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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___RANGES_SUBRANGE_H
#define _LIBCPP___RANGES_SUBRANGE_H
#include <__concepts/constructible.h>
#include <__concepts/convertible_to.h>
#include <__concepts/copyable.h>
#include <__concepts/derived_from.h>
#include <__concepts/different_from.h>
#include <__config>
#include <__debug>
#include <__iterator/advance.h>
#include <__iterator/concepts.h>
#include <__iterator/incrementable_traits.h>
#include <__iterator/iterator_traits.h>
#include <__ranges/access.h>
#include <__ranges/concepts.h>
#include <__ranges/dangling.h>
#include <__ranges/enable_borrowed_range.h>
#include <__ranges/size.h>
#include <__ranges/view_interface.h>
#include <__tuple>
#include <__utility/move.h>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
namespace ranges {
template<class _From, class _To>
concept __uses_nonqualification_pointer_conversion =
is_pointer_v<_From> && is_pointer_v<_To> &&
!convertible_to<remove_pointer_t<_From>(*)[], remove_pointer_t<_To>(*)[]>;
template<class _From, class _To>
concept __convertible_to_non_slicing =
convertible_to<_From, _To> &&
!__uses_nonqualification_pointer_conversion<decay_t<_From>, decay_t<_To>>;
template<class _Tp>
concept __pair_like =
!is_reference_v<_Tp> && requires(_Tp __t) {
typename tuple_size<_Tp>::type; // Ensures `tuple_size<T>` is complete.
requires derived_from<tuple_size<_Tp>, integral_constant<size_t, 2>>;
typename tuple_element_t<0, remove_const_t<_Tp>>;
typename tuple_element_t<1, remove_const_t<_Tp>>;
{ std::get<0>(__t) } -> convertible_to<const tuple_element_t<0, _Tp>&>;
{ std::get<1>(__t) } -> convertible_to<const tuple_element_t<1, _Tp>&>;
};
template<class _Pair, class _Iter, class _Sent>
concept __pair_like_convertible_from =
!range<_Pair> && __pair_like<_Pair> &&
constructible_from<_Pair, _Iter, _Sent> &&
__convertible_to_non_slicing<_Iter, tuple_element_t<0, _Pair>> &&
convertible_to<_Sent, tuple_element_t<1, _Pair>>;
enum class _LIBCPP_ENUM_VIS subrange_kind : bool { unsized, sized };
template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent = _Iter,
subrange_kind _Kind = sized_sentinel_for<_Sent, _Iter>
? subrange_kind::sized
: subrange_kind::unsized>
requires (_Kind == subrange_kind::sized || !sized_sentinel_for<_Sent, _Iter>)
class _LIBCPP_TEMPLATE_VIS subrange
: public view_interface<subrange<_Iter, _Sent, _Kind>>
{
private:
static constexpr bool _StoreSize = (_Kind == subrange_kind::sized && !sized_sentinel_for<_Sent, _Iter>);
static constexpr bool _MustProvideSizeAtConstruction = !_StoreSize; // just to improve compiler diagnostics
struct _Empty { constexpr _Empty(auto) noexcept { } };
using _Size = conditional_t<_StoreSize, make_unsigned_t<iter_difference_t<_Iter>>, _Empty>;
_LIBCPP_NO_UNIQUE_ADDRESS _Iter __begin_ = _Iter();
_LIBCPP_NO_UNIQUE_ADDRESS _Sent __end_ = _Sent();
_LIBCPP_NO_UNIQUE_ADDRESS _Size __size_ = 0;
public:
_LIBCPP_HIDE_FROM_ABI
subrange() requires default_initializable<_Iter> = default;
_LIBCPP_HIDE_FROM_ABI
constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent)
requires _MustProvideSizeAtConstruction
: __begin_(std::move(__iter)), __end_(std::move(__sent))
{ }
_LIBCPP_HIDE_FROM_ABI
constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent,
make_unsigned_t<iter_difference_t<_Iter>> __n)
requires (_Kind == subrange_kind::sized)
: __begin_(std::move(__iter)), __end_(std::move(__sent)), __size_(__n)
{
if constexpr (sized_sentinel_for<_Sent, _Iter>)
_LIBCPP_ASSERT((__end_ - __begin_) == static_cast<iter_difference_t<_Iter>>(__n),
"std::ranges::subrange was passed an invalid size hint");
}
template<__different_from<subrange> _Range>
requires borrowed_range<_Range> &&
__convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
convertible_to<sentinel_t<_Range>, _Sent>
_LIBCPP_HIDE_FROM_ABI
constexpr subrange(_Range&& __range)
requires (!_StoreSize)
: subrange(ranges::begin(__range), ranges::end(__range))
{ }
template<__different_from<subrange> _Range>
requires borrowed_range<_Range> &&
__convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
convertible_to<sentinel_t<_Range>, _Sent>
_LIBCPP_HIDE_FROM_ABI
constexpr subrange(_Range&& __range)
requires _StoreSize && sized_range<_Range>
: subrange(__range, ranges::size(__range))
{ }
template<borrowed_range _Range>
