xref: /freebsd/usr.bin/primes/primes.c (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Landon Curt Noll.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
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. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #ifndef lint
34 static const char copyright[] =
35 "@(#) Copyright (c) 1989, 1993\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)primes.c	8.5 (Berkeley) 5/10/95";
42 #endif
43 static const char rcsid[] =
44  "$FreeBSD$";
45 #endif /* not lint */
46 
47 /*
48  * primes - generate a table of primes between two values
49  *
50  * By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo
51  *
52  * chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\
53  *
54  * usage:
55  *	primes [-h] [start [stop]]
56  *
57  *	Print primes >= start and < stop.  If stop is omitted,
58  *	the value 4294967295 (2^32-1) is assumed.  If start is
59  *	omitted, start is read from standard input.
60  *
61  * validation check: there are 664579 primes between 0 and 10^7
62  */
63 
64 #include <capsicum_helpers.h>
65 #include <ctype.h>
66 #include <err.h>
67 #include <errno.h>
68 #include <inttypes.h>
69 #include <limits.h>
70 #include <math.h>
71 #include <stdio.h>
72 #include <stdlib.h>
73 #include <string.h>
74 #include <nl_types.h>
75 #include <unistd.h>
76 
77 #include "primes.h"
78 
79 /*
80  * Eratosthenes sieve table
81  *
82  * We only sieve the odd numbers.  The base of our sieve windows are always
83  * odd.  If the base of table is 1, table[i] represents 2*i-1.  After the
84  * sieve, table[i] == 1 if and only if 2*i-1 is prime.
85  *
86  * We make TABSIZE large to reduce the overhead of inner loop setup.
87  */
88 static char table[TABSIZE];	 /* Eratosthenes sieve of odd numbers */
89 
90 static int	hflag;
91 
92 static void	primes(ubig, ubig);
93 static ubig	read_num_buf(void);
94 static void	usage(void);
95 
96 int
97 main(int argc, char *argv[])
98 {
99 	ubig start;		/* where to start generating */
100 	ubig stop;		/* don't generate at or above this value */
101 	int ch;
102 	char *p;
103 
104 	caph_cache_catpages();
105 	if (caph_enter() < 0)
106 		err(1, "cap_enter");
107 
108 	while ((ch = getopt(argc, argv, "h")) != -1)
109 		switch (ch) {
110 		case 'h':
111 			hflag++;
112 			break;
113 		case '?':
114 		default:
115 			usage();
116 		}
117 	argc -= optind;
118 	argv += optind;
119 
120 	start = 0;
121 	stop = (uint64_t)(-1);
122 
123 	/*
124 	 * Convert low and high args.  Strtoumax(3) sets errno to
125 	 * ERANGE if the number is too large, but, if there's
126 	 * a leading minus sign it returns the negation of the
127 	 * result of the conversion, which we'd rather disallow.
128 	 */
129 	switch (argc) {
130 	case 2:
131 		/* Start and stop supplied on the command line. */
132 		if (argv[0][0] == '-' || argv[1][0] == '-')
133 			errx(1, "negative numbers aren't permitted.");
134 
135 		errno = 0;
136 		start = strtoumax(argv[0], &p, 0);
137 		if (errno)
138 			err(1, "%s", argv[0]);
139 		if (*p != '\0')
140 			errx(1, "%s: illegal numeric format.", argv[0]);
141 
142 		errno = 0;
143 		stop = strtoumax(argv[1], &p, 0);
144 		if (errno)
145 			err(1, "%s", argv[1]);
146 		if (*p != '\0')
147 			errx(1, "%s: illegal numeric format.", argv[1]);
148 		break;
149 	case 1:
150 		/* Start on the command line. */
151 		if (argv[0][0] == '-')
152 			errx(1, "negative numbers aren't permitted.");
153 
154 		errno = 0;
155 		start = strtoumax(argv[0], &p, 0);
156 		if (errno)
157 			err(1, "%s", argv[0]);
158 		if (*p != '\0')
159 			errx(1, "%s: illegal numeric format.", argv[0]);
160 		break;
161 	case 0:
162 		start = read_num_buf();
163 		break;
164 	default:
165 		usage();
166 	}
167 
168 	if (start > stop)
169 		errx(1, "start value must be less than stop value.");
170 	primes(start, stop);
171 	return (0);
172 }
173 
174 /*
175  * read_num_buf --
176  *	This routine returns a number n, where 0 <= n && n <= BIG.
