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/*
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright © 2020 Keith Packard
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#define _DEFAULT_SOURCE
#include <strings.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
static long long int
rand_long_long(void)
{
unsigned long long int r = 0;
size_t x;
for (x = 0; x < sizeof(r) / 4; x++)
r = (r << 32) | (lrand48() & 0xffffffffL);
return r;
}
static int
slow_ffs(int i)
{
int p;
if (!i)
return 0;
for (p = 1; (i & (1U << (p - 1))) == 0; p++)
;
return p;
}
static int
slow_ffsl(long int i)
{
int p;
if (!i)
return 0;
for (p = 1; (i & (1UL << (p - 1))) == 0; p++)
;
return p;
}
static int
slow_ffsll(long long int i)
{
int p;
if (!i)
return 0;
for (p = 1; (i & (1ULL << (p - 1))) == 0; p++)
;
return p;
}
static int
check(long long int x, int got, int expect, char *which)
{
long int low = x & 0xffffffffl;
long int high = ((x >> 16) >> 16) & 0xffffffffl;
if (got != expect) {
printf("failed %s(%08lx%08lx): got %d expect %d\n", which, high, low, got, expect);
return 1;
}
return 0;
}
int
main(void)
{
int ret = 0;
/* Test zero */
ret += check(0, ffs(0), slow_ffs(0), "ffs");
ret += check(0, ffsl(0), slow_ffsl(0), "ffsl");
ret += check(0, ffsll(0), slow_ffsll(0), "ffsll");
/* Test every bit position in a long long */
for (size_t i = 0; i < sizeof(long long) * 8; i++) {
long long int xll = 1ULL << i;
long xl = (long)xll;
int x = (int)xll;
ret += check(x, ffs(x), slow_ffs(x), "ffs");
ret += check(xl, ffsl(xl), slow_ffsl(xl), "ffsl");
ret += check(xll, ffsll(xll), slow_ffsll(xll), "ffsll");
}
/* Test another few random values */
#define N 100000
for (int32_t i = 0; i < N; i++) {
long long int xll = rand_long_long();
long xl = (long)xll;
int x = (int)xll;
ret += check(x, ffs(x), slow_ffs(x), "ffs");
ret += check(xl, ffsl(xl), slow_ffsl(xl), "ffsl");
ret += check(xll, ffsll(xll), slow_ffsll(xll), "ffsll");
}
return ret;
}