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_BEGIN_NAMESPACE_STD 26 27 // __unwrap_range and __rewrap_range are used to unwrap ranges which may have different iterator and sentinel types. 28 // __unwrap_iter and __rewrap_iter don't work for this, because they assume that the iterator and sentinel have 29 // the same type. __unwrap_range tries to get two iterators and then forward to __unwrap_iter. 30 31 #if _LIBCPP_STD_VER > 17 32 template <class _Iter, class _Sent> 33 struct __unwrap_range_impl { 34 _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __sent) 35 requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter> 36 { 37 auto __last = ranges::next(__first, __sent); 38 return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))}; 39 } 40 41 _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __last) { 42 return pair{std::move(__first), std::move(__last)}; 43 } 44 45 _LIBCPP_HIDE_FROM_ABI static constexpr auto 46 __rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(__orig_iter)) __iter) 47 requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter> 48 { 49 return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter)); 50 } 51 52 _LIBCPP_HIDE_FROM_ABI static constexpr auto __rewrap(const _Iter&, _Iter __iter) 53 requires (!(random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>)) 54 { 55 return __iter; 56 } 57 }; 58 59 template <class _Iter> 60 struct __unwrap_range_impl<_Iter, _Iter> { 61 _LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Iter __last) { 62 return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))}; 63 } 64 65 _LIBCPP_HIDE_FROM_ABI static constexpr auto 66 __rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(__orig_iter)) __iter) { 67 return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter)); 68 } 69 }; 70 71 template <class _Iter, class _Sent> 72 _LIBCPP_HIDE_FROM_ABI constexpr auto __unwrap_range(_Iter __first, _Sent __last) { 73 return __unwrap_range_impl<_Iter, _Sent>::__unwrap(std::move(__first), std::move(__last)); 74 } 75 76 template < 77 class _Sent, 78 class _Iter, 79 class _Unwrapped = decltype(std::__unwrap_range(std::declval<_Iter>(), std::declval<_Sent>()))> 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 > 17 84 template <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 89 template <class _Iter, class _Unwrapped = decltype(std::__unwrap_iter(std::declval<_Iter>()))> 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 > 17 94 95 _LIBCPP_END_NAMESPACE_STD 96 97 #endif // _LIBCPP___ALGORITHM_UNWRAP_RANGE_H 98