95827e1b9f
PR libstdc++/108362 libstdc++-v3/ChangeLog: * include/std/ranges (__detail::__can_single_view): New concept. (_Single::operator()): Constrain it. Move [[nodiscard]] to the end of the function declarator. (__detail::__can_iota_view): New concept. (_Iota::operator()): Constrain it. Move [[nodiscard]] to the end of the function declarator. (__detail::__can_istream_view): New concept. (_Istream::operator()): Constrain it. Move [[nodiscard]] to the end of the function declarator. * testsuite/std/ranges/iota/iota_view.cc (test07): New test. * testsuite/std/ranges/istream_view.cc (test08): New test. * testsuite/std/ranges/single_view.cc (test07): New test.
135 lines
3.3 KiB
C++
135 lines
3.3 KiB
C++
// Copyright (C) 2019-2023 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// { dg-options "-std=gnu++2a" }
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// { dg-do run { target c++2a } }
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#include <ranges>
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#include <utility> // as_const
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#include <testsuite_hooks.h>
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void
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test01()
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{
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std::ranges::single_view s{4};
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static_assert(std::same_as<std::ranges::range_value_t<decltype(s)>, int>);
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static_assert(std::ranges::size(s) == 1);
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int count = 0;
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for (auto i : s)
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++count;
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VERIFY(count == 1);
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VERIFY(*std::ranges::begin(s) == 4);
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}
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void
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test02()
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{
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std::ranges::single_view<long> s2;
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static_assert(std::same_as<std::ranges::range_value_t<decltype(s2)>, long>);
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static_assert(std::ranges::size(s2) == 1);
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int count = 0;
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for (auto l : s2)
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++count;
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VERIFY(count == 1);
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VERIFY(*std::ranges::begin(s2) == 0L);
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}
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void
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test03()
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{
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auto s3 = std::ranges::views::single('a');
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static_assert(std::same_as<std::ranges::range_value_t<decltype(s3)>, char>);
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static_assert(std::ranges::size(s3) == 1);
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VERIFY(*std::ranges::begin(s3) == 'a');
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}
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void
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test04()
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{
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// PR libstdc++/100475
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struct A {
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A() = default;
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A(int, int) { }
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A(std::initializer_list<int>) = delete;
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void operator&() const = delete;
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};
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std::ranges::single_view<A> s(std::in_place, 0, 0);
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s.data();
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std::as_const(s).data();
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}
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void
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test05()
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{
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int i = 0;
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static_assert(noexcept(std::ranges::single_view<int>()));
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static_assert(noexcept(std::ranges::single_view<int>(i)));
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static_assert(noexcept(std::ranges::single_view<int>(1)));
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static_assert(noexcept(std::ranges::single_view<int>(std::in_place, 2)));
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static_assert(noexcept(std::ranges::views::single(i)));
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auto s = std::ranges::views::single(i);
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static_assert(noexcept(s.begin()));
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static_assert(noexcept(s.end()));
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static_assert(noexcept(s.size()));
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static_assert(noexcept(s.data()));
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static_assert(noexcept(s.empty())); // view_interface::empty()
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const auto cs = s;
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static_assert(noexcept(cs.begin()));
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static_assert(noexcept(cs.end()));
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static_assert(noexcept(cs.size()));
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static_assert(noexcept(cs.data()));
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static_assert(noexcept(cs.empty())); // view_interface::empty()
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}
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void
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test06()
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{
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// PR libstdc++/100475 comment #7
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struct S {
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S() = default;
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S(std::initializer_list<S>) = delete;
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S(const S&) {}
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};
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S obj;
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auto x = std::views::single(obj);
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auto y = std::views::single(std::move(obj));
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}
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template<auto single = std::views::single>
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void
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test07()
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{
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// Verify SFINAE behavior.
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struct uncopyable {
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uncopyable();
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uncopyable(const uncopyable&) = delete;
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};
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static_assert(!requires { single(uncopyable{}); });
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}
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int main()
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{
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test01();
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test02();
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test03();
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test04();
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test05();
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test06();
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test07();
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}
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