Imported and adapted from FreeBSD svn r272166 and r272207; this fixes

false positives for products of primes larger than 2^16. For example,
before this commit:

  $ /usr/games/primes 4295360521 4295360522
  4295360521
but
  $ /usr/games/factor 4295360521
  4295360521: 65539 65539

or
  $ /usr/games/primes 3825123056546413049 3825123056546413050
  3825123056546413049
yet
  $ /usr/games/factor 3825123056546413049
  3825123056546413049: 165479 23115459100831

or
  $ /usr/games/primes 18446744073709551577
  18446744073709551577
although
  $ /usr/games/factor 18446744073709551577
  18446744073709551577: 139646831 132095686967

Incidentally, the above examples show the smallest and largest cases that
were erroneously stated as prime in the range 2^32 .. 3825123056546413049
.. 2^64; the primes(6) program now stops at 3825123056546413050 as
primality tests on larger integers would be by brute force factorization.

In addition, special to the NetBSD version:
. for -d option, skip first difference when start is >65537 as it is incorrect
. corrected usage to mention both the existing -d as well as the new -h option

For original FreeBSD commit message by Colin Percival, see:
http://svnweb.freebsd.org/base?view=revision&revision=272166
This commit is contained in:
ast 2014-10-02 21:36:37 +00:00
parent 4460f134df
commit bfe1fbfe02
9 changed files with 344 additions and 124 deletions

View File

@ -1,4 +1,4 @@
.\" $NetBSD: factor.6,v 1.12 2010/05/15 21:22:39 joerg Exp $
.\" $NetBSD: factor.6,v 1.13 2014/10/02 21:36:37 ast Exp $
.\"
.\" Copyright (c) 1989, 1993
.\" The Regents of the University of California. All rights reserved.
@ -33,9 +33,7 @@
.\" @(#)factor.6 8.1 (Berkeley) 5/31/93
.\"
.\"
.\" By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
.\"
.\" chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
.\" By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
.\"
.Dd May 15, 2010
.Dt FACTOR 6
@ -88,10 +86,7 @@ is compiled without OpenSSL it is limited to the maximum value of
.Vt unsigned long .
.Sh DIAGNOSTICS
Out of range or invalid input results in
an appropriate error message
being written to standard error.
.\".Sh BUGS
.\".Nm
.\"cannot handle the
.\".Dq 10 most wanted
.\"factor list.
an appropriate error message to standard error.
.Sh AUTHORS
Originally by
.An Landon Curt Noll .

View File

@ -1,4 +1,4 @@
/* $NetBSD: factor.c,v 1.26 2011/11/09 20:17:44 drochner Exp $ */
/* $NetBSD: factor.c,v 1.27 2014/10/02 21:36:37 ast Exp $ */
/*
* Copyright (c) 1989, 1993
@ -42,16 +42,14 @@ __COPYRIGHT("@(#) Copyright (c) 1989, 1993\
#if 0
static char sccsid[] = "@(#)factor.c 8.4 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: factor.c,v 1.26 2011/11/09 20:17:44 drochner Exp $");
__RCSID("$NetBSD: factor.c,v 1.27 2014/10/02 21:36:37 ast Exp $");
#endif
#endif /* not lint */
/*
* factor - factor a number into primes
*
* By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
*
* chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
* By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
*
* usage:
* factor [number] ...
@ -72,6 +70,7 @@ __RCSID("$NetBSD: factor.c,v 1.26 2011/11/09 20:17:44 drochner Exp $");
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <inttypes.h>
#ifdef HAVE_OPENSSL
#include <openssl/bn.h>
@ -93,8 +92,7 @@ static int BN_dec2bn(BIGNUM **a, const char *str);
* We are able to sieve 2^32-1 because this byte table yields all primes
* up to 65537 and 65537^2 > 2^32-1.
*/
extern const ubig prime[];
extern const ubig *pr_limit; /* largest prime in the prime array */
#if 0 /* debugging: limit table use to stress the "pollard" code */
#define pr_limit &prime[0]
#endif
@ -198,7 +196,7 @@ main(int argc, char *argv[])
static void
pr_fact(BIGNUM *val)
{
const ubig *fact; /* The factor found. */
const uint64_t *fact; /* The factor found. */
/* Firewall - catch 0 and 1. */
if (BN_is_zero(val) || BN_is_one(val))
@ -239,7 +237,7 @@ pr_fact(BIGNUM *val)
/* Divide factor out until none are left. */
do {
printf(" %lu", *fact);
printf(" %" PRIu64, *fact);
BN_div_word(val, (BN_ULONG)*fact);
} while (BN_mod_word(val, (BN_ULONG)*fact) == 0);

