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// unsigned long to_ulong() const; // constexpr since C++23
10
11#include <bitset>
12#include <algorithm>
13#include <type_traits>
14#include <limits>
15#include <climits>
16#include <cassert>
17
18#include "test_macros.h"
19
20template <std::size_t N>
21TEST_CONSTEXPR_CXX23 void test_to_ulong() {
22 const std::size_t M = sizeof(unsigned long) * CHAR_BIT < N ? sizeof(unsigned long) * CHAR_BIT : N;
23 const bool is_M_zero = std::integral_constant<bool, M == 0>::value; // avoid compiler warnings
24 const std::size_t X = is_M_zero ? sizeof(unsigned long) * CHAR_BIT - 1 : sizeof(unsigned long) * CHAR_BIT - M;
25 const std::size_t max = is_M_zero ? 0 : std::size_t(std::numeric_limits<unsigned long>::max()) >> X;
26 std::size_t tests[] = {
27 0,
28 std::min<std::size_t>(1, max),
29 std::min<std::size_t>(2, max),
30 std::min<std::size_t>(3, max),
31 std::min(max, max-3),
32 std::min(max, max-2),
33 std::min(max, max-1),
34 max
35 };
36 for (std::size_t j : tests) {
37 std::bitset<N> v(j);
38 assert(j == v.to_ulong());
39 }
40
41 { // test values bigger than can fit into the bitset
42 const unsigned long val = 0x5AFFFFA5UL;
43 const bool canFit = N < sizeof(unsigned long) * CHAR_BIT;
44 const unsigned long mask = canFit ? (1UL << (canFit ? N : 0)) - 1 : (unsigned long)(-1); // avoid compiler warnings
45 std::bitset<N> v(val);
46 assert(v.to_ulong() == (val & mask)); // we shouldn't return bit patterns from outside the limits of the bitset.
47 }
48}
49
50TEST_CONSTEXPR_CXX23 bool test() {
51 test_to_ulong<0>();
52 test_to_ulong<1>();
53 test_to_ulong<31>();
54 test_to_ulong<32>();
55 test_to_ulong<33>();
56 test_to_ulong<63>();
57 test_to_ulong<64>();
58 test_to_ulong<65>();
59 test_to_ulong<1000>();
60
61 return true;
62}
63
64int main(int, char**) {
65 test();
66#if TEST_STD_VER > 20
67 static_assert(test());
68#endif
69
70 return 0;
71}
72

source code of libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp