1//===----------------------------------------------------------------------===//
 2//
 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 4// See https://llvm.org/LICENSE.txt for license information.
 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 6//
 7//===----------------------------------------------------------------------===//
 8
 9#ifndef _LIBCPP___ALGORITHM_UNWRAP_RANGE_H
10#define _LIBCPP___ALGORITHM_UNWRAP_RANGE_H
11
12#include <__algorithm/unwrap_iter.h>
13#include <__concepts/constructible.h>
14#include <__config>
15#include <__iterator/concepts.h>
16#include <__iterator/next.h>
17#include <__utility/declval.h>
18#include <__utility/move.h>
19#include <__utility/pair.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_LIBCPP_BEGIN_NAMESPACE_STD
29
30// __unwrap_range and __rewrap_range are used to unwrap ranges which may have different iterator and sentinel types.
31// __unwrap_iter and __rewrap_iter don't work for this, because they assume that the iterator and sentinel have
32// the same type. __unwrap_range tries to get two iterators and then forward to __unwrap_iter.
33
34#if _LIBCPP_STD_VER >= 20
35template <class _Iter, class _Sent>
36struct __unwrap_range_impl {
37  _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __sent)
38    requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>
39  {
40    auto __last = ranges::next(__first, __sent);
41    return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))};
42  }
43
44  _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __last) {
45    return pair{std::move(__first), std::move(__last)};
46  }
47
48  _LIBCPP_HIDE_FROM_ABI static constexpr auto
49  __rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(std::move(__orig_iter))) __iter)
50    requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>
51  {
52    return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
53  }
54
55  _LIBCPP_HIDE_FROM_ABI static constexpr auto __rewrap(const _Iter&, _Iter __iter)
56    requires(!(random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>))
57  {
58    return __iter;
59  }
60};
61
62template <class _Iter>
63struct __unwrap_range_impl<_Iter, _Iter> {
64  _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Iter __last) {
65    return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))};
66  }
67
68  _LIBCPP_HIDE_FROM_ABI static constexpr auto
69  __rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(__orig_iter)) __iter) {
70    return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
71  }
72};
73
74template <class _Iter, class _Sent>
75_LIBCPP_HIDE_FROM_ABI constexpr auto __unwrap_range(_Iter __first, _Sent __last) {
76  return __unwrap_range_impl<_Iter, _Sent>::__unwrap(std::move(__first), std::move(__last));
77}
78
79template < class _Sent, class _Iter, class _Unwrapped>
80_LIBCPP_HIDE_FROM_ABI constexpr _Iter __rewrap_range(_Iter __orig_iter, _Unwrapped __iter) {
81  return __unwrap_range_impl<_Iter, _Sent>::__rewrap(std::move(__orig_iter), std::move(__iter));
82}
83#else  // _LIBCPP_STD_VER >= 20
84template <class _Iter, class _Unwrapped = decltype(std::__unwrap_iter(std::declval<_Iter>()))>
85_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR pair<_Unwrapped, _Unwrapped> __unwrap_range(_Iter __first, _Iter __last) {
86  return std::make_pair(std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last)));
87}
88
89template <class _Iter, class _Unwrapped>
90_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Iter __rewrap_range(_Iter __orig_iter, _Unwrapped __iter) {
91  return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
92}
93#endif // _LIBCPP_STD_VER >= 20
94
95_LIBCPP_END_NAMESPACE_STD
96
97_LIBCPP_POP_MACROS
98
99#endif // _LIBCPP___ALGORITHM_UNWRAP_RANGE_H