libcxx/test/std/strings/basic.string/string.capacity/reserve_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 // <string>
  10
  11 // void reserve(size_type res_arg); // constexpr since C++20
  12
  13 // This test relies on https://llvm.org/PR45368 being fixed, which isn't in
  14 // older Apple dylibs
  15 // XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx{{10.9|10.10|10.11|10.12|10.13|10.14|10.15|11.0}}
  16
  17 #include <string>
  18 #include <stdexcept>
  19 #include <cassert>
  20
  21 #include "test_macros.h"
  22 #include "min_allocator.h"
  23
  24 template <class S>
  25 TEST_CONSTEXPR_CXX20 void
  26 test(typename S::size_type min_cap, typename S::size_type erased_index, typename S::size_type res_arg) {
  27   S s(min_cap, 'a');
  28   s.erase(erased_index);
  29   assert(s.size() == erased_index);
  30   assert(s.capacity() >= min_cap); // Check that we really have at least this capacity.
  31
  32 #if TEST_STD_VER > 17
  33   typename S::size_type old_cap = s.capacity();
  34 #endif
  35   S s0 = s;
  36   if (res_arg <= s.max_size()) {
  37     s.reserve(res_arg);
  38     LIBCPP_ASSERT(s.__invariants());
  39     assert(s == s0);
  40     assert(s.capacity() >= res_arg);
  41     assert(s.capacity() >= s.size());
  42 #if TEST_STD_VER > 17
  43     assert(s.capacity() >= old_cap); // reserve never shrinks as of P0966 (C++20)
  44 #endif
  45   }
  46 #ifndef TEST_HAS_NO_EXCEPTIONS
  47   else if (!TEST_IS_CONSTANT_EVALUATED) {
  48     try {
  49       s.reserve(res_arg);
  50       LIBCPP_ASSERT(s.__invariants());
  51       assert(false);
  52     } catch (std::length_error&) {
  53       assert(res_arg > s.max_size());
  54     }
  55   }
  56 #endif
  57 }
  58
  59 template <class S>
  60 TEST_CONSTEXPR_CXX20 void test_string() {
  61   {
  62     test<S>(0, 0, 5);
  63     test<S>(0, 0, 10);
  64     test<S>(0, 0, 50);
  65   }
  66   {
  67     test<S>(100, 50, 5);
  68     test<S>(100, 50, 10);
  69     test<S>(100, 50, 50);
  70     test<S>(100, 50, 100);
  71     test<S>(100, 50, 1000);
  72     test<S>(100, 50, S::npos);
  73   }
  74 }
  75
  76 TEST_CONSTEXPR_CXX20 bool test() {
  77   test_string<std::string>();
  78 #if TEST_STD_VER >= 11
  79   test_string<std::basic_string<char, std::char_traits<char>, min_allocator<char>>>();
  80 #endif
  81
  82   return true;
  83 }
  84
  85 int main(int, char**) {
  86   test();
  87 #if TEST_STD_VER > 17
  88   static_assert(test());
  89 #endif
  90
  91   return 0;
  92 }