requires __convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
convertible_to<sentinel_t<_Range>, _Sent>
_LIBCPP_HIDE_FROM_ABI
constexpr subrange(_Range&& __range, make_unsigned_t<iter_difference_t<_Iter>> __n)
requires (_Kind == subrange_kind::sized)
: subrange(ranges::begin(__range), ranges::end(__range), __n)
{ }
template<__different_from<subrange> _Pair>
requires __pair_like_convertible_from<_Pair, const _Iter&, const _Sent&>
_LIBCPP_HIDE_FROM_ABI
constexpr operator _Pair() const {
return _Pair(__begin_, __end_);
}
_LIBCPP_HIDE_FROM_ABI
constexpr _Iter begin() const requires copyable<_Iter> {
return __begin_;
}
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Iter begin() requires (!copyable<_Iter>) {
return std::move(__begin_);
}
_LIBCPP_HIDE_FROM_ABI
constexpr _Sent end() const {
return __end_;
}
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const {
return __begin_ == __end_;
}
_LIBCPP_HIDE_FROM_ABI
constexpr make_unsigned_t<iter_difference_t<_Iter>> size() const
requires (_Kind == subrange_kind::sized)
{
if constexpr (_StoreSize)
return __size_;
else
return std::__to_unsigned_like(__end_ - __begin_);
}
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) const&
requires forward_iterator<_Iter>
{
auto __tmp = *this;
__tmp.advance(__n);
return __tmp;
}
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) && {
advance(__n);
return std::move(*this);
}
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange prev(iter_difference_t<_Iter> __n = 1) const
requires bidirectional_iterator<_Iter>
{
auto __tmp = *this;
__tmp.advance(-__n);
return __tmp;
}
_LIBCPP_HIDE_FROM_ABI
constexpr subrange& advance(iter_difference_t<_Iter> __n) {
if constexpr (bidirectional_iterator<_Iter>) {
if (__n < 0) {
ranges::advance(__begin_, __n);
if constexpr (_StoreSize)
__size_ += std::__to_unsigned_like(-__n);
return *this;
}
}
auto __d = __n - ranges::advance(__begin_, __n, __end_);
if constexpr (_StoreSize)
__size_ -= std::__to_unsigned_like(__d);
return *this;
}
};
template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
subrange(_Iter, _Sent) -> subrange<_Iter, _Sent>;
template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
subrange(_Iter, _Sent, make_unsigned_t<iter_difference_t<_Iter>>)
-> subrange<_Iter, _Sent, subrange_kind::sized>;
template<borrowed_range _Range>
subrange(_Range&&) -> subrange<iterator_t<_Range>, sentinel_t<_Range>,
(sized_range<_Range> || sized_sentinel_for<sentinel_t<_Range>, iterator_t<_Range>>)
? subrange_kind::sized : subrange_kind::unsized>;
template<borrowed_range _Range>
subrange(_Range&&, make_unsigned_t<range_difference_t<_Range>>)
-> subrange<iterator_t<_Range>, sentinel_t<_Range>, subrange_kind::sized>;
template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind>
requires ((_Index == 0 && copyable<_Iter>) || _Index == 1)
_LIBCPP_HIDE_FROM_ABI
constexpr auto get(const subrange<_Iter, _Sent, _Kind>& __subrange) {
if constexpr (_Index == 0)
return __subrange.begin();
else
return __subrange.end();
}
template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind>
requires (_Index < 2)
_LIBCPP_HIDE_FROM_ABI
constexpr auto get(subrange<_Iter, _Sent, _Kind>&& __subrange) {
if constexpr (_Index == 0)
return __subrange.begin();
else
return __subrange.end();
}
template<class _Ip, class _Sp, subrange_kind _Kp>
inline constexpr bool enable_borrowed_range<subrange<_Ip, _Sp, _Kp>> = true;
template<range _Rp>
using borrowed_subrange_t = _If<borrowed_range<_Rp>, subrange<iterator_t<_Rp>>, dangling>;
} // namespace ranges
// [range.subrange.general]
using ranges::get;
// [ranges.syn]
template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
struct tuple_size<ranges::subrange<_Ip, _Sp, _Kp>> : integral_constant<size_t, 2> {};
template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
struct tuple_element<0, ranges::subrange<_Ip, _Sp, _Kp>> {
using type = _Ip;
};
template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
struct tuple_element<1, ranges::subrange<_Ip, _Sp, _Kp>> {
using type = _Sp;
};
template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
struct tuple_element<0, const ranges::subrange<_Ip, _Sp, _Kp>> {
using type = _Ip;
};
template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
struct tuple_element<1, const ranges::subrange<_Ip, _Sp, _Kp>> {
using type = _Sp;
};
#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___RANGES_SUBRANGE_H
|
