1 /* $NetBSD: primes.c,v 1.21 2014/10/04 13:15:50 wiz Exp $ */
2
3 /*
4 * Copyright (c) 1989, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Landon Curt Noll.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/cdefs.h>
36 #ifndef lint
37 __COPYRIGHT("@(#) Copyright (c) 1989, 1993\
38 The Regents of the University of California. All rights reserved.");
39 #endif /* not lint */
40
41 #ifndef lint
42 #if 0
43 static char sccsid[] = "@(#)primes.c 8.5 (Berkeley) 5/10/95";
44 #else
45 __RCSID("$NetBSD: primes.c,v 1.21 2014/10/04 13:15:50 wiz Exp $");
46 #endif
47 #endif /* not lint */
48
49 /*
50 * primes - generate a table of primes between two values
51 *
52 * By Landon Curt Noll, http://www.isthe.com/chongo/index.html /\oo/\
53 *
54 * usage:
55 * primes [-dh] [start [stop]]
56 *
57 * Print primes >= start and < stop. If stop is omitted,
58 * the value SPSPMAX is assumed. If start is
59 * omitted, start is read from standard input.
60 * -d: print difference to previous prime, e.g. 3 (1)
61 * -h: print primes in hexadecimal
62 *
63 * validation check: there are 664579 primes between 0 and 10^7
64 */
65
66 #include <ctype.h>
67 #include <err.h>
68 #include <errno.h>
69 #include <inttypes.h>
70 #include <limits.h>
71 #include <math.h>
72 #include <stdio.h>
73 #include <stdlib.h>
74 #include <string.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 dflag, hflag;
91
92 static void primes(uint64_t, uint64_t);
93 static uint64_t read_num_buf(void);
94 static void usage(void) __dead;
95
96
97 int
main(int argc,char * argv[])98 main(int argc, char *argv[])
99 {
100 uint64_t start; /* where to start generating */
101 uint64_t stop; /* don't generate at or above this value */
102 int ch;
103 char *p;
104
105 while ((ch = getopt(argc, argv, "dh")) != -1)
106 switch (ch) {
107 case 'd':
108 dflag++;
109 break;
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 = SPSPMAX;
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 if (stop > SPSPMAX)
149 errx(1, "%s: stop value too large (>%" PRIu64 ").",
150 argv[1], (uint64_t) SPSPMAX);
151 break;
152 case 1:
153 /* Start on the command line. */
154 if (argv[0][0] == '-')
155 errx(1, "negative numbers aren't permitted.");
156
157 errno = 0;
158 start = strtoumax(argv[0], &p, 0);
159 if (errno)
160 err(1, "%s", argv[0]);
161 if (*p != '\0')
162 errx(1, "%s: illegal numeric format.", argv[0]);
163 break;
164 case 0:
165 start = read_num_buf();
166 break;
167 default:
168 usage();
169 }
170
171 if (start > stop)
172 errx(1, "start value must be less than stop value.");
173 primes(start, stop);
174 return (0);
175 }
176
177 /*
178 * read_num_buf --
179 * This routine returns a number n, where 0 <= n && n <= ULONG_MAX.
180 */
181 static uint64_t
read_num_buf(void)182 read_num_buf(void)
183 {
184 uint64_t val;
185 char *p, buf[LINE_MAX]; /* > max number of digits. */
186
187 for (;;) {
188 if (fgets(buf, sizeof(buf), stdin) == NULL) {
189 if (ferror(stdin))
190 err(1, "stdin");
191 exit(0);
192 }
193 for (p = buf; isblank((unsigned char)*p); ++p);
194 if (*p == '\n' || *p == '\0')
195 continue;
196 if (*p == '-')
197 errx(1, "negative numbers aren't permitted.");
198 errno = 0;
199 val = strtoumax(buf, &p, 0);
200 if (errno)
201 err(1, "%s", buf);
202 if (*p != '\n')
203 errx(1, "%s: illegal numeric format.", buf);
204 return (val);
205 }
206 }
207
208 /*
209 * primes - sieve and print primes from start up to and but not including stop
210 */
211 static void
primes(uint64_t start,uint64_t stop)212 primes(uint64_t start, uint64_t stop)
213 {
214 char *q; /* sieve spot */
215 uint64_t factor; /* index and factor */
216 char *tab_lim; /* the limit to sieve on the table */
217 const uint64_t *p; /* prime table pointer */
218 uint64_t fact_lim; /* highest prime for current block */
219 uint64_t mod; /* temp storage for mod */
220 uint64_t prev = 0;
221
222 /*
223 * A number of systems can not convert double values into unsigned
224 * longs when the values are larger than the largest signed value.
