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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>
// Test default iteration:
//
// template<class... Indices>
// constexpr index_type operator()(Indices...) const noexcept;
//
// Constraints:
// * sizeof...(Indices) == extents_type::rank() is true,
// * (is_convertible_v<Indices, index_type> && ...) is true, and
// * (is_nothrow_constructible_v<index_type, Indices> && ...) is true.
//
// Preconditions:
// * extents_type::index-cast(i) is a multidimensional index in extents_.
#include <mdspan>
#include <cassert>
#include <cstdint>
#include "test_macros.h"
#include "../ConvertibleToIntegral.h"
template<class Mapping, class ... Indices>
concept operator_constraints = requires(Mapping m, Indices ... idxs) {
{std::is_same_v<decltype(m(idxs...)), typename Mapping::index_type>};
};
template<class Mapping, class ... Indices>
requires(
operator_constraints<Mapping, Indices...>
)
constexpr bool check_operator_constraints(Mapping m, Indices ... idxs) {
(void) m(idxs...);
return true;
}
template<class Mapping, class ... Indices>
constexpr bool check_operator_constraints(Mapping, Indices ...) {
return false;
}
template <class M, class T, class... Args>
constexpr void iterate_left(M m, T& count, Args... args) {
constexpr int r = static_cast<int>(M::extents_type::rank()) - 1 - static_cast<int>(sizeof...(Args));
if constexpr (-1 == r) {
ASSERT_NOEXCEPT(m(args...));
assert(count == m(args...));
count++;
} else {
for (typename M::index_type i = 0; i < m.extents().extent(r); i++) {
iterate_left(m, count, i, args...);
}
}
}
template <class E, class... Args>
constexpr void test_iteration(Args... args) {
using M = std::layout_left::mapping<E>;
M m(E(args...));
typename E::index_type count = 0;
iterate_left(m, count);
}
constexpr bool test() {
constexpr size_t D = std::dynamic_extent;
test_iteration<std::extents<int>>();
test_iteration<std::extents<unsigned, D>>(1);
test_iteration<std::extents<unsigned, D>>(7);
test_iteration<std::extents<unsigned, 7>>();
test_iteration<std::extents<unsigned, 7, 8>>();
test_iteration<std::extents<signed char, D, D, D, D>>(1, 1, 1, 1);
// Check operator constraint for number of arguments
static_assert(check_operator_constraints(std::layout_left::mapping<std::extents<int, D>>(std::extents<int, D>(1)), 0));
static_assert(!check_operator_constraints(std::layout_left::mapping<std::extents<int, D>>(std::extents<int, D>(1)), 0, 0));
// Check operator constraint for convertibility of arguments to index_type
static_assert(check_operator_constraints(std::layout_left::mapping<std::extents<int, D>>(std::extents<int, D>(1)), IntType(0)));
static_assert(!check_operator_constraints(std::layout_left::mapping<std::extents<unsigned, D>>(std::extents<unsigned, D>(1)), IntType(0)));
// Check operator constraint for no-throw-constructibility of index_type from arguments
static_assert(!check_operator_constraints(std::layout_left::mapping<std::extents<unsigned char, D>>(std::extents<unsigned char, D>(1)), IntType(0)));
return true;
}
constexpr bool test_large() {
constexpr size_t D = std::dynamic_extent;
test_iteration<std::extents<int64_t, D, 8, D, D>>(7, 9, 10);
test_iteration<std::extents<int64_t, D, 8, 1, D>>(7, 10);
return true;
}
int main(int, char**) {
test();
static_assert(test());
// The large test iterates over ~10k loop indices.
// With assertions enabled this triggered the maximum default limit
// for steps in consteval expressions. Assertions roughly double the
// total number of instructions, so this was already close to the maximum.
test_large();
return 0;
}
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