View File

@ -1,8 +1,8 @@
# $NetBSD: Makefile,v 1.7 2004/02/08 13:16:25 jsm Exp $
# $NetBSD: Makefile,v 1.8 2014/10/02 21:36:37 ast Exp $
# @(#)Makefile 8.1 (Berkeley) 5/31/93
PROG= primes
SRCS= pattern.c pr_tbl.c primes.c
SRCS= pattern.c pr_tbl.c primes.c spsp.c
MAN= primes.6
DPADD= ${LIBM}
LDADD= -lm

View File

@ -1,4 +1,4 @@
/* $NetBSD: pattern.c,v 1.6 2003/08/07 09:37:33 agc Exp $ */
/* $NetBSD: pattern.c,v 1.7 2014/10/02 21:36:37 ast Exp $ */
/*
* Copyright (c) 1989, 1993
@ -32,21 +32,20 @@
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include <sys/types.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)pattern.c 8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: pattern.c,v 1.6 2003/08/07 09:37:33 agc Exp $");
__RCSID("$NetBSD: pattern.c,v 1.7 2014/10/02 21:36:37 ast Exp $");
#endif
#endif /* not lint */
/*
* pattern - the Eratosthenes sieve on odd numbers for 3,5,7,11 and 13
*
* By: Landon Curt Noll chongo@toad.com
*
* chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
* By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
*
* To avoid excessive sieves for small factors, we use the table below to
* setup our sieve blocks. Each element represents a odd number starting
@ -440,4 +439,4 @@ const char pattern[] = {
0,0,1,1,0,0,0,0,1,1,0,0,1,0,1,0,0,0,0,0,0,1,0,1,1,0,1,1,0,1,0,0,0,1,0,0,1,0,1,
0,0,1,1,0,1,0,0,1,1,0,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,0,0,0,0,0,0,1
};
const int pattern_size = (sizeof(pattern)/sizeof(pattern[0]));
const size_t pattern_size = (sizeof(pattern)/sizeof(pattern[0]));

View File

@ -1,4 +1,4 @@
/* $NetBSD: pr_tbl.c,v 1.7 2003/08/07 09:37:33 agc Exp $ */
/* $NetBSD: pr_tbl.c,v 1.8 2014/10/02 21:36:37 ast Exp $ */
/*
* Copyright (c) 1989, 1993
@ -37,24 +37,24 @@
#if 0
static char sccsid[] = "@(#)pr_tbl.c 8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: pr_tbl.c,v 1.7 2003/08/07 09:37:33 agc Exp $");
__RCSID("$NetBSD: pr_tbl.c,v 1.8 2014/10/02 21:36:37 ast Exp $");
#endif
#endif /* not lint */
/*
* prime - prime table
*
* By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
* By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
*
* chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
*
* We are able to sieve 2^32-1 because this table has primes up to 65537
* We are able to sieve 2^32-1 because this table has primes up to 65537
* and 65537^2 > 2^32-1.
*/
#include <stddef.h>
#include "primes.h"
const ubig prime[] = {
const uint64_t prime[] = {
2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,
107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,
211,223,227,229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,
@ -546,4 +546,4 @@ const ubig prime[] = {
};
/* pr_limit - largest prime in the prime table */
const ubig *pr_limit = &prime[(sizeof(prime)/sizeof(prime[0]))-1];
const uint64_t *const pr_limit = &prime[(sizeof(prime)/sizeof(prime[0]))-1];

