usr.bin/shuffle/shuffle.c

   1 /*      $NetBSD: shuffle.c,v 1.21 2011/09/16 15:39:29 joerg 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 1.21 2011/09/16 15:39:29 joerg 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 __dead 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 /*
  56  * get_shuffle --
  57  *      Construct a random shuffle array of t elements
  58  */
  59 static size_t *
  60 get_shuffle(size_t t)
  61 {
  62         size_t *shuffle;
  63         size_t i, j, k, temp;
  64
  65         shuffle = emalloc(t * sizeof(size_t));
  66
  67         for (i = 0; i < t; i++)
  68                 shuffle[i] = i;
  69
  70         /*
  71          * This algorithm taken from Knuth, Seminumerical Algorithms,
  72          * 2nd Ed., page 139.
  73          */
  74
  75         for (j = t - 1; j > 0; j--) {
  76                 k = arc4random() % (j + 1);
  77                 temp = shuffle[j];
  78                 shuffle[j] = shuffle[k];
  79                 shuffle[k] = temp;
  80         }
  81
  82         return shuffle;
  83 }
  84
  85 /*
  86  * usage --
  87  *      Print a usage message and exit
  88  */
  89 static void
  90 usage(void)
  91 {
  92
  93         (void) fprintf(stderr,
  94     "usage: %s [-0] [-f <filename>] [-n <number>] [-p <number>] [<arg> ...]\n",
  95                 getprogname());
  96         exit(1);
  97 }
  98
  99
 100 /*
 101  * get_lines --
 102  *      Return an array of lines read from input
 103  */
 104 static void
 105 get_lines(const char *fname, char ***linesp, size_t *nlinesp)
 106 {
 107         FILE *fp;
 108         char *line;
 109         size_t size, nlines = 0, maxlines = 128;
 110         char **lines = emalloc(sizeof(char *) * maxlines);
 111
 112         if (strcmp(fname, "-") == 0)
 113                 fp = stdin;
 114         else
 115                 if ((fp = fopen(fname, "r")) == NULL)
 116                         err(1, "Cannot open `%s'", fname);
 117
 118         while ((line = fgetln(fp, &size)) != NULL) {
 119                 if (size > 0 && line[size - 1] == '\n')
 120                         size--;
 121                 lines[nlines] = emalloc(size + 1);
 122                 (void)memcpy(lines[nlines], line, size);
 123                 lines[nlines++][size] = '\0';
 124                 if (nlines >= maxlines) {
 125                         maxlines *= 2;
 126                         lines = erealloc(lines, (sizeof(char *) * maxlines));
 127                 }
 128         }
 129         lines[nlines] = NULL;
 130
 131         *linesp = lines;
 132         *nlinesp = nlines;
 133         if (strcmp(fname, "-") != 0)
 134                 (void)fclose(fp);
 135 }
 136
 137 /*
 138  * get_number --
 139  *      Return a number or exit on error
 140  */
 141 static size_t
 142 get_number(const char *str, int ch)
 143 {
 144         char *estr;
 145         long number;
 146
 147         errno = 0;
 148         number = strtol(str, &estr, 0);
 149         if ((number == LONG_MIN || number == LONG_MAX) && errno == ERANGE)
 150                 err(1, "bad -%c argument `%s'", ch, str);
 151         if (*estr)
 152                 errx(1, "non numeric -%c argument `%s'", ch, str);
 153         if (number < 0)
 154                 errx(1, "negative -%c argument `%s'", ch, str);
 155         return (size_t) number;
 156 }
 157
 158 int
 159 main(int argc, char *argv[])
 160 {
 161         int nflag = 0, pflag = 0, ch;
 162         char *fname = NULL;
 163         size_t *shuffle = NULL;
 164         char **lines = NULL;
 165         size_t nlines = 0, pick = 0, i;
 166         char sep = '\n';
 167
 168         while ((ch = getopt(argc, argv, "0f:n:p:")) != -1) {
 169                 switch(ch) {
 170                 case '0':
 171                         sep = '\0';
 172                         break;
 173                 case 'f':
 174                         fname = optarg;
 175                         break;
 176                 case 'n':
 177                         nlines = get_number(optarg, ch);
 178                         nflag = 1;
 179                         break;
 180                 case 'p':
 181                         pick = get_number(optarg, ch);
 182                         pflag = 1;
 183                         break;
 184                 case '?':
 185                 default:
 186                         usage();
 187                 }
 188         }
 189         argc -= optind;
 190         argv += optind;
 191
 192         if ((fname && nflag) || (nflag && (argc > 0)))
 193                 usage();
 194
 195         if (fname != NULL)
 196                 get_lines(fname, &lines, &nlines);
 197         else if (nflag == 0) {
 198                 lines = argv;
 199                 nlines = argc;
 200         }
 201
 202         if (nlines > 0)
 203                 shuffle = get_shuffle(nlines);
 204
 205         if (pflag) {
 206                 if (pick > nlines)
 207                         errx(1, "-p specified more components than exist.");
 208                 nlines = pick;
 209         }
 210
 211         for (i = 0; i < nlines; i++) {
 212                 if (nflag)
 213                         printf("%ld", (long)shuffle[i]);
 214                 else
 215                         printf("%s", lines[shuffle[i]]);
 216                 putc(sep, stdout);
 217         }
 218
 219         return 0;
 220 }