPLATE ranges::sentinel_t
template <range _Rng>
using sentinel_t = decltype(_RANGES end(_STD declval<_Rng&>()));
// ALIAS TEMPLATE ranges::range_difference_t
template <range _Rng>
using range_difference_t = iter_difference_t<iterator_t<_Rng>>;
// ALIAS TEMPLATE ranges::range_value_t
template <range _Rng>
using range_value_t = iter_value_t<iterator_t<_Rng>>;
// ALIAS TEMPLATE ranges::range_reference_t
template <range _Rng>
using range_reference_t = iter_reference_t<iterator_t<_Rng>>;
// ALIAS TEMPLATE ranges::range_rvalue_reference_t
template <range _Rng>
using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<_Rng>>;
// CUSTOMIZATION POINT OBJECT ranges::cbegin
struct _Cbegin_fn {
// clang-format off
template <class _Ty, class _CTy = _Const_thru_ref<_Ty>>
_NODISCARD constexpr auto operator()(_Ty&& _Val) const
noexcept(noexcept(_RANGES begin(static_cast<_CTy&&>(_Val))))
requires requires { _RANGES begin(static_cast<_CTy&&>(_Val)); } {
return _RANGES begin(static_cast<_CTy&&>(_Val));
}
// clang-format on
};
inline namespace _Cpos {
inline constexpr _Cbegin_fn cbegin;
}
// CUSTOMIZATION POINT OBJECT ranges::cend
struct _Cend_fn {
// clang-format off
template <class _Ty, class _CTy = _Const_thru_ref<_Ty>>
_NODISCARD constexpr auto operator()(_Ty&& _Val) const
noexcept(noexcept(_RANGES end(static_cast<_CTy&&>(_Val))))
requires requires { _RANGES end(static_cast<_CTy&&>(_Val)); } {
return _RANGES end(static_cast<_CTy&&>(_Val));
}
// clang-format on
};
inline namespace _Cpos {
inline constexpr _Cend_fn cend;
}
// CUSTOMIZATION POINT OBJECT ranges::rbegin
namespace _Rbegin {
template <class _Ty>
void rbegin(_Ty&) = delete;
template <class _Ty>
void rbegin(const _Ty&) = delete;
// clang-format off
template <class _Ty>
concept _Has_member = requires(_Ty __t) {
{ _Fake_decay_copy(__t.rbegin()) } -> input_or_output_iterator;
};
template <class _Ty>
concept _Has_ADL = _Has_class_or_enum_type<_Ty> && requires(_Ty __t) {
{ _Fake_decay_copy(rbegin(__t)) } -> input_or_output_iterator;
};
template <class _Ty>
concept _Can_make_reverse = requires(_Ty __t) {
{ _RANGES begin(__t) } -> bidirectional_iterator;
{ _RANGES end(__t) } -> same_as<decltype(_RANGES begin(__t))>;
};
// clang-format on
class _Cpo {
private:
enum class _St { _None, _Member, _Non_member, _Make_reverse };
template <class _Ty>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
_STL_INTERNAL_STATIC_ASSERT(is_lvalue_reference_v<_Ty>);
if constexpr (_Has_member<_Ty>) {
return {_St::_Member, noexcept(_Fake_decay_copy(_STD declval<_Ty>().rbegin()))};
} else if constexpr (_Has_ADL<_Ty>) {
return {_St::_Non_member, noexcept(_Fake_decay_copy(rbegin(_STD declval<_Ty>())))};
} else if constexpr (_Can_make_reverse<_Ty>) {
return {_St::_Make_reverse, noexcept(_STD make_reverse_iterator(_RANGES end(_STD declval<_Ty>())))};
} else {
return {_St::_None};
}
}
template <class _Ty>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty>();
public:
// clang-format off
template <_Should_range_access _Ty>
requires (_Choice<_Ty&>._Strategy != _St::_None)
_NODISCARD constexpr auto operator()(_Ty&& _Val) const noexcept(_Choice<_Ty&>._No_throw) {
if constexpr (_Choice<_Ty&>._Strategy == _St::_Member) {
return _Val.rbegin();
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Non_member) {
return rbegin(_Val);
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Make_reverse) {
return _STD make_reverse_iterator(_RANGES end(_Val));
} else {
static_assert(_Always_false<_Ty>, "should be unreachable");
}
}
// clang-format on
};
} // namespace _Rbegin
inline namespace _Cpos {
inline constexpr _Rbegin::_Cpo rbegin;
}
// CUSTOMIZATION POINT OBJECT ranges::rend
namespace _Rend {
template <class _Ty>
void rend(_Ty&) = delete;
template <class _Ty>
void rend(const _Ty&) = delete;
// clang-format off
template <class _Ty>
concept _Has_member = requires(_Ty __t) {
{ _Fake_decay_copy(__t.rend()) } -> sentinel_for<decltype(_RANGES rbegin(__t))>;
};
template <class _Ty>
concept _Has_ADL = _Has_class_or_enum_type<_Ty> && requires(_Ty __t) {
{ _Fake_decay_copy(rend(__t)) } -> sentinel_for<decltype(_RANGES rbegin(__t))>;
};
template <class _Ty>
concept _Can_make_reverse = requires(_Ty __t) {
{ _RANGES begin(__t) } -> bidirectional_iterator;
{ _RANGES end(__t) } -> same_as<decltype(_RANGES begin(__t))>;
};
// clang-format on
class _Cpo {
private:
enum class _St { _None, _Member, _Non_member, _Make_reverse };
template <class _Ty>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
_STL_INTERNAL_STATIC_ASSERT(is_lvalue_reference_v<_Ty>);
if constexpr (_Has_member<_Ty>) {
return {_St::_Member, noexcept(_Fake_decay_copy(_STD declval<_Ty>().rend()))};
} else if constexpr (_Has_ADL<_Ty>) {
return {_St::_Non_member, noexcept(_Fake_decay_copy(rend(_STD declval<_Ty>())))};
} else if constexpr (_Can_make_reverse<_Ty>) {
return {
_St::_Make_reverse, noexcept(_STD make_reverse_iterator(_RANGES begin(_STD declval<_Ty>())))};
} else {
return {_St::_None};
}
}
template <class _Ty>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty>();
public:
// clang-format off
template <_Should_range_access _Ty>
requires (_Choice<_Ty&>._Strategy != _St::_None)
_NODISCARD constexpr auto operator()(_Ty&& _Val) const noexcept(_Choice<_Ty&>._No_throw) {
if constexpr (_Choice<_Ty&>._Strategy == _St::_Member) {
return _Val.rend();
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Non_member) {
return rend(_Val);
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Make_reverse) {
return _STD make_reverse_iterator(_RANGES begin(_Val));
} else {
static_assert(_Always_false<_Ty>, "should be unreachable");
}
}
// clang-format on
};
} // namespace _Rend
inline namespace _Cpos {
inline constexpr _Rend::_Cpo rend;
}
// CUSTOMIZATION POINT OBJECT ranges::crbegin
struct _Crbegin_fn {
// clang-format off
template <class _Ty, class _CTy = _Const_thru_ref<_Ty>>
_NODISCARD constexpr auto operator()(_Ty&& _Val) const
noexcept(noexcept(_RANGES rbegin(static_cast<_CTy&&>(_Val))))
requires requires { _RANGES rbegin(static_cast<_CTy&&>(_Val)); } {
return _RANGES rbegin(static_cast<_CTy&&>(_Val));
}
// clang-format on
};
inline namespace _Cpos {
inline constexpr _Crbegin_fn crbegin;
}
// CUSTOMIZATION POINT OBJECT ranges::crend
struct _Crend_fn {
// clang-format off
template <class _Ty, class _CTy = _Const_thru_ref<_Ty>>
_NODISCARD constexpr auto operator()(_Ty&& _Val) const
noexcept(noexcept(_RANGES rend(static_cast<_CTy&&>(_Val))))
requires requires { _RANGES rend(static_cast<_CTy&&>(_Val)); } {
return _RANGES rend(static_cast<_CTy&&>(_Val));
}
// clang-format on
};
inline namespace _Cpos {
inline constexpr _Crend_fn crend;
}
// VARIABLE TEMPLATE ranges::disable_sized_range
template <class>
inline constexpr bool disable_sized_range = false;
// CUSTOMIZATION POINT OBJECT ranges::size
namespace _Size {
template <class _Ty>
void size(_Ty&) = delete;
template <class _Ty>
void size(const _Ty&) = delete;
// clang-format off
template <class _Ty, class _UnCV>
concept _Has_member = !disable_sized_range<_UnCV> && requires(_Ty __t) {
{ _Fake_decay_copy(__t.size()) } -> integral;
};
template <class _Ty, class _UnCV>
concept _Has_ADL = _Has_class_or_enum_type<_Ty> && !disable_sized_range<_UnCV> && requires(_Ty __t) {
{ _Fake_decay_copy(size(__t)) } -> integral;
};
template <class _Ty>
concept _Can_difference = requires(_Ty __t) {
{ _RANGES begin(__t) } -> forward_iterator;
{ _RANGES end(__t) } -> sized_sentinel_for<decltype(_RANGES begin(__t))>;
};
// clang-format on
class _Cpo {
private:
enum class _St { _None, _Array, _Member, _Non_member, _Subtract };
template <class _Ty>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
_STL_INTERNAL_STATIC_ASSERT(is_lvalue_reference_v<_Ty>);
using _UnCV = remove_cvref_t<_Ty>;
if constexpr (is_array_v<_UnCV>) {
if constexpr (extent_v<_UnCV> != 0) {
return {_St::_Array, true};
} else {
return {_St::_None};
}
} else if constexpr (_Has_member<_Ty, _UnCV>) {
return {_St::_Member, noexcept(_Fake_decay_copy(_STD declval<_Ty>().size()))};
} else if constexpr (_Has_ADL<_Ty, _UnCV>) {
return {_St::_Non_member, noexcept(_Fake_decay_copy(size(_STD declval<_Ty>())))};
} else if constexpr (_Can_difference<_Ty>) {
return {_St::_Subtract,
noexcept(_RANGES end(_STD declval<_Ty>()) - _RANGES begin(_STD declval<_Ty>()))};
} else {
return {_St::_None};
}
}
template <class _Ty>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty>();
public:
// clang-format off
template <class _Ty>
requires (_Choice<_Ty&>._Strategy != _St::_None)
_NODISCARD constexpr auto operator()([[maybe_unused]] _Ty&& _Val) const noexcept(_Choice<_Ty&>._No_throw) {
if constexpr (_Choice<_Ty&>._Strategy == _St::_Array) {
// extent_v<remove_cvref_t<_Ty&>> reuses specializations from _Choose
return extent_v<remove_cvref_t<_Ty&>>;
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Member) {
return _Val.size();
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Non_member) {
return size(_Val);
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Subtract) {
const auto _Delta = _RANGES end(_Val) - _RANGES begin(_Val);
return static_cast<_Make_unsigned_like_t<remove_cv_t<decltype(_Delta)>>>(_Delta);
} else {
static_assert(_Always_false<_Ty>, "should be unreachable");
}
}
// clang-format on
};
} // namespace _Size
inline namespace _Cpos {
inline constexpr _Size::_Cpo size;
}
// CUSTOMIZATION POINT OBJECT ranges::empty
namespace _Empty {
// clang-format off
template <class _Ty>
concept _Has_member = requires(_Ty __t) {
static_cast<bool>(__t.empty());
};
template <class _Ty>
concept _Has_size = requires(_Ty __t) {
_RANGES size(__t);
};
template <class _Ty>
concept _Can_begin_end = requires(_Ty __t) {
{ _RANGES begin(__t) } -> forward_iterator;
_RANGES end(__t);
};
// clang-format on
class _Cpo {
private:
enum class _St { _None, _Member, _Size, _Compare };
template <class _Ty>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
_STL_INTERNAL_STATIC_ASSERT(is_lvalue_reference_v<_Ty>);
if constexpr (is_unbounded_array_v<remove_reference_t<_Ty>>) {
return {_St::_None};
} else if constexpr (_Has_member<_Ty>) {
return {_St::_Member, noexcept(static_cast<bool>(_STD declval<_Ty>().empty()))};
} else if constexpr (_Has_size<_Ty>) {
return {_St::_Size, noexcept(_RANGES size(_STD declval<_Ty>()))};
} else if constexpr (_Can_begin_end<_Ty>) {
constexpr auto _Nothrow = noexcept(
static_cast<bool>(_RANGES begin(_STD declval<_Ty>()) == _RANGES end(_STD declval<_Ty>())));
return {_St::_Compare, _Nothrow};
} else {
return {_St::_None};
}
}
template <class _Ty>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty>();
public:
// clang-format off
template <class _Ty>
requires (_Choice<_Ty&>._Strategy != _St::_None)
_NODISCARD constexpr bool operator()([[maybe_unused]] _Ty&& _Val) const noexcept(_Choice<_Ty&>._No_throw) {
if constexpr (_Choice<_Ty&>._Strategy == _St::_Member) {
return static_cast<bool>(_Val.empty());
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Size) {
return _RANGES size(_Val) == 0;
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Compare) {
return static_cast<bool>(_RANGES begin(_Val) == _RANGES end(_Val));
} else {
static_assert(_Always_false<_Ty>, "should be unreachable");
}
}
// clang-format on
};
} // namespace _Empty
inline namespace _Cpos {
inline constexpr _Empty::_Cpo empty;
}
// CUSTOMIZATION POINT OBJECT ranges::data
namespace _Data {
// clang-format off
template <class _Ty>
concept _Points_to_object = is_pointer_v<_Ty> && is_object_v<remove_pointer_t<_Ty>>;
template <class _Ty>
concept _Has_member = requires(_Ty __t) {
{ _Fake_decay_copy(__t.data()) } -> _Points_to_object;
};
template <class _Ty>
concept _Has_contiguous_iterator = requires(_Ty __t) {
{ _RANGES begin(__t) } -> contiguous_iterator;
};
// clang-format on
class _Cpo {
private:
enum class _St { _None, _Member, _Address };
template <class _Ty>
_NODISCARD static _CONSTEVAL _Choice_t<_St> _Choose() noexcept {
_STL_INTERNAL_STATIC_ASSERT(is_lvalue_reference_v<_Ty>);
if constexpr (_Has_member<_Ty>) {
return {_St::_Member, noexcept(_STD declval<_Ty>().data())};
} else if constexpr (_Has_contiguous_iterator<_Ty>) {
return {_St::_Address, noexcept(_STD to_address(_RANGES begin(_STD declval<_Ty>())))};
} else {
return {_St::_None};
}
}
template <class _Ty>
static constexpr _Choice_t<_St> _Choice = _Choose<_Ty>();
public:
// clang-format off
template <_Should_range_access _Ty>
requires (_Choice<_Ty&>._Strategy != _St::_None)
_NODISCARD constexpr auto operator()(_Ty&& _Val) const noexcept(_Choice<_Ty&>._No_throw) {
if constexpr (_Choice<_Ty&>._Strategy == _St::_Member) {
return _Val.data();
} else if constexpr (_Choice<_Ty&>._Strategy == _St::_Address) {
return _STD to_address(_RANGES begin(_Val));
} else {
static_assert(_Always_false<_Ty>, "should be unreachable");
}
}
// clang-format on
};
} // namespace _Data
inline namespace _Cpos {
inline constexpr _Data::_Cpo data;
}
// CUSTOMIZATION POINT OBJECT ranges::cdata
struct _Cdata_fn {
// clang-format off
template <class _Ty, class _CTy = _Const_thru_ref<_Ty>>
_NODISCARD constexpr auto operator()(_Ty&& _Val) const
noexcept(noexcept(_RANGES data(static_cast<_CTy&&>(_Val))))
requires requires { _RANGES data(static_cast<_CTy&&>(_Val)); } {
return _RANGES data(static_cast<_CTy&&>(_Val));
}
// clang-format on
};
inline namespace _Cpos {
inline constexpr _Cdata_fn cdata;
}
// clang-format off
// CONCEPT ranges::sized_range
template <class _Rng>
concept sized_range = range<_Rng> && requires(_Rng& __r) {
_RANGES size(__r);
};
// clang-format on
// ALIAS TEMPLATE ranges::range_size_t
template <sized_range _Rng>
using range_size_t = decltype(_RANGES size(_STD declval<_Rng&>()));
// STRUCT ranges::view_base
struct view_base {};
// VARIABLE TEMPLATE ranges::enable_view
template <class _Ty>
inline constexpr bool enable_view = derived_from<_Ty, view_base>;
// clang-format off
// CONCEPT ranges::view
template <class _Ty>
concept view = range<_Ty> && movable<_Ty> && default_initializable<_Ty> && enable_view<_Ty>;
// CONCEPT ranges::output_range
template <class _Rng, class _Ty>
concept output_range = range<_Rng> && output_iterator<iterator_t<_Rng>, _Ty>;
// CONCEPT ranges::input_range
template <class _Rng>
concept input_range = range<_Rng> && input_iterator<iterator_t<_Rng>>;
// CONCEPT ranges::forward_range
template <class _Rng>
concept forward_range = range<_Rng> && forward_iterator<iterator_t<_Rng>>;
// CONCEPT ranges::bidirectional_range
template <class _Rng>
concept bidirectional_range = range<_Rng> && bidirectional_iterator<iterator_t<_Rng>>;
// CONCEPT ranges::random_access_range
template <class _Rng>
concept random_access_range = range<_Rng> && random_access_iterator<iterator_t<_Rng>>;
// CONCEPT ranges::contiguous_range
template <class _Rng>
concept contiguous_range = range<_Rng> && contiguous_iterator<iterator_t<_Rng>> && requires(_Rng& __r) {
{ _RANGES data(__r) } -> same_as<add_pointer_t<range_reference_t<_Rng>>>;
};
// clang-format on
// CLASS ranges::_Not_quite_object
class _Not_quite_object {
public:
// Some overload sets in the library have the property that their constituent function templates are not visible
// to argument-dependent name lookup (ADL) and that they inhibit ADL when found via unqualified name lookup.
