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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// unsigned long to_ulong() const; // constexpr since C++23
#include <bitset>
#include <algorithm>
#include <type_traits>
#include <limits>
#include <climits>
#include <cassert>
#include <stdexcept>
#include "test_macros.h"
template <std::size_t N>
TEST_CONSTEXPR_CXX23 void test_to_ulong() {
const std::size_t M = sizeof(unsigned long) * CHAR_BIT < N ? sizeof(unsigned long) * CHAR_BIT : N;
const bool is_M_zero = std::integral_constant < bool, M == 0 > ::value; // avoid compiler warnings
const std::size_t X = is_M_zero ? sizeof(unsigned long) * CHAR_BIT - 1 : sizeof(unsigned long) * CHAR_BIT - M;
const std::size_t max = is_M_zero ? 0 : std::size_t(std::numeric_limits<unsigned long>::max()) >> X;
std::size_t tests[] = {
0,
std::min<std::size_t>(1, max),
std::min<std::size_t>(2, max),
std::min<std::size_t>(3, max),
std::min(max, max - 3),
std::min(max, max - 2),
std::min(max, max - 1),
max};
for (std::size_t j : tests) {
std::bitset<N> v(j);
assert(j == v.to_ulong());
}
{ // test values bigger than can fit into the bitset
const unsigned long val = 0x5AFFFFA5UL;
const bool canFit = N < sizeof(unsigned long) * CHAR_BIT;
const unsigned long mask = canFit ? (1UL << (canFit ? N : 0)) - 1 : (unsigned long)(-1); // avoid compiler warnings
std::bitset<N> v(val);
assert(v.to_ulong() == (val & mask)); // we shouldn't return bit patterns from outside the limits of the bitset.
}
}
TEST_CONSTEXPR_CXX23 bool test() {
test_to_ulong<0>();
test_to_ulong<1>();
test_to_ulong<31>();
test_to_ulong<32>();
test_to_ulong<33>();
test_to_ulong<63>();
test_to_ulong<64>();
test_to_ulong<65>();
test_to_ulong<1000>();
#ifndef TEST_HAS_NO_EXCEPTIONS
if (!TEST_IS_CONSTANT_EVALUATED) {
// bitset has true bits beyond the size of unsigned long
std::bitset<std::numeric_limits<unsigned long>::digits + 1> q(0);
q.flip();
try {
(void)q.to_ulong(); // throws
assert(false);
} catch (const std::overflow_error&) {
// expected
} catch (...) {
assert(false);
}
}
#endif // TEST_HAS_NO_EXCEPTIONS
return true;
}
int main(int, char**) {
test();
#if TEST_STD_VER > 20
static_assert(test());
#endif
return 0;
}
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