177  */
178 static ubig
179 read_num_buf(void)
180 {
181 	ubig val;
182 	char *p, buf[LINE_MAX];		/* > max number of digits. */
183 
184 	for (;;) {
185 		if (fgets(buf, sizeof(buf), stdin) == NULL) {
186 			if (ferror(stdin))
187 				err(1, "stdin");
188 			exit(0);
189 		}
190 		for (p = buf; isblank(*p); ++p);
191 		if (*p == '\n' || *p == '\0')
192 			continue;
193 		if (*p == '-')
194 			errx(1, "negative numbers aren't permitted.");
195 		errno = 0;
196 		val = strtoumax(buf, &p, 0);
197 		if (errno)
198 			err(1, "%s", buf);
199 		if (*p != '\n')
200 			errx(1, "%s: illegal numeric format.", buf);
201 		return (val);
202 	}
203 }
204 
205 /*
206  * primes - sieve and print primes from start up to and but not including stop
207  */
208 static void
209 primes(ubig start, ubig stop)
210 {
211 	char *q;		/* sieve spot */
212 	ubig factor;		/* index and factor */
213 	char *tab_lim;		/* the limit to sieve on the table */
214 	const ubig *p;		/* prime table pointer */
215 	ubig fact_lim;		/* highest prime for current block */
216 	ubig mod;		/* temp storage for mod */
217 
218 	/*
219 	 * A number of systems can not convert double values into unsigned
220 	 * longs when the values are larger than the largest signed value.
221 	 * We don't have this problem, so we can go all the way to BIG.
222 	 */
223 	if (start < 3) {
224 		start = (ubig)2;
225 	}
226 	if (stop < 3) {
227 		stop = (ubig)2;
228 	}
229 	if (stop <= start) {
230 		return;
231 	}
232 
233 	/*
234 	 * be sure that the values are odd, or 2
235 	 */
236 	if (start != 2 && (start&0x1) == 0) {
237 		++start;
238 	}
239 	if (stop != 2 && (stop&0x1) == 0) {
240 		++stop;
241 	}
242 
243 	/*
244 	 * quick list of primes <= pr_limit
245 	 */
246 	if (start <= *pr_limit) {
247 		/* skip primes up to the start value */
248 		for (p = &prime[0], factor = prime[0];
249 		    factor < stop && p <= pr_limit; factor = *(++p)) {
250 			if (factor >= start) {
251 				printf(hflag ? "%" PRIx64 "\n" : "%" PRIu64 "\n", factor);
252 			}
253 		}
254 		/* return early if we are done */
255 		if (p <= pr_limit) {
256 			return;
257 		}
258 		start = *pr_limit+2;
259 	}
260 
261 	/*
262 	 * we shall sieve a bytemap window, note primes and move the window
263 	 * upward until we pass the stop point
264 	 */
265 	while (start < stop) {
266 		/*
267 		 * factor out 3, 5, 7, 11 and 13
268 		 */
269 		/* initial pattern copy */
270 		factor = (start%(2*3*5*7*11*13))/2; /* starting copy spot */
271 		memcpy(table, &pattern[factor], pattern_size-factor);
272 		/* main block pattern copies */
273 		for (fact_lim=pattern_size-factor;
274 		    fact_lim+pattern_size<=TABSIZE; fact_lim+=pattern_size) {
275 			memcpy(&table[fact_lim], pattern, pattern_size);
276 		}
277 		/* final block pattern copy */
278 		memcpy(&table[fact_lim], pattern, TABSIZE-fact_lim);
279 
280 		/*
281 		 * sieve for primes 17 and higher
282 		 */
283 		/* note highest useful factor and sieve spot */
284 		if (stop-start > TABSIZE+TABSIZE) {
285 			tab_lim = &table[TABSIZE]; /* sieve it all */
286 			fact_lim = sqrt(start+1.0+TABSIZE+TABSIZE);
287 		} else {
288 			tab_lim = &table[(stop-start)/2]; /* partial sieve */
289 			fact_lim = sqrt(stop+1.0);
290 		}
291 		/* sieve for factors >= 17 */
292 		factor = 17;	/* 17 is first prime to use */
293 		p = &prime[7];	/* 19 is next prime, pi(19)=7 */
294 		do {
295 			/* determine the factor's initial sieve point */
296 			mod = start%factor;
297 			if (mod & 0x1) {
298 				q = &table[(factor-mod)/2];
299 			} else {
300 				q = &table[mod ? factor-(mod/2) : 0];
301 			}
302 			/* sive for our current factor */
303 			for ( ; q < tab_lim; q += factor) {
304 				*q = '\0'; /* sieve out a spot */
305 			}
306 			factor = *p++;
307 		} while (factor <= fact_lim);
308 
309 		/*
310 		 * print generated primes
311 		 */
312 		for (q = table; q < tab_lim; ++q, start+=2) {
313 			if (*q) {
314 				if (start > SIEVEMAX) {
315 					if (!isprime(start))
316 						continue;
317 				}
318 				printf(hflag ? "%" PRIx64 "\n" : "%" PRIu64 "\n", start);
319 			}
320 		}
321 	}
322 }
323 
324 static void
325 usage(void)
326 {
327 	fprintf(stderr, "usage: primes [-h] [start [stop]]\n");
328 	exit(1);
329 }
330