libcxx/test/std/numerics/bit/bitops.count/popcount.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is dual licensed under the MIT and the University of Illinois Open
   6 // Source Licenses. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17
  10
  11 // template <class T>
  12 //   constexpr int popcount(T x) noexcept;
  13
  14 // Constraints: T is an unsigned integer type
  15 // Returns: The number of bits set to one in the value of x.
  16
  17 #include <bit>
  18 #include <cassert>
  19 #include <cstdint>
  20 #include <limits>
  21 #include <type_traits>
  22
  23 #include "test_macros.h"
  24
  25 struct A {};
  26 enum       E1 : unsigned char { rEd };
  27 enum class E2 : unsigned char { red };
  28
  29 template <class T>
  30 constexpr bool test()
  31 {
  32     ASSERT_SAME_TYPE(decltype(std::popcount(T())), int);
  33     ASSERT_NOEXCEPT(std::popcount(T()));
  34     T max = std::numeric_limits<T>::max();
  35
  36     assert(std::popcount(T(0)) == 0);
  37     assert(std::popcount(T(1)) == 1);
  38     assert(std::popcount(T(2)) == 1);
  39     assert(std::popcount(T(3)) == 2);
  40     assert(std::popcount(T(4)) == 1);
  41     assert(std::popcount(T(5)) == 2);
  42     assert(std::popcount(T(6)) == 2);
  43     assert(std::popcount(T(7)) == 3);
  44     assert(std::popcount(T(8)) == 1);
  45     assert(std::popcount(T(9)) == 2);
  46     assert(std::popcount(T(121)) == 5);
  47     assert(std::popcount(T(127)) == 7);
  48     assert(std::popcount(T(128)) == 1);
  49     assert(std::popcount(T(130)) == 2);
  50     assert(std::popcount(T(max >> 1)) == std::numeric_limits<T>::digits - 1);
  51     assert(std::popcount(T(max - 1)) == std::numeric_limits<T>::digits - 1);
  52     assert(std::popcount(max) == std::numeric_limits<T>::digits);
  53
  54 #ifndef TEST_HAS_NO_INT128
  55     if constexpr (std::is_same_v<T, __uint128_t>) {
  56         T val = 128;
  57         assert(std::popcount(val-1) ==  7);
  58         assert(std::popcount(val)   ==  1);
  59         assert(std::popcount(val+1) ==  2);
  60         val <<= 32;
  61         assert(std::popcount(val-1) == 39);
  62         assert(std::popcount(val)   ==  1);
  63         assert(std::popcount(val+1) ==  2);
  64         val <<= 60;
  65         assert(std::popcount(val-1) == 99);
  66         assert(std::popcount(val)   ==  1);
  67         assert(std::popcount(val+1) ==  2);
  68
  69         T x = T(1) << 63;
  70         T y = T(1) << 64;
  71         assert(std::popcount(x) == 1);
  72         assert(std::popcount(y) == 1);
  73         assert(std::popcount(x+y) == 2);
  74     }
  75 #endif
  76
  77     return true;
  78 }
  79
  80 int main(int, char**)
  81 {
  82     {
  83     auto lambda = [](auto x) -> decltype(std::popcount(x)) {};
  84     using L = decltype(lambda);
  85
  86     static_assert(!std::is_invocable_v<L, signed char>);
  87     static_assert(!std::is_invocable_v<L, short>);
  88     static_assert(!std::is_invocable_v<L, int>);
  89     static_assert(!std::is_invocable_v<L, long>);
  90     static_assert(!std::is_invocable_v<L, long long>);
  91 #ifndef TEST_HAS_NO_INT128
  92     static_assert(!std::is_invocable_v<L, __int128_t>);
  93 #endif
  94
  95     static_assert(!std::is_invocable_v<L, std::int8_t>);
  96     static_assert(!std::is_invocable_v<L, std::int16_t>);
  97     static_assert(!std::is_invocable_v<L, std::int32_t>);
  98     static_assert(!std::is_invocable_v<L, std::int64_t>);
  99     static_assert(!std::is_invocable_v<L, std::intmax_t>);
 100     static_assert(!std::is_invocable_v<L, std::intptr_t>);
 101     static_assert(!std::is_invocable_v<L, std::ptrdiff_t>);
 102
 103     static_assert(!std::is_invocable_v<L, bool>);
 104     static_assert(!std::is_invocable_v<L, char>);
 105     static_assert(!std::is_invocable_v<L, wchar_t>);
 106 #ifndef TEST_HAS_NO_CHAR8_T
 107     static_assert(!std::is_invocable_v<L, char8_t>);
 108 #endif
 109     static_assert(!std::is_invocable_v<L, char16_t>);
 110     static_assert(!std::is_invocable_v<L, char32_t>);
 111
 112     static_assert(!std::is_invocable_v<L, A>);
 113     static_assert(!std::is_invocable_v<L, A*>);
 114     static_assert(!std::is_invocable_v<L, E1>);
 115     static_assert(!std::is_invocable_v<L, E2>);
 116     }
 117
 118     static_assert(test<unsigned char>());
 119     static_assert(test<unsigned short>());
 120     static_assert(test<unsigned int>());
 121     static_assert(test<unsigned long>());
 122     static_assert(test<unsigned long long>());
 123 #ifndef TEST_HAS_NO_INT128
 124     static_assert(test<__uint128_t>());
 125 #endif
 126     static_assert(test<std::uint8_t>());
 127     static_assert(test<std::uint16_t>());
 128     static_assert(test<std::uint32_t>());
 129     static_assert(test<std::uint64_t>());
 130     static_assert(test<std::uintmax_t>());
 131     static_assert(test<std::uintptr_t>());
 132     static_assert(test<std::size_t>());
 133
 134     test<unsigned char>();
 135     test<unsigned short>();
 136     test<unsigned int>();
 137     test<unsigned long>();
 138     test<unsigned long long>();
 139 #ifndef TEST_HAS_NO_INT128
 140     test<__uint128_t>();
 141 #endif
 142     test<std::uint8_t>();
 143     test<std::uint16_t>();
 144     test<std::uint32_t>();
 145     test<std::uint64_t>();
 146     test<std::uintmax_t>();
 147     test<std::uintptr_t>();
 148     test<std::size_t>();
 149
 150     return 0;
 151 }