119 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++14, c++17, c++2010 11// <mdspan>12 13// namespace std {14// template<class Extents>15// class layout_stride::mapping {16//17// ...18// static constexpr bool is_always_unique() noexcept { return true; }19// static constexpr bool is_always_exhaustive() noexcept { return false; }20// static constexpr bool is_always_strided() noexcept { return true; }21//22// static constexpr bool is_unique() noexcept { return true; }23// static constexpr bool is_exhaustive() noexcept;24// static constexpr bool is_strided() noexcept { return true; }25// ...26// };27// }28//29//30// layout_stride::mapping<E> is a trivially copyable type that models regular for each E.31//32// constexpr bool is_exhaustive() const noexcept;33//34// Returns:35// - true if rank_ is 0.36// - Otherwise, true if there is a permutation P of the integers in the range [0, rank_) such that37// stride(p0) equals 1, and stride(pi) equals stride(pi_1) * extents().extent(pi_1) for i in the38// range [1, rank_), where pi is the ith element of P.39// - Otherwise, false.40 41#include <array>42#include <cassert>43#include <concepts>44#include <cstddef>45#include <mdspan>46#include <type_traits>47 48#include "test_macros.h"49 50template <class E>51constexpr void52test_layout_mapping_stride(E ext, std::array<typename E::index_type, E::rank()> strides, bool exhaustive) {53 using M = std::layout_stride::mapping<E>;54 M m(ext, strides);55 const M c_m = m;56 assert(m.strides() == strides);57 assert(c_m.strides() == strides);58 assert(m.extents() == ext);59 assert(c_m.extents() == ext);60 assert(M::is_unique() == true);61 assert(m.is_exhaustive() == exhaustive);62 assert(c_m.is_exhaustive() == exhaustive);63 assert(M::is_strided() == true);64 assert(M::is_always_unique() == true);65 assert(M::is_always_exhaustive() == false);66 assert(M::is_always_strided() == true);67 68 ASSERT_NOEXCEPT(m.strides());69 ASSERT_NOEXCEPT(c_m.strides());70 ASSERT_NOEXCEPT(m.extents());71 ASSERT_NOEXCEPT(c_m.extents());72 ASSERT_NOEXCEPT(M::is_unique());73 ASSERT_NOEXCEPT(m.is_exhaustive());74 ASSERT_NOEXCEPT(c_m.is_exhaustive());75 ASSERT_NOEXCEPT(M::is_strided());76 ASSERT_NOEXCEPT(M::is_always_unique());77 ASSERT_NOEXCEPT(M::is_always_exhaustive());78 ASSERT_NOEXCEPT(M::is_always_strided());79 80 for (typename E::rank_type r = 0; r < E::rank(); r++) {81 assert(m.stride(r) == strides[r]);82 assert(c_m.stride(r) == strides[r]);83 ASSERT_NOEXCEPT(m.stride(r));84 ASSERT_NOEXCEPT(c_m.stride(r));85 }86 87 typename E::index_type expected_size = 1;88 for (typename E::rank_type r = 0; r < E::rank(); r++) {89 if (ext.extent(r) == 0) {90 expected_size = 0;91 break;92 }93 expected_size += (ext.extent(r) - 1) * static_cast<typename E::index_type>(strides[r]);94 }95 assert(m.required_span_size() == expected_size);96 assert(c_m.required_span_size() == expected_size);97 ASSERT_NOEXCEPT(m.required_span_size());98 ASSERT_NOEXCEPT(c_m.required_span_size());99 100 static_assert(std::is_trivially_copyable_v<M>);101 static_assert(std::regular<M>);102}103 104constexpr bool test() {105 constexpr size_t D = std::dynamic_extent;106 test_layout_mapping_stride(std::extents<int>(), std::array<int, 0>{}, true);107 test_layout_mapping_stride(std::extents<signed char, 4, 5>(), std::array<signed char, 2>{1, 4}, true);108 test_layout_mapping_stride(std::extents<signed char, 4, 5>(), std::array<signed char, 2>{1, 5}, false);109 test_layout_mapping_stride(std::extents<unsigned, D, 4>(7), std::array<unsigned, 2>{20, 2}, false);110 test_layout_mapping_stride(std::extents<size_t, D, D, D, D>(3, 3, 3, 3), std::array<size_t, 4>{3, 1, 9, 27}, true);111 return true;112}113 114int main(int, char**) {115 test();116 static_assert(test());117 return 0;118}119