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. 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. 23 * 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 34 * SUCH DAMAGE. 35 * 36 * @(#) Copyright (c) 1989, 1993 The Regents of the University of California. All rights reserved. 37 * @(#)primes.c 8.5 (Berkeley) 5/10/95 38 * $FreeBSD: src/games/primes/primes.c,v 1.15.2.2 2002/10/23 14:59:14 fanf Exp $ 39 * $DragonFly: src/games/primes/primes.c,v 1.2 2003/06/17 04:25:24 dillon Exp $ 40 */ 41 42 /* 43 * primes - generate a table of primes between two values 44 * 45 * By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo 46 * 47 * chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\ 48 * 49 * usage: 50 * primes [-h] [start [stop]] 51 * 52 * Print primes >= start and < stop. If stop is omitted, 53 * the value 4294967295 (2^32-1) is assumed. If start is 54 * omitted, start is read from standard input. 55 * 56 * validation check: there are 664579 primes between 0 and 10^7 57 */ 58 59 #include <ctype.h> 60 #include <err.h> 61 #include <errno.h> 62 #include <limits.h> 63 #include <math.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <unistd.h> 68 69 #include "primes.h" 70 71 /* 72 * Eratosthenes sieve table 73 * 74 * We only sieve the odd numbers. The base of our sieve windows are always 75 * odd. If the base of table is 1, table[i] represents 2*i-1. After the 76 * sieve, table[i] == 1 if and only if 2*i-1 is prime. 77 * 78 * We make TABSIZE large to reduce the overhead of inner loop setup. 79 */ 80 static char table[TABSIZE]; /* Eratosthenes sieve of odd numbers */ 81 82 static int hflag; 83 84 static void primes(ubig, ubig); 85 static ubig read_num_buf(void); 86 static void usage(void); 87 88 int 89 main(int argc, char *argv[]) 90 { 91 ubig start; /* where to start generating */ 92 ubig stop; /* don't generate at or above this value */ 93 int ch; 94 char *p; 95 96 while ((ch = getopt(argc, argv, "h")) != -1) 97 switch (ch) { 98 case 'h': 99 hflag++; 100 break; 101 case '?': 102 default: 103 usage(); 104 } 105 argc -= optind; 106 argv += optind; 107 108 start = 0; 109 stop = BIG; 110 111 /* 112 * Convert low and high args. Strtoul(3) sets errno to 113 * ERANGE if the number is too large, but, if there's 114 * a leading minus sign it returns the negation of the 115 * result of the conversion, which we'd rather disallow. 116 */ 117 switch (argc) { 118 case 2: 119 /* Start and stop supplied on the command line. */ 120 if (argv[0][0] == '-' || argv[1][0] == '-') 121 errx(1, "negative numbers aren't permitted."); 122 123 errno = 0; 124 start = strtoul(argv[0], &p, 0); 125 if (errno) 126 err(1, "%s", argv[0]); 127 if (*p != '\0') 128 errx(1, "%s: illegal numeric format.", argv[0]); 129 130 errno = 0; 131 stop = strtoul(argv[1], &p, 0); 132 if (errno) 133 err(1, "%s", argv[1]); 134 if (*p != '\0') 135 errx(1, "%s: illegal numeric format.", argv[1]); 136 break; 137 case 1: 138 /* Start on the command line. */ 139 if (argv[0][0] == '-') 140 errx(1, "negative numbers aren't permitted."); 141 142 errno = 0; 143 start = strtoul(argv[0], &p, 0); 144 if (errno) 145 err(1, "%s", argv[0]); 146 if (*p != '\0') 147 errx(1, "%s: illegal numeric format.", argv[0]); 148 break; 149 case 0: 150 start = read_num_buf(); 151 break; 152 default: 153 usage(); 154 } 155 156 if (start > stop) 157 errx(1, "start value must be less than stop value."); 158 primes(start, stop); 159 return (0); 160 } 161 162 /* 163 * read_num_buf -- 164 * This routine returns a number n, where 0 <= n && n <= BIG. 165 */ 166 static ubig 167 read_num_buf(void) 168 { 169 ubig val; 170 char *p, buf[LINE_MAX]; /* > max number of digits. */ 171 172 