libcxx/test/std/numerics/bit/bit.pow.two/has_single_bit.pass.cpp

   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 bool has_single_bit(T x) noexcept;
  13
  14 // Constraints: T is an unsigned integer type
  15
  16 #include <bit>
  17 #include <cassert>
  18 #include <cstdint>
  19 #include <limits>
  20 #include <type_traits>
  21
  22 #include "test_macros.h"
  23
  24 struct A {};
  25 enum       E1 : unsigned char { rEd };
  26 enum class E2 : unsigned char { red };
  27
  28 template <class T>
  29 constexpr bool test()
  30 {
  31     ASSERT_SAME_TYPE(decltype(std::has_single_bit(T())), bool);
  32     ASSERT_NOEXCEPT(std::has_single_bit(T()));
  33     T max = std::numeric_limits<T>::max();
  34
  35     assert(!std::has_single_bit(T(0)));
  36     assert( std::has_single_bit(T(1)));
  37     assert( std::has_single_bit(T(2)));
  38     assert(!std::has_single_bit(T(3)));
  39     assert( std::has_single_bit(T(4)));
  40     assert(!std::has_single_bit(T(5)));
  41     assert(!std::has_single_bit(T(6)));
  42     assert(!std::has_single_bit(T(7)));
  43     assert( std::has_single_bit(T(8)));
  44     assert(!std::has_single_bit(T(9)));
  45     assert(!std::has_single_bit(T(127)));
  46     assert( std::has_single_bit(T(128)));
  47     assert(!std::has_single_bit(T(129)));
  48     assert(!std::has_single_bit(max));
  49
  50 #ifndef TEST_HAS_NO_INT128
  51     if constexpr (std::is_same_v<T, __uint128_t>) {
  52         T val = T(1) << 32;
  53         assert(!std::has_single_bit(val-1));
  54         assert( std::has_single_bit(val));
  55         assert(!std::has_single_bit(val+1));
  56         val <<= 60;
  57         assert(!std::has_single_bit(val-1));
  58         assert( std::has_single_bit(val));
  59         assert(!std::has_single_bit(val+1));
  60
  61         T x = (T(1) << 63);
  62         T y = (T(1) << 64);
  63         assert( std::has_single_bit(x));
  64         assert( std::has_single_bit(y));
  65         assert(!std::has_single_bit(x + y));
  66     }
  67 #endif
  68
  69     return true;
  70 }
  71
  72 int main(int, char**)
  73 {
  74     {
  75     auto lambda = [](auto x) -> decltype(std::has_single_bit(x)) {};
  76     using L = decltype(lambda);
  77
  78     static_assert(!std::is_invocable_v<L, signed char>);
  79     static_assert(!std::is_invocable_v<L, short>);
  80     static_assert(!std::is_invocable_v<L, int>);
  81     static_assert(!std::is_invocable_v<L, long>);
  82     static_assert(!std::is_invocable_v<L, long long>);
  83 #ifndef TEST_HAS_NO_INT128
  84     static_assert(!std::is_invocable_v<L, __int128_t>);
  85 #endif
  86
  87     static_assert(!std::is_invocable_v<L, std::int8_t>);
  88     static_assert(!std::is_invocable_v<L, std::int16_t>);
  89     static_assert(!std::is_invocable_v<L, std::int32_t>);
  90     static_assert(!std::is_invocable_v<L, std::int64_t>);
  91     static_assert(!std::is_invocable_v<L, std::intmax_t>);
  92     static_assert(!std::is_invocable_v<L, std::intptr_t>);
  93     static_assert(!std::is_invocable_v<L, std::ptrdiff_t>);
  94
  95     static_assert(!std::is_invocable_v<L, bool>);
  96     static_assert(!std::is_invocable_v<L, char>);
  97     static_assert(!std::is_invocable_v<L, wchar_t>);
  98 #ifndef TEST_HAS_NO_CHAR8_T
  99     static_assert(!std::is_invocable_v<L, char8_t>);
 100 #endif
 101     static_assert(!std::is_invocable_v<L, char16_t>);
 102     static_assert(!std::is_invocable_v<L, char32_t>);
 103
 104     static_assert(!std::is_invocable_v<L, A>);
 105     static_assert(!std::is_invocable_v<L, A*>);
 106     static_assert(!std::is_invocable_v<L, E1>);
 107     static_assert(!std::is_invocable_v<L, E2>);
 108     }
 109
 110     static_assert(test<unsigned char>());
 111     static_assert(test<unsigned short>());
 112     static_assert(test<unsigned int>());
 113     static_assert(test<unsigned long>());
 114     static_assert(test<unsigned long long>());
 115 #ifndef TEST_HAS_NO_INT128
 116     static_assert(test<__uint128_t>());
 117 #endif
 118     static_assert(test<std::uint8_t>());
 119     static_assert(test<std::uint16_t>());
 120     static_assert(test<std::uint32_t>());
 121     static_assert(test<std::uint64_t>());
 122     static_assert(test<std::uintmax_t>());
 123     static_assert(test<std::uintptr_t>());
 124     static_assert(test<std::size_t>());
 125
 126     test<unsigned char>();
 127     test<unsigned short>();
 128     test<unsigned int>();
 129     test<unsigned long>();
 130     test<unsigned long long>();
 131 #ifndef TEST_HAS_NO_INT128
 132     test<__uint128_t>();
 133 #endif
 134     test<std::uint8_t>();
 135     test<std::uint16_t>();
 136     test<std::uint32_t>();
 137     test<std::uint64_t>();
 138     test<std::uintmax_t>();
 139     test<std::uintptr_t>();
 140     test<std::size_t>();
 141
 142     return 0;
 143 }