// This property allows these overload sets to be implemented as function objects. We derive such function
// objects from this type to remove some typical object-ish behaviors which helps users avoid depending on their
// non-specified object-ness.
struct _Construct_tag {
explicit _Construct_tag() = default;
};
_Not_quite_object() = delete;
constexpr explicit _Not_quite_object(_Construct_tag) noexcept {}
_Not_quite_object(const _Not_quite_object&) = delete;
_Not_quite_object& operator=(const _Not_quite_object&) = delete;
void operator&() const = delete;
protected:
~_Not_quite_object() = default;
};
// CLASS ranges::_Advance_fn
class _Advance_fn : private _Not_quite_object {
public:
using _Not_quite_object::_Not_quite_object;
template <input_or_output_iterator _It>
constexpr void operator()(_It& _Where, iter_difference_t<_It> _Off) const {
if constexpr (random_access_iterator<_It>) {
_Where += _Off;
} else {
if constexpr (!bidirectional_iterator<_It>) {
_STL_ASSERT(_Off >= 0, "negative advance of non-bidirectional iterator");
}
auto&& _UWhere = _Get_unwrapped_n(_STD move(_Where), _Off);
constexpr bool _Need_rewrap = !is_reference_v<decltype(_Get_unwrapped_n(_STD move(_Where), _Off))>;
if constexpr (bidirectional_iterator<_It>) {
for (; _Off < 0; ++_Off) {
--_UWhere;
}
}
for (; _Off > 0; --_Off) {
++_UWhere;
}
if constexpr (_Need_rewrap) {
_Seek_wrapped(_Where, _STD move(_UWhere));
}
}
}
template <input_or_output_iterator _It, sentinel_for<_It> _Se>
constexpr void operator()(_It& _Where, _Se _Last) const {
if constexpr (assignable_from<_It&, _Se>) {
_Where = static_cast<_Se&&>(_Last);
} else if constexpr (sized_sentinel_for<_Se, _It>) {
(*this)(_Where, _Last - _Where);
} else {
_Adl_verify_range(_Where, _Last);
auto&& _UWhere = _Get_unwrapped(static_cast<_It&&>(_Where));
constexpr bool _Need_rewrap = !is_reference_v<decltype(_Get_unwrapped(static_cast<_It&&>(_Where)))>;
auto&& _ULast = _Get_unwrapped(static_cast<_Se&&>(_Last));
while (_UWhere != _ULast) {
++_UWhere;
}
if constexpr (_Need_rewrap) {
_Seek_wrapped(_Where, static_cast<_It&&>(_UWhere));
}
}
}
template <input_or_output_iterator _It, sentinel_for<_It> _Se>
constexpr iter_difference_t<_It> operator()(_It& _Where, iter_difference_t<_It> _Off, _Se _Last) const {
if constexpr (sized_sentinel_for<_Se, _It>) {
const iter_difference_t<_It> _Delta = _Last - _Where;
if ((_Off < 0 && _Off <= _Delta) || (_Off > 0 && _Off >= _Delta)) {
if constexpr (assignable_from<_It&, _Se>) {
_Where = static_cast<_Se&&>(_Last);
} else {
(*this)(_Where, _Delta);
}
return _Off - _Delta;
}
(*this)(_Where, _Off);
return 0;
} else {
// performance note: develop unwrapping technology for (i, n, s)?
if constexpr (bidirectional_iterator<_It>) {
for (; _Off < 0 && _Where != _Last; ++_Off) {
--_Where;
}
} else {
_STL_ASSERT(_Off >= 0, "negative advance of non-bidirectional iterator");
}
for (; _Off > 0 && _Where != _Last; --_Off) {
++_Where;
}
return _Off;
}
}
};
// VARIABLE ranges::advance
inline constexpr _Advance_fn advance{_Not_quite_object::_Construct_tag{}};
// CLASS ranges::_Distance_fn
class _Distance_fn : private _Not_quite_object {
public:
using _Not_quite_object::_Not_quite_object;
template <input_or_output_iterator _It, sentinel_for<_It> _Se>
_NODISCARD constexpr iter_difference_t<_It> operator()(_It _First, _Se _Last) const {
if constexpr (sized_sentinel_for<_Se, _It>) {
return _Last - _First;
} else {
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(static_cast<_It&&>(_First));
const auto _ULast = _Get_unwrapped(static_cast<_Se&&>(_Last));
iter_difference_t<_It> _Count = 0;
for (; _UFirst != _ULast; ++_UFirst) {
++_Count;
}
return _Count;
}
}
template <range _Rng>
_NODISCARD constexpr range_difference_t<_Rng> operator()(_Rng&& _Val) const {
if constexpr (sized_range<_Rng>) {
return static_cast<range_difference_t<_Rng>>(_RANGES size(_Val));
} else {
return (*this)(_RANGES begin(_Val), _RANGES end(_Val));
}
}
};
// VARIABLE ranges::distance
inline constexpr _Distance_fn distance{_Not_quite_object::_Construct_tag{}};
// CLASS ranges::_Next_fn
class _Next_fn : private _Not_quite_object {
public:
using _Not_quite_object::_Not_quite_object;
template <input_or_output_iterator _It>
_NODISCARD constexpr _It operator()(_It _Where) const {
++_Where;
return _Where;
}
template <input_or_output_iterator _It>
_NODISCARD constexpr _It operator()(_It _Where, const iter_difference_t<_It> _Off) const {
_RANGES advance(_Where, _Off);
return _Where;
}
template <input_or_output_iterator _It, sentinel_for<_It> _Se>
_NODISCARD constexpr _It operator()(_It _Where, _Se _Last) const {
_RANGES advance(_Where, static_cast<_Se&&>(_Last));
return _Where;
}
template <input_or_output_iterator _It, sentinel_for<_It> _Se>
_NODISCARD constexpr _It operator()(_It _Where, const iter_difference_t<_It> _Off, _Se _Last) const {
_RANGES advance(_Where, _Off, static_cast<_Se&&>(_Last));
return _Where;
}
};
// VARIABLE ranges::next
inline constexpr _Next_fn next{_Not_quite_object::_Construct_tag{}};
// CLASS ranges::_Prev_fn
class _Prev_fn : private _Not_quite_object {
public:
using _Not_quite_object::_Not_quite_object;
template <bidirectional_iterator _It>
_NODISCARD constexpr _It operator()(_It _Where) const {
--_Where;
return _Where;
}
template <bidirectional_iterator _It>
_NODISCARD constexpr _It operator()(_It _Where, const iter_difference_t<_It> _Off) const {
_STL_ASSERT(_Off != _Min_possible_v<iter_difference_t<_It>>, "integer overflow");
_RANGES advance(_Where, -_Off);
return _Where;
}
template <bidirectional_iterator _It>
_NODISCARD constexpr _It operator()(_It _Where, const iter_difference_t<_It> _Off, _It _Last) const {
_STL_ASSERT(_Off != _Min_possible_v<iter_difference_t<_It>>, "integer overflow");
_RANGES advance(_Where, -_Off, static_cast<_It&&>(_Last));
return _Where;
}
};
// VARIABLE ranges::prev
inline constexpr _Prev_fn prev{_Not_quite_object::_Construct_tag{}};
// STRUCT ranges::equal_to
struct equal_to {
// clang-format off
template <class _Ty1, class _Ty2>
requires equality_comparable_with<_Ty1, _Ty2> // TRANSITION, GH-489
_NODISCARD constexpr bool operator()(_Ty1&& _Left, _Ty2&& _Right) const noexcept(noexcept(
static_cast<bool>(static_cast<_Ty1&&>(_Left) == static_cast<_Ty2&&>(_Right)))) /* strengthened */ {
return static_cast<bool>(static_cast<_Ty1&&>(_Left) == static_cast<_Ty2&&>(_Right));
}
// clang-format on
using is_transparent = int;
};
// STRUCT ranges::less
struct less {
// clang-format off
template <class _Ty1, class _Ty2>
requires totally_ordered_with<_Ty1, _Ty2> // TRANSITION, GH-489
_NODISCARD constexpr bool operator()(_Ty1&& _Left, _Ty2&& _Right) const noexcept(noexcept(
static_cast<bool>(static_cast<_Ty1&&>(_Left) < static_cast<_Ty2&&>(_Right)))) /* strengthened */ {
return static_cast<bool>(static_cast<_Ty1&&>(_Left) < static_cast<_Ty2&&>(_Right));
}
// clang-format on
using is_transparent = int;
};
// CONCEPT _Not_same_as
template <class _Ty1, class _Ty2>
concept _Not_same_as = !same_as<remove_cvref_t<_Ty1>, remove_cvref_t<_Ty2>>;
// CONCEPT ranges::common_range
// clang-format off
template <class _Rng>
concept common_range = range<_Rng>
&& same_as<iterator_t<_Rng>, sentinel_t<_Rng>>;
// CLASS TEMPLATE ranges::view_interface
template <class _Ty>
concept _Can_empty = requires(_Ty __t) { _RANGES empty(__t); };
template <class _Derived>
requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>
class view_interface : public view_base {
private:
_NODISCARD constexpr _Derived& _Cast() noexcept {
static_assert(derived_from<_Derived, view_interface>,
"view_interface's template argument D must derive from view_interface<D> (N4849 [view.interface]/2).");
static_assert(view<_Derived>,
"view_interface's template argument must model the view concept (N4849 [view.interface]/2).");
return static_cast<_Derived&>(*this);
}
_NODISCARD constexpr const _Derived& _Cast() const noexcept {
static_assert(derived_from<_Derived, view_interface>,
"view_interface's template argument D must derive from view_interface<D> (N4849 [view.interface]/2).");
static_assert(view<_Derived>,
"view_interface's template argument must model the view concept (N4849 [view.interface]/2).");
return static_cast<const _Derived&>(*this);
}
public:
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr bool empty() requires forward_range<_Dx>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr bool empty() requires forward_range<_Derived>
#endif // TRANSITION, LLVM-44833
{
auto& _Self = _Cast();
return _RANGES begin(_Self) == _RANGES end(_Self);
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr bool empty() const requires forward_range<const _Dx>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr bool empty() const requires forward_range<const _Derived>
#endif // TRANSITION, LLVM-44833
{
auto& _Self = _Cast();
return _RANGES begin(_Self) == _RANGES end(_Self);
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
constexpr explicit operator bool() requires _Can_empty<_Dx>
#else // ^^^ workaround / no workaround vvv
constexpr explicit operator bool() requires _Can_empty<_Derived>
#endif // TRANSITION, LLVM-44833
{
return !_RANGES empty(_Cast());
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
constexpr explicit operator bool() const requires _Can_empty<const _Dx>
#else // ^^^ workaround / no workaround vvv
constexpr explicit operator bool() const requires _Can_empty<const _Derived>
#endif // TRANSITION, LLVM-44833
{
return !_RANGES empty(_Cast());
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr auto data() requires contiguous_iterator<iterator_t<_Dx>>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr auto data() requires contiguous_iterator<iterator_t<_Derived>>
#endif // TRANSITION, LLVM-44833
{
return _STD to_address(_RANGES begin(_Cast()));
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr auto data() const
requires range<const _Dx> && contiguous_iterator<iterator_t<const _Dx>>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr auto data() const
requires range<const _Derived> && contiguous_iterator<iterator_t<const _Derived>>
#endif // TRANSITION, LLVM-44833
{
return _STD to_address(_RANGES begin(_Cast()));
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr auto size()
requires forward_range<_Dx> && sized_sentinel_for<sentinel_t<_Dx>, iterator_t<_Dx>>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr auto size()
requires forward_range<_Derived> && sized_sentinel_for<sentinel_t<_Derived>, iterator_t<_Derived>>
#endif // TRANSITION, LLVM-44833
{
auto& _Self = _Cast();
return _RANGES end(_Self) - _RANGES begin(_Self);
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr auto size() const requires forward_range<const _Dx>
&& sized_sentinel_for<sentinel_t<const _Dx>, iterator_t<const _Dx>>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr auto size() const requires forward_range<const _Derived>
&& sized_sentinel_for<sentinel_t<const _Derived>, iterator_t<const _Derived>>
#endif // TRANSITION, LLVM-44833
{
auto& _Self = _Cast();
return _RANGES end(_Self) - _RANGES begin(_Self);
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr decltype(auto) front() requires forward_range<_Dx>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr decltype(auto) front() requires forward_range<_Derived>
#endif // TRANSITION, LLVM-44833
{
auto& _Self = _Cast();
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(!_RANGES empty(_Self), "front called on empty view_interface");
#endif // _CONTAINER_DEBUG_LEVEL > 0
return *_RANGES begin(_Self);
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr decltype(auto) front() const requires forward_range<const _Dx>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr decltype(auto) front() const requires forward_range<const _Derived>
#endif // TRANSITION, LLVM-44833
{
auto& _Self = _Cast();
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(!_RANGES empty(_Self), "front called on empty view_interface");
#endif // _CONTAINER_DEBUG_LEVEL > 0
return *_RANGES begin(_Self);
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr decltype(auto) back() requires bidirectional_range<_Dx> && common_range<_Dx>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr decltype(auto) back() requires bidirectional_range<_Derived> && common_range<_Derived>
#endif // TRANSITION, LLVM-44833
{
auto& _Self = _Cast();
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(!_RANGES empty(_Self), "back called on empty view_interface");
#endif // _CONTAINER_DEBUG_LEVEL > 0
auto _Last = _RANGES end(_Self);
return *--_Last;
}
#ifdef __clang__ // TRANSITION, LLVM-44833
template <class _Dx = _Derived>
_NODISCARD constexpr decltype(auto) back() const
requires bidirectional_range<const _Dx> && common_range<const _Dx>
#else // ^^^ workaround / no workaround vvv
_NODISCARD constexpr decltype(auto) back() const
requires bidirectional_range<const _Derived> && common_range<const _Derived>
#endif // TRANSITION, LLVM-44833
{
auto& _Self = _Cast();
#if _CONTAINER_DEBUG_LEVEL > 0
_STL_VERIFY(!_RANGES empty(_Self), "back called on empty view_interface");
#endif // _CONTAINER_DEBUG_LEVEL > 0
auto _Last = _RANGES end(_Self);
return *--_Last;
}
template <random_access_range _Rng = _Derived>
_NODISCARD constexpr decltype(auto) operator[](const range_difference_t<_Rng> _Idx) {
auto& _Self = _Cast();
#if _CONTAINER_DEBUG_LEVEL > 0
if constexpr (sized_range<_Derived>) {
_STL_VERIFY(_Idx < _RANGES size(_Self), "index out of range for view_interface");
}
#endif // _CONTAINER_DEBUG_LEVEL > 0
return _RANGES begin(_Self)[_Idx];
}
template <random_access_range _Rng = const _Derived>
_NODISCARD constexpr decltype(auto) operator[](const range_difference_t<_Rng> _Idx) const {
auto& _Self = _Cast();
#if _CONTAINER_DEBUG_LEVEL > 0
if constexpr (sized_range<_Derived>) {
_STL_VERIFY(_Idx < _RANGES size(_Self), "index out of range for view_interface");
}
#endif // _CONTAINER_DEBUG_LEVEL > 0
return _RANGES begin(_Self)[_Idx];
}
};
// ENUM CLASS ranges::subrange_kind
enum class subrange_kind : bool { unsized, sized };
// clang-format on
} // namespace ranges
// These declarations must be visible to qualified name lookup for _STD get in _Pair_like below, even if <tuple> hasn't
// yet been included.
