134 lines
5.5 KiB
C++
134 lines
5.5 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: c++03, c++11, c++14, c++17
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// UNSUPPORTED: libcpp-no-concepts
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// UNSUPPORTED: libcpp-has-no-incomplete-ranges
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// template<class R>
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// concept viewable_range;
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#include <ranges>
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#include <type_traits>
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#include "test_iterators.h"
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#include "test_range.h"
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// The constraints we have in viewable_range are:
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// range<T>
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// view<remove_cvref_t<T>>
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// constructible_from<remove_cvref_t<T>, T>
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// borrowed_range<T>
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//
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// We test all the relevant combinations of satisfying/not satisfying those constraints.
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// viewable_range<T> is not satisfied for (range=false, view=*, constructible_from=*, borrowed_range=*)
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struct T1 { };
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static_assert(!std::ranges::range<T1>);
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static_assert(!std::ranges::viewable_range<T1>);
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static_assert(!std::ranges::viewable_range<T1&>);
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static_assert(!std::ranges::viewable_range<T1 const>);
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static_assert(!std::ranges::viewable_range<T1 const&>);
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// viewable_range<T> is satisfied for (range=true, view=true, constructible_from=true, borrowed_range=true)
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struct T2 : test_range<cpp20_input_iterator>, std::ranges::view_base {
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T2(T2 const&) = default;
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};
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template<> constexpr bool std::ranges::enable_borrowed_range<T2> = true;
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static_assert(std::ranges::range<T2>);
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static_assert(std::ranges::view<T2>);
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static_assert(std::constructible_from<T2, T2>);
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static_assert(std::ranges::borrowed_range<T2>);
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static_assert(std::ranges::viewable_range<T2>);
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static_assert(std::ranges::viewable_range<T2&>);
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static_assert(std::ranges::viewable_range<T2 const>);
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static_assert(std::ranges::viewable_range<T2 const&>);
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// viewable_range<T> is satisfied for (range=true, view=true, constructible_from=true, borrowed_range=false)
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struct T3 : test_range<cpp20_input_iterator>, std::ranges::view_base {
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T3(T3 const&) = default;
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};
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template<> constexpr bool std::ranges::enable_borrowed_range<T3> = false;
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static_assert(std::ranges::range<T3>);
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static_assert(std::ranges::view<T3>);
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static_assert(std::constructible_from<T3, T3>);
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static_assert(!std::ranges::borrowed_range<T3>);
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static_assert(std::ranges::viewable_range<T3>);
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static_assert(std::ranges::viewable_range<T3&>);
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static_assert(std::ranges::viewable_range<T3 const>);
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static_assert(std::ranges::viewable_range<T3 const&>);
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// viewable_range<T> is not satisfied for (range=true, view=true, constructible_from=false, borrowed_range=true)
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struct T4 : test_range<cpp20_input_iterator>, std::ranges::view_base {
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T4(T4 const&) = delete;
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T4(T4&&) = default; // necessary to model view
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T4& operator=(T4&&) = default; // necessary to model view
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};
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static_assert(std::ranges::range<T4 const&>);
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static_assert(std::ranges::view<std::remove_cvref_t<T4 const&>>);
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static_assert(!std::constructible_from<std::remove_cvref_t<T4 const&>, T4 const&>);
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static_assert(std::ranges::borrowed_range<T4 const&>);
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static_assert(!std::ranges::viewable_range<T4 const&>);
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// A type that satisfies (range=true, view=true, constructible_from=false, borrowed_range=false) can't be formed
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// viewable_range<T> is satisfied for (range=true, view=false, constructible_from=true, borrowed_range=true)
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struct T5 : test_range<cpp20_input_iterator> { };
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template<> constexpr bool std::ranges::enable_borrowed_range<T5> = true;
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static_assert(std::ranges::range<T5>);
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static_assert(!std::ranges::view<T5>);
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static_assert(std::constructible_from<T5, T5>);
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static_assert(std::ranges::borrowed_range<T5>);
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static_assert(std::ranges::viewable_range<T5>);
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// viewable_range<T> is not satisfied for (range=true, view=false, constructible_from=true, borrowed_range=false)
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struct T6 : test_range<cpp20_input_iterator> { };
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template<> constexpr bool std::ranges::enable_borrowed_range<T6> = false;
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static_assert(std::ranges::range<T6>);
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static_assert(!std::ranges::view<T6>);
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static_assert(std::constructible_from<T6, T6>);
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static_assert(!std::ranges::borrowed_range<T6>);
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static_assert(!std::ranges::viewable_range<T6>);
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// viewable_range<T> is satisfied for (range=true, view=false, constructible_from=false, borrowed_range=true)
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struct T7 : test_range<cpp20_input_iterator> {
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T7(T7 const&) = delete;
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};
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static_assert(std::ranges::range<T7&>);
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static_assert(!std::ranges::view<std::remove_cvref_t<T7&>>);
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static_assert(!std::constructible_from<std::remove_cvref_t<T7&>, T7&>);
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static_assert(std::ranges::borrowed_range<T7&>);
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static_assert(std::ranges::viewable_range<T7&>);
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// A type that satisfies (range=true, view=false, constructible_from=false, borrowed_range=false) can't be formed
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struct T8 : test_range<cpp20_input_iterator> {
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T8(T8 const&) = delete;
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};
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static_assert(std::ranges::range<T8>);
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static_assert(!std::ranges::view<T8>);
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static_assert(!std::constructible_from<T8, T8>);
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static_assert(!std::ranges::borrowed_range<T8>);
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static_assert(!std::ranges::viewable_range<T8>);
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// Test with a few degenerate types
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static_assert(!std::ranges::viewable_range<void>);
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static_assert(!std::ranges::viewable_range<int>);
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static_assert(!std::ranges::viewable_range<int (*)(char)>);
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static_assert(!std::ranges::viewable_range<int[]>);
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static_assert(!std::ranges::viewable_range<int[10]>);
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static_assert(!std::ranges::viewable_range<int(&)[]>); // unbounded array is not a range
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static_assert( std::ranges::viewable_range<int(&)[10]>);
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