From 3ad39e9878310e5317ee73c9b353c1e2c1c5c4ee Mon Sep 17 00:00:00 2001 From: Richard Qin Date: Sat, 11 Jul 2026 22:48:30 +0800 Subject: lib: establish Zircon libc++ and KTL foundation --- third_party/libcxx/include/c++/v1/span | 662 +++++++++++++++++++++++++++++++++ 1 file changed, 662 insertions(+) create mode 100644 third_party/libcxx/include/c++/v1/span (limited to 'third_party/libcxx/include/c++/v1/span') diff --git a/third_party/libcxx/include/c++/v1/span b/third_party/libcxx/include/c++/v1/span new file mode 100644 index 0000000..1911bad --- /dev/null +++ b/third_party/libcxx/include/c++/v1/span @@ -0,0 +1,662 @@ +// -*- 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_SPAN +#define _LIBCPP_SPAN + +/* + span synopsis + +namespace std { + +// constants +inline constexpr size_t dynamic_extent = numeric_limits::max(); + +template + concept integral-constant-like = // exposition only, since C++26 + is_integral_v && + !is_same_v> && + convertible_to && + equality_comparable_with && + bool_constant::value && + bool_constant(T()) == T::value>::value; + +template + constexpr size_t maybe-static-ext = dynamic_extent; // exposition only, since C++26 +template + constexpr size_t maybe-static-ext = {T::value}; + +// [views.span], class template span +template + class span; + +template + inline constexpr bool ranges::enable_view> = true; + +template + inline constexpr bool ranges::enable_borrowed_range> = true; + +// [span.objectrep], views of object representation +template + span as_bytes(span s) noexcept; + +template + span< byte, ((Extent == dynamic_extent) ? dynamic_extent : + (sizeof(ElementType) * Extent))> as_writable_bytes(span s) noexcept; + + +template +class span { +public: + // constants and types + using element_type = ElementType; + using value_type = remove_cv_t; + using size_type = size_t; + using difference_type = ptrdiff_t; + using pointer = element_type*; + using const_pointer = const element_type*; + using reference = element_type&; + using const_reference = const element_type&; + using iterator = implementation-defined; + using reverse_iterator = std::reverse_iterator; + static constexpr size_type extent = Extent; + + // [span.cons], span constructors, copy, assignment, and destructor + constexpr span() noexcept; + template + constexpr explicit(Extent != dynamic_extent) span(It first, size_type count); + template + constexpr explicit(Extent != dynamic_extent) span(It first, End last); + template + constexpr span(type_identity_t (&arr)[N]) noexcept; + template + constexpr span(array& arr) noexcept; + template + constexpr span(const array& arr) noexcept; + template + constexpr explicit(Extent != dynamic_extent) span(R&& r); + constexpr explicit(extent != dynamic_extent) span(std::initializer_list il); // Since C++26 + constexpr span(const span& other) noexcept = default; + template + constexpr explicit(Extent != dynamic_extent) span(const span& s) noexcept; + constexpr span& operator=(const span& other) noexcept = default; + + // [span.sub], span subviews + template + constexpr span first() const; + template + constexpr span last() const; + template + constexpr span subspan() const; + + constexpr span first(size_type count) const; + constexpr span last(size_type count) const; + constexpr span subspan(size_type offset, size_type count = dynamic_extent) const; + + // [span.obs], span observers + constexpr size_type size() const noexcept; + constexpr size_type size_bytes() const noexcept; + [[nodiscard]] constexpr bool empty() const noexcept; + + // [span.elem], span element access + constexpr reference operator[](size_type idx) const; + constexpr reference at(size_type idx) const; // since C++26 + constexpr reference front() const; + constexpr reference back() const; + constexpr pointer data() const noexcept; + + // [span.iterators], span iterator support + constexpr iterator begin() const noexcept; + constexpr iterator end() const noexcept; + constexpr reverse_iterator rbegin() const noexcept; + constexpr reverse_iterator rend() const noexcept; + +private: + pointer data_; // exposition only + size_type size_; // exposition only +}; + +template + span(It, EndOrSize) -> span>>; // until C++26 +template + span(It, EndOrSize) -> span>, maybe-static-ext>; // since C++26 + +template + span(T (&)[N]) -> span; + +template + span(array&) -> span; + +template + span(const array&) -> span; + +template + span(R&&) -> span>>; + +} // namespace std + +*/ + +#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS) +# include <__cxx03/__config> +#else +# include <__assert> +# include <__concepts/convertible_to.h> +# include <__concepts/equality_comparable.h> +# include <__config> +# include <__cstddef/byte.h> +# include <__cstddef/ptrdiff_t.h> +# include <__fwd/array.h> +# include <__fwd/span.h> +# include <__iterator/bounded_iter.h> +# include <__iterator/concepts.h> +# include <__iterator/iterator_traits.h> +# include <__iterator/reverse_iterator.h> +# include <__iterator/wrap_iter.h> +# include <__memory/pointer_traits.h> +# include <__ranges/concepts.h> +# include <__ranges/data.h> +# include <__ranges/enable_borrowed_range.h> +# include <__ranges/enable_view.h> +# include <__ranges/size.h> +# include <__type_traits/integral_constant.h> +# include <__type_traits/is_array.h> +# include <__type_traits/is_const.h> +# include <__type_traits/is_convertible.h> +# include <__type_traits/is_integral.h> +# include <__type_traits/is_same.h> +# include <__type_traits/remove_const.h> +# include <__type_traits/remove_cv.h> +# include <__type_traits/remove_cvref.h> +# include <__type_traits/remove_reference.h> +# include <__type_traits/type_identity.h> +# include <__utility/forward.h> +# include +# include +# include + +// standard-mandated includes + +// [iterator.range] +# include <__iterator/access.h> +# include <__iterator/data.h> +# include <__iterator/empty.h> +# include <__iterator/reverse_access.h> +# include <__iterator/size.h> + +# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) +# pragma GCC system_header +# endif + +_LIBCPP_PUSH_MACROS +# include <__undef_macros> + +_LIBCPP_BEGIN_NAMESPACE_STD + +# if _LIBCPP_STD_VER >= 20 + +template +struct __is_std_span : false_type {}; + +template +struct __is_std_span> : true_type {}; + +template +concept __span_compatible_range = + !__is_std_span>::value && // + ranges::contiguous_range<_Range> && // + ranges::sized_range<_Range> && // + (ranges::borrowed_range<_Range> || is_const_v<_ElementType>) && // + !__is_std_array_v> && // + !is_array_v> && // + is_convertible_v> (*)[], _ElementType (*)[]>; + +template +concept __span_array_convertible = is_convertible_v<_From (*)[], _To (*)[]>; + +template +concept __span_compatible_iterator = + contiguous_iterator<_It> && __span_array_convertible>, _Tp>; + +template +concept __span_compatible_sentinel_for = sized_sentinel_for<_Sentinel, _It> && !is_convertible_v<_Sentinel, size_t>; + +template +class span { +public: + // constants and types + using element_type = _Tp; + using value_type = remove_cv_t<_Tp>; + using size_type = size_t; + using difference_type = ptrdiff_t; + using pointer = _Tp*; + using const_pointer = const _Tp*; + using reference = _Tp&; + using const_reference = const _Tp&; +# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS + using iterator = __bounded_iter; +# else + using iterator = __wrap_iter; +# endif + using reverse_iterator = std::reverse_iterator; + + static constexpr size_type extent = _Extent; + + // [span.cons], span constructors, copy, assignment, and destructor + template + requires(_Sz == 0) + _LIBCPP_HIDE_FROM_ABI constexpr span() noexcept : __data_{nullptr} {} + +# if _LIBCPP_STD_VER >= 26 + _LIBCPP_HIDE_FROM_ABI constexpr explicit span(std::initializer_list __il) + requires is_const_v + : __data_{__il.begin()} { + _LIBCPP_ASSERT_VALID_INPUT_RANGE( + _Extent == __il.size(), "Size mismatch in span's constructor _Extent != __il.size()."); + } +# endif + + constexpr span(const span&) noexcept = default; + constexpr span& operator=(const span&) noexcept = default; + + template <__span_compatible_iterator _It> + _LIBCPP_HIDE_FROM_ABI constexpr explicit span(_It __first, size_type __count) : __data_{std::to_address(__first)} { + (void)__count; + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Extent == __count, "size mismatch in span's constructor (iterator, len)"); + _LIBCPP_ASSERT_VALID_INPUT_RANGE(__count == 0 || std::to_address(__first) != nullptr, + "passed nullptr with non-zero length in span's constructor (iterator, len)"); + } + + template <__span_compatible_iterator _It, __span_compatible_sentinel_for<_It> _End> + _LIBCPP_HIDE_FROM_ABI constexpr explicit span(_It __first, _End __last) : __data_{std::to_address(__first)} { + // [span.cons]/10 + // Throws: When and what last - first throws. + [[maybe_unused]] auto __dist = __last - __first; + _LIBCPP_ASSERT_VALID_INPUT_RANGE(__dist >= 0, "invalid range in span's constructor (iterator, sentinel)"); + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS( + __dist == _Extent, "invalid range in span's constructor (iterator, sentinel): last - first != extent"); + } + + _LIBCPP_HIDE_FROM_ABI constexpr span(type_identity_t (&__arr)[_Extent]) noexcept : __data_{__arr} {} + + template <__span_array_convertible _OtherElementType> + _LIBCPP_HIDE_FROM_ABI constexpr span(array<_OtherElementType, _Extent>& __arr) noexcept : __data_{__arr.data()} {} + + template + requires __span_array_convertible + _LIBCPP_HIDE_FROM_ABI constexpr span(const array<_OtherElementType, _Extent>& __arr) noexcept + : __data_{__arr.data()} {} + + template <__span_compatible_range _Range> + _LIBCPP_HIDE_FROM_ABI constexpr explicit span(_Range&& __r) : __data_{ranges::data(__r)} { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(ranges::size(__r) == _Extent, "size mismatch in span's constructor (range)"); + } + + template <__span_array_convertible _OtherElementType> + _LIBCPP_HIDE_FROM_ABI constexpr span(const span<_OtherElementType, _Extent>& __other) noexcept + : __data_{__other.data()} {} + + template <__span_array_convertible _OtherElementType> + _LIBCPP_HIDE_FROM_ABI constexpr explicit span(const span<_OtherElementType, dynamic_extent>& __other) noexcept + : __data_{__other.data()} { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Extent == __other.size(), "size mismatch in span's constructor (other span)"); + } + + template + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span first() const noexcept { + static_assert(_Count <= _Extent, "span::first(): Count out of range"); + return span{data(), _Count}; + } + + template + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span last() const noexcept { + static_assert(_Count <= _Extent, "span::last(): Count out of range"); + return span{data() + size() - _Count, _Count}; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span + first(size_type __count) const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__count <= size(), "span::first(count): count out of range"); + return {data(), __count}; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span + last(size_type __count) const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__count <= size(), "span::last(count): count out of range"); + return {data() + size() - __count, __count}; + } + + template + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto subspan() const noexcept + -> span { + static_assert(_Offset <= _Extent, "span::subspan(): Offset out of range"); + static_assert(_Count == dynamic_extent || _Count <= _Extent - _Offset, + "span::subspan(): Offset + Count out of range"); + + using _ReturnType = span; + return _ReturnType{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span + subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__offset <= size(), "span::subspan(offset, count): offset out of range"); + if (__count == dynamic_extent) + return {data() + __offset, size() - __offset}; + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS( + __count <= size() - __offset, "span::subspan(offset, count): offset + count out of range"); + return {data() + __offset, __count}; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_type size() const noexcept { return _Extent; } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_type size_bytes() const noexcept { + return _Extent * sizeof(element_type); + } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const noexcept { return _Extent == 0; } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](size_type __idx) const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__idx < size(), "span::operator[](index): index out of range"); + return __data_[__idx]; + } + +# if _LIBCPP_STD_VER >= 26 + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reference at(size_type __index) const { + if (__index >= size()) + std::__throw_out_of_range("span"); + return __data_[__index]; + } +# endif + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reference front() const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "span::front() on empty span"); + return __data_[0]; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reference back() const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "span::back() on empty span"); + return __data_[size() - 1]; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr pointer data() const noexcept { return __data_; } + + // [span.iter], span iterator support + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iterator begin() const noexcept { +# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS + return std::__make_bounded_iter(data(), data(), data() + size()); +# else + return iterator(data()); +# endif + } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iterator end() const noexcept { +# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS + return std::__make_bounded_iter(data() + size(), data(), data() + size()); +# else + return iterator(data() + size()); +# endif + } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reverse_iterator rbegin() const noexcept { + return reverse_iterator(end()); + } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reverse_iterator rend() const noexcept { + return reverse_iterator(begin()); + } + + _LIBCPP_HIDE_FROM_ABI span __as_bytes() const noexcept { + return span{reinterpret_cast(data()), size_bytes()}; + } + + _LIBCPP_HIDE_FROM_ABI span __as_writable_bytes() const noexcept { + return span{reinterpret_cast(data()), size_bytes()}; + } + +private: + pointer __data_; +}; + +template +class span<_Tp, dynamic_extent> { +public: + // constants and types + using element_type = _Tp; + using value_type = remove_cv_t<_Tp>; + using size_type = size_t; + using difference_type = ptrdiff_t; + using pointer = _Tp*; + using const_pointer = const _Tp*; + using reference = _Tp&; + using const_reference = const _Tp&; +# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS + using iterator = __bounded_iter; +# else + using iterator = __wrap_iter; +# endif + using reverse_iterator = std::reverse_iterator; + + static constexpr size_type extent = dynamic_extent; + + // [span.cons], span constructors, copy, assignment, and destructor + _LIBCPP_HIDE_FROM_ABI constexpr span() noexcept : __data_{nullptr}, __size_{0} {} + +# if _LIBCPP_STD_VER >= 26 + _LIBCPP_HIDE_FROM_ABI constexpr span(std::initializer_list __il) + requires is_const_v + : __data_{__il.begin()}, __size_{__il.size()} {} +# endif + + constexpr span(const span&) noexcept = default; + constexpr span& operator=(const span&) noexcept = default; + + template <__span_compatible_iterator _It> + _LIBCPP_HIDE_FROM_ABI constexpr span(_It __first, size_type __count) + : __data_{std::to_address(__first)}, __size_{__count} { + _LIBCPP_ASSERT_VALID_INPUT_RANGE(__count == 0 || std::to_address(__first) != nullptr, + "passed nullptr with non-zero length in span's constructor (iterator, len)"); + } + + template <__span_compatible_iterator _It, __span_compatible_sentinel_for<_It> _End> + _LIBCPP_HIDE_FROM_ABI constexpr span(_It __first, _End __last) + : __data_(std::to_address(__first)), __size_(__last - __first) { + _LIBCPP_ASSERT_VALID_INPUT_RANGE(__last - __first >= 0, "invalid range in span's constructor (iterator, sentinel)"); + } + + template + _LIBCPP_HIDE_FROM_ABI constexpr span(type_identity_t (&__arr)[_Sz]) noexcept + : __data_{__arr}, __size_{_Sz} {} + + template <__span_array_convertible _OtherElementType, size_t _Sz> + _LIBCPP_HIDE_FROM_ABI constexpr span(array<_OtherElementType, _Sz>& __arr) noexcept + : __data_{__arr.data()}, __size_{_Sz} {} + + template + requires __span_array_convertible + _LIBCPP_HIDE_FROM_ABI constexpr span(const array<_OtherElementType, _Sz>& __arr) noexcept + : __data_{__arr.data()}, __size_{_Sz} {} + + template <__span_compatible_range _Range> + _LIBCPP_HIDE_FROM_ABI constexpr span(_Range&& __r) : __data_(ranges::data(__r)), __size_{ranges::size(__r)} {} + + template <__span_array_convertible _OtherElementType, size_t _OtherExtent> + _LIBCPP_HIDE_FROM_ABI constexpr span(const span<_OtherElementType, _OtherExtent>& __other) noexcept + : __data_{__other.data()}, __size_{__other.size()} {} + + template + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span first() const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Count <= size(), "span::first(): Count out of range"); + return span{data(), _Count}; + } + + template + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span last() const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Count <= size(), "span::last(): Count out of range"); + return span{data() + size() - _Count, _Count}; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span + first(size_type __count) const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__count <= size(), "span::first(count): count out of range"); + return {data(), __count}; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span + last(size_type __count) const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__count <= size(), "span::last(count): count out of range"); + return {data() + size() - __count, __count}; + } + + template + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr span subspan() const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Offset <= size(), "span::subspan(): Offset out of range"); + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(_Count == dynamic_extent || _Count <= size() - _Offset, + "span::subspan(): Offset + Count out of range"); + return span{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count}; + } + + [[nodiscard]] constexpr span _LIBCPP_HIDE_FROM_ABI + subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__offset <= size(), "span::subspan(offset, count): offset out of range"); + if (__count == dynamic_extent) + return {data() + __offset, size() - __offset}; + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS( + __count <= size() - __offset, "span::subspan(offset, count): offset + count out of range"); + return {data() + __offset, __count}; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_type size() const noexcept { return __size_; } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_type size_bytes() const noexcept { + return __size_ * sizeof(element_type); + } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const noexcept { return __size_ == 0; } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](size_type __idx) const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__idx < size(), "span::operator[](index): index out of range"); + return __data_[__idx]; + } + +# if _LIBCPP_STD_VER >= 26 + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reference at(size_type __index) const { + if (__index >= size()) + std::__throw_out_of_range("span"); + return __data_[__index]; + } +# endif + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reference front() const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "span::front() on empty span"); + return __data_[0]; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reference back() const noexcept { + _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "span::back() on empty span"); + return __data_[size() - 1]; + } + + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr pointer data() const noexcept { return __data_; } + + // [span.iter], span iterator support + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iterator begin() const noexcept { +# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS + return std::__make_bounded_iter(data(), data(), data() + size()); +# else + return iterator(data()); +# endif + } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr iterator end() const noexcept { +# ifdef _LIBCPP_ABI_BOUNDED_ITERATORS + return std::__make_bounded_iter(data() + size(), data(), data() + size()); +# else + return iterator(data() + size()); +# endif + } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reverse_iterator rbegin() const noexcept { + return reverse_iterator(end()); + } + [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr reverse_iterator rend() const noexcept { + return reverse_iterator(begin()); + } + + _LIBCPP_HIDE_FROM_ABI span __as_bytes() const noexcept { + return {reinterpret_cast(data()), size_bytes()}; + } + + _LIBCPP_HIDE_FROM_ABI span __as_writable_bytes() const noexcept { + return {reinterpret_cast(data()), size_bytes()}; + } + +private: + pointer __data_; + size_type __size_; +}; + +template +inline constexpr bool ranges::enable_borrowed_range > = true; + +template +inline constexpr bool ranges::enable_view> = true; + +// as_bytes & as_writable_bytes +template +[[nodiscard]] _LIBCPP_HIDE_FROM_ABI auto as_bytes(span<_Tp, _Extent> __s) noexcept { + return __s.__as_bytes(); +} + +template + requires(!is_const_v<_Tp>) +[[nodiscard]] _LIBCPP_HIDE_FROM_ABI auto as_writable_bytes(span<_Tp, _Extent> __s) noexcept { + return __s.__as_writable_bytes(); +} + +# if _LIBCPP_STD_VER >= 26 +template +concept __integral_constant_like = + is_integral_v && !is_same_v> && + convertible_to<_Tp, decltype(_Tp::value)> && equality_comparable_with<_Tp, decltype(_Tp::value)> && + bool_constant<_Tp() == _Tp::value>::value && + bool_constant(_Tp()) == _Tp::value>::value; + +template +inline constexpr size_t __maybe_static_ext = dynamic_extent; + +template <__integral_constant_like _Tp> +inline constexpr size_t __maybe_static_ext<_Tp> = {_Tp::value}; + +template +span(_It, _EndOrSize) -> span>, __maybe_static_ext<_EndOrSize>>; +# else +template +span(_It, _EndOrSize) -> span>>; +# endif + +template +span(_Tp (&)[_Sz]) -> span<_Tp, _Sz>; + +template +span(array<_Tp, _Sz>&) -> span<_Tp, _Sz>; + +template +span(const array<_Tp, _Sz>&) -> span; + +template +span(_Range&&) -> span>>; + +# endif // _LIBCPP_STD_VER >= 20 + +_LIBCPP_END_NAMESPACE_STD + +_LIBCPP_POP_MACROS + +# if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20 +# include +# include +# include +# include +# include +# endif +#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS) + +#endif // _LIBCPP_SPAN -- cgit v1.2.3