libcxx/include/ranges

// -*- 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
#define _LIBCPP_RANGES

/*

#include <compare>              // see [compare.syn]
#include <initializer_list>     // see [initializer.list.syn]
#include <iterator>             // see [iterator.synopsis]

namespace std::ranges {
  inline namespace unspecified {
    // [range.access], range access
    inline constexpr unspecified begin = unspecified;
    inline constexpr unspecified end = unspecified;
    inline constexpr unspecified cbegin = unspecified;
    inline constexpr unspecified cend = unspecified;

    inline constexpr unspecified size = unspecified;
    inline constexpr unspecified ssize = unspecified;
  }

  // [range.range], ranges
  template<class T>
    concept range = see below;

  template<class T>
    inline constexpr bool enable_borrowed_range = false;

  template<class T>
    using iterator_t = decltype(ranges::begin(declval<T&>()));
  template<range R>
    using sentinel_t = decltype(ranges::end(declval<R&>()));
  template<range R>
    using range_difference_t = iter_difference_t<iterator_t<R>>;
  template<sized_range R>
    using range_size_t = decltype(ranges::size(declval<R&>()));
  template<range R>
    using range_value_t = iter_value_t<iterator_t<R>>;
  template<range R>
    using range_reference_t = iter_reference_t<iterator_t<R>>;
  template<range R>
    using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<R>>;
  template <range R>
    using range_common_reference_t = iter_common_reference_t<iterator_t<R>>;

  // [range.sized], sized ranges
  template<class>
    inline constexpr bool disable_sized_range = false;

  template<class T>
    concept sized_range = ...;

  // [range.view], views
  template<class T>
    inline constexpr bool enable_view = ...;

  struct view_base { };

  template<class T>
    concept view = ...;

  // [range.refinements], other range refinements
  template<class R, class T>
    concept output_range = see below;

  template<class T>
    concept input_range = see below;

  template<class T>
    concept forward_range = see below;

  template<class T>
  concept bidirectional_range = see below;

  template<class T>
  concept random_access_range = see below;

  template<class T>
  concept contiguous_range = see below;

  template <class _Tp>
    concept common_range = see below;

  template<class T>
  concept viewable_range = see below;

  // [range.adaptor.object], range adaptor objects
  template<class D>
    requires is_class_v<D> && same_as<D, remove_cv_t<D>>
  class range_adaptor_closure { };  // Since c++23

  // [view.interface], class template view_interface
  template<class D>
    requires is_class_v<D> && same_as<D, remove_cv_t<D>>
  class view_interface;

  // [range.subrange], sub-ranges
  enum class subrange_kind : bool { unsized, sized };

  template<input_or_output_iterator I, sentinel_for<I> S = I, subrange_kind K = see below>
    requires (K == subrange_kind::sized || !sized_sentinel_for<S, I>)
  class subrange;

  template<class I, class S, subrange_kind K>
    inline constexpr bool enable_borrowed_range<subrange<I, S, K>> = true;

  // [range.dangling], dangling iterator handling
  struct dangling;

  // [range.elementsof], class template elements_of
  template<range R, class Allocator = allocator<byte>>
    struct elements_of;

  template<range R>
    using borrowed_iterator_t = see below;

  template<range R>
    using borrowed_subrange_t = see below;

  // [range.elements], elements view
  template<input_range V, size_t N>
    requires see below
  class elements_view;

  template<class T, size_t N>
    inline constexpr bool enable_borrowed_range<elements_view<T, N>> =
      enable_borrowed_range<T>;

  template<class R>
    using keys_view = elements_view<R, 0>;
  template<class R>
    using values_view = elements_view<R, 1>;

  namespace views {
    template<size_t N>
      inline constexpr unspecified elements = unspecified;
    inline constexpr auto keys = elements<0>;
    inline constexpr auto values = elements<1>;
  }

  // [range.utility.conv], range conversions
  template<class C, input_range R, class... Args> requires (!view<C>)
    constexpr C to(R&& r, Args&&... args);     // Since C++23
  template<template<class...> class C, input_range R, class... Args>
    constexpr auto to(R&& r, Args&&... args);  // Since C++23
  template<class C, class... Args> requires (!view<C>)
    constexpr auto to(Args&&... args);         // Since C++23
  template<template<class...> class C, class... Args>
    constexpr auto to(Args&&... args);         // Since C++23

