| // -*- 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++98, c++03, c++11, c++14, c++17 |
| |
| // <span> |
| |
| // constexpr reference back() const noexcept; |
| // Expects: empty() is false. |
| // Effects: Equivalent to: return *(data() + (size() - 1)); |
| // |
| |
| |
| #include <span> |
| #include <cassert> |
| #include <string> |
| |
| #include "test_macros.h" |
| |
| |
| template <typename Span> |
| constexpr bool testConstexprSpan(Span sp) |
| { |
| LIBCPP_ASSERT(noexcept(sp.back())); |
| return std::addressof(sp.back()) == sp.data() + sp.size() - 1; |
| } |
| |
| |
| template <typename Span> |
| void testRuntimeSpan(Span sp) |
| { |
| LIBCPP_ASSERT(noexcept(sp.back())); |
| assert(std::addressof(sp.back()) == sp.data() + sp.size() - 1); |
| } |
| |
| |
| 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**) |
| { |
| static_assert(testConstexprSpan(std::span<const int>(iArr1, 1)), ""); |
| static_assert(testConstexprSpan(std::span<const int>(iArr1, 2)), ""); |
| static_assert(testConstexprSpan(std::span<const int>(iArr1, 3)), ""); |
| static_assert(testConstexprSpan(std::span<const int>(iArr1, 4)), ""); |
| |
| static_assert(testConstexprSpan(std::span<const int, 1>(iArr1, 1)), ""); |
| static_assert(testConstexprSpan(std::span<const int, 2>(iArr1, 2)), ""); |
| static_assert(testConstexprSpan(std::span<const int, 3>(iArr1, 3)), ""); |
| static_assert(testConstexprSpan(std::span<const int, 4>(iArr1, 4)), ""); |
| |
| |
| testRuntimeSpan(std::span<int>(iArr2, 1)); |
| testRuntimeSpan(std::span<int>(iArr2, 2)); |
| testRuntimeSpan(std::span<int>(iArr2, 3)); |
| testRuntimeSpan(std::span<int>(iArr2, 4)); |
| |
| |
| testRuntimeSpan(std::span<int, 1>(iArr2, 1)); |
| testRuntimeSpan(std::span<int, 2>(iArr2, 2)); |
| testRuntimeSpan(std::span<int, 3>(iArr2, 3)); |
| testRuntimeSpan(std::span<int, 4>(iArr2, 4)); |
| |
| std::string s; |
| testRuntimeSpan(std::span<std::string> (&s, 1)); |
| testRuntimeSpan(std::span<std::string, 1>(&s, 1)); |
| |
| return 0; |
| } |