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
10
11// template <class T>
12// constexpr int countl_one(T x) noexcept;
13
14// Constraints: T is an unsigned integer type
15// The number of consecutive 1 bits, starting from the most significant bit.
16// [ Note: Returns N if x == std::numeric_limits<T>::max(). ]
17
18#include <bit>
19#include <cassert>
20#include <cstddef>
21#include <cstdint>
22#include <limits>
23#include <type_traits>
24
25#include "test_macros.h"
26
27struct A {};
28enum E1 : unsigned char { rEd };
29enum class E2 : unsigned char { red };
30
31template <class T>
32constexpr bool test()
33{
34 ASSERT_SAME_TYPE(decltype(std::countl_one(T())), int);
35 ASSERT_NOEXCEPT(std::countl_one(T()));
36 T max = std::numeric_limits<T>::max();
37
38 assert(std::countl_one(T(0)) == 0);
39 assert(std::countl_one(T(1)) == 0);
40 assert(std::countl_one(T(10)) == 0);
41 assert(std::countl_one(T(100)) == 0);
42 assert(std::countl_one(max) == std::numeric_limits<T>::digits);
43 assert(std::countl_one(T(max - 1)) == std::numeric_limits<T>::digits - 1);
44 assert(std::countl_one(T(max - 2)) == std::numeric_limits<T>::digits - 2);
45 assert(std::countl_one(T(max - 3)) == std::numeric_limits<T>::digits - 2);
46 assert(std::countl_one(T(max - 4)) == std::numeric_limits<T>::digits - 3);
47 assert(std::countl_one(T(max - 5)) == std::numeric_limits<T>::digits - 3);
48 assert(std::countl_one(T(max - 6)) == std::numeric_limits<T>::digits - 3);
49 assert(std::countl_one(T(max - 7)) == std::numeric_limits<T>::digits - 3);
50 assert(std::countl_one(T(max - 8)) == std::numeric_limits<T>::digits - 4);
51 assert(std::countl_one(T(max - 9)) == std::numeric_limits<T>::digits - 4);
52 assert(std::countl_one(T(max - 126)) == std::numeric_limits<T>::digits - 7);
53 assert(std::countl_one(T(max - 127)) == std::numeric_limits<T>::digits - 7);
54 assert(std::countl_one(T(max - 128)) == std::numeric_limits<T>::digits - 8);
55
56#ifndef TEST_HAS_NO_INT128
57 if constexpr (std::is_same_v<T, __uint128_t>) {
58 T val = 128;
59 assert(std::countl_one(~val) == 120);
60 val <<= 32;
61 assert(std::countl_one(~val) == 88);
62 val <<= 60;
63 assert(std::countl_one(~val) == 28);
64 }
65#endif
66
67 return true;
68}
69
70int main(int, char**)
71{
72 {
73 auto lambda = [](auto x) -> decltype(std::countl_one(x)) {};
74 using L = decltype(lambda);
75
76 static_assert(!std::is_invocable_v<L, signed char>);
77 static_assert(!std::is_invocable_v<L, short>);
78 static_assert(!std::is_invocable_v<L, int>);
79 static_assert(!std::is_invocable_v<L, long>);
80 static_assert(!std::is_invocable_v<L, long long>);
81#ifndef TEST_HAS_NO_INT128
82 static_assert(!std::is_invocable_v<L, __int128_t>);
83#endif
84
85 static_assert(!std::is_invocable_v<L, std::int8_t>);
86 static_assert(!std::is_invocable_v<L, std::int16_t>);
87 static_assert(!std::is_invocable_v<L, std::int32_t>);
88 static_assert(!std::is_invocable_v<L, std::int64_t>);
89 static_assert(!std::is_invocable_v<L, std::intmax_t>);
90 static_assert(!std::is_invocable_v<L, std::intptr_t>);
91 static_assert(!std::is_invocable_v<L, std::ptrdiff_t>);
92
93 static_assert(!std::is_invocable_v<L, bool>);
94 static_assert(!std::is_invocable_v<L, char>);
95 static_assert(!std::is_invocable_v<L, wchar_t>);
96#ifndef TEST_HAS_NO_CHAR8_T
97 static_assert(!std::is_invocable_v<L, char8_t>);
98#endif
99 static_assert(!std::is_invocable_v<L, char16_t>);
100 static_assert(!std::is_invocable_v<L, char32_t>);
101
102 static_assert(!std::is_invocable_v<L, A>);
103 static_assert(!std::is_invocable_v<L, A*>);
104 static_assert(!std::is_invocable_v<L, E1>);
105 static_assert(!std::is_invocable_v<L, E2>);
106 }
107
108 static_assert(test<unsigned char>());
109 static_assert(test<unsigned short>());
110 static_assert(test<unsigned int>());
111 static_assert(test<unsigned long>());
112 static_assert(test<unsigned long long>());
113#ifndef TEST_HAS_NO_INT128
114 static_assert(test<__uint128_t>());
115#endif
116 static_assert(test<std::uint8_t>());
117 static_assert(test<std::uint16_t>());
118 static_assert(test<std::uint32_t>());
119 static_assert(test<std::uint64_t>());
120 static_assert(test<std::uintmax_t>());
121 static_assert(test<std::uintptr_t>());
122 static_assert(test<std::size_t>());
123
124 test<unsigned char>();
125 test<unsigned short>();
126 test<unsigned int>();
127 test<unsigned long>();
128 test<unsigned long long>();
129#ifndef TEST_HAS_NO_INT128
130 test<__uint128_t>();
131#endif
132 test<std::uint8_t>();
133 test<std::uint16_t>();
134 test<std::uint32_t>();
135 test<std::uint64_t>();
136 test<std::uintmax_t>();
137 test<std::uintptr_t>();
138 test<std::size_t>();
139
140 return 0;
141}
142

source code of libcxx/test/std/numerics/bit/bitops.count/countl_one.pass.cpp