  // [range.empty], empty view
  template<class T>
    requires is_object_v<T>
  class empty_view;

  template<class T>
    inline constexpr bool enable_borrowed_range<empty_view<T>> = true;

  namespace views {
    template<class T>
      inline constexpr empty_view<T> empty{};
  }

  // [range.all], all view
  namespace views {
    inline constexpr unspecified all = unspecified;

    template<viewable_range R>
      using all_t = decltype(all(declval<R>()));
  }

  template<range R>
    requires is_object_v<R>
  class ref_view;

  template<class T>
    inline constexpr bool enable_borrowed_range<ref_view<T>> = true;

  template<range R>
    requires see below
  class owning_view;

  template<class T>
    inline constexpr bool enable_borrowed_range<owning_view<T>> = enable_borrowed_range<T>;

  // [range.filter], filter view
  template<input_range V, indirect_unary_predicate<iterator_t<V>> Pred>
    requires view<V> && is_object_v<Pred>
  class filter_view;

  namespace views {
    inline constexpr unspecified filter = unspecified;
  }

  // [range.concat], concat view
  template <input_range... Views>
      requires (view<Views> && ...) && (sizeof...(Views) > 0) &&
                concatable<Views...>
  class concat_view;

  namespace views {
    inline constexpr unspecified concat = unspecified;
  }

  // [range.drop], drop view
  template<view V>
    class drop_view;

  template<class T>
    inline constexpr bool enable_borrowed_range<drop_view<T>> = enable_borrowed_range<T>;

  // [range.drop.while], drop while view
  template<view V, class Pred>
    requires input_range<V> && is_object_v<Pred> &&
             indirect_unary_predicate<const Pred, iterator_t<V>>
    class drop_while_view;

  template<class T, class Pred>
    inline constexpr bool enable_borrowed_range<drop_while_view<T, Pred>> =
      enable_borrowed_range<T>;

  namespace views { inline constexpr unspecified drop_while = unspecified; }

  // [range.transform], transform view
  template<input_range V, copy_constructible F>
    requires view<V> && is_object_v<F> &&
             regular_invocable<F&, range_reference_t<V>> &&
             can-reference<invoke_result_t<F&, range_reference_t<V>>>
  class transform_view;

  // [range.counted], counted view
  namespace views { inline constexpr unspecified counted = unspecified; }

  // [range.common], common view
  template<view V>
    requires (!common_range<V> && copyable<iterator_t<V>>)
  class common_view;

 // [range.reverse], reverse view
  template<view V>
    requires bidirectional_range<V>
  class reverse_view;

  template<class T>
    inline constexpr bool enable_borrowed_range<reverse_view<T>> = enable_borrowed_range<T>;

  template<class T>
  inline constexpr bool enable_borrowed_range<common_view<T>> = enable_borrowed_range<T>;

   // [range.take], take view
  template<view> class take_view;

  template<class T>
  inline constexpr bool enable_borrowed_range<take_view<T>> = enable_borrowed_range<T>;

    // [range.take.while], take while view
  template<view V, class Pred>
    requires input_range<V> && is_object_v<Pred> &&
             indirect_unary_predicate<const Pred, iterator_t<V>>
    class take_while_view;

  namespace views { inline constexpr unspecified take_while = unspecified; }

  template<copy_constructible T>
    requires is_object_v<T>
  class single_view;

  template<weakly_incrementable W, semiregular Bound = unreachable_sentinel_t>
    requires weakly-equality-comparable-with<W, Bound> && copyable<W>
  class iota_view;

  template<class W, class Bound>
    inline constexpr bool enable_borrowed_range<iota_view<W, Bound>> = true;

  namespace views {
    inline constexpr unspecified iota = unspecified;
    inline constexpr unspecified indices = unspecified; // Since C++26
  }

