| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // <string> |
| |
| // void reserve(); // Deprecated in C++20. |
| // void reserve(size_type); |
| |
| // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS |
| |
| // This test ensures that libc++ implements https://wg21.link/P0966R1 (reserve never shrinks) |
| // even before C++20. This is required in order to avoid ODR violations because basic_string::reserve(size) |
| // is compiled into the shared library. Hence, it needs to have the same definition in all Standard modes. |
| // |
| // However, note that reserve() does shrink, and it does so in all Standard modes. |
| // |
| // Reported as https://llvm.org/PR53170. |
| |
| // reserve(n) used to shrink the string until https://llvm.org/D117332 was shipped. |
| // XFAIL: stdlib=apple-libc++ && target={{.+}}-apple-macosx{{10.9|10.10|10.11|10.12|10.13|10.14|10.15|11.0|12.0}} |
| |
| #include <string> |
| #include <stdexcept> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| #include "min_allocator.h" |
| |
| template <class S> |
| TEST_CONSTEXPR_CXX20 bool test() { |
| // Test that a call to reserve() does shrink the string. |
| if (!TEST_IS_CONSTANT_EVALUATED) { |
| S s(1000, 'a'); |
| typename S::size_type old_cap = s.capacity(); |
| s.resize(20); |
| assert(s.capacity() == old_cap); |
| |
| s.reserve(); |
| assert(s.capacity() < old_cap); |
| } |
| |
| // Test that a call to reserve(smaller-than-capacity) never shrinks the string. |
| { |
| S s(1000, 'a'); |
| typename S::size_type old_cap = s.capacity(); |
| s.resize(20); |
| assert(s.capacity() == old_cap); |
| |
| s.reserve(10); |
| assert(s.capacity() == old_cap); |
| } |
| |
| // In particular, test that reserve(0) does NOT shrink the string. |
| { |
| S s(1000, 'a'); |
| typename S::size_type old_cap = s.capacity(); |
| s.resize(20); |
| assert(s.capacity() == old_cap); |
| |
| s.reserve(0); |
| assert(s.capacity() == old_cap); |
| } |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test<std::string>(); |
| |
| #if TEST_STD_VER >= 11 |
| test<std::basic_string<char, std::char_traits<char>, min_allocator<char> > >(); |
| #endif |
| |
| #if TEST_STD_VER > 17 |
| static_assert(test<std::string>()); |
| #endif |
| |
| return 0; |
| } |