text: // -*- C++ -*-
  //===------------------------------ span ---------------------------------===//
  //
  // 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
  
  // <span>
  
  // constexpr pointer data() const noexcept;
  //
  
  
  #include <span>
  #include <cassert>
  #include <string>
  
  #include "test_macros.h"
  
  
  template <typename Span>
  constexpr bool testConstexprSpan(Span sp, typename Span::pointer ptr)
  {
      ASSERT_NOEXCEPT(sp.data());
      return sp.data() == ptr;
  }
  
  
  template <typename Span>
  void testRuntimeSpan(Span sp, typename Span::pointer ptr)
  {
      ASSERT_NOEXCEPT(sp.data());
      assert(sp.data() == ptr);
  }
  
  struct A{};
  constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
            int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
  
  int main(int, char**)
  {
  
  //  dynamic size
      static_assert(testConstexprSpan(std::span<int>(), nullptr),         "");
      static_assert(testConstexprSpan(std::span<long>(), nullptr),        "");
      static_assert(testConstexprSpan(std::span<double>(), nullptr),      "");
      static_assert(testConstexprSpan(std::span<A>(), nullptr),           "");
      static_assert(testConstexprSpan(std::span<std::string>(), nullptr), "");
  
      static_assert(testConstexprSpan(std::span<const int>(iArr1, 1), iArr1), "");
      static_assert(testConstexprSpan(std::span<const int>(iArr1, 2), iArr1), "");
      static_assert(testConstexprSpan(std::span<const int>(iArr1, 3), iArr1), "");
      static_assert(testConstexprSpan(std::span<const int>(iArr1, 4), iArr1), "");
  
      static_assert(testConstexprSpan(std::span<const int>(iArr1 + 1, 1), iArr1 + 1), "");
      static_assert(testConstexprSpan(std::span<const int>(iArr1 + 2, 2), iArr1 + 2), "");
      static_assert(testConstexprSpan(std::span<const int>(iArr1 + 3, 3), iArr1 + 3), "");
      static_assert(testConstexprSpan(std::span<const int>(iArr1 + 4, 4), iArr1 + 4), "");
  
  //  static size
      static_assert(testConstexprSpan(std::span<int, 0>(), nullptr),         "");
      static_assert(testConstexprSpan(std::span<long, 0>(), nullptr),        "");
      static_assert(testConstexprSpan(std::span<double, 0>(), nullptr),      "");
      static_assert(testConstexprSpan(std::span<A, 0>(), nullptr),           "");
      static_assert(testConstexprSpan(std::span<std::string, 0>(), nullptr), "");
  
      static_assert(testConstexprSpan(std::span<const int, 1>(iArr1, 1), iArr1), "");
      static_assert(testConstexprSpan(std::span<const int, 2>(iArr1, 2), iArr1), "");
      static_assert(testConstexprSpan(std::span<const int, 3>(iArr1, 3), iArr1), "");
      static_assert(testConstexprSpan(std::span<const int, 4>(iArr1, 4), iArr1), "");
  
      static_assert(testConstexprSpan(std::span<const int, 1>(iArr1 + 1, 1), iArr1 + 1), "");
      static_assert(testConstexprSpan(std::span<const int, 2>(iArr1 + 2, 2), iArr1 + 2), "");
      static_assert(testConstexprSpan(std::span<const int, 3>(iArr1 + 3, 3), iArr1 + 3), "");
      static_assert(testConstexprSpan(std::span<const int, 4>(iArr1 + 4, 4), iArr1 + 4), "");
  
  
  //  dynamic size
      testRuntimeSpan(std::span<int>(), nullptr);
      testRuntimeSpan(std::span<long>(), nullptr);
      testRuntimeSpan(std::span<double>(), nullptr);
      testRuntimeSpan(std::span<A>(), nullptr);
      testRuntimeSpan(std::span<std::string>(), nullptr);
  
      testRuntimeSpan(std::span<int>(iArr2, 1), iArr2);
      testRuntimeSpan(std::span<int>(iArr2, 2), iArr2);
      testRuntimeSpan(std::span<int>(iArr2, 3), iArr2);
      testRuntimeSpan(std::span<int>(iArr2, 4), iArr2);
  
      testRuntimeSpan(std::span<int>(iArr2 + 1, 1), iArr2 + 1);
      testRuntimeSpan(std::span<int>(iArr2 + 2, 2), iArr2 + 2);
      testRuntimeSpan(std::span<int>(iArr2 + 3, 3), iArr2 + 3);
      testRuntimeSpan(std::span<int>(iArr2 + 4, 4), iArr2 + 4);
  
  //  static size
      testRuntimeSpan(std::span<int, 0>(), nullptr);
      testRuntimeSpan(std::span<long, 0>(), nullptr);
      testRuntimeSpan(std::span<double, 0>(), nullptr);
      testRuntimeSpan(std::span<A, 0>(), nullptr);
      testRuntimeSpan(std::span<std::string, 0>(), nullptr);
  
      testRuntimeSpan(std::span<int, 1>(iArr2, 1), iArr2);
      testRuntimeSpan(std::span<int, 2>(iArr2, 2), iArr2);
      testRuntimeSpan(std::span<int, 3>(iArr2, 3), iArr2);
      testRuntimeSpan(std::span<int, 4>(iArr2, 4), iArr2);
  
      testRuntimeSpan(std::span<int, 1>(iArr2 + 1, 1), iArr2 + 1);
      testRuntimeSpan(std::span<int, 2>(iArr2 + 2, 2), iArr2 + 2);
      testRuntimeSpan(std::span<int, 3>(iArr2 + 3, 3), iArr2 + 3);
      testRuntimeSpan(std::span<int, 4>(iArr2 + 4, 4), iArr2 + 4);
  
  
      std::string s;
      testRuntimeSpan(std::span<std::string>(&s, 1), &s);
      testRuntimeSpan(std::span<std::string, 1>(&s, 1), &s);
  
  
    return 0;
  }
  