1 files changed, 408 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__ranges/transform_view.h b/contrib/llvm-project/libcxx/include/__ranges/transform_view.h
new file mode 100644
index 000000000000..4243dc0366e9
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__ranges/transform_view.h
@@ -0,0 +1,408 @@
+// -*- 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_TRANSFORM_VIEW_H
+#define _LIBCPP___RANGES_TRANSFORM_VIEW_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/iter_swap.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/copyable_box.h>
+#include <__ranges/empty.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+
+template<class _View, class _Fn>
+concept __transform_view_constraints =
+           view<_View> && is_object_v<_Fn> &&
+           regular_invocable<_Fn&, range_reference_t<_View>> &&
+           __referenceable<invoke_result_t<_Fn&, range_reference_t<_View>>>;
+
+template<input_range _View, copy_constructible _Fn>
+  requires __transform_view_constraints<_View, _Fn>
+class transform_view : public view_interface<transform_view<_View, _Fn>> {
+  template<bool> class __iterator;
+  template<bool> class __sentinel;
+
+  [[no_unique_address]] __copyable_box<_Fn> __func_;
+  [[no_unique_address]] _View __base_ = _View();
+
+public:
+  _LIBCPP_HIDE_FROM_ABI
+  transform_view()
+    requires default_initializable<_View> && default_initializable<_Fn> = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr transform_view(_View __base, _Fn __func)
+    : __func_(_VSTD::in_place, _VSTD::move(__func)), __base_(_VSTD::move(__base)) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _View base() && { return _VSTD::move(__base_); }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator<false> begin() {
+    return __iterator<false>{*this, ranges::begin(__base_)};
+  }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator<true> begin() const
+    requires range<const _View> &&
+             regular_invocable<const _Fn&, range_reference_t<const _View>>
+  {
+    return __iterator<true>(*this, ranges::begin(__base_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __sentinel<false> end() {
+    return __sentinel<false>(ranges::end(__base_));
+  }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator<false> end()
+    requires common_range<_View>
+  {
+    return __iterator<false>(*this, ranges::end(__base_));
+  }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __sentinel<true> end() const
+    requires range<const _View> &&
+             regular_invocable<const _Fn&, range_reference_t<const _View>>
+  {
+    return __sentinel<true>(ranges::end(__base_));
+  }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator<true> end() const
+    requires common_range<const _View> &&
+             regular_invocable<const _Fn&, range_reference_t<const _View>>
+  {
+    return __iterator<true>(*this, ranges::end(__base_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto size() requires sized_range<_View> { return ranges::size(__base_); }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto size() const requires sized_range<const _View> { return ranges::size(__base_); }
+};
+
+template<class _Range, class _Fn>
+transform_view(_Range&&, _Fn) -> transform_view<views::all_t<_Range>, _Fn>;
+
+template<class _View>
+struct __transform_view_iterator_concept { using type = input_iterator_tag; };
+
+template<random_access_range _View>
+struct __transform_view_iterator_concept<_View> { using type = random_access_iterator_tag; };
+
+template<bidirectional_range _View>
+struct __transform_view_iterator_concept<_View> { using type = bidirectional_iterator_tag; };
+
+template<forward_range _View>
+struct __transform_view_iterator_concept<_View> { using type = forward_iterator_tag; };
+
+template<class, class>
+struct __transform_view_iterator_category_base {};
+
+template<forward_range _View, class _Fn>
+struct __transform_view_iterator_category_base<_View, _Fn> {
+  using _Cat = typename iterator_traits<iterator_t<_View>>::iterator_category;
+
+  using iterator_category = conditional_t<
+    is_lvalue_reference_v<invoke_result_t<_Fn&, range_reference_t<_View>>>,
+    conditional_t<
+      derived_from<_Cat, contiguous_iterator_tag>,
+      random_access_iterator_tag,
+      _Cat
+    >,
+    input_iterator_tag
+  >;
+};
+
+template<input_range _View, copy_constructible _Fn>
+  requires __transform_view_constraints<_View, _Fn>
+template<bool _Const>
+class transform_view<_View, _Fn>::__iterator
+  : public __transform_view_iterator_category_base<_View, _Fn> {
+
+  using _Parent = __maybe_const<_Const, transform_view>;
+  using _Base = __maybe_const<_Const, _View>;
+
+  _Parent *__parent_ = nullptr;
+
+  template<bool>
+  friend class transform_view<_View, _Fn>::__iterator;
+
+  template<bool>
+  friend class transform_view<_View, _Fn>::__sentinel;
+
+public:
+  iterator_t<_Base> __current_ = iterator_t<_Base>();
+
+  using iterator_concept = typename __transform_view_iterator_concept<_View>::type;
+  using value_type = remove_cvref_t<invoke_result_t<_Fn&, range_reference_t<_Base>>>;
+  using difference_type = range_difference_t<_Base>;
+
+  _LIBCPP_HIDE_FROM_ABI
+  __iterator() requires default_initializable<iterator_t<_Base>> = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator(_Parent& __parent, iterator_t<_Base> __current)
+    : __parent_(_VSTD::addressof(__parent)), __current_(_VSTD::move(__current)) {}
+
+  // Note: `__i` should always be `__iterator<false>`, but directly using
+  // `__iterator<false>` is ill-formed when `_Const` is false
+  // (see http://wg21.link/class.copy.ctor#5).
