xref: /aosp_15_r20/external/cronet/third_party/libc++/src/test/std/containers/views/mdspan/MinimalElementType.h (revision 6777b5387eb2ff775bb5750e3f5d96f37fb7352b)
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 #ifndef TEST_STD_CONTAINERS_VIEWS_MDSPAN_MINIMAL_ELEMENT_TYPE_H
10 #define TEST_STD_CONTAINERS_VIEWS_MDSPAN_MINIMAL_ELEMENT_TYPE_H
11 
12 #include <memory>
13 #include <type_traits>
14 
15 // Idiosyncratic element type for mdspan
16 // Make sure we don't assume copyable, default constructible, movable etc.
17 struct MinimalElementType {
18   int val;
19   constexpr MinimalElementType() = delete;
20   constexpr MinimalElementType(const MinimalElementType&) = delete;
MinimalElementTypeMinimalElementType21   constexpr explicit MinimalElementType(int v) noexcept : val(v){}
22   constexpr MinimalElementType& operator=(const MinimalElementType&) = delete;
23 };
24 
25 // Helper class to create pointer to MinimalElementType
26 template<class T, size_t N>
27 struct ElementPool {
ElementPoolElementPool28   constexpr ElementPool() {
29     ptr_ = std::allocator<std::remove_const_t<T>>().allocate(N);
30     for (int i = 0; i != N; ++i)
31       std::construct_at(ptr_ + i, 42);
32   }
33 
get_ptrElementPool34   constexpr T* get_ptr() { return ptr_; }
35 
~ElementPoolElementPool36   constexpr ~ElementPool() {
37     for (int i = 0; i != N; ++i)
38       std::destroy_at(ptr_ + i);
39     std::allocator<std::remove_const_t<T>>().deallocate(ptr_, N);
40   }
41 
42 private:
43   std::remove_const_t<T>* ptr_;
44 };
45 
46 #endif // TEST_STD_CONTAINERS_VIEWS_MDSPAN_MINIMAL_ELEMENT_TYPE_H
47