1 /* $NetBSD: shuffle.c,v 1.22 2017/02/06 02:26:44 dholland 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 1.22 2017/02/06 02:26:44 dholland 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 *
get_shuffle(size_t 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_uniform(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
usage(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
get_lines(const char * fname,char *** linesp,size_t * nlinesp)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
get_number(const char * str,int ch)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
main(int argc,char * argv[])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 }
221