llvm-project/libcxx/include/__ranges/common_view.h

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// -*- 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_COMMON_VIEW_H
#define _LIBCPP___RANGES_COMMON_VIEW_H
#include <__config>
#include <__iterator/common_iterator.h>
#include <__iterator/iterator_traits.h>
#include <__ranges/access.h>
#include <__ranges/all.h>
#include <__ranges/concepts.h>
#include <__ranges/enable_borrowed_range.h>
#include <__ranges/size.h>
#include <__ranges/view_interface.h>
#include <__utility/move.h>
#include <concepts>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if !defined(_LIBCPP_HAS_NO_RANGES)
namespace ranges {
template<view _View>
requires (!common_range<_View> && copyable<iterator_t<_View>>)
class common_view : public view_interface<common_view<_View>> {
_View __base_ = _View();
public:
_LIBCPP_HIDE_FROM_ABI
common_view() requires default_initializable<_View> = default;
_LIBCPP_HIDE_FROM_ABI
constexpr explicit common_view(_View __v) : __base_(_VSTD::move(__v)) { }
_LIBCPP_HIDE_FROM_ABI
constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
_LIBCPP_HIDE_FROM_ABI
constexpr _View base() && { return _VSTD::move(__base_); }
_LIBCPP_HIDE_FROM_ABI
constexpr auto begin() {
if constexpr (random_access_range<_View> && sized_range<_View>)
return ranges::begin(__base_);
else
return common_iterator<iterator_t<_View>, sentinel_t<_View>>(ranges::begin(__base_));
}
_LIBCPP_HIDE_FROM_ABI
constexpr auto begin() const requires range<const _View> {
if constexpr (random_access_range<const _View> && sized_range<const _View>)
return ranges::begin(__base_);
else
return common_iterator<iterator_t<const _View>, sentinel_t<const _View>>(ranges::begin(__base_));
}
_LIBCPP_HIDE_FROM_ABI
constexpr auto end() {
if constexpr (random_access_range<_View> && sized_range<_View>)
return ranges::begin(__base_) + ranges::size(__base_);
else
return common_iterator<iterator_t<_View>, sentinel_t<_View>>(ranges::end(__base_));
}
_LIBCPP_HIDE_FROM_ABI
constexpr auto end() const requires range<const _View> {
if constexpr (random_access_range<const _View> && sized_range<const _View>)
return ranges::begin(__base_) + ranges::size(__base_);
else
return common_iterator<iterator_t<const _View>, sentinel_t<const _View>>(ranges::end(__base_));
}
_LIBCPP_HIDE_FROM_ABI
constexpr auto size() requires sized_range<_View> {
return ranges::size(__base_);
}
_LIBCPP_HIDE_FROM_ABI
constexpr auto size() const requires sized_range<const _View> {
return ranges::size(__base_);
}
};
template<class _Range>
common_view(_Range&&)
-> common_view<views::all_t<_Range>>;
template<class _View>
inline constexpr bool enable_borrowed_range<common_view<_View>> = enable_borrowed_range<_View>;
} // namespace ranges
#endif // !defined(_LIBCPP_HAS_NO_RANGES)
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___RANGES_COMMON_VIEW_H