libcxx/test/std/strings/basic.string/string.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 // <string>
  10
  11 //       reverse_iterator rend(); // constexpr since C++20
  12 // const_reverse_iterator rend() const; // constexpr since C++20
  13
  14 #include <string>
  15 #include <cassert>
  16 #include <cstddef>
  17
  18 #include "test_macros.h"
  19 #include "min_allocator.h"
  20
  21 template <class S>
  22 TEST_CONSTEXPR_CXX20 void test(S s) {
  23   const S& cs                           = s;
  24   typename S::reverse_iterator e        = s.rend();
  25   typename S::const_reverse_iterator ce = cs.rend();
  26   if (s.empty()) {
  27     assert(e == s.rbegin());
  28     assert(ce == cs.rbegin());
  29   }
  30   assert(static_cast<std::size_t>(e - s.rbegin()) == s.size());
  31   assert(static_cast<std::size_t>(ce - cs.rbegin()) == cs.size());
  32 }
  33
  34 template <class S>
  35 TEST_CONSTEXPR_CXX20 void test_string() {
  36   test(S());
  37   test(S("123"));
  38 }
  39
  40 TEST_CONSTEXPR_CXX20 bool test() {
  41   test_string<std::string>();
  42 #if TEST_STD_VER >= 11
  43   test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char> > >();
  44 #endif
  45
  46   return true;
  47 }
  48
  49 int main(int, char**) {
  50   test();
  51 #if TEST_STD_VER > 17
  52   static_assert(test());
  53 #endif
  54
  55   return 0;
  56 }