usr.bin/shuffle/shuffle.c

   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 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, i;
 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 }