libcxx/test/std/strings/basic.string/string.capacity/max_size.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: no-exceptions
  10 // <string>
  11
  12 // size_type max_size() const; // constexpr since C++20
  13
  14 // NOTE: asan and msan will fail for one of two reasons
  15 // 1. If allocator_may_return_null=0 then they will fail because the allocation
  16 //    returns null.
  17 // 2. If allocator_may_return_null=1 then they will fail because the allocation
  18 //    is too large to succeed.
  19 // UNSUPPORTED: sanitizer-new-delete
  20
  21 #include <string>
  22 #include <cassert>
  23 #include <new>
  24
  25 #include "test_macros.h"
  26 #include "min_allocator.h"
  27
  28 template <class S>
  29 TEST_CONSTEXPR_CXX20 void test_resize_max_size_minus_1(const S& s) {
  30   S s2(s);
  31   const std::size_t sz = s2.max_size() - 1;
  32   try {
  33     s2.resize(sz, 'x');
  34   } catch (const std::bad_alloc&) {
  35     return;
  36   }
  37   assert(s2.size() == sz);
  38 }
  39
  40 template <class S>
  41 TEST_CONSTEXPR_CXX20 void test_resize_max_size(const S& s) {
  42   S s2(s);
  43   const std::size_t sz = s2.max_size();
  44   try {
  45     s2.resize(sz, 'x');
  46   } catch (const std::bad_alloc&) {
  47     return;
  48   }
  49   assert(s.size() == sz);
  50 }
  51
  52 template <class S>
  53 TEST_CONSTEXPR_CXX20 void test_string() {
  54   {
  55     S s;
  56     assert(s.max_size() >= s.size());
  57     assert(s.max_size() > 0);
  58     if (!TEST_IS_CONSTANT_EVALUATED) {
  59       test_resize_max_size_minus_1(s);
  60       test_resize_max_size(s);
  61     }
  62   }
  63   {
  64     S s("123");
  65     assert(s.max_size() >= s.size());
  66     assert(s.max_size() > 0);
  67     if (!TEST_IS_CONSTANT_EVALUATED) {
  68       test_resize_max_size_minus_1(s);
  69       test_resize_max_size(s);
  70     }
  71   }
  72   {
  73     S s("12345678901234567890123456789012345678901234567890");
  74     assert(s.max_size() >= s.size());
  75     assert(s.max_size() > 0);
  76     if (!TEST_IS_CONSTANT_EVALUATED) {
  77       test_resize_max_size_minus_1(s);
  78       test_resize_max_size(s);
  79     }
  80   }
  81 }
  82
  83 TEST_CONSTEXPR_CXX20 bool test() {
  84   test_string<std::string>();
  85 #if TEST_STD_VER >= 11
  86   test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char> > >();
  87 #endif
  88
  89   return true;
  90 }
  91
  92 int main(int, char**) {
  93   test();
  94 #if TEST_STD_VER >= 20
  95   static_assert(test());
  96 #endif
  97
  98   return 0;
  99 }