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/* Test for the C++ implementation of iszero.
Copyright (C) 2016-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#define _GNU_SOURCE 1
#include <math.h>
#include <stdio.h>
#include <limits>
/* Support for _Float128 in std::numeric_limits is limited.
Include ieee754_float128.h and use the bitfields in the union
ieee854_float128.ieee_nan to build corner-case inputs. */
#if __HAVE_DISTINCT_FLOAT128
# include <ieee754_float128.h>
#endif
static bool errors;
static void
check (int actual, int expected, const char *actual_expr, int line)
{
if (actual != expected)
{
errors = true;
printf ("%s:%d: error: %s\n", __FILE__, line, actual_expr);
printf ("%s:%d: expected: %d\n", __FILE__, line, expected);
printf ("%s:%d: actual: %d\n", __FILE__, line, actual);
}
}
#define CHECK(actual, expected) \
check ((actual), (expected), #actual, __LINE__)
template <class T>
static void
check_type ()
{
typedef std::numeric_limits<T> limits;
CHECK (iszero (T{}), 1);
CHECK (iszero (T{0}), 1);
CHECK (iszero (T{-0.0}), 1);
CHECK (iszero (T{1}), 0);
CHECK (iszero (T{-1}), 0);
CHECK (iszero (limits::min ()), 0);
CHECK (iszero (-limits::min ()), 0);
CHECK (iszero (limits::max ()), 0);
CHECK (iszero (-limits::max ()), 0);
if (limits::has_infinity)
{
CHECK (iszero (limits::infinity ()), 0);
CHECK (iszero (-limits::infinity ()), 0);
}
CHECK (iszero (limits::epsilon ()), 0);
CHECK (iszero (-limits::epsilon ()), 0);
if (limits::has_quiet_NaN)
CHECK (iszero (limits::quiet_NaN ()), 0);
if (limits::has_signaling_NaN)
CHECK (iszero (limits::signaling_NaN ()), 0);
if (limits::has_signaling_NaN)
CHECK (iszero (limits::signaling_NaN ()), 0);
CHECK (iszero (limits::denorm_min ()),
std::numeric_limits<T>::has_denorm == std::denorm_absent);
CHECK (iszero (-limits::denorm_min ()),
std::numeric_limits<T>::has_denorm == std::denorm_absent);
}
#if __HAVE_DISTINCT_FLOAT128
static void
check_float128 ()
{
ieee854_float128 q;
q.d = 0.0Q;
CHECK (iszero (q.d), 1);
q.d = -0.0Q;
CHECK (iszero (q.d), 1);
q.d = 1.0Q;
CHECK (iszero (q.d), 0);
q.d = -1.0Q;
CHECK (iszero (q.d), 0);
/* Normal min. */
q.ieee.negative = 0;
q.ieee.exponent = 0x0001;
q.ieee.mantissa0 = 0x0000;
q.ieee.mantissa1 = 0x00000000;
q.ieee.mantissa2 = 0x00000000;
q.ieee.mantissa3 = 0x00000000;
CHECK (iszero (q.d), 0);
q.ieee.negative = 1;
CHECK (iszero (q.d), 0);
/* Normal max. */
q.ieee.negative = 0;
q.ieee.exponent = 0x7FFE;
q.ieee.mantissa0 = 0xFFFF;
q.ieee.mantissa1 = 0xFFFFFFFF;
q.ieee.mantissa2 = 0xFFFFFFFF;
q.ieee.mantissa3 = 0xFFFFFFFF;
CHECK (iszero (q.d), 0);
q.ieee.negative = 1;
CHECK (iszero (q.d), 0);
/* Infinity. */
q.ieee.negative = 0;
q.ieee.exponent = 0x7FFF;
q.ieee.mantissa0 = 0x0000;
q.ieee.mantissa1 = 0x00000000;
q.ieee.mantissa2 = 0x00000000;
q.ieee.mantissa3 = 0x00000000;
CHECK (iszero (q.d), 0);
/* Quiet NaN. */
q.ieee_nan.quiet_nan = 1;
q.ieee_nan.mantissa0 = 0x0000;
CHECK (iszero (q.d), 0);
/* Signaling NaN. */
q.ieee_nan.quiet_nan = 0;
q.ieee_nan.mantissa0 = 0x4000;
CHECK (iszero (q.d), 0);
/* Denormal min. */
q.ieee.negative = 0;
q.ieee.exponent = 0x0000;
q.ieee.mantissa0 = 0x0000;
q.ieee.mantissa1 = 0x00000000;
q.ieee.mantissa2 = 0x00000000;
q.ieee.mantissa3 = 0x00000001;
CHECK (iszero (q.d), 0);
q.ieee.negative = 1;
CHECK (iszero (q.d), 0);
}
#endif
static int
do_test (void)
{
check_type<float> ();
check_type<double> ();
check_type<long double> ();
#if __HAVE_DISTINCT_FLOAT128
check_float128 ();
#endif
return errors;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
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