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/* vi: set sw=4 ts=4: */
/*
* head implementation for busybox
*
* Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/* BB_AUDIT SUSv3 compliant */
/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <ctype.h>
#include <unistd.h>
#include "busybox.h"
static const char head_opts[] =
"n:"
#ifdef CONFIG_FEATURE_FANCY_HEAD
"c:qv"
#endif
;
static const char header_fmt_str[] = "\n==> %s <==\n";
int head_main(int argc, char **argv)
{
unsigned long count = 10;
unsigned long i;
#ifdef CONFIG_FEATURE_FANCY_HEAD
int count_bytes = 0;
int header_threshhold = 1;
#endif
FILE *fp;
const char *fmt;
char *p;
int opt;
int c;
int retval = EXIT_SUCCESS;
#if defined CONFIG_FEATURE_SUSv2 || defined CONFIG_FEATURE_FANCY_HEAD
/* Allow legacy syntax of an initial numeric option without -n. */
if ((argc > 1) && (argv[1][0] == '-')
/* && (isdigit)(argv[1][1]) */
&& (((unsigned int)(argv[1][1] - '0')) <= 9)
) {
--argc;
++argv;
p = (*argv) + 1;
goto GET_COUNT;
}
#endif
/* No size benefit in converting this to bb_getopt_ulflags */
while ((opt = getopt(argc, argv, head_opts)) > 0) {
switch(opt) {
#ifdef CONFIG_FEATURE_FANCY_HEAD
case 'q':
header_threshhold = INT_MAX;
break;
case 'v':
header_threshhold = -1;
break;
case 'c':
count_bytes = 1;
/* fall through */
#endif
case 'n':
p = optarg;
GET_COUNT:
count = bb_xgetularg10(p);
break;
default:
bb_show_usage();
}
}
argv += optind;
if (!*argv) {
*--argv = "-";
}
fmt = header_fmt_str + 1;
#ifdef CONFIG_FEATURE_FANCY_HEAD
if (argc - optind <= header_threshhold) {
header_threshhold = 0;
}
#else
if (argc <= optind + 1) {
fmt += 11;
}
/* Now define some things here to avoid #ifdefs in the code below.
* These should optimize out of the if conditions below. */
#define header_threshhold 1
#define count_bytes 0
#endif
do {
if ((fp = bb_wfopen_input(*argv)) != NULL) {
if (fp == stdin) {
*argv = (char *) bb_msg_standard_input;
}
if (header_threshhold) {
bb_printf(fmt, *argv);
}
i = count;
while (i && ((c = getc(fp)) != EOF)) {
if (count_bytes || (c == '\n')) {
--i;
}
putchar(c);
}
if (bb_fclose_nonstdin(fp)) {
bb_perror_msg("%s", *argv); /* Avoid multibyte problems. */
retval = EXIT_FAILURE;
}
bb_xferror_stdout();
}
fmt = header_fmt_str;
} while (*++argv);
bb_fflush_stdout_and_exit(retval);
}
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