template <size_t _Index, class... _Types>
_NODISCARD constexpr tuple_element_t<_Index, tuple<_Types...>>& get(tuple<_Types...>& _Tuple) noexcept;
template <size_t _Index, class... _Types>
_NODISCARD constexpr const tuple_element_t<_Index, tuple<_Types...>>& get(const tuple<_Types...>& _Tuple) noexcept;
template <size_t _Index, class... _Types>
_NODISCARD constexpr tuple_element_t<_Index, tuple<_Types...>>&& get(tuple<_Types...>&& _Tuple) noexcept;
template <size_t _Index, class... _Types>
_NODISCARD constexpr const tuple_element_t<_Index, tuple<_Types...>>&& get(const tuple<_Types...>&& _Tuple) noexcept;
namespace ranges {
// clang-format off
// CLASS TEMPLATE ranges::subrange
template <class _From, class _To>
concept _Convertible_to_non_slicing = convertible_to<_From, _To>
&& !(is_pointer_v<decay_t<_From>>
&& is_pointer_v<decay_t<_To>>
&& _Not_same_as<remove_pointer_t<decay_t<_From>>, remove_pointer_t<decay_t<_To>>>);
template <class _Ty>
concept _Pair_like = !is_reference_v<_Ty> && requires(_Ty __t) {
typename tuple_size<_Ty>::type;
requires derived_from<tuple_size<_Ty>, integral_constant<size_t, 2>>;
typename tuple_element_t<0, remove_const_t<_Ty>>;
typename tuple_element_t<1, remove_const_t<_Ty>>;
{ _STD get<0>(__t) } -> convertible_to<const tuple_element_t<0, _Ty>&>;
{ _STD get<1>(__t) } -> convertible_to<const tuple_element_t<1, _Ty>&>;
};
template <class _Ty, class _First, class _Second>
concept _Pair_like_convertible_from = !range<_Ty> && _Pair_like<_Ty>
&& constructible_from<_Ty, _First, _Second>
&& _Convertible_to_non_slicing<_First, tuple_element_t<0, _Ty>>
&& convertible_to<_Second, tuple_element_t<1, _Ty>>;
template <input_or_output_iterator _It, sentinel_for<_It> _Se = _It,
subrange_kind _Ki = sized_sentinel_for<_Se, _It> ? subrange_kind::sized : subrange_kind::unsized>
requires (_Ki == subrange_kind::sized || !sized_sentinel_for<_Se, _It>)
class subrange;
// clang-format on
template <class _It, class _Se, subrange_kind _Ki,
bool _Store = _Ki == subrange_kind::sized && !sized_sentinel_for<_Se, _It>>
class _Subrange_base : public view_interface<subrange<_It, _Se, _Ki>> { // TRANSITION, [[no_unique_address]]
protected:
using _Size_type = _Make_unsigned_like_t<iter_difference_t<_It>>;
static constexpr bool _Store_size = true;
_Size_type _Size = 0;
public:
_Subrange_base() = default;
constexpr explicit _Subrange_base(const _Size_type& _Size_) noexcept : _Size(_Size_) {}
};
template <class _It, class _Se, subrange_kind _Ki>
class _Subrange_base<_It, _Se, _Ki, false> : public view_interface<subrange<_It, _Se, _Ki>> {
protected:
using _Size_type = _Make_unsigned_like_t<iter_difference_t<_It>>;
static constexpr bool _Store_size = false;
public:
_Subrange_base() = default;
constexpr explicit _Subrange_base(const _Size_type&) noexcept {}
};
// clang-format off
template <input_or_output_iterator _It, sentinel_for<_It> _Se, subrange_kind _Ki>
requires (_Ki == subrange_kind::sized || !sized_sentinel_for<_Se, _It>)
class subrange : public _Subrange_base<_It, _Se, _Ki> {
private:
using _Mybase = _Subrange_base<_It, _Se, _Ki>;
using typename _Mybase::_Size_type;
using _Mybase::_Store_size;
// TRANSITION, [[no_unique_address]]:
/* [[no_unique_address]] */ _It _First{};
/* [[no_unique_address]] */ _Se _Last{};
// [[no_unique_address]] conditional_t<_Store_size, _Size_type, _Nil> _Size{};
template <class _Rng>
constexpr subrange(true_type, _Rng&& _Val) : subrange{_STD forward<_Rng>(_Val), _RANGES size(_Val)} {
// delegation target for subrange(_Rng&&) when we must store the range size
_STL_INTERNAL_STATIC_ASSERT(_Store_size);
}
template <class _Rng>
constexpr subrange(false_type, _Rng&& _Val) : subrange{_RANGES begin(_Val), _RANGES end(_Val)} {
// delegation target for subrange(_Rng&&) when we need not store the range size
_STL_INTERNAL_STATIC_ASSERT(!_Store_size);
}
public:
subrange() = default;
template <_Convertible_to_non_slicing<_It> _It2>
constexpr subrange(_It2 _First_, _Se _Last_) requires (!_Store_size)
: _First(_STD move(_First_)), _Last(_STD move(_Last_)) {}
template <_Convertible_to_non_slicing<_It> _It2>
constexpr subrange(_It2 _First_, _Se _Last_, const _Size_type _Size_) requires (_Ki == subrange_kind::sized)
: _Mybase(_Size_), _First(_STD move(_First_)), _Last(_STD move(_Last_)) {
if constexpr (sized_sentinel_for<_Se, _It>) {
_STL_ASSERT(_Size_ == static_cast<_Size_type>(_Last - _First),
"This constructor's third argument should be equal to the distance "
"between the first and second arguments (N4849 [range.subrange.ctor]/3).");
}
}
template <_Not_same_as<subrange> _Rng>
requires borrowed_range<_Rng>
&& _Convertible_to_non_slicing<iterator_t<_Rng>, _It>
&& convertible_to<sentinel_t<_Rng>, _Se>
constexpr subrange(_Rng&& _Val) requires (!_Store_size || sized_range<_Rng>)
: subrange{bool_constant<_Store_size>{}, _STD forward<_Rng>(_Val)} {}
template <borrowed_range _Rng>
requires _Convertible_to_non_slicing<iterator_t<_Rng>, _It> && convertible_to<sentinel_t<_Rng>, _Se>
constexpr subrange(_Rng&& _Val, const _Size_type _Count) requires (_Ki == subrange_kind::sized)
: subrange{_RANGES begin(_Val), _RANGES end(_Val), _Count} {}
template <_Not_same_as<subrange> _Pair_like>
requires _Pair_like_convertible_from<_Pair_like, const _It&, const _Se&>
constexpr operator _Pair_like() const {
return _Pair_like(_First, _Last);
}
_NODISCARD constexpr _It begin() const requires copyable<_It> {
return _First;
}
_NODISCARD constexpr _It begin() requires (!copyable<_It>) {
return _STD move(_First);
}
_NODISCARD constexpr _Se end() const {
return _Last;
}
_NODISCARD constexpr bool empty() const {
return _First == _Last;
}
_NODISCARD constexpr _Size_type size() const requires (_Ki == subrange_kind::sized) {
if constexpr (_Store_size) {
return this->_Size;
} else {
return static_cast<_Size_type>(_Last - _First);
}
}
_NODISCARD constexpr subrange next() const & requires forward_iterator<_It> {
auto _Tmp = *this;
if (_Tmp._First != _Tmp._Last) {
++_Tmp._First;
if constexpr (_Store_size) {
--_Tmp._Size;
}
}
return _Tmp;
}
_NODISCARD constexpr subrange next(const iter_difference_t<_It> _Count) const & requires forward_iterator<_It> {
auto _Tmp = *this;
_Tmp.advance(_Count);
return _Tmp;
}
_NODISCARD constexpr subrange next() && {
if (_First != _Last) {
++_First;
if constexpr (_Store_size) {
--this->_Size;
}
}
return _STD move(*this);
}
_NODISCARD constexpr subrange next(const iter_difference_t<_It> _Count) && {
advance(_Count);
return _STD move(*this);
}
_NODISCARD constexpr subrange prev() const requires bidirectional_iterator<_It> {
auto _Tmp = *this;
--_Tmp._First;
if constexpr (_Store_size) {
++_Tmp._Size;
}
return _Tmp;
}
_NODISCARD constexpr subrange prev(const iter_difference_t<_It> _Count) const
requires bidirectional_iterator<_It> {
auto _Tmp = *this;
_Tmp.advance(-_Count);
return _Tmp;
}
constexpr subrange& advance(const iter_difference_t<_It> _Count) {
// Per LWG-3413, this has defined behavior when _Count < 0.
if constexpr (bidirectional_iterator<_It>) {
if (_Count < 0) {
_RANGES advance(_First, _Count);
if constexpr (_Store_size) {
this->_Size += static_cast<_Size_type>(-_Count);
}
return *this;
}
}
const auto _Remainder = _RANGES advance(_First, _Count, _Last);
if constexpr (_Store_size) {
this->_Size -= static_cast<_Size_type>(_Count - _Remainder);
}
return *this;
}
};
// clang-format on
template <input_or_output_iterator _It, sentinel_for<_It> _Se>
subrange(_It, _Se) -> subrange<_It, _Se>;
template <input_or_output_iterator _It, sentinel_for<_It> _Se>
subrange(_It, _Se, _Make_unsigned_like_t<iter_difference_t<_It>>) -> subrange<_It, _Se, subrange_kind::sized>;
template <borrowed_range _Rng>
subrange(_Rng &&) -> subrange<iterator_t<_Rng>, sentinel_t<_Rng>,
(sized_range<_Rng> || sized_sentinel_for<sentinel_t<_Rng>, iterator_t<_Rng>>) ? subrange_kind::sized
: subrange_kind::unsized>;
template <borrowed_range _Rng>
subrange(_Rng&&, _Make_unsigned_like_t<range_difference_t<_Rng>>)
-> subrange<iterator_t<_Rng>, sentinel_t<_Rng>, subrange_kind::sized>;
template <class _It, class _Se, subrange_kind _Ki>
inline constexpr bool enable_borrowed_range<subrange<_It, _Se, _Ki>> = true;
// clang-format off
template <size_t _Idx, class _It, class _Se, subrange_kind _Ki>
requires (_Idx < 2)
_NODISCARD constexpr auto get(const subrange<_It, _Se, _Ki>& _Val) {
if constexpr (_Idx == 0) {
return _Val.begin();
} else {
return _Val.end();
}
}
template <size_t _Idx, class _It, class _Se, subrange_kind _Ki>
requires (_Idx < 2)
_NODISCARD constexpr auto get(subrange<_It, _Se, _Ki>&& _Val) {
if constexpr (_Idx == 0) {
return _Val.begin();
} else {
return _Val.end();
}
}
// clang-format on
} // namespace ranges
using ranges::get;
template <class _It, class _Se, ranges::subrange_kind _Ki>
struct tuple_size<ranges::subrange<_It, _Se, _Ki>> : integral_constant<size_t, 2> {};
template <class _It, class _Se, ranges::subrange_kind _Ki>
struct tuple_element<0, ranges::subrange<_It, _Se, _Ki>> {
using type = _It;
};
template <class _It, class _Se, ranges::subrange_kind _Ki>
struct tuple_element<1, ranges::subrange<_It, _Se, _Ki>> {
using type = _Se;
};
template <class _It, class _Se, ranges::subrange_kind _Ki>
struct tuple_element<0, const ranges::subrange<_It, _Se, _Ki>> {
using type = _It;
};
template <class _It, class _Se, ranges::subrange_kind _Ki>
struct tuple_element<1, const ranges::subrange<_It, _Se, _Ki>> {
using type = _Se;
};
namespace ranges {
// STRUCT ranges::dangling
struct dangling {
constexpr dangling() noexcept = default;
template <class... _Args>
constexpr dangling(_Args&&...) noexcept {}
};
// ALIAS TEMPLATE ranges::borrowed_iterator_t
template <range _Rng>
using borrowed_iterator_t = conditional_t<borrowed_range<_Rng>, iterator_t<_Rng>, dangling>;
// ALIAS TEMPLATE ranges::borrowed_subrange_t
template <range _Rng>
using borrowed_subrange_t = conditional_t<borrowed_range<_Rng>, subrange<iterator_t<_Rng>>, dangling>;
} // namespace ranges
#endif // __cpp_lib_concepts
struct _Container_proxy;
struct _Iterator_base12;
// STRUCT _Default_sentinel
struct _Default_sentinel {}; // empty struct to serve as the end of a range
// CLASS TEMPLATE move_iterator
#ifdef __cpp_lib_concepts
template <semiregular>
class move_sentinel;
#endif // __cpp_lib_concepts
template <class _Iter>
class move_iterator {
public:
using iterator_type = _Iter;
#ifdef __cpp_lib_concepts
using iterator_concept = input_iterator_tag;
using iterator_category = conditional_t<derived_from<_Iter_cat_t<_Iter>, random_access_iterator_tag>,
random_access_iterator_tag, _Iter_cat_t<_Iter>>;
#else // ^^^ __cpp_lib_concepts / !__cpp_lib_concepts vvv
using iterator_category = _Iter_cat_t<_Iter>;
#endif // __cpp_lib_concepts
using value_type = _Iter_value_t<_Iter>;
using difference_type = _Iter_diff_t<_Iter>;
using pointer = _Iter;
#ifdef __cpp_lib_concepts
using reference = iter_rvalue_reference_t<_Iter>;
#else // ^^^ __cpp_lib_concepts / !__cpp_lib_concepts vvv
using reference =
conditional_t<is_reference_v<_Iter_ref_t<_Iter>>, remove_reference_t<_Iter_ref_t<_Iter>>&&, _Iter_ref_t<_Iter>>;
#endif // __cpp_lib_concepts
_CONSTEXPR17 move_iterator() = default;
_CONSTEXPR17 explicit move_iterator(_Iter _Right) noexcept(is_nothrow_move_constructible_v<_Iter>) // strengthened
: current(_STD move(_Right)) {}
// clang-format off
template <class _Other>
#ifdef __cpp_lib_concepts
// per LWG-3435
requires (!is_same_v<_Other, _Iter>) && convertible_to<const _Other&, _Iter>
#endif // __cpp_lib_concepts
_CONSTEXPR17 move_iterator(const move_iterator<_Other>& _Right) noexcept(
is_nothrow_constructible_v<_Iter, const _Other&>) // strengthened
: current(_Right.base()) {}
template <class _Other>
#ifdef __cpp_lib_concepts
// per LWG-3435
requires (!is_same_v<_Other, _Iter>) && convertible_to<const _Other&, _Iter>
&& assignable_from<_Iter&, const _Other&>
#endif // __cpp_lib_concepts
_CONSTEXPR17 move_iterator& operator=(const move_iterator<_Other>& _Right) noexcept(
is_nothrow_assignable_v<_Iter&, const _Other&>) /* strengthened */ {
current = _Right.base();
return *this;
}
// clang-format on
#ifdef __cpp_lib_concepts
_NODISCARD constexpr const iterator_type& base() const& { // Per LWG-3391
return current;
}
_NODISCARD constexpr iterator_type base() && {
return _STD move(current);
}
#else // ^^^ __cpp_lib_concepts / !__cpp_lib_concepts vvv
_NODISCARD _CONSTEXPR17 iterator_type base() const {
return current;
}
#endif // __cpp_lib_concepts
_NODISCARD _CONSTEXPR17 reference operator*() const {
#ifdef __cpp_lib_concepts
return _RANGES iter_move(current);
#else // ^^^ __cpp_lib_concepts / !__cpp_lib_concepts vvv
return static_cast<reference>(*current);
#endif // __cpp_lib_concepts
}
_NODISCARD _CXX20_DEPRECATE_MOVE_ITERATOR_ARROW _CONSTEXPR17 pointer operator->() const {
return current;
}
_CONSTEXPR17 move_iterator& operator++() {
++current;
return *this;
}
_CONSTEXPR17 auto operator++(int) {
#ifdef __cpp_lib_concepts
if constexpr (forward_iterator<_Iter>) {
#endif // __cpp_lib_concepts
move_iterator _Tmp = *this;
++current;
return _Tmp;
#ifdef __cpp_lib_concepts
} else {
++current;
}
#endif // __cpp_lib_concepts
}
_CONSTEXPR17 move_iterator& operator--() {
--current;
return *this;
}
_CONSTEXPR17 move_iterator operator--(int) {
move_iterator _Tmp = *this;
--current;
return _Tmp;
}
template <class _Iter2 = _Iter>
_NODISCARD auto operator==(_Default_sentinel _Sentinel) const noexcept
-> decltype(_STD declval<const _Iter2&>() == _Sentinel) {
return current == _Sentinel;
}
template <class _Iter2 = _Iter>
_NODISCARD auto operator!=(_Default_sentinel _Sentinel) const noexcept
-> decltype(_STD declval<const _Iter2&>() != _Sentinel) {
return current != _Sentinel;
}
_NODISCARD _CONSTEXPR17 move_iterator operator+(const difference_type _Off) const {
return move_iterator(current + _Off);
}
_CONSTEXPR17 move_iterator& operator+=(const difference_type _Off) {
current += _Off;
return *this;
}
_NODISCARD _CONSTEXPR17 move_iterator operator-(const difference_type _Off) const {
return move_iterator(current - _Off);
}
_CONSTEXPR17 move_iterator& operator-=(const difference_type _Off) {
current -= _Off;
return *this;
}
_NODISCARD _CONSTEXPR17 reference operator[](const difference_type _Off) const {
#ifdef __cpp_lib_concepts
return _RANGES iter_move(current + _Off);
#else // ^^^ __cpp_lib_concepts / !__cpp_lib_concepts vvv
return _STD move(current[_Off]);
#endif // __cpp_lib_concepts
}
#ifdef __cpp_lib_concepts
template <sentinel_for<_Iter> _Sent>
_NODISCARD friend constexpr bool operator==(const move_iterator& _Left, const move_sentinel<_Sent>& _Right) {
return _Left.current == _Right._Get_last();
}
template <sized_sentinel_for<_Iter> _Sent>
_NODISCARD friend constexpr difference_type operator-(
const move_sentinel<_Sent>& _Left, const move_iterator& _Right) {
return _Left._Get_last() - _Right.current;
}
template <sized_sentinel_for<_Iter> _Sent>
_NODISCARD friend constexpr difference_type operator-(
