//===----------------------------------------------------------------------===//
//
// 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>

// constexpr reference operator[](size_type idx) const;
//

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

#include "test_macros.h"

template <typename Span>
__host__ __device__ constexpr bool testConstexprSpan(Span sp, size_t idx)
{
  static_assert(noexcept(sp[idx]));

  typename Span::reference r1 = sp[idx];
  typename Span::reference r2 = *(sp.data() + idx);
  return r1 == r2;
}

template <typename Span>
__host__ __device__ void testRuntimeSpan(Span sp, size_t idx)
{
  static_assert(noexcept(sp[idx]));

  typename Span::reference r1 = sp[idx];
  typename Span::reference r2 = *(sp.data() + idx);
  assert(r1 == r2);
}

struct A
{};
constexpr int iArr1[]            = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
TEST_GLOBAL_VARIABLE int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};

int main(int, char**)
{
  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 1), 0), "");

  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 2), 0), "");
  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 2), 1), "");

  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 3), 0), "");
  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 3), 1), "");
  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 3), 2), "");

  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 4), 0), "");
  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 4), 1), "");
  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 4), 2), "");
  static_assert(testConstexprSpan(cuda::std::span<const int>(iArr1, 4), 3), "");

  static_assert(testConstexprSpan(cuda::std::span<const int, 1>(iArr1, 1), 0), "");

  static_assert(testConstexprSpan(cuda::std::span<const int, 2>(iArr1, 2), 0), "");
  static_assert(testConstexprSpan(cuda::std::span<const int, 2>(iArr1, 2), 1), "");

  static_assert(testConstexprSpan(cuda::std::span<const int, 3>(iArr1, 3), 0), "");
  static_assert(testConstexprSpan(cuda::std::span<const int, 3>(iArr1, 3), 1), "");
  static_assert(testConstexprSpan(cuda::std::span<const int, 3>(iArr1, 3), 2), "");

  static_assert(testConstexprSpan(cuda::std::span<const int, 4>(iArr1, 4), 0), "");
  static_assert(testConstexprSpan(cuda::std::span<const int, 4>(iArr1, 4), 1), "");
  static_assert(testConstexprSpan(cuda::std::span<const int, 4>(iArr1, 4), 2), "");
  static_assert(testConstexprSpan(cuda::std::span<const int, 4>(iArr1, 4), 3), "");

  testRuntimeSpan(cuda::std::span<int>(iArr2, 1), 0);

  testRuntimeSpan(cuda::std::span<int>(iArr2, 2), 0);
  testRuntimeSpan(cuda::std::span<int>(iArr2, 2), 1);

  testRuntimeSpan(cuda::std::span<int>(iArr2, 3), 0);
  testRuntimeSpan(cuda::std::span<int>(iArr2, 3), 1);
  testRuntimeSpan(cuda::std::span<int>(iArr2, 3), 2);

  testRuntimeSpan(cuda::std::span<int>(iArr2, 4), 0);
  testRuntimeSpan(cuda::std::span<int>(iArr2, 4), 1);
  testRuntimeSpan(cuda::std::span<int>(iArr2, 4), 2);
  testRuntimeSpan(cuda::std::span<int>(iArr2, 4), 3);

  testRuntimeSpan(cuda::std::span<int, 1>(iArr2, 1), 0);

  testRuntimeSpan(cuda::std::span<int, 2>(iArr2, 2), 0);
  testRuntimeSpan(cuda::std::span<int, 2>(iArr2, 2), 1);

  testRuntimeSpan(cuda::std::span<int, 3>(iArr2, 3), 0);
  testRuntimeSpan(cuda::std::span<int, 3>(iArr2, 3), 1);
  testRuntimeSpan(cuda::std::span<int, 3>(iArr2, 3), 2);

  testRuntimeSpan(cuda::std::span<int, 4>(iArr2, 4), 0);
  testRuntimeSpan(cuda::std::span<int, 4>(iArr2, 4), 1);
  testRuntimeSpan(cuda::std::span<int, 4>(iArr2, 4), 2);
  testRuntimeSpan(cuda::std::span<int, 4>(iArr2, 4), 3);

  return 0;
}
