libcxx/test/std/strings/basic.string/string.access/at.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 // const_reference at(size_type pos) const; // constexpr since C++20
  12 //       reference at(size_type pos); // constexpr since C++20
  13
  14 #include <string>
  15 #include <stdexcept>
  16 #include <cassert>
  17
  18 #include "min_allocator.h"
  19
  20 #include "make_string.h"
  21 #include "test_macros.h"
  22 #include "type_algorithms.h"
  23
  24 template <class S>
  25 TEST_CONSTEXPR_CXX20 void test(S s, typename S::size_type pos) {
  26   const S& cs = s;
  27   if (pos < s.size()) {
  28     assert(s.at(pos) == s[pos]);
  29     assert(cs.at(pos) == cs[pos]);
  30   }
  31 #ifndef TEST_HAS_NO_EXCEPTIONS
  32   else if (!TEST_IS_CONSTANT_EVALUATED) {
  33     try {
  34       TEST_IGNORE_NODISCARD s.at(pos);
  35       assert(false);
  36     } catch (std::out_of_range&) {
  37       assert(pos >= s.size());
  38     }
  39     try {
  40       TEST_IGNORE_NODISCARD cs.at(pos);
  41       assert(false);
  42     } catch (std::out_of_range&) {
  43       assert(pos >= s.size());
  44     }
  45   }
  46 #endif
  47 }
  48
  49 template <class S>
  50 TEST_CONSTEXPR_CXX20 void test_string() {
  51   test(S(), 0);
  52   test(S(MAKE_CSTRING(typename S::value_type, "123")), 0);
  53   test(S(MAKE_CSTRING(typename S::value_type, "123")), 1);
  54   test(S(MAKE_CSTRING(typename S::value_type, "123")), 2);
  55   test(S(MAKE_CSTRING(typename S::value_type, "123")), 3);
  56 }
  57
  58 struct TestCaller {
  59   template <class T>
  60   TEST_CONSTEXPR_CXX20 void operator()() {
  61     test_string<std::basic_string<T> >();
  62 #if TEST_STD_VER >= 11
  63     test_string<std::basic_string<T, std::char_traits<T>, min_allocator<T> > >();
  64 #endif
  65   }
  66 };
  67
  68 TEST_CONSTEXPR_CXX20 bool test() {
  69   types::for_each(types::character_types(), TestCaller());
  70
  71   return true;
  72 }
  73
  74 int main(int, char**) {
  75   test();
  76 #if TEST_STD_VER > 17
  77   static_assert(test());
  78 #endif
  79
  80   return 0;
  81 }