libcxx/test/std/containers/views/mdspan/layout_stride/stride.pass.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-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
  10
  11 // <mdspan>
  12
  13 // constexpr index_type stride(rank_type i) const noexcept;
  14 //
  15 //   Constraints: extents_type::rank() > 0 is true.
  16 //
  17 //   Preconditions: i < extents_type::rank() is true.
  18 //
  19 //   Returns: extents().rev-prod-of-extents(i).
  20
  21 #include <mdspan>
  22 #include <array>
  23 #include <cassert>
  24 #include <cstdint>
  25 #include <cstdio>
  26 #include <span> // dynamic_extent
  27
  28 #include "test_macros.h"
  29
  30 template <class E, class... Args>
  31 constexpr void test_stride(std::array<typename E::index_type, E::rank()> strides, Args... args) {
  32   using M = std::layout_stride::mapping<E>;
  33   M m(E(args...), strides);
  34
  35   ASSERT_NOEXCEPT(m.stride(0));
  36   for (size_t r = 0; r < E::rank(); r++)
  37     assert(strides[r] == m.stride(r));
  38
  39   ASSERT_NOEXCEPT(m.strides());
  40   auto strides_out = m.strides();
  41   static_assert(std::is_same_v<decltype(strides_out), std::array<typename E::index_type, E::rank()>>);
  42   for (size_t r = 0; r < E::rank(); r++)
  43     assert(strides[r] == strides_out[r]);
  44 }
  45
  46 constexpr bool test() {
  47   constexpr size_t D = std::dynamic_extent;
  48   test_stride<std::extents<unsigned, D>>(std::array<unsigned, 1>{1}, 7);
  49   test_stride<std::extents<unsigned, 7>>(std::array<unsigned, 1>{1});
  50   test_stride<std::extents<unsigned, 7, 8>>(std::array<unsigned, 2>{8, 1});
  51   test_stride<std::extents<int64_t, D, 8, D, D>>(std::array<int64_t, 4>{720, 90, 10, 1}, 7, 9, 10);
  52   return true;
  53 }
  54
  55 int main(int, char**) {
  56   test();
  57   static_assert(test());
  58   return 0;
  59 }