const move_iterator& _Left, const move_sentinel<_Sent>& _Right) {
return _Left.current - _Right._Get_last();
}
_NODISCARD friend constexpr reference iter_move(const move_iterator& _It) noexcept(
noexcept(_RANGES iter_move(_It.current))) {
return _RANGES iter_move(_It.current);
}
template <indirectly_swappable<_Iter> _Iter2>
friend constexpr void iter_swap(const move_iterator& _Left, const move_iterator<_Iter2>& _Right) noexcept(
noexcept(_RANGES iter_swap(_Left.current, _Right.base()))) {
_RANGES iter_swap(_Left.current, _Right.base());
}
#endif // __cpp_lib_concepts
template <class _Iter2, enable_if_t<_Range_verifiable_v<_Iter, _Iter2>, int> = 0>
friend constexpr void _Verify_range(const move_iterator& _First, const move_iterator<_Iter2>& _Last) {
_Verify_range(_First.current, _Last.base());
}
#ifdef __cpp_lib_concepts
template <sentinel_for<_Iter> _Sent, enable_if_t<_Range_verifiable_v<_Iter, _Sent>, int> = 0>
friend constexpr void _Verify_range(const move_iterator& _First, const move_sentinel<_Sent>& _Last) {
_Verify_range(_First.current, _Last._Get_last());
}
#endif // __cpp_lib_concepts
using _Prevent_inheriting_unwrap = move_iterator;
template <class _Iter2 = iterator_type, enable_if_t<_Offset_verifiable_v<_Iter2>, int> = 0>
constexpr void _Verify_offset(const difference_type _Off) const {
current._Verify_offset(_Off);
}
template <class _Iter2 = iterator_type, enable_if_t<_Unwrappable_v<const _Iter2&>, int> = 0>
_NODISCARD constexpr move_iterator<_Unwrapped_t<const _Iter2&>> _Unwrapped() const& {
return static_cast<move_iterator<_Unwrapped_t<const _Iter2&>>>(current._Unwrapped());
}
template <class _Iter2 = iterator_type, enable_if_t<_Unwrappable_v<_Iter2>, int> = 0>
_NODISCARD constexpr move_iterator<_Unwrapped_t<_Iter2>> _Unwrapped() && {
return static_cast<move_iterator<_Unwrapped_t<_Iter2>>>(_STD move(current)._Unwrapped());
}
static constexpr bool _Unwrap_when_unverified = _Do_unwrap_when_unverified_v<iterator_type>;
template <class _Src, enable_if_t<_Wrapped_seekable_v<iterator_type, const _Src&>, int> = 0>
constexpr void _Seek_to(const move_iterator<_Src>& _It) {
current._Seek_to(_It.base());
}
template <class _Src, enable_if_t<_Wrapped_seekable_v<iterator_type, _Src>, int> = 0>
constexpr void _Seek_to(move_iterator<_Src>&& _It) {
current._Seek_to(_STD move(_It).base());
}
protected:
iterator_type current{};
};
template <class _Iter1, class _Iter2>
_NODISCARD _CONSTEXPR17 bool operator==(const move_iterator<_Iter1>& _Left, const move_iterator<_Iter2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Left.base() == _Right.base() } -> _Implicitly_convertible_to<bool>;
}
// clang-format on
#endif // __cpp_lib_concepts
{ return _Left.base() == _Right.base(); }
#if !_HAS_CXX20 || __cpp_impl_three_way_comparison < 201902L
template <class _Iter1, class _Iter2>
_NODISCARD _CONSTEXPR17 bool operator!=(const move_iterator<_Iter1>& _Left, const move_iterator<_Iter2>& _Right) {
return !(_Left == _Right);
}
#endif // !_HAS_CXX20 || __cpp_impl_three_way_comparison < 201902L
template <class _Iter1, class _Iter2>
_NODISCARD _CONSTEXPR17 bool operator<(const move_iterator<_Iter1>& _Left, const move_iterator<_Iter2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Left.base() < _Right.base() } -> _Implicitly_convertible_to<bool>;
}
// clang-format on
#endif // __cpp_lib_concepts
{ return _Left.base() < _Right.base(); }
template <class _Iter1, class _Iter2>
_NODISCARD _CONSTEXPR17 bool operator>(const move_iterator<_Iter1>& _Left, const move_iterator<_Iter2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires { _Right < _Left; }
// clang-format on
#endif // __cpp_lib_concepts
{ return _Right < _Left; }
template <class _Iter1, class _Iter2>
_NODISCARD _CONSTEXPR17 bool operator<=(const move_iterator<_Iter1>& _Left, const move_iterator<_Iter2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires { _Right < _Left; }
// clang-format on
#endif // __cpp_lib_concepts
{ return !(_Right < _Left); }
template <class _Iter1, class _Iter2>
_NODISCARD _CONSTEXPR17 bool operator>=(const move_iterator<_Iter1>& _Left, const move_iterator<_Iter2>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires { _Left < _Right; }
// clang-format on
#endif // __cpp_lib_concepts
{ return !(_Left < _Right); }
#if defined(__cpp_impl_three_way_comparison) && defined(__cpp_lib_concepts)
template <class _Iter1, three_way_comparable_with<_Iter1> _Iter2>
_NODISCARD constexpr compare_three_way_result_t<_Iter1, _Iter2> operator<=>(
const move_iterator<_Iter1>& _Left, const move_iterator<_Iter2>& _Right) {
return _Left.base() <=> _Right.base();
}
#endif // defined(__cpp_impl_three_way_comparison) && defined(__cpp_lib_concepts)
template <class _Iter1, class _Iter2>
_NODISCARD _CONSTEXPR17 auto operator-(const move_iterator<_Iter1>& _Left, const move_iterator<_Iter2>& _Right)
-> decltype(_Left.base() - _Right.base()) {
return _Left.base() - _Right.base();
}
template <class _Iter>
_NODISCARD _CONSTEXPR17 move_iterator<_Iter> operator+(
typename move_iterator<_Iter>::difference_type _Off, const move_iterator<_Iter>& _Right)
#ifdef __cpp_lib_concepts
// clang-format off
requires requires {
{ _Right.base() + _Off } -> same_as<_Iter>; // LWG-3293
}
// clang-format on
#endif // __cpp_lib_concepts
{ return move_iterator<_Iter>{_Right.base() + _Off}; }
// FUNCTION TEMPLATE make_move_iterator
template <class _Iter>
_NODISCARD _CONSTEXPR17 move_iterator<_Iter> make_move_iterator(_Iter _It) { // make move_iterator from iterator
return move_iterator<_Iter>(_STD move(_It));
}
#ifdef __cpp_lib_concepts
// STRUCT default_sentinel_t
struct default_sentinel_t {};
// VARIABLE default_sentinel
inline constexpr default_sentinel_t default_sentinel{};
// STRUCT unreachable_sentinel_t
struct unreachable_sentinel_t;
namespace _Unreachable_sentinel_detail {
struct _Base {
template <weakly_incrementable _Winc>
_NODISCARD friend constexpr bool operator==(const unreachable_sentinel_t&, const _Winc&) noexcept {
return false;
}
#if !defined(__cpp_impl_three_way_comparison) || __cpp_impl_three_way_comparison < 201902L
template <weakly_incrementable _Winc>
_NODISCARD friend constexpr bool operator==(const _Winc&, const unreachable_sentinel_t&) noexcept {
return false;
}
template <weakly_incrementable _Winc>
_NODISCARD friend constexpr bool operator!=(const unreachable_sentinel_t&, const _Winc&) noexcept {
return true;
}
template <weakly_incrementable _Winc>
_NODISCARD friend constexpr bool operator!=(const _Winc&, const unreachable_sentinel_t&) noexcept {
return true;
}
#endif // !defined(__cpp_impl_three_way_comparison) || __cpp_impl_three_way_comparison < 201902L
};
} // namespace _Unreachable_sentinel_detail
struct unreachable_sentinel_t : _Unreachable_sentinel_detail::_Base {}; // TRANSITION, /permissive-
// VARIABLE unreachable_sentinel
inline constexpr unreachable_sentinel_t unreachable_sentinel{};
#endif // __cpp_lib_concepts
// FUNCTION TEMPLATE copy
template <class _Source, class _Dest>
struct _Ptr_cat_helper {
using _USource = _Unwrap_enum_t<_Source>;
using _UDest = _Unwrap_enum_t<_Dest>;
static constexpr bool _Really_trivial = conjunction_v<
bool_constant<sizeof(_USource) == sizeof(_UDest) && is_same_v<bool, _USource> == is_same_v<bool, _UDest>>,
is_integral<_USource>, is_integral<_UDest>>;
static constexpr bool _Trivially_copyable = _Really_trivial;
};
template <class _Elem>
struct _Ptr_cat_helper<_Elem, _Elem> { // determines _Ptr_cat's result when the types are the same
static constexpr bool _Really_trivial = is_trivial_v<_Elem>;
static constexpr bool _Trivially_copyable = is_trivially_copyable_v<_Elem>;
};
template <class _Anything>
struct _Ptr_cat_helper<_Anything*, const _Anything*> {
// determines _Ptr_cat's result when all we do is add const to a pointer
static constexpr bool _Really_trivial = true;
static constexpr bool _Trivially_copyable = true;
};
template <class _Anything>
struct _Ptr_cat_helper<_Anything*, volatile _Anything*> {
// determines _Ptr_cat's result when all we do is add volatile to a pointer
static constexpr bool _Really_trivial = true;
static constexpr bool _Trivially_copyable = true;
};
template <class _Anything>
struct _Ptr_cat_helper<_Anything*, const volatile _Anything*> {
// determines _Ptr_cat's result when all we do is add cv to a pointer
static constexpr bool _Really_trivial = true;
static constexpr bool _Trivially_copyable = true;
};
struct _False_copy_cat {
static constexpr bool _Really_trivial = false;
static constexpr bool _Trivially_copyable = false;
};
template <class _Source, class _Dest>
struct _Ptr_copy_cat : _False_copy_cat {}; // unwrap the pointer-like type and dispatch to _Ptr_cat_helper for copy
template <class _Source, class _Dest>
struct _Ptr_copy_cat<_Source*, _Dest*>
: conditional_t<is_trivially_assignable_v<_Dest&, _Source&>,
_Ptr_cat_helper<remove_cv_t<_Source>, remove_cv_t<_Dest>>, _False_copy_cat> {};
template <class _Source, class _Dest>
struct _Ptr_copy_cat<move_iterator<_Source*>, _Dest*> : _Ptr_copy_cat<_Source*, _Dest*> {};
template <class _Source, class _Dest>
struct _Ptr_move_cat : _False_copy_cat {}; // unwrap the pointer-like type and dispatch to _Ptr_cat_helper for move
template <class _Source, class _Dest>
struct _Ptr_move_cat<_Source*, _Dest*>
: conditional_t<is_trivially_assignable_v<_Dest&, _Source>,
_Ptr_cat_helper<remove_cv_t<_Source>, remove_cv_t<_Dest>>, _False_copy_cat> {};
template <class _Source, class _Dest>
struct _Ptr_move_cat<move_iterator<_Source*>, _Dest*> : _Ptr_move_cat<_Source*, _Dest*> {};
template <class _InIt, class _OutIt>
_OutIt _Copy_memmove(_InIt _First, _InIt _Last, _OutIt _Dest) {
const char* const _First_ch = const_cast<const char*>(reinterpret_cast<const volatile char*>(_First));
const char* const _Last_ch = const_cast<const char*>(reinterpret_cast<const volatile char*>(_Last));
char* const _Dest_ch = const_cast<char*>(reinterpret_cast<volatile char*>(_Dest));
const auto _Count = static_cast<size_t>(_Last_ch - _First_ch);
_CSTD memmove(_Dest_ch, _First_ch, _Count);
return reinterpret_cast<_OutIt>(_Dest_ch + _Count);
}
template <class _InIt, class _OutIt>
_OutIt _Copy_memmove(move_iterator<_InIt> _First, move_iterator<_InIt> _Last, _OutIt _Dest) {
return _Copy_memmove(_First.base(), _Last.base(), _Dest);
}
#if _HAS_IF_CONSTEXPR
template <class _InIt, class _OutIt>
_CONSTEXPR20 _OutIt _Copy_unchecked(_InIt _First, _InIt _Last, _OutIt _Dest) {
// copy [_First, _Last) to [_Dest, ...)
// note: _Copy_unchecked has callers other than the copy family
if constexpr (_Ptr_copy_cat<_InIt, _OutIt>::_Trivially_copyable) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
return _Copy_memmove(_First, _Last, _Dest);
}
}
for (; _First != _Last; ++_Dest, (void) ++_First) {
*_Dest = *_First;
}
return _Dest;
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _InIt, class _OutIt>
_OutIt _Copy_unchecked1(_InIt _First, _InIt _Last, _OutIt _Dest, false_type) {
// copy [_First, _Last) to [_Dest, ...), arbitrary iterators
for (; _First != _Last; ++_Dest, (void) ++_First) {
*_Dest = *_First;
}
return _Dest;
}
template <class _InIt, class _OutIt>
_OutIt _Copy_unchecked1(_InIt _First, _InIt _Last, _OutIt _Dest, true_type) {
// copy [_First, _Last) to [_Dest, ...), pointers to trivially copyable
return _Copy_memmove(_First, _Last, _Dest);
}
template <class _InIt, class _OutIt>
_OutIt _Copy_unchecked(_InIt _First, _InIt _Last, _OutIt _Dest) {
// copy [_First, _Last) to [_Dest, ...)
// note: _Copy_unchecked has callers other than the copy family
return _Copy_unchecked1(_First, _Last, _Dest, bool_constant<_Ptr_copy_cat<_InIt, _OutIt>::_Trivially_copyable>{});
}
#endif // _HAS_IF_CONSTEXPR
template <class _InIt, class _OutIt>
_CONSTEXPR20 _OutIt copy(_InIt _First, _InIt _Last, _OutIt _Dest) { // copy [_First, _Last) to [_Dest, ...)
_Adl_verify_range(_First, _Last);
const auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
const auto _UDest = _Get_unwrapped_n(_Dest, _Idl_distance<_InIt>(_UFirst, _ULast));
_Seek_wrapped(_Dest, _Copy_unchecked(_UFirst, _ULast, _UDest));
return _Dest;
}
#if _HAS_CXX17
template <class _ExPo, class _FwdIt1, class _FwdIt2, _Enable_if_execution_policy_t<_ExPo> = 0>
_FwdIt2 copy(_ExPo&&, _FwdIt1 _First, _FwdIt1 _Last, _FwdIt2 _Dest) noexcept /* terminates */ {
// copy [_First, _Last) to [_Dest, ...)
// not parallelized as benchmarks show it isn't worth it
_REQUIRE_PARALLEL_ITERATOR(_FwdIt1);
_REQUIRE_PARALLEL_ITERATOR(_FwdIt2);
return _STD copy(_First, _Last, _Dest);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE copy_n
#if _HAS_IF_CONSTEXPR
template <class _InIt, class _Diff, class _OutIt>
_CONSTEXPR20 _OutIt copy_n(_InIt _First, _Diff _Count_raw, _OutIt _Dest) {
// copy [_First, _First + _Count) to [_Dest, ...)
_Algorithm_int_t<_Diff> _Count = _Count_raw;
if (0 < _Count) {
auto _UFirst = _Get_unwrapped_n(_First, _Count);
auto _UDest = _Get_unwrapped_n(_Dest, _Count);
if constexpr (_Ptr_copy_cat<decltype(_UFirst), decltype(_UDest)>::_Trivially_copyable) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
_UDest = _Copy_memmove(_UFirst, _UFirst + _Count, _UDest);
_Seek_wrapped(_Dest, _UDest);
return _Dest;
}
}
for (;;) {
*_UDest = *_UFirst;
++_UDest;
--_Count;
if (_Count == 0) { // note that we avoid an extra ++_First here to allow istream_iterator to work,
// see LWG-2471
break;
}
++_UFirst;
}
_Seek_wrapped(_Dest, _UDest);
}
return _Dest;
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _InIt, class _Diff, class _OutIt>
_OutIt _Copy_n_unchecked4(_InIt _First, _Diff _Count, _OutIt _Dest, false_type) {
// copy [_First, _First + _Count) to [_Dest, ...), no special optimization
// pre: 0 < _Count
for (;;) {
*_Dest = *_First;
++_Dest;
--_Count;
if (_Count == 0) { // note that we avoid an extra ++_First here to allow istream_iterator to work,
// see LWG-2471
return _Dest;
}
++_First;
}
}
template <class _InIt, class _Diff, class _OutIt>
_OutIt _Copy_n_unchecked4(_InIt _First, _Diff _Count, _OutIt _Dest, true_type) {
// copy [_First, _First + _Count) to [_Dest, ...), memmove optimization
// pre: 0 < _Count
return _Copy_memmove(_First, _First + _Count, _Dest);
}
template <class _InIt, class _Diff, class _OutIt>
_OutIt copy_n(_InIt _First, _Diff _Count_raw, _OutIt _Dest) { // copy [_First, _First + _Count) to [_Dest, ...)
const _Algorithm_int_t<_Diff> _Count = _Count_raw;
if (0 < _Count) {
auto _UFirst = _Get_unwrapped_n(_First, _Count);
auto _UDest = _Get_unwrapped_n(_Dest, _Count);
_Seek_wrapped(
_Dest, _Copy_n_unchecked4(_UFirst, _Count, _UDest,
bool_constant<_Ptr_copy_cat<decltype(_UFirst), decltype(_UDest)>::_Trivially_copyable>{}));
}
return _Dest;
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
template <class _ExPo, class _FwdIt1, class _Diff, class _FwdIt2, _Enable_if_execution_policy_t<_ExPo> = 0>
_FwdIt2 copy_n(_ExPo&&, _FwdIt1 _First, _Diff _Count_raw, _FwdIt2 _Dest) noexcept /* terminates */ {
// copy [_First, _First + _Count) to [_Dest, ...)
