1 /* $NetBSD: shuffle.c,v 1.19 2006/08/26 18:17:43 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1998 5 * Perry E. Metzger. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgment: 17 * This product includes software developed for the NetBSD Project 18 * by Perry E. Metzger. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 #ifndef lint 36 __RCSID("$NetBSD: shuffle.c,v 1.19 2006/08/26 18:17:43 christos Exp $"); 37 #endif /* not lint */ 38 39 #include <sys/time.h> 40 41 #include <err.h> 42 #include <errno.h> 43 #include <limits.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 #include <util.h> 49 50 static size_t *get_shuffle(size_t); 51 static void usage(void); 52 static void get_lines(const char *, char ***, size_t *); 53 static size_t get_number(const char *, int); 54 55 int main(int, char *[]); 56 57 /* 58 * get_shuffle -- 59 * Construct a random shuffle array of t elements 60 */ 61 static size_t * 62 get_shuffle(size_t t) 63 { 64 size_t *shuffle; 65 size_t i, j, k, temp; 66 67 shuffle = emalloc(t * sizeof(size_t)); 68 69 for (i = 0; i < t; i++) 70 shuffle[i] = i; 71 72 /* 73 * This algorithm taken from Knuth, Seminumerical Algorithms, 74 * 2nd Ed., page 139. 75 */ 76 77 for (j = t - 1; j > 0; j--) { 78 k = arc4random() % (j + 1); 79 temp = shuffle[j]; 80 shuffle[j] = shuffle[k]; 81 shuffle[k] = temp; 82 } 83 84 return shuffle; 85 } 86 87 /* 88 * usage -- 89 * Print a usage message and exit 90 */ 91 static void 92 usage(void) 93 { 94 95 (void) fprintf(stderr, 96 "usage: %s [-0] [-f <filename>] [-n <number>] [-p <number>] [<arg> ...]\n", 97 getprogname()); 98 exit(1); 99 } 100 101 102 /* 103 * get_lines -- 104 * Return an array of lines read from input 105 */ 106 static void 107 get_lines(const char *fname, char ***linesp, size_t *nlinesp) 108 { 109 FILE *fp; 110 char *line; 111 size_t size, nlines = 0, maxlines = 128; 112 char **lines = emalloc(sizeof(char *) * maxlines); 113 114 if (strcmp(fname, "-") == 0) 115 fp = stdin; 116 else 117 if ((fp = fopen(fname, "r")) == NULL) 118 err(1, "Cannot open `%s'", fname); 119 120 while ((line = fgetln(fp, &size)) != NULL) { 121 if (size > 0 && line[size - 1] == '\n') 122 size--; 123 lines[nlines] = emalloc(size + 1); 124 (void)memcpy(lines[nlines], line, size); 125 lines[nlines++][size] = '\0'; 126 if (nlines >= maxlines) { 127 maxlines *= 2; 128 lines = erealloc(lines, (sizeof(char *) * maxlines)); 129 } 130 } 131 lines[nlines] = NULL; 132 133 *linesp = lines; 134 *nlinesp = nlines; 135 if (strcmp(fname, "-") != 0) 136 (void)fclose(fp); 137 } 138 139 /* 140 * get_number -- 141 * Return a number or exit on error 142 */ 143 static size_t 144 get_number(const char *str, int ch) 145 { 146 char *estr; 147 long number; 148 149 errno = 0; 150 number = strtol(str, &estr, 0); 151 if ((number == LONG_MIN || number == LONG_MAX) && errno == ERANGE) 152 err(1, "bad -%c argument `%s'", ch, str); 153 if (*estr) 154 errx(1, "non numeric -%c argument `%s'", ch, str); 155 if (number < 0) 156 errx(1, "negative -%c argument `%s'", ch, str); 157 return (size_t) number; 158 } 159 160 int 161 main(int argc, char *argv[]) 162 { 163 int i, nflag = 0, pflag = 0, ch; 164 char *fname = NULL; 165 size_t *shuffle = NULL; 166 char **lines = NULL; 167 size_t nlines = 0, pick = 0; 168 char sep = '\n'; 169 170 while ((ch = getopt(argc, argv, "0f:n:p:")) != -1) { 171 switch(ch) { 172 case '0': 173 sep = '\0'; 174 break; 175 case 'f': 176 fname = optarg; 177 break; 178 case 'n': 179 nlines = get_number(optarg, ch); 180 nflag = 1; 181 break; 182 case 'p': 183 pick = get_number(optarg, ch); 184 pflag = 1; 185 break; 186 case '?': 187 default: 188 usage(); 189 } 190 } 191 argc -= optind; 192 argv += optind; 193 194 if ((fname && nflag) || (nflag && (argc > 0))) 195 usage(); 196 197 if (fname != NULL) 198 get_lines(fname, &lines, &nlines); 199 else if (nflag == 0) { 200 lines = argv; 201 nlines = argc; 202 } 203 204 if (nlines > 0) 205 shuffle = get_shuffle(nlines); 206 207 if (pflag) { 208 if (pick > nlines) 209 errx(1, "-p specified more components than exist."); 210 nlines = pick; 211 } 212 213 for (i = 0; i < nlines; i++) { 214 if (nflag) 215 printf("%ld", (long)shuffle[i]); 216 else 217 printf("%s", lines[shuffle[i]]); 218 putc(sep, stdout); 219 } 220 221 return 0; 222 } 223