  // [range.repeat], repeat view
  template<class T>
    concept integer-like-with-usable-difference-type =  // exposition only
      is-signed-integer-like<T> || (is-integer-like<T> && weakly_incrementable<T>);

  template<move_constructible T, semiregular Bound = unreachable_sentinel_t>
    requires (is_object_v<T> && same_as<T, remove_cv_t<T>> &&
              (integer-like-with-usable-difference-type<Bound> ||
               same_as<Bound, unreachable_sentinel_t>))
  class repeat_view;

  namespace views { inline constexpr unspecified repeat = unspecified; }

  // [range.join], join view
  template<input_range V>
    requires view<V> && input_range<range_reference_t<V>>
  class join_view;

  // [range.join.with], join with view
  template<input_range V, forward_range Pattern>
    requires view<V> && input_range<range_reference_t<V>>
          && view<Pattern>
          && concatable<range_reference_t<V>, Pattern>
  class join_with_view;                                                     // since C++23

  namespace views { inline constexpr unspecified join_with = unspecified; } // since C++23

  // [range.lazy.split], lazy split view
  template<class R>
    concept tiny-range = see below;   // exposition only

  template<input_range V, forward_range Pattern>
    requires view<V> && view<Pattern> &&
             indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to> &&
             (forward_range<V> || tiny-range<Pattern>)
  class lazy_split_view;

  // [range.split], split view
  template<forward_range V, forward_range Pattern>
    requires view<V> && view<Pattern> &&
             indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to>
  class split_view;

  namespace views {
    inline constexpr unspecified lazy_split = unspecified;
    inline constexpr unspecified split = unspecified;
  }

  // [range.istream], istream view
  template<movable Val, class CharT, class Traits = char_traits<CharT>>
    requires see below
  class basic_istream_view;

  template<class Val>
    using istream_view = basic_istream_view<Val, char>;

  template<class Val>
    using wistream_view = basic_istream_view<Val, wchar_t>;

  namespace views { template<class T> inline constexpr unspecified istream = unspecified; }

  // [range.enumerate], enumerate view
  template<view View>
    requires see below
  class enumerate_view;                                                             // since C++23

  template<class View>
    constexpr bool enable_borrowed_range<enumerate_view<View>> =                    // since C++23
      enable_borrowed_range<View>;

  namespace views { inline constexpr unspecified enumerate = unspecified; }         // since C++23

  // [range.zip], zip view
  template<input_range... Views>
    requires (view<Views> && ...) && (sizeof...(Views) > 0)
  class zip_view;        // C++23

  template<class... Views>
    inline constexpr bool enable_borrowed_range<zip_view<Views...>> =       // C++23
      (enable_borrowed_range<Views> && ...);

  namespace views { inline constexpr unspecified zip = unspecified; }       // C++23

  // [range.zip.transform], zip transform view
  template<move_constructible F, input_range... Views>
    requires (view<Views> && ...) && (sizeof...(Views) > 0) && is_object_v<F> &&
             regular_invocable<F&, range_reference_t<Views>...> &&
             can-reference<invoke_result_t<F&, range_reference_t<Views>...>>
  class zip_transform_view;                                                         // C++23

  namespace views { inline constexpr unspecified zip_transform = unspecified; }     // C++23

  // [range.adjacent], adjacent view
  template<forward_range V, size_t N>
    requires view<V> && (N > 0)
  class adjacent_view;

  template<class V, size_t N>
    constexpr bool enable_borrowed_range<adjacent_view<V, N>> =
      enable_borrowed_range<V>;

  namespace views {
    template<size_t N>
      constexpr unspecified adjacent = unspecified;
    inline constexpr auto pairwise = adjacent<2>;
  }

  // [range.adjacent.transform], adjacent transform view
  template<forward_range V, move_constructible F, size_t N>
    requires see below
  class adjacent_transform_view;

  namespace views {
    template<size_t N>
      constexpr unspecified adjacent_transform = unspecified;
    inline constexpr auto pairwise_transform = adjacent_transform<2>;
  }

  // [range.as.rvalue]
  template <view V>
    requires input_range<V>
  class as_rvalue_view;                                                     // C++23

  namespace views { inline constexpr unspecified as_rvalue ) unspecified; } // C++23

  [range.chunk.by]
  template<forward_range V, indirect_binary_predicate<iterator_t<V>, iterator_t<V>> Pred>
    requires view<V> && is_object_v<Pred>
  class chunk_by_view;                                                      // C++23

  namespace views { inline constexpr unspecified chunk_by = unspecified; }  // C++23

