xref: /llvm-project/libcxx/test/std/numerics/bit/byteswap.pass.cpp (revision e99c4906e44ae3f921fa05356909d006cda8d954)
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 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
10 
11 #include <bit>
12 #include <cassert>
13 #include <cstddef>
14 #include <cstdint>
15 #include <utility>
16 
17 #include "test_macros.h"
18 
19 template <class T>
20 concept has_byteswap = requires(T t) {
21   std::byteswap(t);
22 };
23 
24 static_assert(!has_byteswap<void*>);
25 static_assert(!has_byteswap<float>);
26 static_assert(!has_byteswap<char[2]>);
27 static_assert(!has_byteswap<std::byte>);
28 
29 template <class T>
30 constexpr void test_num(T in, T expected) {
31   assert(std::byteswap(in) == expected);
32   ASSERT_SAME_TYPE(decltype(std::byteswap(in)), decltype(in));
33   ASSERT_NOEXCEPT(std::byteswap(in));
34 }
35 
36 template <class T>
37 constexpr std::pair<T, T> get_test_data() {
38   switch (sizeof(T)) {
39   case 2:
40     return {static_cast<T>(0x1234), static_cast<T>(0x3412)};
41   case 4:
42     return {static_cast<T>(0x60AF8503), static_cast<T>(0x0385AF60)};
43   case 8:
44     return {static_cast<T>(0xABCDFE9477936406), static_cast<T>(0x0664937794FECDAB)};
45   default:
46     assert(false);
47     return {}; // for MSVC, whose `assert` is tragically not [[noreturn]]
48   }
49 }
50 
51 template <class T>
52 constexpr void test_implementation_defined_size() {
53   const auto [in, expected] = get_test_data<T>();
54   test_num<T>(in, expected);
55 }
56 
57 constexpr bool test() {
58   test_num<std::uint8_t>(0xAB, 0xAB);
59   test_num<std::uint16_t>(0xCDEF, 0xEFCD);
60   test_num<std::uint32_t>(0x01234567, 0x67452301);
61   test_num<std::uint64_t>(0x0123456789ABCDEF, 0xEFCDAB8967452301);
62 
63   test_num<std::int8_t>(static_cast<std::int8_t>(0xAB), static_cast<std::int8_t>(0xAB));
64   test_num<std::int16_t>(static_cast<std::int16_t>(0xCDEF), static_cast<std::int16_t>(0xEFCD));
65   test_num<std::int32_t>(0x01234567, 0x67452301);
66   test_num<std::int64_t>(0x0123456789ABCDEF, 0xEFCDAB8967452301);
67 
68 #ifndef TEST_HAS_NO_INT128
69   const auto in = static_cast<__uint128_t>(0x0123456789ABCDEF) << 64 | 0x13579BDF02468ACE;
70   const auto expected = static_cast<__uint128_t>(0xCE8A4602DF9B5713) << 64 | 0xEFCDAB8967452301;
71   test_num<__uint128_t>(in, expected);
72   test_num<__int128_t>(in, expected);
73 #endif
74 
75   test_num<bool>(true, true);
76   test_num<bool>(false, false);
77   test_num<char>(static_cast<char>(0xCD), static_cast<char>(0xCD));
78   test_num<unsigned char>(0xEF, 0xEF);
79   test_num<signed char>(0x45, 0x45);
80   test_num<char8_t>(0xAB, 0xAB);
81   test_num<char16_t>(0xABCD, 0xCDAB);
82   test_num<char32_t>(0xABCDEF01, 0x01EFCDAB);
83 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
84   test_implementation_defined_size<wchar_t>();
85 #endif
86 
87   test_implementation_defined_size<short>();
88   test_implementation_defined_size<unsigned short>();
89   test_implementation_defined_size<int>();
90   test_implementation_defined_size<unsigned int>();
91   test_implementation_defined_size<long>();
92   test_implementation_defined_size<unsigned long>();
93   test_implementation_defined_size<long long>();
94   test_implementation_defined_size<unsigned long long>();
95   return true;
96 }
97 
98 int main(int, char**) {
99   test();
100   static_assert(test());
101 
102   return 0;
103 }
104