NetBSD/usr.sbin/sysinst/factor.c
dholland 50dbef1a09 Move sysinst sources to usr.sbin.
This commit only physically moves the sources - there are no other
changes, to maximize the probability that this will be treated as a
rename if we ever do manage to migrate away from CVS.

Moving sysinst has been discussed on and off for years and has two
goals: making it easier to work on sysinst, and also making sysinst
available on running systems for use installing chroots and VM images
and other such things. None of the latter is possible yet, but as they
say, one thing at a time.

Doing this now was approved in an impromptu fashion by mrg, riz,
riastradh, me, and groo.
2014-07-26 19:30:39 +00:00

152 lines
3.8 KiB
C

/* $NetBSD: factor.c,v 1.1 2014/07/26 19:30:44 dholland Exp $ */
/*
* Copyright 1997 Piermont Information Systems Inc.
* All rights reserved.
*
* Written by Philip A. Nelson for Piermont Information Systems Inc.
*
* 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. The name of Piermont Information Systems Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY PIERMONT INFORMATION SYSTEMS INC. ``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 PIERMONT INFORMATION SYSTEMS INC. 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.
*
*/
/* Prototypes for strict prototyping. */
#include <sys/cdefs.h>
#include <stdio.h>
/*
* primes - prime table, built to include up to 46345 because
* sqrt(2^31) = 46340.9500118415
*
* building the table instead of storing a precomputed table saves
* about 19K of space on the binary image.
*/
#ifdef TESTING
long primes[4800];
int num_primes = 2;
static void build_primes (long max);
void factor (long val, long *fact_list, int fact_size, int *num_fact);
static void
build_primes(max)
long max;
{
long pc;
int j;
long rem;
/*
* Initialise primes at run-time rather than compile time
* so it's put in bss rather than data.
*/
primes[0] = 2;
primes[1] = 3;
for (pc = primes[num_primes-1]; pc < 46345 && pc*pc <= max; pc+=2) {
j = 0;
rem = 1;
while (j < num_primes && primes[j] * primes[j] <= pc) {
if ((rem = pc % primes[j]) == 0)
break;
j++;
}
if (rem)
primes[num_primes++] = pc;
}
}
/* factor: prepare a list of prime factors of val.
The last number may not be a prime factor is the list is not
long enough. */
void
factor(val, fact_list, fact_size, num_fact)
long val;
long *fact_list;
int fact_size;
int *num_fact;
{
int i;
/* Check to make sure we have enough primes. */
build_primes(val);
i = 0;
*num_fact = 0;
while (*num_fact < fact_size-1 && val > 1 && i < num_primes) {
/* Find the next prime that divides. */
while (i < num_primes && val % primes[i] != 0) i++;
/* Put factors in array. */
while (*num_fact < fact_size-1 && i < num_primes &&
val % primes[i] == 0) {
fact_list[(*num_fact)++] = primes[i];
val /= primes[i];
}
}
if (val > 1)
fact_list[(*num_fact)++] = val;
}
#include <stdio.h>
#include <stdlib.h>
int
main(int argc, char **argv)
{
long facts[30];
long val;
int i, nfact;
int arg;
if (argc < 2) {
fprintf (stderr, "usage: %s numbers\n", argv[0]);
exit(1);
}
/* Factor each arg! */
for (arg = 1; arg < argc; arg++) {
val = atol(argv[arg]);
factor (val, facts, 30, &nfact);
printf ("%ld:", val);
for (i = 0; i<nfact; i++)
printf (" %ld", facts[i]);
printf ("\n");
}
return 0;
}
#endif