  // [range.stride.view], stride view
  template<input_range V>
    requires view<V>
  class stride_view;                                                       // C++23

  template<class V>
    constexpr bool enable_borrowed_range<stride_view<V>> =
      enable_borrowed_range<V>;                                            // C++23

  namespace views { inline constexpr unspecified stride = unspecified; }   // C++23
}

namespace std {
  namespace views = ranges::views;

  template<class T> struct tuple_size;
  template<size_t I, class T> struct tuple_element;

  template<class I, class S, ranges::subrange_kind K>
  struct tuple_size<ranges::subrange<I, S, K>>
    : integral_constant<size_t, 2> {};

  template<class I, class S, ranges::subrange_kind K>
  struct tuple_element<0, ranges::subrange<I, S, K>> {
    using type = I;
  };

  template<class I, class S, ranges::subrange_kind K>
  struct tuple_element<1, ranges::subrange<I, S, K>> {
    using type = S;
  };

  template<class I, class S, ranges::subrange_kind K>
  struct tuple_element<0, const ranges::subrange<I, S, K>> {
    using type = I;
  };

  template<class I, class S, ranges::subrange_kind K>
  struct tuple_element<1, const ranges::subrange<I, S, K>> {
    using type = S;
  };

  struct from_range_t { explicit from_range_t() = default; };  // Since C++23
  inline constexpr from_range_t from_range{};                  // Since C++23
}
*/

#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
#  include <__cxx03/__config>
#else
#  include <__config>

#  if _LIBCPP_STD_VER >= 20
#    include <__ranges/access.h>
#    include <__ranges/all.h>
#    include <__ranges/common_view.h>
#    include <__ranges/concepts.h>
#    include <__ranges/counted.h>
#    include <__ranges/dangling.h>
#    include <__ranges/data.h>
#    include <__ranges/drop_view.h>
#    include <__ranges/drop_while_view.h>
#    include <__ranges/elements_of.h>
#    include <__ranges/elements_view.h>
#    include <__ranges/empty.h>
#    include <__ranges/empty_view.h>
#    include <__ranges/enable_borrowed_range.h>
#    include <__ranges/enable_view.h>
#    include <__ranges/filter_view.h>
#    include <__ranges/iota_view.h>
#    include <__ranges/join_view.h>
#    include <__ranges/lazy_split_view.h>
#    include <__ranges/rbegin.h>
#    include <__ranges/ref_view.h>
#    include <__ranges/rend.h>
#    include <__ranges/reverse_view.h>
#    include <__ranges/single_view.h>
#    include <__ranges/size.h>
#    include <__ranges/split_view.h>
#    include <__ranges/subrange.h>
#    include <__ranges/take_view.h>
#    include <__ranges/take_while_view.h>
#    include <__ranges/transform_view.h>
#    include <__ranges/view_interface.h>
#    include <__ranges/views.h>

#    if _LIBCPP_HAS_LOCALIZATION
#      include <__ranges/istream_view.h>
#    endif
#  endif

#  if _LIBCPP_STD_VER >= 23
#    include <__ranges/adjacent_transform_view.h>
#    include <__ranges/adjacent_view.h>
#    include <__ranges/as_rvalue_view.h>
#    include <__ranges/chunk_by_view.h>
#    include <__ranges/enumerate_view.h>
#    include <__ranges/from_range.h>
#    include <__ranges/join_with_view.h>
#    include <__ranges/repeat_view.h>
#    include <__ranges/stride_view.h>
#    include <__ranges/to.h>
#    include <__ranges/zip_transform_view.h>
#    include <__ranges/zip_view.h>
#  endif

#  if _LIBCPP_STD_VER >= 26
#    include <__ranges/concat_view.h>
#  endif

#  include <version>

// standard-mandated includes

// [ranges.syn]
#  include <compare>
#  include <initializer_list>
#  include <iterator>

// [tuple.helper]
#  include <__tuple/tuple_element.h>
#  include <__tuple/tuple_size.h>

#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#    pragma GCC system_header
#  endif

#  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER >= 20 && _LIBCPP_STD_VER <= 23
#    include <optional>
#  endif
#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)

#endif // _LIBCPP_RANGES