1// -*- C++ -*-
  2//===----------------------------------------------------------------------===//
  3//
  4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  5// See https://llvm.org/LICENSE.txt for license information.
  6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  7//
  8//===----------------------------------------------------------------------===//
  9
 10#ifndef _LIBCPP___FLAT_SET_RA_ITERATOR_H
 11#define _LIBCPP___FLAT_SET_RA_ITERATOR_H
 12
 13#include "__type_traits/is_same.h"
 14#include <__compare/three_way_comparable.h>
 15#include <__config>
 16#include <__iterator/incrementable_traits.h>
 17#include <__iterator/iterator_traits.h>
 18#include <__type_traits/is_constructible.h>
 19#include <__utility/move.h>
 20
 21#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 22#  pragma GCC system_header
 23#endif
 24
 25_LIBCPP_PUSH_MACROS
 26#include <__undef_macros>
 27
 28#if _LIBCPP_STD_VER >= 23
 29
 30_LIBCPP_BEGIN_NAMESPACE_STD
 31
 32/**
 33 * __ra_iterator is a random access iterator that wraps an underlying iterator.
 34 * It also stores the underlying container type in its type so that algorithms
 35 * can optimize based on the underlying container type, and to avoid inadvertently
 36 * mixing iterators coming from different containers..
 37 */
 38template <class _Container, class _Iterator>
 39struct __ra_iterator {
 40private:
 41  _Iterator __iter_;
 42
 43  friend _Container;
 44
 45  // note: checking the concept random_access_iterator does not work for incomplete types
 46  static_assert(_IsSame<typename iterator_traits<_Iterator>::iterator_category, random_access_iterator_tag>::value,
 47                "Underlying iterator must be a random access iterator");
 48
 49public:
 50  using iterator_concept  = random_access_iterator_tag; // deliberately lower contiguous_iterator
 51  using iterator_category = random_access_iterator_tag;
 52  using value_type        = iter_value_t<_Iterator>;
 53  using difference_type   = iter_difference_t<_Iterator>;
 54
 55  _LIBCPP_HIDE_FROM_ABI __ra_iterator()
 56    requires is_default_constructible_v<_Iterator>
 57  = default;
 58
 59  _LIBCPP_HIDE_FROM_ABI explicit constexpr __ra_iterator(_Iterator __iter) : __iter_(std::move(__iter)) {}
 60
 61  _LIBCPP_HIDE_FROM_ABI constexpr _Iterator __base() const noexcept(noexcept(_Iterator(__iter_))) { return __iter_; }
 62
 63  _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator*() const { return *__iter_; }
 64  _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator->() const
 65    requires requires { __iter_.operator->(); }
 66  {
 67    return __iter_.operator->();
 68  }
 69
 70  _LIBCPP_HIDE_FROM_ABI constexpr __ra_iterator& operator++() {
 71    ++__iter_;
 72    return *this;
 73  }
 74
 75  _LIBCPP_HIDE_FROM_ABI constexpr __ra_iterator operator++(int) {
 76    __ra_iterator __tmp(*this);
 77    ++*this;
 78    return __tmp;
 79  }
 80
 81  _LIBCPP_HIDE_FROM_ABI constexpr __ra_iterator& operator--() {
 82    --__iter_;
 83    return *this;
 84  }
 85
 86  _LIBCPP_HIDE_FROM_ABI constexpr __ra_iterator operator--(int) {
 87    __ra_iterator __tmp(*this);
 88    --*this;
 89    return __tmp;
 90  }
 91
 92  _LIBCPP_HIDE_FROM_ABI constexpr __ra_iterator& operator+=(difference_type __x) {
 93    __iter_ += __x;
 94    return *this;
 95  }
 96
 97  _LIBCPP_HIDE_FROM_ABI constexpr __ra_iterator& operator-=(difference_type __x) {
 98    __iter_ -= __x;
 99    return *this;
100  }
101
102  _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator[](difference_type __n) const { return *(*this + __n); }
103
104  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator==(const __ra_iterator& __x, const __ra_iterator& __y) {
105    return __x.__iter_ == __y.__iter_;
106  }
107
108  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<(const __ra_iterator& __x, const __ra_iterator& __y) {
109    return __x.__iter_ < __y.__iter_;
110  }
111
112  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>(const __ra_iterator& __x, const __ra_iterator& __y) {
113    return __y < __x;
114  }
115
116  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator<=(const __ra_iterator& __x, const __ra_iterator& __y) {
117    return !(__y < __x);
118  }
119
120  _LIBCPP_HIDE_FROM_ABI friend constexpr bool operator>=(const __ra_iterator& __x, const __ra_iterator& __y) {
121    return !(__x < __y);
122  }
123
124  _LIBCPP_HIDE_FROM_ABI friend constexpr auto operator<=>(const __ra_iterator& __x, const __ra_iterator& __y)
125    requires three_way_comparable<_Iterator>
126  {
127    return __x.__iter_ <=> __y.__iter_;
128  }
129
130  _LIBCPP_HIDE_FROM_ABI friend constexpr __ra_iterator operator+(const __ra_iterator& __i, difference_type __n) {
131    auto __tmp = __i;
132    __tmp += __n;
133    return __tmp;
134  }
135
136  _LIBCPP_HIDE_FROM_ABI friend constexpr __ra_iterator operator+(difference_type __n, const __ra_iterator& __i) {
137    return __i + __n;
138  }
139
140  _LIBCPP_HIDE_FROM_ABI friend constexpr __ra_iterator operator-(const __ra_iterator& __i, difference_type __n) {
141    auto __tmp = __i;
142    __tmp -= __n;
143    return __tmp;
144  }
145
146  _LIBCPP_HIDE_FROM_ABI friend constexpr difference_type operator-(const __ra_iterator& __x, const __ra_iterator& __y) {
147    return __x.__iter_ - __y.__iter_;
148  }
149};
150
151_LIBCPP_END_NAMESPACE_STD
152
153#endif // _LIBCPP_STD_VER >= 23
154
155_LIBCPP_POP_MACROS
156
157#endif // _LIBCPP___FLAT_SET_RA_ITERATOR_H