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//===----------------------------------------------------------------------===//
//
// 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___ALGORITHM_UNWRAP_RANGE_H
#define _LIBCPP___ALGORITHM_UNWRAP_RANGE_H
#include <__algorithm/unwrap_iter.h>
#include <__concepts/constructible.h>
#include <__config>
#include <__iterator/concepts.h>
#include <__iterator/next.h>
#include <__utility/declval.h>
#include <__utility/move.h>
#include <__utility/pair.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
// __unwrap_range and __rewrap_range are used to unwrap ranges which may have different iterator and sentinel types.
// __unwrap_iter and __rewrap_iter don't work for this, because they assume that the iterator and sentinel have
// the same type. __unwrap_range tries to get two iterators and then forward to __unwrap_iter.
#if _LIBCPP_STD_VER > 17
template <class _Iter, class _Sent>
struct __unwrap_range_impl {
_LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __sent)
requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>
{
auto __last = ranges::next(__first, __sent);
return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))};
}
_LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Sent __last) {
return pair{std::move(__first), std::move(__last)};
}
_LIBCPP_HIDE_FROM_ABI static constexpr auto
__rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(__orig_iter)) __iter)
requires random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>
{
return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
}
_LIBCPP_HIDE_FROM_ABI static constexpr auto __rewrap(const _Iter&, _Iter __iter)
requires (!(random_access_iterator<_Iter> && sized_sentinel_for<_Sent, _Iter>))
{
return __iter;
}
};
template <class _Iter>
struct __unwrap_range_impl<_Iter, _Iter> {
_LIBCPP_HIDE_FROM_ABI static constexpr auto __unwrap(_Iter __first, _Iter __last) {
return pair{std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last))};
}
_LIBCPP_HIDE_FROM_ABI static constexpr auto
__rewrap(_Iter __orig_iter, decltype(std::__unwrap_iter(__orig_iter)) __iter) {
return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
}
};
template <class _Iter, class _Sent>
_LIBCPP_HIDE_FROM_ABI constexpr auto __unwrap_range(_Iter __first, _Sent __last) {
return __unwrap_range_impl<_Iter, _Sent>::__unwrap(std::move(__first), std::move(__last));
}
template <
class _Sent,
class _Iter,
class _Unwrapped = decltype(std::__unwrap_range(std::declval<_Iter>(), std::declval<_Sent>()))>
_LIBCPP_HIDE_FROM_ABI constexpr _Iter __rewrap_range(_Iter __orig_iter, _Unwrapped __iter) {
return __unwrap_range_impl<_Iter, _Sent>::__rewrap(std::move(__orig_iter), std::move(__iter));
}
#else // _LIBCPP_STD_VER > 17
template <class _Iter, class _Unwrapped = decltype(std::__unwrap_iter(std::declval<_Iter>()))>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR pair<_Unwrapped, _Unwrapped> __unwrap_range(_Iter __first, _Iter __last) {
return std::make_pair(std::__unwrap_iter(std::move(__first)), std::__unwrap_iter(std::move(__last)));
}
template <class _Iter, class _Unwrapped = decltype(std::__unwrap_iter(std::declval<_Iter>()))>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Iter __rewrap_range(_Iter __orig_iter, _Unwrapped __iter) {
return std::__rewrap_iter(std::move(__orig_iter), std::move(__iter));
}
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_UNWRAP_RANGE_H