2f28e1db53
Implement `ranges::stride_view` in libc++. This PR was migrated from Phabricator (https://reviews.llvm.org/D156924). Closes #105198 Co-authored-by: Louis Dionne <ldionne.2@gmail.com> Co-authored-by: A. Jiang <de34@live.cn>
73 lines
2.1 KiB
C++
73 lines
2.1 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, c++20
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// constexpr explicit stride_view(V base, range_difference_t<V> stride)
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#include <cassert>
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#include <ranges>
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#include <type_traits>
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#include <utility>
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#include "test_convertible.h"
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#include "test_iterators.h"
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#include "types.h"
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constexpr bool test() {
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{
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// There is no default ctor for stride_view.
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using View = BasicTestView<cpp17_input_iterator<int*>>;
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static_assert(!std::is_default_constructible_v<std::ranges::stride_view<View>>);
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// Test that the stride_view can only be explicitly constructed.
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static_assert(!test_convertible<std::ranges::stride_view<View>, View, int>());
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}
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{
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int arr[] = {1, 2, 3};
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// Test that what we will stride over is move only.
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using View = MoveOnlyView<cpp17_input_iterator<int*>>;
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static_assert(!std::is_copy_constructible_v<View>);
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static_assert(std::is_move_constructible_v<View>);
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View mov(cpp17_input_iterator<int*>(arr), cpp17_input_iterator<int*>(arr + 3));
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// Because MoveOnlyView is, well, move only, we can test that it is moved
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// from when the stride view is constructed.
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std::ranges::stride_view<View> strided(std::move(mov), 1);
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// While we are here, make sure that the ctor captured the stride.
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assert(strided.stride() == 1);
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}
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{
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// Verify salient properties after construction.
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int arr[] = {10, 20, 30, 40, 50};
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using Base = BasicTestView<int*, int*>;
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auto strided = std::ranges::stride_view(Base(arr, arr + 5), 2);
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assert(strided.stride() == 2);
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assert(*strided.begin() == 10);
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auto it = strided.begin();
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++it;
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assert(*it == 30);
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++it;
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assert(*it == 50);
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++it;
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assert(it == strided.end());
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}
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return true;
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}
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int main(int, char**) {
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test();
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static_assert(test());
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return 0;
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}
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