include/__ranges/subrange.h

64   template<class _Pair, class _Iter, class _Sent>
67     constructible_from<_Pair, _Iter, _Sent> &&
68     __convertible_to_non_slicing<_Iter, tuple_element_t<0, _Pair>> &&
71   template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent = _Iter,
72            subrange_kind _Kind = sized_sentinel_for<_Sent, _Iter>
75     requires (_Kind == subrange_kind::sized || !sized_sentinel_for<_Sent, _Iter>)
77     : public view_interface<subrange<_Iter, _Sent, _Kind>>
81     static constexpr bool _StoreSize = (_Kind == subrange_kind::sized && !sized_sentinel_for<_Sent, _Iter>);
86     using _Size = conditional_t<_StoreSize, make_unsigned_t<iter_difference_t<_Iter>>, _Empty>;
87     _LIBCPP_NO_UNIQUE_ADDRESS _Iter __begin_ = _Iter();
93     subrange() requires default_initializable<_Iter> = default;
96     constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent)
102     constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent,
103                        make_unsigned_t<iter_difference_t<_Iter>> __n)
107       if constexpr (sized_sentinel_for<_Sent, _Iter>)
108         _LIBCPP_ASSERT((__end_ - __begin_) == static_cast<iter_difference_t<_Iter>>(__n),
114                __convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
124                __convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
133       requires __convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
136     constexpr subrange(_Range&& __range, make_unsigned_t<iter_difference_t<_Iter>> __n)
142       requires __pair_like_convertible_from<_Pair, const _Iter&, const _Sent&>
149     constexpr _Iter begin() const requires copyable<_Iter> {
153     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Iter begin() requires (!copyable<_Iter>) {
167     constexpr make_unsigned_t<iter_difference_t<_Iter>> size() const
176     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) const&
177       requires forward_iterator<_Iter>
184     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) && {
189     [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange prev(iter_difference_t<_Iter> __n = 1) const
190       requires bidirectional_iterator<_Iter>
198     constexpr subrange& advance(iter_difference_t<_Iter> __n) {
199       if constexpr (bidirectional_iterator<_Iter>) {
215   template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
216   subrange(_Iter, _Sent) -> subrange<_Iter, _Sent>;
218   template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
219   subrange(_Iter, _Sent, make_unsigned_t<iter_difference_t<_Iter>>)
220     -> subrange<_Iter, _Sent, subrange_kind::sized>;
231   template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind>
232     requires ((_Index == 0 && copyable<_Iter>) || _Index == 1)
234   constexpr auto get(const subrange<_Iter, _Sent, _Kind>& __subrange) {
241   template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind>
244   constexpr auto get(subrange<_Iter, _Sent, _Kind>&& __subrange) {