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 * @(#) Copyright (c) 1989, 1993 The Regents of the University of California. All rights reserved. 33 * @(#)primes.c 8.5 (Berkeley) 5/10/95 34 * $FreeBSD: src/games/primes/primes.c,v 1.15.2.2 2002/10/23 14:59:14 fanf Exp $ 35 * $DragonFly: src/games/primes/primes.c,v 1.2 2003/06/17 04:25:24 dillon Exp $ 36 */ 37 38 /* 39 * primes - generate a table of primes between two values 40 * 41 * By: Landon Curt Noll chongo@toad.com, ...!{sun,tolsoft}!hoptoad!chongo 42 * 43 * chongo <for a good prime call: 391581 * 2^216193 - 1> /\oo/\ 44 * 45 * usage: 46 * primes [-h] [start [stop]] 47 * 48 * Print primes >= start and < stop. If stop is omitted, 49 * the value 4294967295 (2^32-1) is assumed. If start is 50 * omitted, start is read from standard input. 51 * 52 * validation check: there are 664579 primes between 0 and 10^7 53 */ 54 55 #include <ctype.h> 56 #include <err.h> 57 #include <errno.h> 58 #include <limits.h> 59 #include <math.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <unistd.h> 64 65 #include "primes.h" 66 67 /* 68 * Eratosthenes sieve table 69 * 70 * We only sieve the odd numbers. The base of our sieve windows are always 71 * odd. If the base of table is 1, table[i] represents 2*i-1. After the 72 * sieve, table[i] == 1 if and only if 2*i-1 is prime. 73 * 74 * We make TABSIZE large to reduce the overhead of inner loop setup. 75 */ 76 static char table[TABSIZE]; /* Eratosthenes sieve of odd numbers */ 77 78 static int hflag; 79 80 static void primes(ubig, ubig); 81 static ubig read_num_buf(void); 82 static void usage(void); 83 84 int 85 main(int argc, char *argv[]) 86 { 87 ubig start; /* where to start generating */ 88 ubig stop; /* don't generate at or above this value */ 89 int ch; 90 char *p; 91 92 while ((ch = getopt(argc, argv, "h")) != -1) 93 switch (ch) { 94 case 'h': 95 hflag++; 96 break; 97 case '?': 98 default: 99 usage(); 100 } 101 argc -= optind; 102 argv += optind; 103 104 start = 0; 105 stop = BIG; 106 107 /* 108 * Convert low and high args. Strtoul(3) sets errno to 109 * ERANGE if the number is too large, but, if there's 110 * a leading minus sign it returns the negation of the 111 * result of the conversion, which we'd rather disallow. 112 */ 113 switch (argc) { 114 case 2: 115 /* Start and stop supplied on the command line. */ 116 if (argv[0][0] == '-' || argv[1][0] == '-') 117 errx(1, "negative numbers aren't permitted."); 118 119 errno = 0; 120 start = strtoul(argv[0], &p, 0); 121 if (errno) 122 err(1, "%s", argv[0]); 123 if (*p != '\0') 124 errx(1, "%s: illegal numeric format.", argv[0]); 125 126 errno = 0; 127 stop = strtoul(argv[1], &p, 0); 128 if (errno) 129 err(1, "%s", argv[1]); 130 if (*p != '\0') 131 errx(1, "%s: illegal numeric format.", argv[1]); 132 break; 133 case 1: 134 /* Start on the command line. */ 135 if (argv[0][0] == '-') 136 errx(1, "negative numbers aren't permitted."); 137 138 errno = 0; 139 start = strtoul(argv[0], &p, 0); 140 if (errno) 141 err(1, "%s", argv[0]); 142 if (*p != '\0') 143 errx(1, "%s: illegal numeric format.", argv[0]); 144 break; 145 case 0: 146 start = read_num_buf(); 147 break; 148 default: 149 usage(); 150 } 151 152 if (start > stop) 153 errx(1, "start value must be less than stop value."); 154 primes(start, stop); 155 return (0); 156 } 157 158 /* 159 * read_num_buf -- 160 * This routine returns a number n, where 0 <= n && n <= BIG. 161 */ 162 static ubig 163 read_num_buf(void) 164 { 165 ubig val; 166 char *p, buf[LINE_MAX]; /* > max number of digits. */ 167 168 for (;;) { 169 if (fgets(buf, sizeof(buf), stdin) == NULL) { 170 