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//===----------------------------------------------------------------------===//
//
// 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 <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(size_t) { return &t; }
constexpr void deallocate(T*, size_t) {}
};
template <class T>
struct has_allocate_at_least {
using value_type = T;
T t1;
T t2;
constexpr T* allocate(size_t) { return &t1; }
constexpr void deallocate(T*, size_t) {}
constexpr std::allocation_result<T*> allocate_at_least(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;
}
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