//===----------------------------------------------------------------------===//
//
// 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
// SPDX-FileCopyrightText: Copyright (c) 2023 NVIDIA CORPORATION & AFFILIATES.
//
//===----------------------------------------------------------------------===//

// <span>

// template<size_t N>
//     constexpr span(element_type (&arr)[N]) noexcept;
//
// Remarks: These constructors shall not participate in overload resolution unless:
//   — extent == dynamic_extent || N == extent is true, and
//   — remove_pointer_t<decltype(data(arr))>(*)[] is convertible to ElementType(*)[].
//

#include <cuda/std/array>
#include <cuda/std/cassert>
#include <cuda/std/span>

#include "test_macros.h"

__device__ int arr[]                  = {1, 2, 3};
__device__ const int carr[]           = {4, 5, 6};
__device__ volatile int varr[]        = {7, 8, 9};
__device__ const volatile int cvarr[] = {1, 3, 5};

__host__ __device__ void checkCV()
{
  //  Types the same (dynamic sized)
  {
    cuda::std::span<int> s1{arr}; // a cuda::std::span<               int> pointing at int.
    cuda::std::span<const int> s2{carr}; // a cuda::std::span<const          int> pointing at const int.
    cuda::std::span<volatile int> s3{varr}; // a cuda::std::span<      volatile int> pointing at volatile int.
    cuda::std::span<const volatile int> s4{cvarr}; // a cuda::std::span<const volatile int> pointing at const volatile
                                                   // int.
    assert(s1.size() + s2.size() + s3.size() + s4.size() == 12);
  }

  //  Types the same (static sized)
  {
    cuda::std::span<int, 3> s1{arr}; // a cuda::std::span<               int> pointing at int.
    cuda::std::span<const int, 3> s2{carr}; // a cuda::std::span<const          int> pointing at const int.
    cuda::std::span<volatile int, 3> s3{varr}; // a cuda::std::span<      volatile int> pointing at volatile int.
    cuda::std::span<const volatile int, 3> s4{cvarr}; // a cuda::std::span<const volatile int> pointing at const
                                                      // volatile int.
    assert(s1.size() + s2.size() + s3.size() + s4.size() == 12);
  }

  //  types different (dynamic sized)
  {
    cuda::std::span<const int> s1{arr}; // a cuda::std::span<const          int> pointing at int.
    cuda::std::span<volatile int> s2{arr}; // a cuda::std::span<      volatile int> pointing at int.
    cuda::std::span<volatile int> s3{arr}; // a cuda::std::span<      volatile int> pointing at const int.
    cuda::std::span<const volatile int> s4{arr}; // a cuda::std::span<const volatile int> pointing at int.
    cuda::std::span<const volatile int> s5{carr}; // a cuda::std::span<const volatile int> pointing at const int.
    cuda::std::span<const volatile int> s6{varr}; // a cuda::std::span<const volatile int> pointing at volatile int.
    assert(s1.size() + s2.size() + s3.size() + s4.size() + s5.size() + s6.size() == 18);
  }

  //  types different (static sized)
  {
    cuda::std::span<const int, 3> s1{arr}; // a cuda::std::span<const          int> pointing at int.
    cuda::std::span<volatile int, 3> s2{arr}; // a cuda::std::span<      volatile int> pointing at int.
    cuda::std::span<volatile int, 3> s3{arr}; // a cuda::std::span<      volatile int> pointing at const int.
    cuda::std::span<const volatile int, 3> s4{arr}; // a cuda::std::span<const volatile int> pointing at int.
    cuda::std::span<const volatile int, 3> s5{carr}; // a cuda::std::span<const volatile int> pointing at const int.
    cuda::std::span<const volatile int, 3> s6{varr}; // a cuda::std::span<const volatile int> pointing at volatile int.
    assert(s1.size() + s2.size() + s3.size() + s4.size() + s5.size() + s6.size() == 18);
  }
}

template <class T>
__host__ __device__ constexpr bool testSpan()
{
  T val[2] = {};

  static_assert(noexcept(cuda::std::span<T>{val}));
  static_assert(noexcept(cuda::std::span<T, 2>{val}));
  static_assert(noexcept(cuda::std::span<const T>{val}));
  static_assert(noexcept(cuda::std::span<const T, 2>{val}));

  cuda::std::span<T> s1          = val;
  cuda::std::span<T, 2> s2       = val;
  cuda::std::span<const T> s3    = val;
  cuda::std::span<const T, 2> s4 = val;
  assert(s1.data() == val && s1.size() == 2);
  assert(s2.data() == val && s2.size() == 2);
  assert(s3.data() == val && s3.size() == 2);
  assert(s4.data() == val && s4.size() == 2);

  cuda::std::span<const int> s5    = {cuda::std::array<int, 2>{1, 2}};
  cuda::std::span<const int, 2> s6 = {cuda::std::array<int, 2>{1, 2}};
  assert(s5.size() == 2); // and it dangles
  assert(s6.size() == 2); // and it dangles

  return true;
}

struct A
{};

int main(int, char**)
{
  testSpan<int>();
  testSpan<double>();
  testSpan<A>();

  static_assert(testSpan<int>(), "");
  static_assert(testSpan<double>(), "");
  static_assert(testSpan<A>(), "");

  checkCV();

  return 0;
}