for (;;) { 173 if (fgets(buf, sizeof(buf), stdin) == NULL) { 174 if (ferror(stdin)) 175 err(1, "stdin"); 176 exit(0); 177 } 178 for (p = buf; isblank(*p); ++p); 179 if (*p == '\n' || *p == '\0') 180 continue; 181 if (*p == '-') 182 errx(1, "negative numbers aren't permitted."); 183 errno = 0; 184 val = strtoul(buf, &p, 0); 185 if (errno) 186 err(1, "%s", buf); 187 if (*p != '\n') 188 errx(1, "%s: illegal numeric format.", buf); 189 return (val); 190 } 191 } 192 193 /* 194 * primes - sieve and print primes from start up to and but not including stop 195 */ 196 static void 197 primes(ubig start, ubig stop) 198 { 199 char *q; /* sieve spot */ 200 ubig factor; /* index and factor */ 201 char *tab_lim; /* the limit to sieve on the table */ 202 const ubig *p; /* prime table pointer */ 203 ubig fact_lim; /* highest prime for current block */ 204 ubig mod; /* temp storage for mod */ 205 206 /* 207 * A number of systems can not convert double values into unsigned 208 * longs when the values are larger than the largest signed value. 209 * We don't have this problem, so we can go all the way to BIG. 210 */ 211 if (start < 3) { 212 start = (ubig)2; 213 } 214 if (stop < 3) { 215 stop = (ubig)2; 216 } 217 if (stop <= start) { 218 return; 219 } 220 221 /* 222 * be sure that the values are odd, or 2 223 */ 224 if (start != 2 && (start&0x1) == 0) { 225 ++start; 226 } 227 if (stop != 2 && (stop&0x1) == 0) { 228 ++stop; 229 } 230 231 /* 232 * quick list of primes <= pr_limit 233 */ 234 if (start <= *pr_limit) { 235 /* skip primes up to the start value */ 236 for (p = &prime[0], factor = prime[0]; 237 factor < stop && p <= pr_limit; factor = *(++p)) { 238 if (factor >= start) { 239 printf(hflag ? "0x%lx\n" : "%lu\n", factor); 240 } 241 } 242 /* return early if we are done */ 243 if (p <= pr_limit) { 244 return; 245 } 246 start = *pr_limit+2; 247 } 248 249 /* 250 * we shall sieve a bytemap window, note primes and move the window 251 * upward until we pass the stop point 252 */ 253 while (start < stop) { 254 /* 255 * factor out 3, 5, 7, 11 and 13 256 */ 257 /* initial pattern copy */ 258 factor = (start%(2*3*5*7*11*13))/2; /* starting copy spot */ 259 memcpy(table, &pattern[factor], pattern_size-factor); 260 /* main block pattern copies */ 261 for (fact_lim=pattern_size-factor; 262 fact_lim+pattern_size<=TABSIZE; fact_lim+=pattern_size) { 263 memcpy(&table[fact_lim], pattern, pattern_size); 264 } 265 /* final block pattern copy */ 266 memcpy(&table[fact_lim], pattern, TABSIZE-fact_lim); 267 268 /* 269 * sieve for primes 17 and higher 270 */ 271 /* note highest useful factor and sieve spot */ 272 if (stop-start > TABSIZE+TABSIZE) { 273 tab_lim = &table[TABSIZE]; /* sieve it all */ 274 fact_lim = sqrt(start+1.0+TABSIZE+TABSIZE); 275 } else { 276 tab_lim = &table[(stop-start)/2]; /* partial sieve */ 277 fact_lim = sqrt(stop+1.0); 278 } 279 /* sieve for factors >= 17 */ 280 factor = 17; /* 17 is first prime to use */ 281 p = &prime[7]; /* 19 is next prime, pi(19)=7 */ 282 do { 283 /* determine the factor's initial sieve point */ 284 mod = start%factor; 285 if (mod & 0x1) { 286 q = &table[(factor-mod)/2]; 287 } else { 288 q = &table[mod ? factor-(mod/2) : 0]; 289 } 290 /* sive for our current factor */ 291 for ( ; q < tab_lim; q += factor) { 292 *q = '\0'; /* sieve out a spot */ 293 } 294 factor = *p++; 295 } while (factor <= fact_lim); 296 297 /* 298 * print generated primes 299 */ 300 for (q = table; q < tab_lim; ++q, start+=2) { 301 if (*q) { 302 printf(hflag ? "0x%lx\n" : "%lu\n", start); 303 } 304 } 305 } 306 } 307 308 static void 309 usage(void) 310 { 311 fprintf(stderr, "usage: primes [-h] [start [stop]]\n"); 312 exit(1); 313 } 314