View File

@ -1,4 +1,4 @@
.\" $NetBSD: primes.6,v 1.3 2008/02/03 03:29:17 wiz Exp $
.\" $NetBSD: primes.6,v 1.4 2014/10/02 21:36:37 ast Exp $
.\"
.\" Copyright (c) 1989, 1993
.\" The Regents of the University of California. All rights reserved.
@ -33,9 +33,7 @@
.\" @(#)factor.6 8.1 (Berkeley) 5/31/93
.\"
.\"
.\" By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
.\"
.\" chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
.\" By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
.\"
.Dd February 3, 2008
.Dt PRIMES 6
@ -46,6 +44,7 @@
.Sh SYNOPSIS
.Nm primes
.Op Fl d
.Op Fl h
.Op Ar start Op Ar stop
.Sh DESCRIPTION
The
@ -61,18 +60,18 @@ value must be at least 0 and not greater than
.Ar stop .
The
.Ar stop
value must not be greater than 4294967295.
value must not be greater than 3825123056546413050.
The default value of
.Ar stop
is 4294967295.
is 3825123056546413050.
.Pp
When the
.Nm
utility is invoked with no arguments,
.Ar start
is read from standard input.
is read from standard input and
.Ar stop
is taken to be 4294967295.
is taken to be 3825123056546413050.
The
.Ar start
value may be preceded by a single
@ -81,15 +80,34 @@ The
.Ar start
value is terminated by a non-digit character (such as a newline).
The input line must not be longer than 255 characters.
.Pp
When given the
.Fl d
argument,
.Nm
prints the difference between the current and the previous prime.
.Pp
When given the
.Fl h
argument,
.Nm
prints the prime numbers in hexadecimal.
.Sh DIAGNOSTICS
Out of range or invalid input results in
an appropriate error message
being written to standard error.
.Sh BUGS
an appropriate error message to standard error.
.Sh AUTHORS
Originally by
.An Landon Curt Noll ,
extended to some 64-bit primes by
.An Colin Percival .
.Sh CAVEATS
This
.Nm
won't get you a world record.
program won't get you a world record.
.Pp
The program is not able to list primes between
3825123056546413050 and 18446744073709551615 (2^64
- 1) as it relies on strong pseudoprime tests after
sieving, and it is yet unknown how many of those
tests are needed to prove primality for integers
larger than 3825123056546413050.

