| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20 |
| |
| // <memory> |
| |
| // template<class Allocator> |
| // [[nodiscard]] constexpr allocation_result<typename allocator_traits<Allocator>::pointer> |
| // allocate_at_least(Allocator& a, size_t n); |
| |
| #include <cassert> |
| #include <concepts> |
| #include <cstddef> |
| #include <memory> |
| |
| // check that std::allocation_result exists and isn't restricted to pointers |
| using AllocResult = std::allocation_result<int>; |
| |
| template <class T> |
| struct no_allocate_at_least { |
| using value_type = T; |
| T t; |
| |
| constexpr T* allocate(std::size_t) { return &t; } |
| constexpr void deallocate(T*, std::size_t) {} |
| }; |
| |
| template <class T> |
| struct has_allocate_at_least { |
| using value_type = T; |
| T t1; |
| T t2; |
| |
| constexpr T* allocate(std::size_t) { return &t1; } |
| constexpr void deallocate(T*, std::size_t) {} |
| constexpr std::allocation_result<T*> allocate_at_least(std::size_t) { |
| return {&t2, 2}; |
| } |
| }; |
| |
| constexpr bool test() { |
| { // check that std::allocate_at_least forwards to allocator::allocate if no allocate_at_least exists |
| no_allocate_at_least<int> alloc; |
| std::same_as<std::allocation_result<int*>> decltype(auto) ret = std::allocate_at_least(alloc, 1); |
| assert(ret.count == 1); |
| assert(ret.ptr == &alloc.t); |
| } |
| |
| { // check that std::allocate_at_least forwards to allocator::allocate_at_least if allocate_at_least exists |
| has_allocate_at_least<int> alloc; |
| std::same_as<std::allocation_result<int*>> decltype(auto) ret = std::allocate_at_least(alloc, 1); |
| assert(ret.count == 2); |
| assert(ret.ptr == &alloc.t2); |
| } |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| |
| return 0; |
| } |