libcxx/test/std/strings/string.view/string.view.iterators/rend.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: !stdlib=libc++ && (c++03 || c++11 || c++14)
  10
  11 // <string_view>
  12
  13 // constexpr const_iterator rend() const;
  14
  15 #include <string_view>
  16 #include <cassert>
  17 #include <cstddef>
  18
  19 #include "test_macros.h"
  20
  21 template <class S>
  22 void test(S s) {
  23   const S& cs                            = s;
  24   typename S::reverse_iterator e         = s.rend();
  25   typename S::const_reverse_iterator ce1 = cs.rend();
  26   typename S::const_reverse_iterator ce2 = s.crend();
  27
  28   if (s.empty()) {
  29     assert(e == s.rbegin());
  30     assert(ce1 == cs.rbegin());
  31     assert(ce2 == s.rbegin());
  32   } else {
  33     assert(e != s.rbegin());
  34     assert(ce1 != cs.rbegin());
  35     assert(ce2 != s.rbegin());
  36   }
  37
  38   assert(static_cast<std::size_t>(e - s.rbegin()) == s.size());
  39   assert(static_cast<std::size_t>(ce1 - cs.rbegin()) == cs.size());
  40   assert(static_cast<std::size_t>(ce2 - s.crbegin()) == s.size());
  41
  42   assert(e == ce1);
  43   assert(e == ce2);
  44   assert(ce1 == ce2);
  45 }
  46
  47 int main(int, char**) {
  48   typedef std::string_view string_view;
  49 #ifndef TEST_HAS_NO_CHAR8_T
  50   typedef std::u8string_view u8string_view;
  51 #endif
  52   typedef std::u16string_view u16string_view;
  53   typedef std::u32string_view u32string_view;
  54
  55   test(string_view());
  56   test(u16string_view());
  57   test(u32string_view());
  58   test(string_view("123"));
  59 #ifndef TEST_HAS_NO_CHAR8_T
  60   test(u8string_view{u8"123"});
  61 #endif
  62 #if TEST_STD_VER >= 11
  63   test(u16string_view{u"123"});
  64   test(u32string_view{U"123"});
  65 #endif
  66
  67 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  68   typedef std::wstring_view wstring_view;
  69   test(wstring_view());
  70   test(wstring_view(L"123"));
  71 #endif
  72
  73 #if TEST_STD_VER > 14
  74   {
  75     constexpr string_view sv{"123", 3};
  76 #  ifndef TEST_HAS_NO_CHAR8_T
  77     constexpr u8string_view u8sv{u8"123", 3};
  78 #  endif
  79     constexpr u16string_view u16sv{u"123", 3};
  80     constexpr u32string_view u32sv{U"123", 3};
  81
  82     static_assert(*--sv.rend() == sv[0], "");
  83 #  ifndef TEST_HAS_NO_CHAR8_T
  84     static_assert(*--u8sv.rend() == u8sv[0], "");
  85 #  endif
  86     static_assert(*--u16sv.rend() == u16sv[0], "");
  87     static_assert(*--u32sv.rend() == u32sv[0], "");
  88
  89     static_assert(*--sv.crend() == sv[0], "");
  90 #  ifndef TEST_HAS_NO_CHAR8_T
  91     static_assert(*--u8sv.crend() == u8sv[0], "");
  92 #  endif
  93     static_assert(*--u16sv.crend() == u16sv[0], "");
  94     static_assert(*--u32sv.crend() == u32sv[0], "");
  95
  96 #  ifndef TEST_HAS_NO_WIDE_CHARACTERS
  97     {
  98       constexpr wstring_view wsv{L"123", 3};
  99       static_assert(*--wsv.rend() == wsv[0], "");
 100       static_assert(*--wsv.crend() == wsv[0], "");
 101     }
 102 #  endif
 103   }
 104 #endif // TEST_STD_VER > 14
 105
 106   return 0;
 107 }