// not parallelized as benchmarks show it isn't worth it
_REQUIRE_PARALLEL_ITERATOR(_FwdIt1);
_REQUIRE_PARALLEL_ITERATOR(_FwdIt2);
return _STD copy_n(_First, _Count_raw, _Dest);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE copy_backward
template <class _BidIt1, class _BidIt2>
_BidIt2 _Copy_backward_memmove(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest) {
// implement copy_backward-like function as memmove
const char* const _First_ch = const_cast<const char*>(reinterpret_cast<const volatile char*>(_First));
const char* const _Last_ch = const_cast<const char*>(reinterpret_cast<const volatile char*>(_Last));
char* const _Dest_ch = const_cast<char*>(reinterpret_cast<volatile char*>(_Dest));
const auto _Count = static_cast<size_t>(_Last_ch - _First_ch);
return static_cast<_BidIt2>(_CSTD memmove(_Dest_ch - _Count, _First_ch, _Count));
}
template <class _BidIt1, class _BidIt2>
_BidIt2 _Copy_backward_memmove(move_iterator<_BidIt1> _First, move_iterator<_BidIt1> _Last, _BidIt2 _Dest) {
return _Copy_backward_memmove(_First.base(), _Last.base(), _Dest);
}
#if _HAS_IF_CONSTEXPR
template <class _BidIt1, class _BidIt2>
_CONSTEXPR20 _BidIt2 copy_backward(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest) {
// copy [_First, _Last) backwards to [..., _Dest)
_Adl_verify_range(_First, _Last);
const auto _UFirst = _Get_unwrapped(_First);
auto _ULast = _Get_unwrapped(_Last);
auto _UDest = _Get_unwrapped_n(_Dest, -_Idl_distance<_BidIt1>(_UFirst, _ULast));
if constexpr (_Ptr_copy_cat<decltype(_ULast), decltype(_UDest)>::_Trivially_copyable) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
_UDest = _Copy_backward_memmove(_UFirst, _ULast, _UDest);
_Seek_wrapped(_Dest, _UDest);
return _Dest;
}
}
while (_UFirst != _ULast) {
*--_UDest = *--_ULast;
}
_Seek_wrapped(_Dest, _UDest);
return _Dest;
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _BidIt1, class _BidIt2>
_BidIt2 _Copy_backward_unchecked(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest, false_type) {
// copy [_First, _Last) backwards to [..., _Dest), no special optimization
while (_First != _Last) {
*--_Dest = *--_Last;
}
return _Dest;
}
template <class _BidIt1, class _BidIt2>
_BidIt2 _Copy_backward_unchecked(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest, true_type) {
// copy [_First, _Last) backwards to [..., _Dest), memmove optimization
return _Copy_backward_memmove(_First, _Last, _Dest);
}
template <class _BidIt1, class _BidIt2>
_BidIt2 copy_backward(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest) { // copy [_First, _Last) backwards to [..., _Dest)
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
auto _UDest = _Get_unwrapped_n(_Dest, -_Idl_distance<_BidIt1>(_UFirst, _ULast));
_Seek_wrapped(_Dest, _Copy_backward_unchecked(_UFirst, _ULast, _UDest,
bool_constant<_Ptr_copy_cat<decltype(_UFirst), decltype(_UDest)>::_Trivially_copyable>{}));
return _Dest;
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
template <class _ExPo, class _BidIt1, class _BidIt2, _Enable_if_execution_policy_t<_ExPo> = 0>
_BidIt2 copy_backward(_ExPo&&, _BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest) noexcept /* terminates */ {
// copy [_First, _Last) backwards to [..., _Dest)
// not parallelized as benchmarks show it isn't worth it
return _STD copy_backward(_First, _Last, _Dest);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE move
#if _HAS_IF_CONSTEXPR
template <class _InIt, class _OutIt>
_CONSTEXPR20 _OutIt _Move_unchecked(_InIt _First, _InIt _Last, _OutIt _Dest) {
// move [_First, _Last) to [_Dest, ...)
// note: _Move_unchecked has callers other than the move family
if constexpr (_Ptr_move_cat<_InIt, _OutIt>::_Trivially_copyable) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
return _Copy_memmove(_First, _Last, _Dest);
}
}
for (; _First != _Last; ++_Dest, (void) ++_First) {
*_Dest = _STD move(*_First);
}
return _Dest;
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _InIt, class _OutIt>
_OutIt _Move_unchecked1(_InIt _First, _InIt _Last, _OutIt _Dest, false_type) {
// move [_First, _Last) to [_Dest, ...), no special optimization
for (; _First != _Last; ++_Dest, (void) ++_First) {
*_Dest = _STD move(*_First);
}
return _Dest;
}
template <class _InIt, class _OutIt>
_OutIt _Move_unchecked1(_InIt _First, _InIt _Last, _OutIt _Dest, true_type) {
// move [_First, _Last) to [_Dest, ...), memmove optimization
return _Copy_memmove(_First, _Last, _Dest);
}
template <class _InIt, class _OutIt>
_OutIt _Move_unchecked(_InIt _First, _InIt _Last, _OutIt _Dest) {
// move [_First, _Last) to [_Dest, ...), choose optimization
// note: _Move_unchecked has callers other than the move family
return _Move_unchecked1(_First, _Last, _Dest, bool_constant<_Ptr_move_cat<_InIt, _OutIt>::_Trivially_copyable>{});
}
#endif // _HAS_IF_CONSTEXPR
template <class _InIt, class _OutIt>
_CONSTEXPR20 _OutIt move(_InIt _First, _InIt _Last, _OutIt _Dest) {
// move [_First, _Last) to [_Dest, ...)
_Adl_verify_range(_First, _Last);
const auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
const auto _UDest = _Get_unwrapped_n(_Dest, _Idl_distance<_InIt>(_UFirst, _ULast));
_Seek_wrapped(_Dest, _Move_unchecked(_UFirst, _ULast, _UDest));
return _Dest;
}
#if _HAS_CXX17
template <class _ExPo, class _FwdIt1, class _FwdIt2, _Enable_if_execution_policy_t<_ExPo> = 0>
_FwdIt2 move(_ExPo&&, _FwdIt1 _First, _FwdIt1 _Last, _FwdIt2 _Dest) noexcept /* terminates */ {
// move [_First, _Last) to [_Dest, ...)
// not parallelized as benchmarks show it isn't worth it
_REQUIRE_PARALLEL_ITERATOR(_FwdIt1);
_REQUIRE_PARALLEL_ITERATOR(_FwdIt2);
return _STD move(_First, _Last, _Dest);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE move_backward
#if _HAS_IF_CONSTEXPR
template <class _BidIt1, class _BidIt2>
_CONSTEXPR20 _BidIt2 _Move_backward_unchecked(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest) {
// move [_First, _Last) backwards to [..., _Dest)
// note: _Move_backward_unchecked has callers other than the move_backward family
if constexpr (_Ptr_move_cat<_BidIt1, _BidIt2>::_Trivially_copyable) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
return _Copy_backward_memmove(_First, _Last, _Dest);
}
}
while (_First != _Last) {
*--_Dest = _STD move(*--_Last);
}
return _Dest;
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _BidIt1, class _BidIt2>
_BidIt2 _Move_backward_unchecked1(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest, false_type) {
// move [_First, _Last) backwards to [..., _Dest), no special optimization
while (_First != _Last) {
*--_Dest = _STD move(*--_Last);
}
return _Dest;
}
template <class _BidIt1, class _BidIt2>
_BidIt2 _Move_backward_unchecked1(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest, true_type) {
// move [_First, _Last) backwards to [..., _Dest), memmove optimization
return _Copy_backward_memmove(_First, _Last, _Dest);
}
template <class _BidIt1, class _BidIt2>
_BidIt2 _Move_backward_unchecked(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest) {
// move [_First, _Last) backwards to [..., _Dest), choose optimization
// note: _Move_backward_unchecked has callers other than the move_backward family
return _Move_backward_unchecked1(
_First, _Last, _Dest, bool_constant<_Ptr_move_cat<_BidIt1, _BidIt2>::_Trivially_copyable>{});
}
#endif // _HAS_IF_CONSTEXPR
template <class _BidIt1, class _BidIt2>
_CONSTEXPR20 _BidIt2 move_backward(_BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest) {
// move [_First, _Last) backwards to [..., _Dest)
_Adl_verify_range(_First, _Last);
const auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
const auto _UDest = _Get_unwrapped_n(_Dest, -_Idl_distance<_BidIt1>(_UFirst, _ULast));
_Seek_wrapped(_Dest, _Move_backward_unchecked(_UFirst, _ULast, _UDest));
return _Dest;
}
#if _HAS_CXX17
template <class _ExPo, class _BidIt1, class _BidIt2, _Enable_if_execution_policy_t<_ExPo> = 0>
_BidIt2 move_backward(_ExPo&&, _BidIt1 _First, _BidIt1 _Last, _BidIt2 _Dest) noexcept /* terminates */ {
// move [_First, _Last) backwards to [..., _Dest)
// not parallelized as benchmarks show it isn't worth it
return _STD move_backward(_First, _Last, _Dest);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE fill
template <class _Ty>
struct _Is_character : false_type {}; // by default, not a character type
template <>
struct _Is_character<char> : true_type {}; // chars are characters
template <>
struct _Is_character<signed char> : true_type {}; // signed chars are also characters
template <>
struct _Is_character<unsigned char> : true_type {}; // unsigned chars are also characters
#ifdef __cpp_char8_t
template <>
struct _Is_character<char8_t> : true_type {}; // UTF-8 code units are sort-of characters
#endif // __cpp_char8_t
template <class _Ty>
struct _Is_character_or_byte : _Is_character<_Ty>::type {};
#ifdef __cpp_lib_byte
template <>
struct _Is_character_or_byte<byte> : true_type {};
#endif // __cpp_lib_byte
// _Fill_memset_is_safe determines if _FwdIt and _Ty are eligible for memset optimization in fill
template <class _FwdIt, class _Ty, bool = is_pointer_v<_FwdIt>>
_INLINE_VAR constexpr bool _Fill_memset_is_safe = conjunction_v<
disjunction<conjunction<_Is_character_or_byte<_Unwrap_enum_t<_Ty>>,
_Is_character_or_byte<_Unwrap_enum_t<_Iter_value_t<_FwdIt>>>>,
conjunction<is_same<bool, _Unwrap_enum_t<_Ty>>, is_same<bool, _Unwrap_enum_t<_Iter_value_t<_FwdIt>>>>>,
is_assignable<_Iter_ref_t<_FwdIt>, const _Ty&>>;
template <class _FwdIt, class _Ty>
_INLINE_VAR constexpr bool _Fill_memset_is_safe<_FwdIt, _Ty, false> = false;
#if _HAS_IF_CONSTEXPR
template <class _FwdIt, class _Ty>
_CONSTEXPR20 void fill(const _FwdIt _First, const _FwdIt _Last, const _Ty& _Val) {
// copy _Val through [_First, _Last)
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
if constexpr (_Fill_memset_is_safe<decltype(_UFirst), _Ty>) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
_CSTD memset(_UFirst, static_cast<unsigned char>(_Val), static_cast<size_t>(_ULast - _UFirst));
return;
}
}
for (; _UFirst != _ULast; ++_UFirst) {
*_UFirst = _Val;
}
}
#else // ^^^ _HAS_IF_CONSTEXPR // !_HAS_IF_CONSTEXPR vvv
template <class _FwdIt, class _Ty>
void _Fill_unchecked1(_FwdIt _First, _FwdIt _Last, const _Ty& _Val, false_type) {
// copy _Val through [_First, _Last), no special optimization
for (; _First != _Last; ++_First) {
*_First = _Val;
}
}
template <class _FwdIt, class _Ty>
void _Fill_unchecked1(_FwdIt _First, _FwdIt _Last, const _Ty& _Val, true_type) {
// copy _Val through [_First, _Last), memset optimization
_CSTD memset(_First, static_cast<unsigned char>(_Val), static_cast<size_t>(_Last - _First));
}
template <class _FwdIt, class _Ty>
void fill(_FwdIt _First, _FwdIt _Last, const _Ty& _Val) { // copy _Val through [_First, _Last)
_Adl_verify_range(_First, _Last);
_Fill_unchecked1(_Get_unwrapped(_First), _Get_unwrapped(_Last), _Val,
bool_constant<_Fill_memset_is_safe<_Unwrapped_t<const _FwdIt&>, _Ty>>{});
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
template <class _ExPo, class _FwdIt, class _Ty, _Enable_if_execution_policy_t<_ExPo> = 0>
void fill(_ExPo&&, _FwdIt _First, _FwdIt _Last, const _Ty& _Val) noexcept /* terminates */ {
// copy _Val through [_First, _Last)
// not parallelized as benchmarks show it isn't worth it
_REQUIRE_PARALLEL_ITERATOR(_FwdIt);
return _STD fill(_First, _Last, _Val);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE fill_n
#if _HAS_IF_CONSTEXPR
template <class _OutIt, class _Diff, class _Ty>
_CONSTEXPR20 _OutIt fill_n(_OutIt _Dest, const _Diff _Count_raw, const _Ty& _Val) {
// copy _Val _Count times through [_Dest, ...)
_Algorithm_int_t<_Diff> _Count = _Count_raw;
if (0 < _Count) {
auto _UDest = _Get_unwrapped_n(_Dest, _Count);
if constexpr (_Fill_memset_is_safe<decltype(_UDest), _Ty>) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
_CSTD memset(_UDest, static_cast<unsigned char>(_Val), static_cast<size_t>(_Count));
_UDest += _Count;
_Seek_wrapped(_Dest, _UDest);
return _Dest;
}
}
for (; 0 < _Count; --_Count, (void) ++_UDest) {
*_UDest = _Val;
}
_Seek_wrapped(_Dest, _UDest);
}
return _Dest;
}
#else // ^^^ _HAS_IF_CONSTEXPR // !_HAS_IF_CONSTEXPR vvv
template <class _OutIt, class _Diff, class _Ty>
_OutIt _Fill_n_unchecked2(_OutIt _Dest, _Diff _Count, const _Ty& _Val, false_type) {
// copy _Val _Count times through [_Dest, ...), no special optimization
for (; 0 < _Count; --_Count, (void) ++_Dest) {
*_Dest = _Val;
}
return _Dest;
}
template <class _OutIt, class _Diff, class _Ty>
_OutIt _Fill_n_unchecked2(_OutIt _Dest, _Diff _Count, const _Ty& _Val, true_type) {
// copy _Val _Count times through [_Dest, ...), memset optimization
_CSTD memset(_Dest, static_cast<unsigned char>(_Val), static_cast<size_t>(_Count));
return _Dest + _Count;
}
template <class _OutIt, class _Diff, class _Ty>
_OutIt fill_n(_OutIt _Dest, const _Diff _Count_raw, const _Ty& _Val) {
// copy _Val _Count times through [_Dest, ...)
const _Algorithm_int_t<_Diff> _Count = _Count_raw;
if (0 < _Count) {
auto _UDest = _Get_unwrapped_n(_Dest, _Count);
_Seek_wrapped(_Dest,
_Fill_n_unchecked2(_UDest, _Count, _Val, bool_constant<_Fill_memset_is_safe<decltype(_UDest), _Ty>>{}));
}
return _Dest;
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
template <class _ExPo, class _FwdIt, class _Diff, class _Ty, _Enable_if_execution_policy_t<_ExPo> = 0>
_FwdIt fill_n(_ExPo&&, _FwdIt _Dest, _Diff _Count_raw, const _Ty& _Val) noexcept /* terminates */ {
// copy _Val _Count times through [_Dest, ...)
