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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_ISTREAM_VIEW_H
#define _LIBCPP___RANGES_ISTREAM_VIEW_H
#include <__concepts/constructible.h>
#include <__concepts/derived_from.h>
#include <__concepts/movable.h>
#include <__config>
#include <__iterator/default_sentinel.h>
#include <__iterator/iterator_traits.h>
#include <__memory/addressof.h>
#include <__ranges/view_interface.h>
#include <__type_traits/remove_cvref.h>
#include <__utility/forward.h>
#include <cstddef>
#include <iosfwd>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
#if _LIBCPP_STD_VER >= 20
_LIBCPP_BEGIN_NAMESPACE_STD
namespace ranges {
template <class _Val, class _CharT, class _Traits>
concept __stream_extractable = requires(basic_istream<_CharT, _Traits>& __is, _Val& __t) { __is >> __t; };
template <movable _Val, class _CharT, class _Traits = char_traits<_CharT>>
requires default_initializable<_Val> && __stream_extractable<_Val, _CharT, _Traits>
class basic_istream_view : public view_interface<basic_istream_view<_Val, _CharT, _Traits>> {
class __iterator;
public:
_LIBCPP_HIDE_FROM_ABI constexpr explicit basic_istream_view(basic_istream<_CharT, _Traits>& __stream)
: __stream_(std::addressof(__stream)) {}
_LIBCPP_HIDE_FROM_ABI constexpr auto begin() {
*__stream_ >> __value_;
return __iterator{*this};
}
_LIBCPP_HIDE_FROM_ABI constexpr default_sentinel_t end() const noexcept { return default_sentinel; }
private:
basic_istream<_CharT, _Traits>* __stream_;
_LIBCPP_NO_UNIQUE_ADDRESS _Val __value_ = _Val();
};
template <movable _Val, class _CharT, class _Traits>
requires default_initializable<_Val> && __stream_extractable<_Val, _CharT, _Traits>
class basic_istream_view<_Val, _CharT, _Traits>::__iterator {
public:
using iterator_concept = input_iterator_tag;
using difference_type = ptrdiff_t;
using value_type = _Val;
_LIBCPP_HIDE_FROM_ABI constexpr explicit __iterator(
basic_istream_view<_Val, _CharT, _Traits>& __parent) noexcept
: __parent_(std::addressof(__parent)) {}
__iterator(const __iterator&) = delete;
_LIBCPP_HIDE_FROM_ABI __iterator(__iterator&&) = default;
__iterator& operator=(const __iterator&) = delete;
_LIBCPP_HIDE_FROM_ABI __iterator& operator=(__iterator&&) = default;
_LIBCPP_HIDE_FROM_ABI __iterator& operator++() {
*__parent_->__stream_ >> __parent_->__value_;
return *this;
}
_LIBCPP_HIDE_FROM_ABI void operator++(int) { ++*this; }
_LIBCPP_HIDE_FROM_ABI _Val& operator*() const { return __parent_->__value_; }
_LIBCPP_HIDE_FROM_ABI friend bool operator==(const __iterator& __x, default_sentinel_t) {
return !*__x.__get_parent_stream();
}
private:
basic_istream_view<_Val, _CharT, _Traits>* __parent_;
_LIBCPP_HIDE_FROM_ABI constexpr basic_istream<_CharT, _Traits>* __get_parent_stream() const {
return __parent_->__stream_;
}
};
template <class _Val>
using istream_view = basic_istream_view<_Val, char>;
# ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
template <class _Val>
using wistream_view = basic_istream_view<_Val, wchar_t>;
# endif
namespace views {
namespace __istream {
// clang-format off
template <class _Tp>
struct __fn {
template <class _Up, class _UnCVRef = remove_cvref_t<_Up>>
requires derived_from<_UnCVRef, basic_istream<typename _UnCVRef::char_type,
typename _UnCVRef::traits_type>>
_LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Up&& __u) const
noexcept(noexcept(basic_istream_view<_Tp, typename _UnCVRef::char_type,
typename _UnCVRef::traits_type>(std::forward<_Up>(__u))))
-> decltype( basic_istream_view<_Tp, typename _UnCVRef::char_type,
typename _UnCVRef::traits_type>(std::forward<_Up>(__u)))
{ return basic_istream_view<_Tp, typename _UnCVRef::char_type,
typename _UnCVRef::traits_type>(std::forward<_Up>(__u));
}
};
// clang-format on
} // namespace __istream
inline namespace __cpo {
template <class _Tp>
inline constexpr auto istream = __istream::__fn<_Tp>{};
} // namespace __cpo
} // namespace views
} // namespace ranges
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_STD_VER >= 20
#endif // _LIBCPP___RANGES_ISTREAM_VIEW_H
|
