88 lines · 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-exception6//7//===----------------------------------------------------------------------===//8 9// unsigned long to_ulong() const; // constexpr since C++2310 11#include <bitset>12#include <algorithm>13#include <type_traits>14#include <limits>15#include <climits>16#include <cassert>17#include <stdexcept>18 19#include "test_macros.h"20 21template <std::size_t N>22TEST_CONSTEXPR_CXX23 void test_to_ulong() {23 const std::size_t M = sizeof(unsigned long) * CHAR_BIT < N ? sizeof(unsigned long) * CHAR_BIT : N;24 const bool is_M_zero = std::integral_constant < bool, M == 0 > ::value; // avoid compiler warnings25 const std::size_t X = is_M_zero ? sizeof(unsigned long) * CHAR_BIT - 1 : sizeof(unsigned long) * CHAR_BIT - M;26 const std::size_t max = is_M_zero ? 0 : std::size_t(std::numeric_limits<unsigned long>::max()) >> X;27 std::size_t tests[] = {28 0,29 std::min<std::size_t>(1, max),30 std::min<std::size_t>(2, max),31 std::min<std::size_t>(3, max),32 std::min(max, max - 3),33 std::min(max, max - 2),34 std::min(max, max - 1),35 max};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 bitset42 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 warnings45 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#ifndef TEST_HAS_NO_EXCEPTIONS62 if (!TEST_IS_CONSTANT_EVALUATED) {63 // bitset has true bits beyond the size of unsigned long64 std::bitset<std::numeric_limits<unsigned long>::digits + 1> q(0);65 q.flip();66 try {67 (void)q.to_ulong(); // throws68 assert(false);69 } catch (const std::overflow_error&) {70 // expected71 } catch (...) {72 assert(false);73 }74 }75#endif // TEST_HAS_NO_EXCEPTIONS76 77 return true;78}79 80int main(int, char**) {81 test();82#if TEST_STD_VER > 2083 static_assert(test());84#endif85 86 return 0;87}88