// not parallelized as benchmarks show it isn't worth it
_REQUIRE_PARALLEL_ITERATOR(_FwdIt);
return _STD fill_n(_Dest, _Count_raw, _Val);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE equal
template <class _Elem1, class _Elem2>
struct _Value_equality_is_bitwise_equality : bool_constant<static_cast<_Elem1>(-1) == static_cast<_Elem2>(-1)> {
// Tests whether the usual arithmetic conversions will preserve the bit-pattern when promoting to int
// e.g. short == unsigned short -> false
// int == unsigned int -> true
};
template <class _Elem1, class _Elem2, class _Pr>
struct _Equal_memcmp_is_safe_helper : false_type {
// determines whether it is safe to call memcmp to compare things; defaults to false
};
template <class _Elem1, class _Elem2>
struct _Equal_memcmp_is_safe_helper<_Elem1, _Elem2, equal_to<>>
: bool_constant<conjunction_v<bool_constant<sizeof(_Elem1) == sizeof(_Elem2)
&& _Is_nonbool_integral<_Elem1> && _Is_nonbool_integral<_Elem2>>,
negation<is_volatile<_Elem1>>, negation<is_volatile<_Elem2>>,
// order matters here: being integral is a precondition of _Value_equality_is_bitwise_equality
_Value_equality_is_bitwise_equality<_Elem1, _Elem2>>> {
// allow memcmping same-size integral non-bool non-volatile bitwise types using equal_to<>
};
template <class _Elem1, class _Elem2>
struct _Equal_memcmp_is_safe_helper<_Elem1*, _Elem2*, equal_to<>>
: is_same<remove_cv_t<_Elem1>, remove_cv_t<_Elem2>>::type {}; // allow memcmping pointers-to-cv-T with equal_to<>
#ifdef __cpp_lib_byte
template <>
struct _Equal_memcmp_is_safe_helper<byte, byte, equal_to<>> : true_type {}; // allow memcmping std::byte
#endif // __cpp_lib_byte
template <class _Elem>
struct _Equal_memcmp_is_safe_helper<_Elem, _Elem, equal_to<_Elem>>
: _Equal_memcmp_is_safe_helper<_Elem, _Elem, equal_to<>>::type {
// treat equal_to with exact T as equal_to<> this is safe because we only activate the optimization for builtin
// _Elem (and std::byte)
};
template <class _Iter1, class _Iter2, class _Pr>
false_type _Equal_memcmp_is_safe(const _Iter1&, const _Iter2&, const _Pr&) {
// return equal optimization category for arbitrary iterators
return {};
}
template <class _Obj1, class _Obj2, class _Pr>
typename _Equal_memcmp_is_safe_helper<remove_const_t<_Obj1>, remove_const_t<_Obj2>, _Pr>::type _Equal_memcmp_is_safe(
_Obj1* const&, _Obj2* const&, const _Pr&) { // return equal optimization category for pointers
return {};
}
#if _HAS_IF_CONSTEXPR
template <class _InIt1, class _InIt2, class _Pr>
_NODISCARD _CONSTEXPR20 bool equal(const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2, _Pr _Pred) {
// compare [_First1, _Last1) to [_First2, ...) using _Pred
_Adl_verify_range(_First1, _Last1);
auto _UFirst1 = _Get_unwrapped(_First1);
const auto _ULast1 = _Get_unwrapped(_Last1);
auto _UFirst2 = _Get_unwrapped_n(_First2, _Idl_distance<_InIt1>(_UFirst1, _ULast1));
if constexpr (decltype(_Equal_memcmp_is_safe(_UFirst1, _UFirst2, _Pred))::value) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
const auto _First1_ch = reinterpret_cast<const char*>(_UFirst1);
const auto _First2_ch = reinterpret_cast<const char*>(_UFirst2);
const auto _Count = static_cast<size_t>(reinterpret_cast<const char*>(_ULast1) - _First1_ch);
return _CSTD memcmp(_First1_ch, _First2_ch, _Count) == 0;
}
}
for (; _UFirst1 != _ULast1; ++_UFirst1, (void) ++_UFirst2) {
if (!_Pred(*_UFirst1, *_UFirst2)) {
return false;
}
}
return true;
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _InIt1, class _InIt2, class _Pr>
bool _Equal_unchecked1(_InIt1 _First1, const _InIt1 _Last1, _InIt2 _First2, _Pr _Pred, false_type) {
// compare [_First1, _Last1) to [_First2, ...) using _Pred, no special optimization
for (; _First1 != _Last1; ++_First1, (void) ++_First2) {
if (!_Pred(*_First1, *_First2)) {
return false;
}
}
return true;
}
template <class _InIt1, class _InIt2, class _Pr>
bool _Equal_unchecked1(const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2, _Pr, true_type) {
// compare [_First1, _Last1) to [_First2, ...), memcmp optimization
const auto _First1_ch = reinterpret_cast<const char*>(_First1);
const auto _First2_ch = reinterpret_cast<const char*>(_First2);
const auto _Count = static_cast<size_t>(reinterpret_cast<const char*>(_Last1) - _First1_ch);
return _CSTD memcmp(_First1_ch, _First2_ch, _Count) == 0;
}
template <class _InIt1, class _InIt2, class _Pr>
bool _Equal_unchecked(const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2, _Pr _Pred) {
// compare [_First1, _Last1) to [_First2, ...) using _Pred, choose optimization
return _Equal_unchecked1(_First1, _Last1, _First2, _Pred, _Equal_memcmp_is_safe(_First1, _First2, _Pred));
}
template <class _InIt1, class _InIt2, class _Pr>
_NODISCARD bool equal(const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2, _Pr _Pred) {
// compare [_First1, _Last1) to [_First2, ...) using _Pred
_Adl_verify_range(_First1, _Last1);
const auto _UFirst1 = _Get_unwrapped(_First1);
const auto _ULast1 = _Get_unwrapped(_Last1);
const auto _UFirst2 = _Get_unwrapped_n(_First2, _Idl_distance<_InIt1>(_UFirst1, _ULast1));
return _Equal_unchecked(_UFirst1, _ULast1, _UFirst2, _Pass_fn(_Pred));
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
template <class _ExPo, class _FwdIt1, class _FwdIt2, class _Pr, _Enable_if_execution_policy_t<_ExPo> = 0>
_NODISCARD bool equal(_ExPo&& _Exec, const _FwdIt1 _First1, const _FwdIt1 _Last1, const _FwdIt2 _First2,
_Pr _Pred) noexcept; // terminates
#endif // _HAS_CXX17
template <class _InIt1, class _InIt2>
_NODISCARD _CONSTEXPR20 bool equal(const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2) {
// compare [_First1, _Last1) to [_First2, ...)
return _STD equal(_First1, _Last1, _First2, equal_to<>());
}
#if _HAS_CXX17
template <class _ExPo, class _FwdIt1, class _FwdIt2, _Enable_if_execution_policy_t<_ExPo> = 0>
_NODISCARD bool equal(_ExPo&& _Exec, const _FwdIt1 _First1, const _FwdIt1 _Last1, const _FwdIt2 _First2) noexcept
/* terminates */ {
// compare [_First1, _Last1) to [_First2, ...)
return _STD equal(_STD forward<_ExPo>(_Exec), _First1, _Last1, _First2, equal_to<>());
}
#endif // _HAS_CXX17
#if _HAS_IF_CONSTEXPR
template <class _InIt1, class _InIt2, class _Pr>
_NODISCARD _CONSTEXPR20 bool equal(
const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2, const _InIt2 _Last2, _Pr _Pred) {
// compare [_First1, _Last1) to [_First2, _Last2) using _Pred
_Adl_verify_range(_First1, _Last1);
_Adl_verify_range(_First2, _Last2);
auto _UFirst1 = _Get_unwrapped(_First1);
const auto _ULast1 = _Get_unwrapped(_Last1);
auto _UFirst2 = _Get_unwrapped(_First2);
const auto _ULast2 = _Get_unwrapped(_Last2);
if constexpr (_Is_random_iter_v<_InIt1> && _Is_random_iter_v<_InIt2>) {
if (_ULast1 - _UFirst1 != _ULast2 - _UFirst2) {
return false;
}
return _STD equal(_UFirst1, _ULast1, _UFirst2, _Pass_fn(_Pred));
} else {
for (;;) {
if (_UFirst1 == _ULast1) {
return _UFirst2 == _ULast2;
}
if (_UFirst2 == _ULast2) {
return false;
}
if (!_Pred(*_UFirst1, *_UFirst2)) {
return false;
}
++_UFirst1;
++_UFirst2;
}
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _InIt1, class _InIt2, class _Pr>
bool _Equal_unchecked(_InIt1 _First1, const _InIt1 _Last1, _InIt2 _First2, const _InIt2 _Last2, _Pr _Pred,
input_iterator_tag, input_iterator_tag) {
// compare [_First1, _Last1) to [_First2, _Last2) using _Pred, arbitrary iterators
for (;;) {
if (_First1 == _Last1) {
return _First2 == _Last2;
}
if (_First2 == _Last2) {
return false;
}
if (!_Pred(*_First1, *_First2)) {
return false;
}
++_First1;
++_First2;
}
}
template <class _InIt1, class _InIt2, class _Pr>
bool _Equal_unchecked(const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2, const _InIt2 _Last2, _Pr _Pred,
random_access_iterator_tag, random_access_iterator_tag) {
// compare [_First1, _Last1) to [_First2, _Last2) using _Pred, random-access iterators
if (_Last1 - _First1 != _Last2 - _First2) {
return false;
}
return _Equal_unchecked(_First1, _Last1, _First2, _Pred);
}
template <class _InIt1, class _InIt2, class _Pr>
_NODISCARD bool equal(const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2, const _InIt2 _Last2, _Pr _Pred) {
// compare [_First1, _Last1) to [_First2, _Last2) using _Pred
_Adl_verify_range(_First1, _Last1);
_Adl_verify_range(_First2, _Last2);
return _Equal_unchecked(_Get_unwrapped(_First1), _Get_unwrapped(_Last1), _Get_unwrapped(_First2),
_Get_unwrapped(_Last2), _Pass_fn(_Pred), _Iter_cat_t<_InIt1>(), _Iter_cat_t<_InIt2>());
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
template <class _ExPo, class _FwdIt1, class _FwdIt2, class _Pr, _Enable_if_execution_policy_t<_ExPo> = 0>
_NODISCARD bool equal(_ExPo&& _Exec, const _FwdIt1 _First1, const _FwdIt1 _Last1, const _FwdIt2 _First2,
const _FwdIt2 _Last2, _Pr _Pred) noexcept; // terminates
#endif // _HAS_CXX17
template <class _InIt1, class _InIt2>
_NODISCARD _CONSTEXPR20 bool equal(
const _InIt1 _First1, const _InIt1 _Last1, const _InIt2 _First2, const _InIt2 _Last2) {
// compare [_First1, _Last1) to [_First2, _Last2)
return _STD equal(_First1, _Last1, _First2, _Last2, equal_to<>());
}
#if _HAS_CXX17
template <class _ExPo, class _FwdIt1, class _FwdIt2, _Enable_if_execution_policy_t<_ExPo> = 0>
_NODISCARD bool equal(_ExPo&& _Exec, const _FwdIt1 _First1, const _FwdIt1 _Last1, const _FwdIt2 _First2,
const _FwdIt2 _Last2) noexcept /* terminates */ {
// compare [_First1, _Last1) to [_First2, _Last2)
return _STD equal(_STD forward<_ExPo>(_Exec), _First1, _Last1, _First2, _Last2, equal_to<>());
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE lexicographical_compare
template <class _Elem1, class _Elem2, class _FTy>
struct _Lex_compare_check_element_types_helper
: bool_constant<
conjunction_v<_Is_character<_Elem1>, _Is_character<_Elem2>, _Is_character<_FTy>, is_unsigned<_FTy>>> {
// checks the lex_compare element types for memcmp safety for builtin functors (e.g., less<unsigned char>)
};
template <class _Elem1, class _Elem2>
struct _Lex_compare_check_element_types_helper<_Elem1, _Elem2, void>
: bool_constant<
conjunction_v<_Is_character<_Elem1>, _Is_character<_Elem2>, is_unsigned<_Elem1>, is_unsigned<_Elem2>>> {
// checks the lex_compare element types for memcmp safety for transparent functors (e.g. less<>)
};
#ifdef __cpp_lib_byte
template <>
struct _Lex_compare_check_element_types_helper<byte, byte, byte> : true_type {
// std::byte with builtin functors (e.g. less<byte>) is memcmp safe
};
template <>
struct _Lex_compare_check_element_types_helper<byte, byte, void> : true_type {
// std::byte with transparent functors (e.g. less<>) is memcmp safe
};
#endif // __cpp_lib_byte
template <class _Memcmp_pr>
struct _Lex_compare_optimize {
explicit _Lex_compare_optimize() = default;
}; // optimization tag for lexicographical_compare
template <class _Memcmp_pr, class _Obj1, class _Obj2, class _FTy>
using _Lex_compare_check_element_types = _Lex_compare_optimize<conditional_t<
_Lex_compare_check_element_types_helper<remove_const_t<_Obj1>, remove_const_t<_Obj2>, _FTy>::value, _Memcmp_pr,
void>>; // checks the lex_compare element types for memcmp safety
template <class _InIt1, class _InIt2, class _Pr>
constexpr auto _Lex_compare_memcmp_classify(const _InIt1&, const _InIt2&, const _Pr&) {
// return lex_compare optimization category for arbitrary iterators
return _Lex_compare_optimize<void>{};
}
template <class _Obj1, class _Obj2, class _FTy>
constexpr auto _Lex_compare_memcmp_classify(_Obj1* const&, _Obj2* const&, const less<_FTy>&) {
// return lex_compare optimization category for pointer iterators and less<_FTy>
return _Lex_compare_check_element_types<less<int>, _Obj1, _Obj2, _FTy>{};
}
template <class _Obj1, class _Obj2, class _FTy>
constexpr auto _Lex_compare_memcmp_classify(_Obj1* const&, _Obj2* const&, const greater<_FTy>&) {
// return lex_compare optimization category for pointer iterators and greater<_FTy>
return _Lex_compare_check_element_types<greater<int>, _Obj1, _Obj2, _FTy>{};
}
template <class _InIt1, class _InIt2, class _Pr>
_NODISCARD constexpr bool _Lex_compare_unchecked(
_InIt1 _First1, _InIt1 _Last1, _InIt2 _First2, _InIt2 _Last2, _Pr _Pred, _Lex_compare_optimize<void>) {
// order [_First1, _Last1) vs. [_First2, _Last2) using _Pred, no special optimization
for (; _First1 != _Last1 && _First2 != _Last2; ++_First1, (void) ++_First2) { // something to compare, do it
if (_DEBUG_LT_PRED(_Pred, *_First1, *_First2)) {
return true;
} else if (_Pred(*_First2, *_First1)) {
return false;
}
}
return _First1 == _Last1 && _First2 != _Last2;
}
template <class _InIt1, class _InIt2, class _Pr, class _Memcmp_pr>
_NODISCARD _CONSTEXPR20 bool _Lex_compare_unchecked(
_InIt1 _First1, _InIt1 _Last1, _InIt2 _First2, _InIt2 _Last2, _Pr _Pred, _Lex_compare_optimize<_Memcmp_pr>) {
