mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-12 09:17:53 +00:00
104 lines
3.1 KiB
C++
104 lines
3.1 KiB
C++
// -*- 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_SINGLE_VIEW_H
|
|
#define _LIBCPP___RANGES_SINGLE_VIEW_H
|
|
|
|
#include <__concepts/constructible.h>
|
|
#include <__config>
|
|
#include <__ranges/copyable_box.h>
|
|
#include <__ranges/range_adaptor.h>
|
|
#include <__ranges/view_interface.h>
|
|
#include <__type_traits/decay.h>
|
|
#include <__type_traits/is_object.h>
|
|
#include <__utility/forward.h>
|
|
#include <__utility/in_place.h>
|
|
#include <__utility/move.h>
|
|
#include <cstddef>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
# pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
#if _LIBCPP_STD_VER >= 20
|
|
|
|
namespace ranges {
|
|
template<copy_constructible _Tp>
|
|
requires is_object_v<_Tp>
|
|
class single_view : public view_interface<single_view<_Tp>> {
|
|
__copyable_box<_Tp> __value_;
|
|
|
|
public:
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
single_view() requires default_initializable<_Tp> = default;
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr explicit single_view(const _Tp& __t) : __value_(in_place, __t) {}
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr explicit single_view(_Tp&& __t) : __value_(in_place, std::move(__t)) {}
|
|
|
|
template<class... _Args>
|
|
requires constructible_from<_Tp, _Args...>
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr explicit single_view(in_place_t, _Args&&... __args)
|
|
: __value_{in_place, std::forward<_Args>(__args)...} {}
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr _Tp* begin() noexcept { return data(); }
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr const _Tp* begin() const noexcept { return data(); }
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr _Tp* end() noexcept { return data() + 1; }
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr const _Tp* end() const noexcept { return data() + 1; }
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
static constexpr size_t size() noexcept { return 1; }
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr _Tp* data() noexcept { return __value_.operator->(); }
|
|
|
|
_LIBCPP_HIDE_FROM_ABI
|
|
constexpr const _Tp* data() const noexcept { return __value_.operator->(); }
|
|
};
|
|
|
|
template<class _Tp>
|
|
single_view(_Tp) -> single_view<_Tp>;
|
|
|
|
namespace views {
|
|
namespace __single_view {
|
|
|
|
struct __fn : __range_adaptor_closure<__fn> {
|
|
template<class _Range>
|
|
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI
|
|
constexpr auto operator()(_Range&& __range) const
|
|
noexcept(noexcept(single_view<decay_t<_Range&&>>(std::forward<_Range>(__range))))
|
|
-> decltype( single_view<decay_t<_Range&&>>(std::forward<_Range>(__range)))
|
|
{ return single_view<decay_t<_Range&&>>(std::forward<_Range>(__range)); }
|
|
};
|
|
} // namespace __single_view
|
|
|
|
inline namespace __cpo {
|
|
inline constexpr auto single = __single_view::__fn{};
|
|
} // namespace __cpo
|
|
|
|
} // namespace views
|
|
} // namespace ranges
|
|
|
|
#endif // _LIBCPP_STD_VER >= 20
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
#endif // _LIBCPP___RANGES_SINGLE_VIEW_H
|