libcxx/test/std/language.support/support.limits/limits/numeric.limits.members/digits.pass.cpp

//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

// test numeric_limits

// digits

#include <limits>
#include <cfloat>

#include "test_macros.h"

template <class T, int expected>
void
test()
{
    static_assert(std::numeric_limits<T>::digits == expected, "digits test 1");
    static_assert(std::numeric_limits<const T>::digits == expected, "digits test 2");
    static_assert(std::numeric_limits<volatile T>::digits == expected, "digits test 3");
    static_assert(std::numeric_limits<const volatile T>::digits == expected, "digits test 4");
}

int main(int, char**)
{
    test<bool, 1>();
    test<char, std::numeric_limits<char>::is_signed ? 7 : 8>();
    test<signed char, 7>();
    test<unsigned char, 8>();
    test<wchar_t, std::numeric_limits<wchar_t>::is_signed ? sizeof(wchar_t)*8-1 : sizeof(wchar_t)*8>();
#if TEST_STD_VER > 17 && defined(__cpp_char8_t)
    test<char8_t, 8>();
#endif
    test<char16_t, 16>();
    test<char32_t, 32>();
    test<short, 15>();
    test<unsigned short, 16>();
    test<int, 31>();
    test<unsigned int, 32>();
    test<long, sizeof(long) == 4 ? 31 : 63>();
    test<unsigned long, sizeof(long) == 4 ? 32 : 64>();
    test<long long, 63>();
    test<unsigned long long, 64>();
#ifndef TEST_HAS_NO_INT128
    test<__int128_t, 127>();
    test<__uint128_t, 128>();
#endif
    test<float, FLT_MANT_DIG>();
    test<double, DBL_MANT_DIG>();
    test<long double, LDBL_MANT_DIG>();

    // _BitInt(N): digits must equal N for unsigned and N-1 for signed,
    // regardless of padding bits for non-byte-aligned widths.
#if TEST_HAS_EXTENSION(bit_int)
    // Byte-aligned widths.
    test<unsigned _BitInt(8), 8>();
    test<signed _BitInt(8), 7>();
    test<unsigned _BitInt(32), 32>();
    test<signed _BitInt(32), 31>();
    test<unsigned _BitInt(64), 64>();
    test<signed _BitInt(64), 63>();

    // Non-byte-aligned widths.
    test<unsigned _BitInt(7), 7>();
    test<signed _BitInt(7), 6>();
    test<unsigned _BitInt(13), 13>();
    test<signed _BitInt(13), 12>();
    test<unsigned _BitInt(37), 37>();
    test<signed _BitInt(37), 36>();
#  if __BITINT_MAXWIDTH__ >= 128
    test<unsigned _BitInt(77), 77>();
    test<signed _BitInt(77), 76>();
    test<unsigned _BitInt(128), 128>();
    test<signed _BitInt(128), 127>();
#  endif
#  if __BITINT_MAXWIDTH__ >= 256
    test<unsigned _BitInt(129), 129>();
    test<signed _BitInt(129), 128>();
    test<unsigned _BitInt(255), 255>();
    test<signed _BitInt(255), 254>();
    test<unsigned _BitInt(256), 256>();
    test<signed _BitInt(256), 255>();
#  endif
#  if __BITINT_MAXWIDTH__ >= 4096
    test<unsigned _BitInt(4096), 4096>();
    test<signed _BitInt(4096), 4095>();
#  endif
#endif // TEST_HAS_EXTENSION(bit_int)

    return 0;
}