View File

@ -1,4 +1,4 @@
/* $NetBSD: primes.c,v 1.19 2011/08/30 02:58:04 jakllsch Exp $ */
/* $NetBSD: primes.c,v 1.20 2014/10/02 21:36:37 ast Exp $ */
/*
* Copyright (c) 1989, 1993
@ -42,23 +42,23 @@ __COPYRIGHT("@(#) Copyright (c) 1989, 1993\
#if 0
static char sccsid[] = "@(#)primes.c 8.5 (Berkeley) 5/10/95";
#else
__RCSID("$NetBSD: primes.c,v 1.19 2011/08/30 02:58:04 jakllsch Exp $");
__RCSID("$NetBSD: primes.c,v 1.20 2014/10/02 21:36:37 ast Exp $");
#endif
#endif /* not lint */
/*
* primes - generate a table of primes between two values
*
* By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
*
* chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
* By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
*
* usage:
* primes [start [stop]]
* primes [-d] [-h] [start [stop]]
*
* Print primes >= start and < stop. If stop is omitted,
* the value 4294967295 (2^32-1) is assumed. If start is
* the value SPSPMAX is assumed. If start is
* omitted, start is read from standard input.
* -h: print primes in hexadecimal
* -d: print difference to previous prime, e.g. 3 (1)
*
* validation check: there are 664579 primes between 0 and 10^7
*/
@ -66,11 +66,12 @@ __RCSID("$NetBSD: primes.c,v 1.19 2011/08/30 02:58:04 jakllsch Exp $");
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <memory.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "primes.h"
@ -80,48 +81,35 @@ __RCSID("$NetBSD: primes.c,v 1.19 2011/08/30 02:58:04 jakllsch Exp $");
*
* We only sieve the odd numbers. The base of our sieve windows are always
* odd. If the base of table is 1, table[i] represents 2*i-1. After the
* sieve, table[i] == 1 if and only iff 2*i-1 is prime.
* sieve, table[i] == 1 if and only if 2*i-1 is prime.
*
* We make TABSIZE large to reduce the overhead of inner loop setup.
*/
static char table[TABSIZE]; /* Eratosthenes sieve of odd numbers */
/*
* prime[i] is the (i-1)th prime.
*
* We are able to sieve 2^32-1 because this byte table yields all primes
* up to 65537 and 65537^2 > 2^32-1.
*/
extern const ubig prime[];
extern const ubig *pr_limit; /* largest prime in the prime array */
static int dflag, hflag;
/*
* To avoid excessive sieves for small factors, we use the table below to
* setup our sieve blocks. Each element represents a odd number starting
* with 1. All non-zero elements are factors of 3, 5, 7, 11 and 13.
*/
extern const char pattern[];
extern const int pattern_size; /* length of pattern array */
static int dflag;
static void primes(ubig, ubig);
static ubig read_num_buf(void);
static void primes(uint64_t, uint64_t);
static uint64_t read_num_buf(void);
static void usage(void) __dead;
int
main(int argc, char *argv[])
{
ubig start; /* where to start generating */
ubig stop; /* don't generate at or above this value */
uint64_t start; /* where to start generating */
uint64_t stop; /* don't generate at or above this value */
int ch;
char *p;
while ((ch = getopt(argc, argv, "d")) != -1)
while ((ch = getopt(argc, argv, "dh")) != -1)
switch (ch) {
case 'd':
dflag++;
break;
case 'h':
hflag++;
break;
case '?':
default:
usage();
@ -130,10 +118,10 @@ main(int argc, char *argv[])
argv += optind;
start = 0;
stop = BIG;
stop = SPSPMAX;
/*
* Convert low and high args. Strtoul(3) sets errno to
* Convert low and high args. Strtoumax(3) sets errno to
* ERANGE if the number is too large, but, if there's
* a leading minus sign it returns the negation of the
* result of the conversion, which we'd rather disallow.
@ -145,18 +133,21 @@ main(int argc, char *argv[])
errx(1, "negative numbers aren't permitted.");
errno = 0;
start = strtoul(argv[0], &p, 10);
start = strtoumax(argv[0], &p, 0);
if (errno)
err(1, "%s", argv[0]);
if (*p != '\0')
errx(1, "%s: illegal numeric format.", argv[0]);
errno = 0;
stop = strtoul(argv[1], &p, 10);
stop = strtoumax(argv[1], &p, 0);
if (errno)
err(1, "%s", argv[1]);
if (*p != '\0')
errx(1, "%s: illegal numeric format.", argv[1]);
if (stop > SPSPMAX)
errx(1, "%s: stop value too large (>%" PRIu64 ").",
argv[1], (uint64_t) SPSPMAX);
break;
case 1:
/* Start on the command line. */
@ -164,7 +155,7 @@ main(int argc, char *argv[])
errx(1, "negative numbers aren't permitted.");
errno = 0;
start = strtoul(argv[0], &p, 10);
start = strtoumax(argv[0], &p, 0);
if (errno)
err(1, "%s", argv[0]);
if (*p != '\0')
@ -180,18 +171,18 @@ main(int argc, char *argv[])
if (start > stop)
errx(1, "start value must be less than stop value.");
primes(start, stop);
exit(0);
return (0);
}
/*
* read_num_buf --
* This routine returns a number n, where 0 <= n && n <= BIG.
* This routine returns a number n, where 0 <= n && n <= ULONG_MAX.
*/
ubig
static uint64_t
read_num_buf(void)
{
ubig val;
char *p, buf[100]; /* > max number of digits. */
uint64_t val;
char *p, buf[LINE_MAX]; /* > max number of digits. */
for (;;) {
if (fgets(buf, sizeof(buf), stdin) == NULL) {
@ -205,7 +196,7 @@ read_num_buf(void)
if (*p == '-')
errx(1, "negative numbers aren't permitted.");
errno = 0;
val = strtoul(buf, &p, 10);
val = strtoumax(buf, &p, 0);
if (errno)
err(1, "%s", buf);
if (*p != '\n')
@ -216,31 +207,28 @@ read_num_buf(void)
/*
* primes - sieve and print primes from start up to and but not including stop
*
* start where to start generating
* stop don't generate at or above this value
*/
void
primes(ubig start, ubig stop)
static void
primes(uint64_t start, uint64_t stop)
{
char *q; /* sieve spot */
ubig factor; /* index and factor */
uint64_t factor; /* index and factor */
char *tab_lim; /* the limit to sieve on the table */
const ubig *p; /* prime table pointer */
ubig fact_lim; /* highest prime for current block */
ubig mod; /* temp storage for mod */
ubig prev = 0;
const uint64_t *p; /* prime table pointer */
uint64_t fact_lim; /* highest prime for current block */
uint64_t mod; /* temp storage for mod */
uint64_t prev = 0;
/*
* A number of systems can not convert double values into unsigned
* longs when the values are larger than the largest signed value.
* We don't have this problem, so we can go all the way to BIG.
* We don't have this problem, so we can go all the way to ULONG_MAX.
*/
if (start < 3) {
start = (ubig)2;
start = 2;
}
if (stop < 3) {
stop = (ubig)2;
stop = 2;
}
if (stop <= start) {
return;
@ -264,10 +252,9 @@ primes(ubig start, ubig stop)
for (p = &prime[0], factor = prime[0];
factor < stop && p <= pr_limit; factor = *(++p)) {
if (factor >= start) {
printf("%lu", (unsigned long) factor);
printf(hflag ? "%" PRIx64 : "%" PRIu64, factor);
if (dflag) {
printf(" (%lu)",
(unsigned long) factor - prev);
printf(" (%" PRIu64 ")", factor - prev);
}
putchar('\n');
}
@ -305,10 +292,10 @@ primes(ubig start, ubig stop)
/* note highest useful factor and sieve spot */
if (stop-start > TABSIZE+TABSIZE) {
tab_lim = &table[TABSIZE]; /* sieve it all */
fact_lim = sqrt((double)(start)+TABSIZE+TABSIZE+1.0);
fact_lim = sqrt(start+1.0+TABSIZE+TABSIZE);
} else {
tab_lim = &table[(stop-start)/2]; /* partial sieve */
fact_lim = sqrt((double)(stop)+1.0);
fact_lim = sqrt(stop+1.0);
}
/* sieve for factors >= 17 */
factor = 17; /* 17 is first prime to use */
@ -325,28 +312,32 @@ primes(ubig start, ubig stop)
for ( ; q < tab_lim; q += factor) {
*q = '\0'; /* sieve out a spot */
}
} while ((factor=(ubig)(*(p++))) <= fact_lim);
factor = *p++;
} while (factor <= fact_lim);
/*
* print generated primes
*/
for (q = table; q < tab_lim; ++q, start+=2) {
if (*q) {
printf("%lu", (unsigned long) start);
if (dflag) {
printf(" (%lu)",
(unsigned long) start - prev);
prev = start;
if (start > SIEVEMAX) {
if (!isprime(start))
continue;
}
printf(hflag ? "%" PRIx64 : "%" PRIu64, start);
if (dflag && (prev || (start <= *pr_limit))) {
printf(" (%" PRIu64 ")", start - prev);
}
putchar('\n');
prev = start;
}
}
}
}
void
static void
usage(void)
{
(void)fprintf(stderr, "usage: primes [-d] [start [stop]]\n");
(void)fprintf(stderr, "usage: primes [-d] [-h] [start [stop]]\n");
exit(1);
}