225 * We don't have this problem, so we can go all the way to ULONG_MAX.
226 */
227 if (start < 3) {
228 start = 2;
229 }
230 if (stop < 3) {
231 stop = 2;
232 }
233 if (stop <= start) {
234 return;
235 }
236
237 /*
238 * be sure that the values are odd, or 2
239 */
240 if (start != 2 && (start&0x1) == 0) {
241 ++start;
242 }
243 if (stop != 2 && (stop&0x1) == 0) {
244 ++stop;
245 }
246
247 /*
248 * quick list of primes <= pr_limit
249 */
250 if (start <= *pr_limit) {
251 /* skip primes up to the start value */
252 for (p = &prime[0], factor = prime[0];
253 factor < stop && p <= pr_limit; factor = *(++p)) {
254 if (factor >= start) {
255 printf(hflag ? "%" PRIx64 : "%" PRIu64, factor);
256 if (dflag) {
257 printf(" (%" PRIu64 ")", factor - prev);
258 }
259 putchar('\n');
260 }
261 prev = factor;
262 }
263 /* return early if we are done */
264 if (p <= pr_limit) {
265 return;
266 }
267 start = *pr_limit+2;
268 }
269
270 /*
271 * we shall sieve a bytemap window, note primes and move the window
272 * upward until we pass the stop point
273 */
274 while (start < stop) {
275 /*
276 * factor out 3, 5, 7, 11 and 13
277 */
278 /* initial pattern copy */
279 factor = (start%(2*3*5*7*11*13))/2; /* starting copy spot */
280 memcpy(table, &pattern[factor], pattern_size-factor);
281 /* main block pattern copies */
282 for (fact_lim=pattern_size-factor;
283 fact_lim+pattern_size<=TABSIZE; fact_lim+=pattern_size) {
284 memcpy(&table[fact_lim], pattern, pattern_size);
285 }
286 /* final block pattern copy */
287 memcpy(&table[fact_lim], pattern, TABSIZE-fact_lim);
288
289 /*
290 * sieve for primes 17 and higher
291 */
292 /* note highest useful factor and sieve spot */
293 if (stop-start > TABSIZE+TABSIZE) {
294 tab_lim = &table[TABSIZE]; /* sieve it all */
295 fact_lim = sqrt(start+1.0+TABSIZE+TABSIZE);
296 } else {
297 tab_lim = &table[(stop-start)/2]; /* partial sieve */
298 fact_lim = sqrt(stop+1.0);
299 }
300 /* sieve for factors >= 17 */
301 factor = 17; /* 17 is first prime to use */
302 p = &prime[7]; /* 19 is next prime, pi(19)=7 */
303 do {
304 /* determine the factor's initial sieve point */
305 mod = start%factor;
306 if (mod & 0x1) {
307 q = &table[(factor-mod)/2];
308 } else {
309 q = &table[mod ? factor-(mod/2) : 0];
310 }
311 /* sieve for our current factor */
312 for ( ; q < tab_lim; q += factor) {
313 *q = '\0'; /* sieve out a spot */
314 }
315 factor = *p++;
316 } while (factor <= fact_lim);
317
318 /*
319 * print generated primes
320 */
321 for (q = table; q < tab_lim; ++q, start+=2) {
322 if (*q) {
323 if (start > SIEVEMAX) {
324 if (!isprime(start))
325 continue;
326 }
327 printf(hflag ? "%" PRIx64 : "%" PRIu64, start);
328 if (dflag && (prev || (start <= *pr_limit))) {
329 printf(" (%" PRIu64 ")", start - prev);
330 }
331 putchar('\n');
332 prev = start;
333 }
334 }
335 }
336 }
337
338 static void
usage(void)339 usage(void)
340 {
341 (void)fprintf(stderr, "usage: primes [-dh] [start [stop]]\n");
342 exit(1);
343 }
344