libcxx/test/std/ranges/range.factories/range.single.view/begin.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17
  10
  11 // constexpr T* begin() noexcept;
  12 // constexpr const T* begin() const noexcept;
  13
  14 #include <ranges>
  15 #include <cassert>
  16
  17 #include "test_macros.h"
  18
  19 struct Empty {};
  20 struct BigType { char buffer[64] = {10}; };
  21
  22 constexpr bool test() {
  23   {
  24     auto sv = std::ranges::single_view<int>(42);
  25     assert(*sv.begin() == 42);
  26
  27     ASSERT_SAME_TYPE(decltype(sv.begin()), int*);
  28     static_assert(noexcept(sv.begin()));
  29   }
  30   {
  31     const auto sv = std::ranges::single_view<int>(42);
  32     assert(*sv.begin() == 42);
  33
  34     ASSERT_SAME_TYPE(decltype(sv.begin()), const int*);
  35     static_assert(noexcept(sv.begin()));
  36   }
  37
  38   {
  39     auto sv = std::ranges::single_view<Empty>(Empty());
  40     assert(sv.begin() != nullptr);
  41
  42     ASSERT_SAME_TYPE(decltype(sv.begin()), Empty*);
  43   }
  44   {
  45     const auto sv = std::ranges::single_view<Empty>(Empty());
  46     assert(sv.begin() != nullptr);
  47
  48     ASSERT_SAME_TYPE(decltype(sv.begin()), const Empty*);
  49   }
  50
  51   {
  52     auto sv = std::ranges::single_view<BigType>(BigType());
  53     assert(sv.begin()->buffer[0] == 10);
  54
  55     ASSERT_SAME_TYPE(decltype(sv.begin()), BigType*);
  56   }
  57   {
  58     const auto sv = std::ranges::single_view<BigType>(BigType());
  59     assert(sv.begin()->buffer[0] == 10);
  60
  61     ASSERT_SAME_TYPE(decltype(sv.begin()), const BigType*);
  62   }
  63
  64   return true;
  65 }
  66
  67 int main(int, char**) {
  68   test();
  69   static_assert(test());
  70
  71   return 0;
  72 }