View File

@ -1,4 +1,4 @@
/* $NetBSD: primes.h,v 1.5 2003/08/07 09:37:34 agc Exp $ */
/* $NetBSD: primes.h,v 1.6 2014/10/02 21:36:37 ast Exp $ */
/*
* Copyright (c) 1989, 1993
@ -37,14 +37,38 @@
/*
* primes - generate a table of primes between two values
*
* By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
* By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
*
* chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
*/
/* ubig is the type that holds a large unsigned value */
typedef unsigned long ubig; /* must be >=32 bit unsigned value */
#define BIG ULONG_MAX /* largest value will sieve */
#include <stdint.h>
/* bytes in sieve table (must be > 3*5*7*11) */
#define TABSIZE 256*1024
/*
* prime[i] is the (i-1)th prime.
*
* We are able to sieve 2^32-1 because this byte table yields all primes
* up to 65537 and 65537^2 > 2^32-1.
*/
extern const uint64_t prime[]; /* must be >=32 bit unsigned values */
extern const uint64_t *const pr_limit; /* largest prime in the prime array */
/* Maximum size sieving alone can handle. */
#define SIEVEMAX 4295098368ULL
/*
* To avoid excessive sieves for small factors, we use the table below to
* setup our sieve blocks. Each element represents an odd number starting
* with 1. All non-zero elements are factors of 3, 5, 7, 11 and 13.
*/
extern const char pattern[];
extern const size_t pattern_size; /* length of pattern array */
/* Test for primality using strong pseudoprime tests. */
int isprime(uint64_t);
/* Maximum value which the SPSP code can handle. */
#define SPSPMAX 3825123056546413050ULL