// order [_First1, _Last1) vs. [_First2, _Last2) memcmp optimization
#ifdef __cpp_lib_is_constant_evaluated
if (_STD is_constant_evaluated()) {
return _Lex_compare_unchecked(_First1, _Last1, _First2, _Last2, _Pred, _Lex_compare_optimize<void>{});
}
#endif // __cpp_lib_is_constant_evaluated
(void) _Pred;
const auto _Num1 = static_cast<size_t>(_Last1 - _First1);
const auto _Num2 = static_cast<size_t>(_Last2 - _First2);
const int _Ans = _CSTD memcmp(_First1, _First2, _Num1 < _Num2 ? _Num1 : _Num2);
return _Memcmp_pr{}(_Ans, 0) || (_Ans == 0 && _Num1 < _Num2);
}
template <class _InIt1, class _InIt2, class _Pr>
_NODISCARD _CONSTEXPR20 bool lexicographical_compare(
_InIt1 _First1, _InIt1 _Last1, _InIt2 _First2, _InIt2 _Last2, _Pr _Pred) {
// order [_First1, _Last1) vs. [_First2, _Last2) using _Pred
_Adl_verify_range(_First1, _Last1);
_Adl_verify_range(_First2, _Last2);
const auto _UFirst1 = _Get_unwrapped(_First1);
const auto _ULast1 = _Get_unwrapped(_Last1);
const auto _UFirst2 = _Get_unwrapped(_First2);
const auto _ULast2 = _Get_unwrapped(_Last2);
return _Lex_compare_unchecked(
_UFirst1, _ULast1, _UFirst2, _ULast2, _Pass_fn(_Pred), _Lex_compare_memcmp_classify(_UFirst1, _UFirst2, _Pred));
}
template <class _InIt1, class _InIt2>
_NODISCARD _CONSTEXPR20 bool lexicographical_compare(_InIt1 _First1, _InIt1 _Last1, _InIt2 _First2, _InIt2 _Last2) {
// order [_First1, _Last1) vs. [_First2, _Last2)
return _STD lexicographical_compare(_First1, _Last1, _First2, _Last2, less<>());
}
#if _HAS_CXX17
template <class _ExPo, class _FwdIt1, class _FwdIt2, class _Pr, _Enable_if_execution_policy_t<_ExPo> = 0>
_NODISCARD bool lexicographical_compare(
_ExPo&&, _FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred) noexcept /* terminates */ {
// order [_First1, _Last1) vs. [_First2, _Last2) using _Pred
// not parallelized at present, parallelism expected to be feasible in a future release
_REQUIRE_PARALLEL_ITERATOR(_FwdIt1);
_REQUIRE_PARALLEL_ITERATOR(_FwdIt2);
return _STD lexicographical_compare(_First1, _Last1, _First2, _Last2, _Pass_fn(_Pred));
}
template <class _ExPo, class _FwdIt1, class _FwdIt2, _Enable_if_execution_policy_t<_ExPo> = 0>
_NODISCARD bool lexicographical_compare(
_ExPo&&, _FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2) noexcept /* terminates */ {
// order [_First1, _Last1) vs. [_First2, _Last2)
// not parallelized at present, parallelism expected to be feasible in a future release
_REQUIRE_PARALLEL_ITERATOR(_FwdIt1);
_REQUIRE_PARALLEL_ITERATOR(_FwdIt2);
return _STD lexicographical_compare(_First1, _Last1, _First2, _Last2);
}
#endif // _HAS_CXX17
#if defined(__cpp_impl_three_way_comparison) && defined(__cpp_lib_concepts)
// FUNCTION TEMPLATE lexicographical_compare_three_way
template <class _InIt1, class _InIt2, class _Cmp>
_NODISCARD constexpr auto lexicographical_compare_three_way(
_InIt1 _First1, _InIt1 _Last1, _InIt2 _First2, _InIt2 _Last2, _Cmp _Comp) -> decltype(_Comp(*_First1, *_First2)) {
_Adl_verify_range(_First1, _Last1);
_Adl_verify_range(_First2, _Last2);
auto _UFirst1 = _Get_unwrapped(_First1);
const auto _ULast1 = _Get_unwrapped(_Last1);
auto _UFirst2 = _Get_unwrapped(_First2);
const auto _ULast2 = _Get_unwrapped(_Last2);
using _UIt1 = decltype(_UFirst1);
using _UIt2 = decltype(_UFirst2);
using _Ty1 = remove_const_t<remove_pointer_t<_UIt1>>;
using _Ty2 = remove_const_t<remove_pointer_t<_UIt2>>;
if constexpr (conjunction_v<is_same<_Cmp, compare_three_way>, is_pointer<_UIt1>, is_pointer<_UIt2>,
disjunction<
#ifdef __cpp_lib_byte
conjunction<is_same<_Ty1, byte>, is_same<_Ty2, byte>>,
#endif // __cpp_lib_byte
conjunction<_Is_character<_Ty1>, is_unsigned<_Ty1>, _Is_character<_Ty2>,
is_unsigned<_Ty2>>>>) {
if (!_STD is_constant_evaluated()) {
const auto _Num1 = static_cast<size_t>(_ULast1 - _UFirst1);
const auto _Num2 = static_cast<size_t>(_ULast2 - _UFirst2);
const int _Ans = _CSTD memcmp(_UFirst1, _UFirst2, (_STD min)(_Num1, _Num2));
if (_Ans == 0) {
return _Num1 <=> _Num2;
} else {
return _Ans <=> 0;
}
}
}
for (;;) {
if (_UFirst1 == _ULast1) {
return _UFirst2 == _ULast2 ? strong_ordering::equal : strong_ordering::less;
}
if (_UFirst2 == _ULast2) {
return strong_ordering::greater;
}
if (const auto _CmpResult = _Comp(*_UFirst1, *_UFirst2); _CmpResult != 0) {
return _CmpResult;
}
++_UFirst1;
++_UFirst2;
}
}
template <class _InIt1, class _InIt2>
_NODISCARD constexpr auto lexicographical_compare_three_way(
_InIt1 _First1, _InIt1 _Last1, _InIt2 _First2, _InIt2 _Last2) {
return _STD lexicographical_compare_three_way(_First1, _Last1, _First2, _Last2, compare_three_way{});
}
#endif // defined(__cpp_impl_three_way_comparison) && defined(__cpp_lib_concepts)
// FUNCTION TEMPLATE find
template <class _Ty>
_NODISCARD constexpr bool _Within_limits(const _Ty& _Val, true_type, true_type, _Any_tag) { // signed _Elem, signed _Ty
return SCHAR_MIN <= _Val && _Val <= SCHAR_MAX;
}
template <class _Ty>
_NODISCARD constexpr bool _Within_limits(const _Ty& _Val, true_type, false_type, true_type) {
// signed _Elem, unsigned _Ty, -1 == static_cast<_Ty>(-1)
return _Val <= SCHAR_MAX || static_cast<_Ty>(SCHAR_MIN) <= _Val;
}
template <class _Ty>
_NODISCARD constexpr bool _Within_limits(const _Ty& _Val, true_type, false_type, false_type) {
// signed _Elem, unsigned _Ty, -1 != static_cast<_Ty>(-1)
return _Val <= SCHAR_MAX;
}
template <class _Ty>
_NODISCARD constexpr bool _Within_limits(const _Ty& _Val, false_type, true_type, _Any_tag) {
// unsigned _Elem, signed _Ty
return 0 <= _Val && _Val <= UCHAR_MAX;
}
template <class _Ty>
_NODISCARD constexpr bool _Within_limits(const _Ty& _Val, false_type, false_type, _Any_tag) {
// unsigned _Elem, unsigned _Ty
return _Val <= UCHAR_MAX;
}
template <class _InIt, class _Ty>
_NODISCARD constexpr bool _Within_limits(_InIt, const _Ty& _Val) { // check whether _Val is within the limits of _Elem
using _Elem = remove_pointer_t<_InIt>;
return _Within_limits(_Val, is_signed<_Elem>{}, is_signed<_Ty>{}, bool_constant<-1 == static_cast<_Ty>(-1)>{});
}
template <class _InIt>
_NODISCARD constexpr bool _Within_limits(_InIt, const bool&) { // bools are always within the limits of _Elem
return true;
}
template <class _InIt, class _Ty>
_NODISCARD constexpr _InIt _Find_unchecked1(_InIt _First, const _InIt _Last, const _Ty& _Val, false_type) {
// find first matching _Val
for (; _First != _Last; ++_First) {
if (*_First == _Val) {
break;
}
}
return _First;
}
template <class _InIt, class _Ty>
_NODISCARD _CONSTEXPR20 _InIt _Find_unchecked1(_InIt _First, const _InIt _Last, const _Ty& _Val, true_type) {
// find first byte matching integral _Val
if (!_Within_limits(_First, _Val)) {
return _Last;
}
#ifdef __cpp_lib_is_constant_evaluated
if (_STD is_constant_evaluated()) {
using _Elem = remove_pointer_t<_InIt>;
return _Find_unchecked1(_First, _Last, static_cast<_Elem>(_Val), false_type{});
}
#endif // __cpp_lib_is_constant_evaluated
_First =
static_cast<_InIt>(_CSTD memchr(_First, static_cast<unsigned char>(_Val), static_cast<size_t>(_Last - _First)));
return _First ? _First : _Last;
}
template <class _InIt, class _Ty>
_NODISCARD _CONSTEXPR20 _InIt _Find_unchecked(const _InIt _First, const _InIt _Last, const _Ty& _Val) {
// find first matching _Val; choose optimization
// activate optimization for pointers to (const) bytes and integral values
using _Memchr_opt = bool_constant<
is_integral_v<_Ty> && _Is_any_of_v<_InIt, char*, signed char*, unsigned char*, //
const char*, const signed char*, const unsigned char*>>;
return _Find_unchecked1(_First, _Last, _Val, _Memchr_opt{});
}
template <class _InIt, class _Ty>
_NODISCARD _CONSTEXPR20 _InIt find(_InIt _First, const _InIt _Last, const _Ty& _Val) { // find first matching _Val
_Adl_verify_range(_First, _Last);
_Seek_wrapped(_First, _Find_unchecked(_Get_unwrapped(_First), _Get_unwrapped(_Last), _Val));
return _First;
}
#if _HAS_CXX17
template <class _ExPo, class _FwdIt, class _Ty, _Enable_if_execution_policy_t<_ExPo> = 0>
_NODISCARD _FwdIt find(_ExPo&& _Exec, _FwdIt _First, const _FwdIt _Last, const _Ty& _Val) noexcept; // terminates
#endif // _HAS_CXX17
// FUNCTION TEMPLATE count
template <class _InIt, class _Ty>
_NODISCARD _CONSTEXPR20 _Iter_diff_t<_InIt> count(const _InIt _First, const _InIt _Last, const _Ty& _Val) {
// count elements that match _Val
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
_Iter_diff_t<_InIt> _Count = 0;
for (; _UFirst != _ULast; ++_UFirst) {
if (*_UFirst == _Val) {
++_Count;
}
}
return _Count;
}
#if _HAS_CXX17
template <class _ExPo, class _FwdIt, class _Ty, _Enable_if_execution_policy_t<_ExPo> = 0>
_NODISCARD _Iter_diff_t<_FwdIt> count(
_ExPo&& _Exec, const _FwdIt _First, const _FwdIt _Last, const _Ty& _Val) noexcept; // terminates
#endif // _HAS_CXX17
// FUNCTION TEMPLATE is_permutation
template <class _InIt, class _Ty, class _Pr>
_NODISCARD constexpr _InIt _Find_pr(_InIt _First, const _InIt _Last, const _Ty& _Val, _Pr _Pred) {
for (; _First != _Last; ++_First) {
if (_Pred(*_First, _Val)) {
break;
}
}
return _First;
}
template <class _InIt, class _Ty, class _Pr>
_NODISCARD constexpr _Iter_diff_t<_InIt> _Count_pr(_InIt _First, const _InIt _Last, const _Ty& _Val, _Pr _Pred) {
_Iter_diff_t<_InIt> _Count = 0;
for (; _First != _Last; ++_First) {
if (_Pred(*_First, _Val)) {
++_Count;
}
}
return _Count;
}
#if !_HAS_IF_CONSTEXPR
template <class _FwdIt1, class _FwdIt2, class _Pr>
void _Trim_matching_suffixes(_FwdIt1&, _FwdIt2&, _Pr, forward_iterator_tag, forward_iterator_tag) {
// trim matching suffixes, forward iterators (do nothing)
}
template <class _FwdIt1, class _FwdIt2, class _Pr>
void _Trim_matching_suffixes(
_FwdIt1& _Last1, _FwdIt2& _Last2, _Pr _Pred, bidirectional_iterator_tag, bidirectional_iterator_tag) {
// trim matching suffixes, bidirectional iterators
// assumptions: same lengths, non-empty, !_Pred(*_First1, *_First2)
do { // find last inequality
--_Last1;
--_Last2;
} while (_Pred(*_Last1, *_Last2));
++_Last1;
++_Last2;
}
#endif // !_HAS_IF_CONSTEXPR
template <class _FwdIt1, class _FwdIt2, class _Pr>
_NODISCARD _CONSTEXPR20 bool _Check_match_counts(
const _FwdIt1 _First1, _FwdIt1 _Last1, const _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred) {
// test if [_First1, _Last1) == permuted [_First2, _Last2), after matching prefix removal
_STL_INTERNAL_CHECK(!_Pred(*_First1, *_First2));
_STL_INTERNAL_CHECK(_STD distance(_First1, _Last1) == _STD distance(_First2, _Last2));
#if _HAS_IF_CONSTEXPR
if constexpr (_Is_bidi_iter_v<_FwdIt1> && _Is_bidi_iter_v<_FwdIt2>) {
do { // find last inequality
--_Last1;
--_Last2;
} while (_Pred(*_Last1, *_Last2));
++_Last1;
++_Last2;
}
#else // ^^^ _HAS_IF_CONSTEXPR // !_HAS_IF_CONSTEXPR vvv
_Trim_matching_suffixes(_Last1, _Last2, _Pred, _Iter_cat_t<_FwdIt1>(), _Iter_cat_t<_FwdIt2>());
#endif // _HAS_IF_CONSTEXPR
for (_FwdIt1 _Next1 = _First1; _Next1 != _Last1; ++_Next1) {
if (_Next1 == _Find_pr(_First1, _Next1, *_Next1, _Pred)) { // new value, compare match counts
_Iter_diff_t<_FwdIt2> _Count2 = _Count_pr(_First2, _Last2, *_Next1, _Pred);
if (_Count2 == 0) {
return false; // second range lacks value, not a permutation
}
_FwdIt1 _Skip1 = _Next_iter(_Next1);
_Iter_diff_t<_FwdIt1> _Count1 = _Count_pr(_Skip1, _Last1, *_Next1, _Pred) + 1;
if (_Count2 != _Count1) {
return false; // match counts differ, not a permutation
}
}
}
return true;
}
template <class _FwdIt1, class _FwdIt2, class _Pr>
_NODISCARD _CONSTEXPR20 bool _Is_permutation_unchecked(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _Pr _Pred) {
// test if [_First1, _Last1) == permuted [_First2, ...), using _Pred
for (; _First1 != _Last1; ++_First1, (void) ++_First2) { // trim matching prefix
if (!_Pred(*_First1, *_First2)) {
// found first inequality, check match counts in suffix
//
// narrowing _Iter_diff_t<_FwdIt1> to _Iter_diff_t<_FwdIt2> is OK because if the second range is shorter
// than the first, the user already triggered UB
auto _Last2 = _STD next(_First2, static_cast<_Iter_diff_t<_FwdIt2>>(_STD distance(_First1, _Last1)));
return _Check_match_counts(_First1, _Last1, _First2, _Last2, _Pred);
}
}
return true;
}
template <class _FwdIt1, class _FwdIt2, class _Pr>
_NODISCARD _CONSTEXPR20 bool is_permutation(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _Pr _Pred) {
// test if [_First1, _Last1) == permuted [_First2, ...), using _Pred
_Adl_verify_range(_First1, _Last1);
const auto _UFirst1 = _Get_unwrapped(_First1);
const auto _ULast1 = _Get_unwrapped(_Last1);
const auto _UFirst2 = _Get_unwrapped_n(_First2, _Idl_distance<_FwdIt1>(_UFirst1, _ULast1));
return _Is_permutation_unchecked(_UFirst1, _ULast1, _UFirst2, _Pass_fn(_Pred));
}
template <class _FwdIt1, class _FwdIt2>
_NODISCARD _CONSTEXPR20 bool is_permutation(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2) {
// test if [_First1, _Last1) == permuted [_First2, ...)
