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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
// <mdspan>
// template<class OtherExtents>
// constexpr explicit(!is_convertible_v<OtherExtents, extents_type>)
// mapping(const layout_right::mapping<OtherExtents>&) noexcept;
// Constraints:
// - extents_type::rank() <= 1 is true, and
// - is_constructible_v<extents_type, OtherExtents> is true.
//
// Preconditions: other.required_span_size() is representable as a value of type index_type
#include <mdspan>
#include <type_traits>
#include <cassert>
#include <limits>
#include "test_macros.h"
template <class To, class From>
constexpr void test_implicit_conversion(To dest, From src) {
assert(dest.extents() == src.extents());
}
template <bool implicit, class ToE, class FromE>
constexpr void test_conversion(FromE src_exts) {
using To = std::layout_left::mapping<ToE>;
using From = std::layout_right::mapping<FromE>;
From src(src_exts);
ASSERT_NOEXCEPT(To(src));
To dest(src);
assert(dest.extents() == src.extents());
if constexpr (implicit) {
dest = src;
assert(dest.extents() == src.extents());
test_implicit_conversion<To, From>(src, src);
}
}
template <class T1, class T2>
constexpr void test_conversion() {
constexpr size_t D = std::dynamic_extent;
constexpr bool idx_convertible =
static_cast<size_t>(std::numeric_limits<T1>::max()) >= static_cast<size_t>(std::numeric_limits<T2>::max());
// clang-format off
test_conversion<idx_convertible && true, std::extents<T1>>(std::extents<T2>());
test_conversion<idx_convertible && true, std::extents<T1, D>>(std::extents<T2, D>(5));
test_conversion<idx_convertible && false, std::extents<T1, 5>>(std::extents<T2, D>(5));
test_conversion<idx_convertible && true, std::extents<T1, 5>>(std::extents<T2, 5>());
// clang-format on
}
template <class IdxT, size_t... Extents>
using lr_mapping_t = std::layout_right::mapping<std::extents<IdxT, Extents...>>;
template <class IdxT, size_t... Extents>
using ll_mapping_t = std::layout_left::mapping<std::extents<IdxT, Extents...>>;
constexpr void test_no_implicit_conversion() {
constexpr size_t D = std::dynamic_extent;
// Sanity check that one static to dynamic conversion works
static_assert(std::is_constructible_v<ll_mapping_t<int, D>, lr_mapping_t<int, 5>>);
static_assert(std::is_convertible_v<lr_mapping_t<int, 5>, ll_mapping_t<int, D>>);
// Check that dynamic to static conversion only works explicitly
static_assert(std::is_constructible_v<ll_mapping_t<int, 5>, lr_mapping_t<int, D>>);
static_assert(!std::is_convertible_v<lr_mapping_t<int, D>, ll_mapping_t<int, 5>>);
// Sanity check that smaller index_type to larger index_type conversion works
static_assert(std::is_constructible_v<ll_mapping_t<size_t, 5>, lr_mapping_t<int, 5>>);
static_assert(std::is_convertible_v<lr_mapping_t<int, 5>, ll_mapping_t<size_t, 5>>);
// Check that larger index_type to smaller index_type conversion works explicitly only
static_assert(std::is_constructible_v<ll_mapping_t<int, 5>, lr_mapping_t<size_t, 5>>);
static_assert(!std::is_convertible_v<lr_mapping_t<size_t, 5>, ll_mapping_t<int, 5>>);
}
constexpr void test_rank_mismatch() {
constexpr size_t D = std::dynamic_extent;
static_assert(!std::is_constructible_v<lr_mapping_t<int, D>, lr_mapping_t<int>>);
static_assert(!std::is_constructible_v<lr_mapping_t<int>, lr_mapping_t<int, D, D>>);
static_assert(!std::is_constructible_v<lr_mapping_t<int, D>, lr_mapping_t<int, D, D>>);
static_assert(!std::is_constructible_v<lr_mapping_t<int, D, D, D>, lr_mapping_t<int, D, D>>);
}
constexpr void test_static_extent_mismatch() {
static_assert(!std::is_constructible_v<ll_mapping_t<int, 5>, lr_mapping_t<int, 4>>);
}
constexpr void test_rank_greater_one() {
constexpr size_t D = std::dynamic_extent;
static_assert(!std::is_constructible_v<ll_mapping_t<int, D, D>, lr_mapping_t<int, D, D>>);
static_assert(!std::is_constructible_v<ll_mapping_t<int, 1, 1>, lr_mapping_t<int, 1, 1>>);
static_assert(!std::is_constructible_v<ll_mapping_t<int, D, D, D>, lr_mapping_t<int, D, D, D>>);
}
constexpr bool test() {
test_conversion<int, int>();
test_conversion<int, size_t>();
test_conversion<size_t, int>();
test_conversion<size_t, long>();
test_no_implicit_conversion();
test_rank_mismatch();
test_static_extent_mismatch();
test_rank_greater_one();
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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