96a509bca2
implement `std::ranges::basic_istream_view` and `std::views::istream`. Although the view itself is constexpr, the constructor argument is a base class std::istream where its ctor/dtor are not constexpr. So no tests are performed in constexpr Differential Revision: https://reviews.llvm.org/D133317
74 lines
2.4 KiB
C++
74 lines
2.4 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: no-localization
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// concept checking istream_view
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#include <istream>
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#include <ranges>
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#include "test_macros.h"
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template <class Val, class CharT, class Traits = std::char_traits<CharT>>
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concept HasIstreamView = requires { typename std::ranges::basic_istream_view<Val, CharT, Traits>; };
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static_assert(HasIstreamView<int, char>);
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#ifndef TEST_HAS_NO_WIDE_CHARACTERS
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static_assert(HasIstreamView<int, wchar_t>);
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#endif
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// Unmovable Val
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struct Unmovable {
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Unmovable() = default;
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Unmovable(Unmovable&&) = delete;
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template <class CharT>
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friend std::basic_istream<CharT>& operator>>(std::basic_istream<CharT>& x, const Unmovable&) {
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return x;
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}
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};
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static_assert(!HasIstreamView<Unmovable, char>);
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#ifndef TEST_HAS_NO_WIDE_CHARACTERS
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static_assert(!HasIstreamView<Unmovable, wchar_t>);
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#endif
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// !default_initializable<Val>
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struct NoDefaultCtor {
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NoDefaultCtor(int) {}
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friend std::istream& operator>>(std::istream& x, const NoDefaultCtor&) { return x; }
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};
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static_assert(!HasIstreamView<NoDefaultCtor, char>);
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#ifndef TEST_HAS_NO_WIDE_CHARACTERS
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static_assert(!HasIstreamView<NoDefaultCtor, wchar_t>);
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#endif
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// !stream-extractable<Val, CharT, Traits>
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struct Foo {};
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static_assert(!HasIstreamView<Foo, char>);
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#ifndef TEST_HAS_NO_WIDE_CHARACTERS
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static_assert(!HasIstreamView<Foo, wchar_t>);
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#endif
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template <class T>
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concept OnlyInputRange = std::ranges::input_range<T> && !std::ranges::forward_range<T>;
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static_assert(OnlyInputRange<std::ranges::istream_view<int>>);
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static_assert(OnlyInputRange<std::ranges::istream_view<long>>);
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static_assert(OnlyInputRange<std::ranges::istream_view<double>>);
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static_assert(OnlyInputRange<std::ranges::istream_view<char>>);
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#ifndef TEST_HAS_NO_WIDE_CHARACTERS
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static_assert(OnlyInputRange<std::ranges::wistream_view<int>>);
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static_assert(OnlyInputRange<std::ranges::wistream_view<long>>);
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static_assert(OnlyInputRange<std::ranges::wistream_view<double>>);
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static_assert(OnlyInputRange<std::ranges::wistream_view<wchar_t>>);
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#endif
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