if (ferror(stdin)) 171 err(1, "stdin"); 172 exit(0); 173 } 174 for (p = buf; isblank(*p); ++p); 175 if (*p == '\n' || *p == '\0') 176 continue; 177 if (*p == '-') 178 errx(1, "negative numbers aren't permitted."); 179 errno = 0; 180 val = strtoul(buf, &p, 0); 181 if (errno) 182 err(1, "%s", buf); 183 if (*p != '\n') 184 errx(1, "%s: illegal numeric format.", buf); 185 return (val); 186 } 187 } 188 189 /* 190 * primes - sieve and print primes from start up to and but not including stop 191 */ 192 static void 193 primes(ubig start, ubig stop) 194 { 195 char *q; /* sieve spot */ 196 ubig factor; /* index and factor */ 197 char *tab_lim; /* the limit to sieve on the table */ 198 const ubig *p; /* prime table pointer */ 199 ubig fact_lim; /* highest prime for current block */ 200 ubig mod; /* temp storage for mod */ 201 202 /* 203 * A number of systems can not convert double values into unsigned 204 * longs when the values are larger than the largest signed value. 205 * We don't have this problem, so we can go all the way to BIG. 206 */ 207 if (start < 3) { 208 start = (ubig)2; 209 } 210 if (stop < 3) { 211 stop = (ubig)2; 212 } 213 if (stop <= start) { 214 return; 215 } 216 217 /* 218 * be sure that the values are odd, or 2 219 */ 220 if (start != 2 && (start&0x1) == 0) { 221 ++start; 222 } 223 if (stop != 2 && (stop&0x1) == 0) { 224 ++stop; 225 } 226 227 /* 228 * quick list of primes <= pr_limit 229 */ 230 if (start <= *pr_limit) { 231 /* skip primes up to the start value */ 232 for (p = &prime[0], factor = prime[0]; 233 factor < stop && p <= pr_limit; factor = *(++p)) { 234 if (factor >= start) { 235 printf(hflag ? "0x%lx\n" : "%lu\n", factor); 236 } 237 } 238 /* return early if we are done */ 239 if (p <= pr_limit) { 240 return; 241 } 242 start = *pr_limit+2; 243 } 244 245 /* 246 * we shall sieve a bytemap window, note primes and move the window 247 * upward until we pass the stop point 248 */ 249 while (start < stop) { 250 /* 251 * factor out 3, 5, 7, 11 and 13 252 */ 253 /* initial pattern copy */ 254 factor = (start%(2*3*5*7*11*13))/2; /* starting copy spot */ 255 memcpy(table, &pattern[factor], pattern_size-factor); 256 /* main block pattern copies */ 257 for (fact_lim=pattern_size-factor; 258 fact_lim+pattern_size<=TABSIZE; fact_lim+=pattern_size) { 259 memcpy(&table[fact_lim], pattern, pattern_size); 260 } 261 /* final block pattern copy */ 262 memcpy(&table[fact_lim], pattern, TABSIZE-fact_lim); 263 264 /* 265 * sieve for primes 17 and higher 266 */ 267 /* note highest useful factor and sieve spot */ 268 if (stop-start > TABSIZE+TABSIZE) { 269 tab_lim = &table[TABSIZE]; /* sieve it all */ 270 fact_lim = sqrt(start+1.0+TABSIZE+TABSIZE); 271 } else { 272 tab_lim = &table[(stop-start)/2]; /* partial sieve */ 273 fact_lim = sqrt(stop+1.0); 274 } 275 /* sieve for factors >= 17 */ 276 factor = 17; /* 17 is first prime to use */ 277 p = &prime[7]; /* 19 is next prime, pi(19)=7 */ 278 do { 279 /* determine the factor's initial sieve point */ 280 mod = start%factor; 281 if (mod & 0x1) { 282 q = &table[(factor-mod)/2]; 283 } else { 284 q = &table[mod ? factor-(mod/2) : 0]; 285 } 286 /* sive for our current factor */ 287 for ( ; q < tab_lim; q += factor) { 288 *q = '\0'; /* sieve out a spot */ 289 } 290 factor = *p++; 291 } while (factor <= fact_lim); 292 293 /* 294 * print generated primes 295 */ 296 for (q = table; q < tab_lim; ++q, start+=2) { 297 if (*q) { 298 printf(hflag ? "0x%lx\n" : "%lu\n", start); 299 } 300 } 301 } 302 } 303 304 static void 305 usage(void) 306 { 307 fprintf(stderr, "usage: primes [-h] [start [stop]]\n"); 308 exit(1); 309 } 310