2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 static const char copyright[] =
39 "@(#) Copyright (c) 1989, 1993\n\
40 The Regents of the University of California. All rights reserved.\n";
45 static char sccsid[] = "@(#)factor.c 8.4 (Berkeley) 5/4/95";
46 __RCSID("$NetBSD: factor.c,v 1.13 2002/06/18 23:07:36 simonb Exp $");
48 static const char rcsid[] =
53 * factor - factor a number into primes
55 * By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
57 * chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
60 * factor [-h] [number] ...
62 * The form of the output is:
64 * number: factor1 factor1 factor2 factor3 factor3 factor3 ...
66 * where factor1 < factor2 < factor3 < ...
68 * If no args are given, the list of numbers are read from stdin.
83 #include <openssl/bn.h>
85 #define PRIME_CHECKS 5
87 static void pollard_pminus1(BIGNUM *); /* print factors for big numbers */
92 typedef u_long BN_ULONG;
95 #define BN_CTX_new() NULL
96 #define BN_new() ((BIGNUM *)calloc(sizeof(BIGNUM), 1))
97 #define BN_is_zero(v) (*(v) == 0)
98 #define BN_is_one(v) (*(v) == 1)
99 #define BN_mod_word(a, b) (*(a) % (b))
101 static int BN_dec2bn(BIGNUM **a, const char *str);
102 static int BN_hex2bn(BIGNUM **a, const char *str);
103 static BN_ULONG BN_div_word(BIGNUM *, BN_ULONG);
104 static void BN_print_fp(FILE *, const BIGNUM *);
108 static void BN_print_dec_fp(FILE *, const BIGNUM *);
110 static void pr_fact(BIGNUM *); /* print factors of a value */
111 static void pr_print(BIGNUM *); /* print a prime */
112 static void usage(void);
114 static BN_CTX *ctx; /* just use a global context */
118 main(int argc, char *argv[])
122 char *p, buf[LINE_MAX]; /* > max number of digits. */
127 errx(1, "can't initialise bignum");
129 while ((ch = getopt(argc, argv, "h")) != -1)
141 /* No args supplied, read numbers from stdin. */
144 if (fgets(buf, sizeof(buf), stdin) == NULL) {
149 for (p = buf; isblank(*p); ++p);
150 if (*p == '\n' || *p == '\0')
153 errx(1, "negative numbers aren't permitted.");
154 if (BN_dec2bn(&val, buf) == 0 &&
155 BN_hex2bn(&val, buf) == 0)
156 errx(1, "%s: illegal numeric format.", buf);
159 /* Factor the arguments. */
161 for (; *argv != NULL; ++argv) {
162 if (argv[0][0] == '-')
163 errx(1, "negative numbers aren't permitted.");
164 if (BN_dec2bn(&val, argv[0]) == 0 &&
165 BN_hex2bn(&val, argv[0]) == 0)
166 errx(1, "%s: illegal numeric format.", argv[0]);
173 * pr_fact - print the factors of a number
175 * Print the factors of the number, from the lowest to the highest.
176 * A factor will be printed multiple times if it divides the value
179 * Factors are printed with leading tabs.
184 const ubig *fact; /* The factor found. */
186 /* Firewall - catch 0 and 1. */
187 if (BN_is_zero(val)) /* Historical practice; 0 just exits. */
189 if (BN_is_one(val)) {
198 BN_print_fp(stdout, val);
200 BN_print_dec_fp(stdout, val);
202 for (fact = &prime[0]; !BN_is_one(val); ++fact) {
203 /* Look for the smallest factor. */
205 if (BN_mod_word(val, (BN_ULONG)*fact) == 0)
207 } while (++fact <= pr_limit);
209 /* Watch for primes larger than the table. */
210 if (fact > pr_limit) {
215 BN_set_word(bnfact, *(fact - 1));
216 BN_sqr(bnfact, bnfact, ctx);
217 if (BN_cmp(bnfact, val) > 0)
220 pollard_pminus1(val);
227 /* Divide factor out until none are left. */
229 printf(hflag ? " 0x%lx" : " %lu", *fact);
230 BN_div_word(val, (BN_ULONG)*fact);
231 } while (BN_mod_word(val, (BN_ULONG)*fact) == 0);
233 /* Let the user know we're doing something. */
240 pr_print(BIGNUM *val)
243 fputs(" 0x", stdout);
244 BN_print_fp(stdout, val);
247 BN_print_dec_fp(stdout, val);
254 fprintf(stderr, "usage: factor [-h] [value ...]\n");
260 /* pollard rho, algorithm from Jim Gillogly, May 2000 */
262 pollard_pminus1(BIGNUM *val)
264 BIGNUM *base, *num, *i, *x;
272 BN_set_word(base, 2);
275 BN_mod_exp(base, base, i, val, ctx);
279 BN_gcd(x, x, val, ctx);
282 if (BN_is_prime(x, PRIME_CHECKS, NULL, NULL,
289 BN_div(num, NULL, val, x, ctx);
292 if (BN_is_prime(num, PRIME_CHECKS, NULL, NULL,
305 * Sigh.. No _decimal_ output to file functions in BN.
308 BN_print_dec_fp(FILE *fp, const BIGNUM *num)
312 buf = BN_bn2dec(num);
314 return; /* XXX do anything here? */
322 BN_print_fp(FILE *fp, const BIGNUM *num)
324 fprintf(fp, "%lx", (unsigned long)*num);
328 BN_print_dec_fp(FILE *fp, const BIGNUM *num)
330 fprintf(fp, "%lu", (unsigned long)*num);
334 BN_dec2bn(BIGNUM **a, const char *str)
339 **a = strtoul(str, &p, 10);
340 return (errno == 0 && (*p == '\n' || *p == '\0'));
344 BN_hex2bn(BIGNUM **a, const char *str)
349 **a = strtoul(str, &p, 16);
350 return (errno == 0 && (*p == '\n' || *p == '\0'));
354 BN_div_word(BIGNUM *a, BN_ULONG b)