return _STD is_permutation(_First1, _Last1, _First2, equal_to<>());
}
template <class _FwdIt1, class _FwdIt2, class _Pr>
_CONSTEXPR20 bool _Is_permutation_unchecked(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred,
forward_iterator_tag, forward_iterator_tag) {
// test if [_First1, _Last1) == permuted [_First2, _Last2), using _Pred, arbitrary iterators
for (;;) { // trim matching prefix
if (_First1 == _Last1) {
return _First2 == _Last2;
}
if (_First2 == _Last2) {
return false;
}
if (!_Pred(*_First1, *_First2)) { // found first inequality, check match counts in suffix
break;
}
++_First1;
++_First2;
}
auto _Next1 = _First1;
auto _Next2 = _First2;
for (;;) { // check for same lengths
if (_Next1 == _Last1) {
if (_Next2 == _Last2) {
return _Check_match_counts(_First1, _Last1, _First2, _Last2, _Pred);
}
return false; // sequence 1 is shorter than sequence 2, not a permutation
}
if (_Next2 == _Last2) {
return false; // sequence 1 is longer than sequence 2, not a permutation
}
++_Next1;
++_Next2;
}
}
template <class _FwdIt1, class _FwdIt2, class _Pr>
_CONSTEXPR20 bool _Is_permutation_unchecked(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred,
random_access_iterator_tag, random_access_iterator_tag) {
// test if [_First1, _Last1) == permuted [_First2, _Last2), using _Pred, random-access iterators
if (_Last1 - _First1 != _Last2 - _First2) {
return false;
}
for (; _First1 != _Last1; ++_First1, (void) ++_First2) { // trim matching prefix
if (!_Pred(*_First1, *_First2)) {
// found first inequality, check match counts in suffix
return _Check_match_counts(_First1, _Last1, _First2, _Last2, _Pred);
}
}
return true;
}
template <class _FwdIt1, class _FwdIt2, class _Pr>
_NODISCARD _CONSTEXPR20 bool is_permutation(
_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2, _Pr _Pred) {
// test if [_First1, _Last1) == permuted [_First2, _Last2), using _Pred
_Adl_verify_range(_First1, _Last1);
_Adl_verify_range(_First2, _Last2);
return _Is_permutation_unchecked(_Get_unwrapped(_First1), _Get_unwrapped(_Last1), _Get_unwrapped(_First2),
_Get_unwrapped(_Last2), _Pass_fn(_Pred), _Iter_cat_t<_FwdIt1>(), _Iter_cat_t<_FwdIt2>());
}
template <class _FwdIt1, class _FwdIt2>
_NODISCARD _CONSTEXPR20 bool is_permutation(_FwdIt1 _First1, _FwdIt1 _Last1, _FwdIt2 _First2, _FwdIt2 _Last2) {
// test if [_First1, _Last1) == permuted [_First2, _Last2)
return _STD is_permutation(_First1, _Last1, _First2, _Last2, equal_to<>());
}
// FUNCTION TEMPLATE reverse
#if _HAS_IF_CONSTEXPR
template <class _BidIt>
_CONSTEXPR20 void reverse(const _BidIt _First, const _BidIt _Last) { // reverse elements in [_First, _Last)
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(_First);
auto _ULast = _Get_unwrapped(_Last);
#if _USE_STD_VECTOR_ALGORITHMS
using _Elem = remove_pointer_t<decltype(_UFirst)>;
constexpr bool _Allow_vectorization =
conjunction_v<is_pointer<decltype(_UFirst)>, _Is_trivially_swappable<_Elem>, negation<is_volatile<_Elem>>>;
if constexpr (_Allow_vectorization && sizeof(_Elem) == 1) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
__std_reverse_trivially_swappable_1(_UFirst, _ULast);
return;
}
} else if constexpr (_Allow_vectorization && sizeof(_Elem) == 2) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
__std_reverse_trivially_swappable_2(_UFirst, _ULast);
return;
}
} else if constexpr (_Allow_vectorization && sizeof(_Elem) == 4) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
__std_reverse_trivially_swappable_4(_UFirst, _ULast);
return;
}
} else if constexpr (_Allow_vectorization && sizeof(_Elem) == 8) {
#ifdef __cpp_lib_is_constant_evaluated
if (!_STD is_constant_evaluated())
#endif // __cpp_lib_is_constant_evaluated
{
__std_reverse_trivially_swappable_8(_UFirst, _ULast);
return;
}
}
#endif // _USE_STD_VECTOR_ALGORITHMS
for (; _UFirst != _ULast && _UFirst != --_ULast; ++_UFirst) {
_STD iter_swap(_UFirst, _ULast);
}
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _BidIt>
void _Reverse_unchecked1(_BidIt _First, _BidIt _Last, integral_constant<size_t, 0>) {
// reverse elements in [_First, _Last), general bidirectional iterators
for (; _First != _Last && _First != --_Last; ++_First) {
_STD iter_swap(_First, _Last);
}
}
#if _USE_STD_VECTOR_ALGORITHMS
template <class _BidIt>
void _Reverse_unchecked1(const _BidIt _First, const _BidIt _Last, integral_constant<size_t, 1>) {
// reverse elements in [_First, _Last), pointers to trivially swappable of size 1
__std_reverse_trivially_swappable_1(_First, _Last);
}
template <class _BidIt>
void _Reverse_unchecked1(const _BidIt _First, const _BidIt _Last, integral_constant<size_t, 2>) {
// reverse elements in [_First, _Last), pointers to trivially swappable of size 2
__std_reverse_trivially_swappable_2(_First, _Last);
}
template <class _BidIt>
void _Reverse_unchecked1(const _BidIt _First, const _BidIt _Last, integral_constant<size_t, 4>) {
// reverse elements in [_First, _Last), pointers to trivially swappable of size 4
__std_reverse_trivially_swappable_4(_First, _Last);
}
template <class _BidIt>
void _Reverse_unchecked1(const _BidIt _First, const _BidIt _Last, integral_constant<size_t, 8>) {
// reverse elements in [_First, _Last), pointers to trivially swappable of size 8
__std_reverse_trivially_swappable_8(_First, _Last);
}
#endif // _USE_STD_VECTOR_ALGORITHMS
template <class _BidIt>
void _Reverse_unchecked(const _BidIt _First, const _BidIt _Last) {
// reverse elements in [_First, _Last), choose optimization
#if _USE_STD_VECTOR_ALGORITHMS
using _Elem = remove_pointer_t<_BidIt>;
constexpr size_t _Opt =
is_pointer_v<_BidIt> //
&& _Is_trivially_swappable_v<_Elem> //
&& !is_volatile_v<_Elem> //
&& (sizeof(_Elem) == 1 || sizeof(_Elem) == 2 || sizeof(_Elem) == 4 || sizeof(_Elem) == 8)
? sizeof(_Elem)
: 0;
#else // ^^^ vectorize / no vectorize vvv
constexpr size_t _Opt = 0;
#endif // _USE_STD_VECTOR_ALGORITHMS
_Reverse_unchecked1(_First, _Last, integral_constant<size_t, _Opt>{});
}
template <class _BidIt>
void reverse(const _BidIt _First, const _BidIt _Last) {
// reverse elements in [_First, _Last)
_Adl_verify_range(_First, _Last);
_Reverse_unchecked(_Get_unwrapped(_First), _Get_unwrapped(_Last));
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
template <class _ExPo, class _BidIt, _Enable_if_execution_policy_t<_ExPo> = 0>
void reverse(_ExPo&&, _BidIt _First, _BidIt _Last) noexcept /* terminates */ {
// reverse elements in [_First, _Last)
// not parallelized as benchmarks show it isn't worth it
return _STD reverse(_First, _Last);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE rotate
template <class _BidIt>
constexpr pair<_BidIt, _BidIt> _Reverse_until_sentinel_unchecked(_BidIt _First, _BidIt _Sentinel, _BidIt _Last) {
// reverse until either _First or _Last hits _Sentinel
while (_First != _Sentinel && _Last != _Sentinel) {
_STD iter_swap(_First, --_Last);
++_First;
}
return pair<_BidIt, _BidIt>(_First, _Last);
}
#if _HAS_IF_CONSTEXPR
template <class _FwdIt>
_CONSTEXPR20 _FwdIt rotate(_FwdIt _First, _FwdIt _Mid, _FwdIt _Last) {
// exchange the ranges [_First, _Mid) and [_Mid, _Last)
// that is, rotates [_First, _Last) left by distance(_First, _Mid) positions
// returns the iterator pointing at *_First's new home
_Adl_verify_range(_First, _Mid);
_Adl_verify_range(_Mid, _Last);
auto _UFirst = _Get_unwrapped(_First);
auto _UMid = _Get_unwrapped(_Mid);
const auto _ULast = _Get_unwrapped(_Last);
if (_UFirst == _UMid) {
return _Last;
}
if (_UMid == _ULast) {
return _First;
}
if constexpr (_Is_random_iter_v<_FwdIt>) {
_STD reverse(_UFirst, _UMid);
_STD reverse(_UMid, _ULast);
_STD reverse(_UFirst, _ULast);
_Seek_wrapped(_First, _UFirst + (_ULast - _UMid));
} else if constexpr (_Is_bidi_iter_v<_FwdIt>) {
_STD reverse(_UFirst, _UMid);
_STD reverse(_UMid, _ULast);
auto _Tmp = _Reverse_until_sentinel_unchecked(_UFirst, _UMid, _ULast);
_STD reverse(_Tmp.first, _Tmp.second);
_Seek_wrapped(_First, _UMid != _Tmp.first ? _Tmp.first : _Tmp.second);
} else {
auto _UNext = _UMid;
do { // rotate the first cycle
_STD iter_swap(_UFirst, _UNext);
++_UFirst;
++_UNext;
if (_UFirst == _UMid) {
_UMid = _UNext;
}
} while (_UNext != _ULast);
_Seek_wrapped(_First, _UFirst);
while (_UMid != _ULast) { // rotate subsequent cycles
_UNext = _UMid;
do {
_STD iter_swap(_UFirst, _UNext);
++_UFirst;
++_UNext;
if (_UFirst == _UMid) {
_UMid = _UNext;
}
} while (_UNext != _ULast);
}
}
return _First;
}
#else // ^^^ _HAS_IF_CONSTEXPR / !_HAS_IF_CONSTEXPR vvv
template <class _FwdIt>
_FwdIt _Rotate_unchecked1(_FwdIt _First, _FwdIt _Mid, _FwdIt _Last, forward_iterator_tag) {
// rotate [_First, _Last) left by distance(_First, _Mid) positions, forward iterators
for (_FwdIt _Next = _Mid, _Res = _Last;;) { // swap [_First, ...) into place
_STD iter_swap(_First, _Next);
if (++_First == _Mid) { // quit if done, else define next interval
if (++_Next == _Last) {
return _Res == _Last ? _Mid : _Res;
} else {
_Mid = _Next; // mark end of next interval
}
} else if (++_Next == _Last) { // wrap to last end
if (_Res == _Last) {
_Res = _First;
}
_Next = _Mid;
}
}
}
template <class _BidIt>
_BidIt _Rotate_unchecked1(_BidIt _First, _BidIt _Mid, _BidIt _Last, bidirectional_iterator_tag) {
// rotate [_First, _Last) left by distance(_First, _Mid) positions, bidirectional iterators
_Reverse_unchecked(_First, _Mid);
_Reverse_unchecked(_Mid, _Last);
auto _Tmp = _Reverse_until_sentinel_unchecked(_First, _Mid, _Last);
_Reverse_unchecked(_Tmp.first, _Tmp.second);
return _Mid != _Tmp.first ? _Tmp.first : _Tmp.second;
}
template <class _RanIt>
_RanIt _Rotate_unchecked1(_RanIt _First, _RanIt _Mid, _RanIt _Last, random_access_iterator_tag) {
// rotate [_First, _Last) left by distance(_First, _Mid) positions, random-access iterators
_Reverse_unchecked(_First, _Mid);
_Reverse_unchecked(_Mid, _Last);
_Reverse_unchecked(_First, _Last);
return _First + (_Last - _Mid);
}
template <class _FwdIt>
_FwdIt _Rotate_unchecked(_FwdIt _First, _FwdIt _Mid, _FwdIt _Last) {
// rotate [_First, _Last) left by distance(_First, _Mid) positions
if (_First == _Mid) {
return _Last;
}
if (_Mid == _Last) {
return _First;
}
return _Rotate_unchecked1(_First, _Mid, _Last, _Iter_cat_t<_FwdIt>());
}
template <class _FwdIt>
_FwdIt rotate(_FwdIt _First, _FwdIt _Mid, _FwdIt _Last) {
// exchange the ranges [_First, _Mid) and [_Mid, _Last)
// that is, rotates [_First, _Last) left by distance(_First, _Mid) positions
// returns the iterator pointing at *_First's new home
_Adl_verify_range(_First, _Mid);
_Adl_verify_range(_Mid, _Last);
_Seek_wrapped(_First, _Rotate_unchecked(_Get_unwrapped(_First), _Get_unwrapped(_Mid), _Get_unwrapped(_Last)));
return _First;
}
#endif // _HAS_IF_CONSTEXPR
#if _HAS_CXX17
template <class _ExPo, class _FwdIt, _Enable_if_execution_policy_t<_ExPo> = 0>
_FwdIt rotate(_ExPo&&, _FwdIt _First, _FwdIt _Mid, _FwdIt _Last) noexcept /* terminates */ {
// rotate [_First, _Last) left by distance(_First, _Mid) positions
// not parallelized as benchmarks show it isn't worth it
return _STD rotate(_First, _Mid, _Last);
}
#endif // _HAS_CXX17
// FUNCTION TEMPLATE find_if
template <class _InIt, class _Pr>
_NODISCARD _CONSTEXPR20 _InIt find_if(_InIt _First, const _InIt _Last, _Pr _Pred) { // find first satisfying _Pred
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(_First);
const auto _ULast = _Get_unwrapped(_Last);
for (; _UFirst != _ULast; ++_UFirst) {
if (_Pred(*_UFirst)) {
break;
}
}
_Seek_wrapped(_First, _UFirst);
return _First;
}
// FUNCTION TEMPLATE lower_bound
template <class _FwdIt, class _Ty, class _Pr>
_NODISCARD _CONSTEXPR20 _FwdIt lower_bound(_FwdIt _First, const _FwdIt _Last, const _Ty& _Val, _Pr _Pred) {
// find first element not before _Val, using _Pred
_Adl_verify_range(_First, _Last);
auto _UFirst = _Get_unwrapped(_First);
_Iter_diff_t<_FwdIt> _Count = _STD distance(_UFirst, _Get_unwrapped(_Last));
while (0 < _Count) { // divide and conquer, find half that contains answer
const _Iter_diff_t<_FwdIt> _Count2 = _Count / 2;
const auto _UMid = _STD next(_UFirst, _Count2);
if (_Pred(*_UMid, _Val)) { // try top half
_UFirst = _Next_iter(_UMid);
_Count -= _Count2 + 1;
} else {
_Count = _Count2;
}
}
_Seek_wrapped(_First, _UFirst);
return _First;
}
template <class _FwdIt, class _Ty>
_NODISCARD _CONSTEXPR20 _FwdIt lower_bound(_FwdIt _First, _FwdIt _Last, const _Ty& _Val) {
// find first element not before _Val, using operator<
return _STD lower_bound(_First, _Last, _Val, less<>());
}
// FUNCTION TEMPLATE _Swap_ranges_unchecked
template <class _FwdIt1, class _FwdIt2>
_CONSTEXPR20 _FwdIt2 _Swap_ranges_unchecked(_FwdIt1 _First1, const _FwdIt1 _Last1, _FwdIt2 _First2) {
// swap [_First1, _Last1) with [_First2, ...), no special optimization
for (; _First1 != _Last1; ++_First1, (void) ++_First2) {
_STD iter_swap(_First1, _First2);
}
return _First2;
}
#if _USE_STD_VECTOR_ALGORITHMS
template <class _Ty, enable_if_t<_Is_trivially_swappable_v<_Ty>, int> = 0>
_CONSTEXPR20 _Ty* _Swap_ranges_unchecked(_Ty* _First1, _Ty* const _Last1, _Ty* _First2) {
// swap [_First1, _Last1) with [_First2, ...), trivially swappable optimization
#ifdef __cpp_lib_is_constant_evaluated
if (_STD is_constant_evaluated()) {
for (; _First1 != _Last1; ++_First1, (void) ++_First2) {
_STD iter_swap(_First1, _First2);
}
return _First2;
}
#endif // __cpp_lib_is_constant_evaluated
__std_swap_ranges_trivially_swappable_noalias(_First1, _Last1, _First2);
return _First2 + (_Last1 - _First1);
}
#endif // _USE_STD_VECTOR_ALGORITHMS
// CLASS TEMPLATE _Rng_from_urng
template <class _Diff, class _Urng>
class _Rng_from_urng { // wrap a URNG as an RNG
public:
using _Ty0 = make_unsigned_t<_Diff>;
using _Ty1 = typename _Urng::result_type;
using _Udiff = conditional_t<sizeof(_Ty1) < sizeof(_Ty0), _Ty0, _Ty1>;
explicit _Rng_from_urng(_Urng& _Func) : _Ref(_Func), _Bits(CHAR_BIT * sizeof(_Udiff)), _Bmask(_Udiff(-1)) {
for (; (_Urng::max)() - (_Urng::min)() < _Bmask; _Bmask >>= 1) {
--_Bits;
}
}
_Diff operator()(_Diff _Index) { // adapt _Urng closed range to [0, _Index)
for (;;) { // try a sample random value
_Udiff _Ret = 0; // random bits
_Udiff _Mask = 0; // 2^N - 1, _Ret is within [0, _Mask]
while (_Mask < _Udiff(_Index - 1)) { // need more random bits
_Ret <<= _Bits - 1; // avoid full shift
_Ret <<= 1;
_Ret |= _Get_bits();
_Mask <<= _Bits - 1; // avoid full shift
_Mask <<= 1;
_Mask |= _Bmask;
}
// _Ret is [0, _Mask], _Index - 1 <= _Mask, return if unbiased
if (_Ret / _Index < _Mask / _Index || _Mask % _Index == _Udiff(_Index - 1)) {
return static_cast<_Diff>(_Ret % _Index);
}
}
}
_Udiff _Get_all_bits() {
_Udiff _Ret = 0;
for (size_t _Num = 0; _Num < CHAR_BIT * sizeof(_Udiff); _Num += _Bits) { // don't mask away any bits
_Ret <<= _Bits - 1; // avoid full shift
_Ret <<= 1;
_Ret |= _Get_bits();
}
return _Ret;
}
_Rng_from_urng(const _Rng_from_urng&) = delete;
_Rng_from_urng& operator=(const _Rng_from_urng&) = delete;
private:
_Udiff _Get_bits() { // return a random value within [0, _Bmask]
for (;;) { // repeat until random value is in range
_Udiff _Val = _Ref() - (_Urng::min)();
if (_Val <= _Bmask) {
return _Val;
}
}
}
_Urng& _Ref; // reference to URNG
size_t _Bits; // number of random bits generated by _Get_bits()
_Udiff _Bmask; // 2^_Bits - 1
};
// STRUCT TEMPLATE _Has_allocator_type
template <class _Ty, class _Alloc, class = void>
struct _Has_allocator_type : false_type { // tests for suitable _Ty::allocator_type
};
template <class _Ty, class _Alloc>
struct _Has_allocator_type<_Ty, _Alloc, void_t<typename _Ty::allocator_type>>
: is_convertible<_Alloc, typename _Ty::allocator_type>::type { // tests for suitable _Ty::allocator_type
};
// STRUCT allocator_arg_t
struct allocator_arg_t { // tag type for added allocator argument
explicit allocator_arg_t() = default;
};
_INLINE_VAR constexpr allocator_arg_t allocator_arg{};
[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Xbad_alloc();
[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Xinvalid_argument(_In_z_ const char*);
[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Xlength_error(_In_z_ const char*);
[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Xout_of_range(_In_z_ const char*);
[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Xoverflow_error(_In_z_ const char*);
[[noreturn]] _CRTIMP2_PURE void __CLRCALL_PURE_OR_CDECL _Xruntime_error(_In_z_ const char*);
// STRUCT TEMPLATE uses_allocator
template <class _Ty, class _Alloc>
struct uses_allocator
: _Has_allocator_type<_Ty, _Alloc>::type { // determine whether _Ty has an allocator_type member type
};
template <class _Ty, class _Alloc>
_INLINE_VAR constexpr bool uses_allocator_v = uses_allocator<_Ty, _Alloc>::value;
// STRUCT TEMPLATE iterator
template <class _Category, class _Ty, class _Diff = ptrdiff_t, class _Pointer = _Ty*, class _Reference = _Ty&>
struct _CXX17_DEPRECATE_ITERATOR_BASE_CLASS iterator { // base type for iterator classes
using iterator_category = _Category;
using value_type = _Ty;
using difference_type = _Diff;
using pointer = _Pointer;
using reference = _Reference;
};
_STD_END
#pragma pop_macro("new")
_STL_RESTORE_CLANG_WARNINGS
#pragma warning(pop)
#pragma pack(pop)
#endif // _STL_COMPILER_PREPROCESSOR
#endif // _XUTILITY_
Ссылка в новой задаче Показать git blame Копировать постоянную ссылку