libcxx/test/std/iterators/iterator.range/begin-end.array.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
  10
  11 // <iterator>
  12 //
  13 // template <class T, size_t N> constexpr T* begin(T (&array)[N]) noexcept;
  14 // template <class T, size_t N> constexpr T* end(T (&array)[N]) noexcept;
  15 //
  16 // template <class T, size_t N> constexpr reverse_iterator<T*> rbegin(T (&array)[N]);      // C++14, constexpr since C++17
  17 // template <class T, size_t N> constexpr reverse_iterator<T*> rend(T (&array)[N]);        // C++14, constexpr since C++17
  18
  19 #include <cassert>
  20 #include <iterator>
  21
  22 #include "test_macros.h"
  23
  24 TEST_CONSTEXPR_CXX14 bool test() {
  25   int a[]        = {1, 2, 3};
  26   const auto& ca = a;
  27
  28   // std::begin(T (&)[N]) / std::end(T (&)[N])
  29   {
  30     ASSERT_NOEXCEPT(std::begin(a));
  31     ASSERT_SAME_TYPE(decltype(std::begin(a)), int*);
  32     assert(std::begin(a) == a);
  33
  34     ASSERT_NOEXCEPT(std::end(a));
  35     ASSERT_SAME_TYPE(decltype(std::end(a)), int*);
  36     assert(std::end(a) == a + 3);
  37
  38     // kind of overkill since it follows from the definition, but worth testing
  39     ASSERT_NOEXCEPT(std::begin(ca));
  40     ASSERT_SAME_TYPE(decltype(std::begin(ca)), const int*);
  41     assert(std::begin(ca) == ca);
  42
  43     ASSERT_NOEXCEPT(std::end(ca));
  44     ASSERT_SAME_TYPE(decltype(std::end(ca)), const int*);
  45     assert(std::end(ca) == ca + 3);
  46   }
  47
  48   return true;
  49 }
  50
  51 TEST_CONSTEXPR_CXX17 bool test_r() {
  52 #if TEST_STD_VER >= 14
  53   int a[]        = {1, 2, 3};
  54   const auto& ca = a;
  55
  56   // std::rbegin(T (&)[N]) / std::rend(T (&)[N])
  57   {
  58     ASSERT_SAME_TYPE(decltype(std::rbegin(a)), std::reverse_iterator<int*>);
  59     assert(std::rbegin(a).base() == a + 3);
  60
  61     ASSERT_SAME_TYPE(decltype(std::rend(a)), std::reverse_iterator<int*>);
  62     assert(std::rend(a).base() == a);
  63
  64     // kind of overkill since it follows from the definition, but worth testing
  65     ASSERT_SAME_TYPE(decltype(std::rbegin(ca)), std::reverse_iterator<const int*>);
  66     assert(std::rbegin(ca).base() == ca + 3);
  67
  68     ASSERT_SAME_TYPE(decltype(std::rend(ca)), std::reverse_iterator<const int*>);
  69     assert(std::rend(ca).base() == ca);
  70   }
  71 #endif
  72
  73   return true;
  74 }
  75
  76 int main(int, char**) {
  77   test();
  78   test_r();
  79 #if TEST_STD_VER >= 14
  80   static_assert(test(), "");
  81 #endif
  82 #if TEST_STD_VER >= 17
  83   static_assert(test_r(), "");
  84 #endif
  85
  86   // Make sure std::begin(T (&)[N]) and std::end(T (&)[N]) are constexpr in C++11 too (see LWG2280).
  87   {
  88     static constexpr int a[] = {1, 2, 3};
  89     constexpr auto b         = std::begin(a);
  90     assert(b == a);
  91     constexpr auto e = std::end(a);
  92     assert(e == a + 3);
  93   }
  94
  95   return 0;
  96 }