/* $NetBSD: shuffle.c,v 1.22 2017/02/06 02:26:44 dholland Exp $ */
/*
* Copyright (c) 1998
* Perry E. Metzger. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgment:
* This product includes software developed for the NetBSD Project
* by Perry E. Metzger.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: shuffle.c,v 1.22 2017/02/06 02:26:44 dholland Exp $");
#endif /* not lint */
#include <sys/time.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <util.h>
static size_t *get_shuffle(size_t);
__dead static void usage(void);
static void get_lines(const char *, char ***, size_t *);
static size_t get_number(const char *, int);
/*
* get_shuffle --
* Construct a random shuffle array of t elements
*/
static size_t *
get_shuffle(size_t t)
{
size_t *shuffle;
size_t i, j, k, temp;
shuffle = emalloc(t * sizeof(size_t));
for (i = 0; i < t; i++)
shuffle[i] = i;
/*
* This algorithm taken from Knuth, Seminumerical Algorithms,
* 2nd Ed., page 139.
*/
for (j = t - 1; j > 0; j--) {
k = arc4random_uniform(j + 1);
temp = shuffle[j];
shuffle[j] = shuffle[k];
shuffle[k] = temp;
}
return shuffle;
}
/*
* usage --
* Print a usage message and exit
*/
static void
usage(void)
{
(void) fprintf(stderr,
"usage: %s [-0] [-f <filename>] [-n <number>] [-p <number>] [<arg> ...]\n",
getprogname());
exit(1);
}
/*
* get_lines --
* Return an array of lines read from input
*/
static void
get_lines(const char *fname, char ***linesp, size_t *nlinesp)
{
FILE *fp;
char *line;
size_t size, nlines = 0, maxlines = 128;
char **lines = emalloc(sizeof(char *) * maxlines);
if (strcmp(fname, "-") == 0)
fp = stdin;
else
if ((fp = fopen(fname, "r")) == NULL)
err(1, "Cannot open `%s'", fname);
while ((line = fgetln(fp, &size)) != NULL) {
if (size > 0 && line[size - 1] == '\n')
size--;
lines[nlines] = emalloc(size + 1);
(void)memcpy(lines[nlines], line, size);
lines[nlines++][size] = '\0';
if (nlines >= maxlines) {
maxlines *= 2;
lines = erealloc(lines, (sizeof(char *) * maxlines));
}
}
lines[nlines] = NULL;
*linesp = lines;
*nlinesp = nlines;
if (strcmp(fname, "-") != 0)
(void)fclose(fp);
}
/*
* get_number --
* Return a number or exit on error
*/
static size_t
get_number(const char *str, int ch)
{
char *estr;
long number;
errno = 0;
number = strtol(str, &estr, 0);
if ((number == LONG_MIN || number == LONG_MAX) && errno == ERANGE)
err(1, "bad -%c argument `%s'", ch, str);
if (*estr)
errx(1, "non numeric -%c argument `%s'", ch, str);
if (number < 0)
errx(1, "negative -%c argument `%s'", ch, str);
return (size_t) number;
}
int
main(int argc, char *argv[])
{
int nflag = 0, pflag = 0, ch;
char *fname = NULL;
size_t *shuffle = NULL;
char **lines = NULL;
size_t nlines = 0, pick = 0, i;
char sep = '\n';
while ((ch = getopt(argc, argv, "0f:n:p:")) != -1) {
switch(ch) {
case '0':
sep = '\0';
break;
case 'f':
fname = optarg;
break;
case 'n':
nlines = get_number(optarg, ch);
nflag = 1;
break;
case 'p':
pick = get_number(optarg, ch);
pflag = 1;
break;
case '?':
default:
usage();
}
}
argc -= optind;
argv += optind;
if ((fname && nflag) || (nflag && (argc > 0)))
usage();
if (fname != NULL)
get_lines(fname, &lines, &nlines);
else if (nflag == 0) {
lines = argv;
nlines = argc;
}
if (nlines > 0)
shuffle = get_shuffle(nlines);
if (pflag) {
if (pick > nlines)
errx(1, "-p specified more components than exist.");
nlines = pick;
}
for (i = 0; i < nlines; i++) {
if (nflag)
printf("%ld", (long)shuffle[i]);
else
printf("%s", lines[shuffle[i]]);
putc(sep, stdout);
}
return 0;
}