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator(__iterator<!_Const> __i)
+    requires _Const && convertible_to<iterator_t<_View>, iterator_t<_Base>>
+    : __parent_(__i.__parent_), __current_(_VSTD::move(__i.__current_)) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr iterator_t<_Base> base() const&
+    requires copyable<iterator_t<_Base>>
+  {
+    return __current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr iterator_t<_Base> base() && {
+    return _VSTD::move(__current_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator*() const
+    noexcept(noexcept(_VSTD::invoke(*__parent_->__func_, *__current_)))
+  {
+    return _VSTD::invoke(*__parent_->__func_, *__current_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator& operator++() {
+    ++__current_;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr void operator++(int) { ++__current_; }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator operator++(int)
+    requires forward_range<_Base>
+  {
+    auto __tmp = *this;
+    ++*this;
+    return __tmp;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator& operator--()
+    requires bidirectional_range<_Base>
+  {
+    --__current_;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator operator--(int)
+    requires bidirectional_range<_Base>
+  {
+    auto __tmp = *this;
+    --*this;
+    return __tmp;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator& operator+=(difference_type __n)
+    requires random_access_range<_Base>
+  {
+    __current_ += __n;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator& operator-=(difference_type __n)
+    requires random_access_range<_Base>
+  {
+    __current_ -= __n;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator[](difference_type __n) const
+    noexcept(noexcept(_VSTD::invoke(*__parent_->__func_, __current_[__n])))
+    requires random_access_range<_Base>
+  {
+    return _VSTD::invoke(*__parent_->__func_, __current_[__n]);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)
+    requires equality_comparable<iterator_t<_Base>>
+  {
+    return __x.__current_ == __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ < __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ > __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<=(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ <= __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>=(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ >= __y.__current_;
+  }
+
+// TODO: Fix this as soon as soon as three_way_comparable is implemented.
+//   _LIBCPP_HIDE_FROM_ABI
+//   friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)
+//     requires random_access_range<_Base> && three_way_comparable<iterator_t<_Base>>
+//   {
+//     return __x.__current_ <=> __y.__current_;
+//   }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr __iterator operator+(__iterator __i, difference_type __n)
+    requires random_access_range<_Base>
+  {
+    return __iterator{*__i.__parent_, __i.__current_ + __n};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr __iterator operator+(difference_type __n, __iterator __i)
+    requires random_access_range<_Base>
+  {
+    return __iterator{*__i.__parent_, __i.__current_ + __n};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr __iterator operator-(__iterator __i, difference_type __n)
+    requires random_access_range<_Base>
+  {
+    return __iterator{*__i.__parent_, __i.__current_ - __n};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y)
+    requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
+  {
+    return __x.__current_ - __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr decltype(auto) iter_move(const __iterator& __i)
+    noexcept(noexcept(*__i))
+  {
+    if constexpr (is_lvalue_reference_v<decltype(*__i)>)
+      return _VSTD::move(*__i);
+    else
+      return *__i;
+  }
+};
+
+template<input_range _View, copy_constructible _Fn>
+  requires __transform_view_constraints<_View, _Fn>
+template<bool _Const>
+class transform_view<_View, _Fn>::__sentinel {
+  using _Parent = __maybe_const<_Const, transform_view>;
+  using _Base = __maybe_const<_Const, _View>;
+
+  sentinel_t<_Base> __end_ = sentinel_t<_Base>();
+
+  template<bool>
+  friend class transform_view<_View, _Fn>::__iterator;
+
+  template<bool>
+  friend class transform_view<_View, _Fn>::__sentinel;
+
+public:
+  _LIBCPP_HIDE_FROM_ABI
+  __sentinel() = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr explicit __sentinel(sentinel_t<_Base> __end) : __end_(__end) {}
+
+  // Note: `__i` should always be `__sentinel<false>`, but directly using
+  // `__sentinel<false>` is ill-formed when `_Const` is false
+  // (see http://wg21.link/class.copy.ctor#5).
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __sentinel(__sentinel<!_Const> __i)
+    requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>
+    : __end_(_VSTD::move(__i.__end_)) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr sentinel_t<_Base> base() const { return __end_; }
+
+  template<bool _OtherConst>
+    requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
+    return __x.__current_ == __y.__end_;
+  }
+
+  template<bool _OtherConst>
+    requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>
+  operator-(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
+    return __x.__current_ - __y.__end_;
+  }
+
+  template<bool _OtherConst>
+    requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>
+  operator-(const __sentinel& __x, const __iterator<_OtherConst>& __y) {
+    return __x.__end_ - __y.__current_;
+  }
+};
+
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___RANGES_TRANSFORM_VIEW_H