195
games/primes/spsp.c Normal file
View File

@ -0,0 +1,195 @@
/* $NetBSD: spsp.c,v 1.1 2014/10/02 21:36:37 ast Exp $ */
/*-
* Copyright (c) 2014 Colin Percival
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1989, 1993\
The Regents of the University of California. All rights reserved.");
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)primes.c 8.5 (Berkeley) 5/10/95";
#else
__RCSID("$NetBSD: spsp.c,v 1.1 2014/10/02 21:36:37 ast Exp $");
#endif
#endif /* not lint */
#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include "primes.h"
/* Return a * b % n, where 0 <= a, b < 2^63, 0 < n < 2^63. */
static uint64_t
mulmod(uint64_t a, uint64_t b, uint64_t n)
{
uint64_t x = 0;
while (b != 0) {
if (b & 1)
x = (x + a) % n;
a = (a + a) % n;
b >>= 1;
}
return (x);
}
/* Return a^r % n, where 0 <= a < 2^63, 0 < n < 2^63. */
static uint64_t
powmod(uint64_t a, uint64_t r, uint64_t n)
{
uint64_t x = 1;
while (r != 0) {
if (r & 1)
x = mulmod(a, x, n);
a = mulmod(a, a, n);
r >>= 1;
}
return (x);
}
/* Return non-zero if n is a strong pseudoprime to base p. */
static int
spsp(uint64_t n, uint64_t p)
{
uint64_t x;
uint64_t r = n - 1;
int k = 0;
/* Compute n - 1 = 2^k * r. */
while ((r & 1) == 0) {
k++;
r >>= 1;
}
/* Compute x = p^r mod n. If x = 1, n is a p-spsp. */
x = powmod(p, r, n);
if (x == 1)
return (1);
/* Compute x^(2^i) for 0 <= i < n. If any are -1, n is a p-spsp. */
while (k > 0) {
if (x == n - 1)
return (1);
x = powmod(x, 2, n);
k--;
}
/* Not a p-spsp. */
return (0);
}
/* Test for primality using strong pseudoprime tests. */
int
isprime(uint64_t _n)
{
uint64_t n = _n;
/*
* Values from:
* C. Pomerance, J.L. Selfridge, and S.S. Wagstaff, Jr.,
* The pseudoprimes to 25 * 10^9, Math. Comp. 35(151):1003-1026, 1980.
*/
/* No SPSPs to base 2 less than 2047. */
if (!spsp(n, 2))
return (0);
if (n < 2047ULL)
return (1);
/* No SPSPs to bases 2,3 less than 1373653. */
if (!spsp(n, 3))
return (0);
if (n < 1373653ULL)
return (1);
/* No SPSPs to bases 2,3,5 less than 25326001. */
if (!spsp(n, 5))
return (0);
if (n < 25326001ULL)
return (1);
/* No SPSPs to bases 2,3,5,7 less than 3215031751. */
if (!spsp(n, 7))
return (0);
if (n < 3215031751ULL)
return (1);
/*
* Values from:
* G. Jaeschke, On strong pseudoprimes to several bases,
* Math. Comp. 61(204):915-926, 1993.
*/
/* No SPSPs to bases 2,3,5,7,11 less than 2152302898747. */
if (!spsp(n, 11))
return (0);
if (n < 2152302898747ULL)
return (1);
/* No SPSPs to bases 2,3,5,7,11,13 less than 3474749660383. */
if (!spsp(n, 13))
return (0);
if (n < 3474749660383ULL)
return (1);
/* No SPSPs to bases 2,3,5,7,11,13,17 less than 341550071728321. */
if (!spsp(n, 17))
return (0);
if (n < 341550071728321ULL)
return (1);
/* No SPSPs to bases 2,3,5,7,11,13,17,19 less than 341550071728321. */
if (!spsp(n, 19))
return (0);
if (n < 341550071728321ULL)
return (1);
/*
* Value from:
* Y. Jiang and Y. Deng, Strong pseudoprimes to the first eight prime
* bases, Math. Comp. 83(290):2915-2924, 2014.
*/
/* No SPSPs to bases 2..23 less than 3825123056546413051. */
if (!spsp(n, 23))
return (0);
if (n < 3825123056546413051)
return (1);
/* We can't handle values larger than this. */
assert(n <= SPSPMAX);
/* UNREACHABLE */
return (0);
}