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/* seeker.c; part of GNU CSSC.
*
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007,
* 2008, 2009, 2010, 2001, 2014, 2019 Free Software Foundation, Inc.
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
* Program that determines if the target system can seek on its standard
* input.
*/
#include <config.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#define ERR_USAGE (1)
void usage(const char *name, int retval);
#ifdef HAVE_FSETPOS
static void
try_getpos(FILE *f)
{
fpos_t pos;
int rv;
rv = fgetpos(f, &pos);
printf("fgetpos() returns %d\n", rv);
rv = fsetpos(f, &pos);
printf("fsetpos() returns %d\n", rv);
}
#endif
static void
try_fseek(FILE *f)
{
long lrv;
int rv;
lrv = ftell(f);
printf("ftell() returns %ld\n", lrv);
rv = fseek(f, SEEK_SET, lrv);
printf("fseek() returns %d\n", rv);
}
static void
try_lseek()
{
off_t pos;
pos = lseek(0, 0, SEEK_CUR);
printf("lseek() returns %ld [SEEK_CUR]\n", (long)pos);
pos = lseek(0, pos, SEEK_CUR);
printf("lseek() returns %ld [SEEK_SET]\n", (long)pos);
}
int do_help(const char *name)
{
usage(name, 0);
return 0;
}
int do_unbuffered(const char *name)
{
(void) name;
printf("stdin is unbuffered\n");
setvbuf(stdin, (char*)NULL, _IONBF, 0u);
return 0;
}
int do_blockbuffered(const char *name)
{
(void) name;
printf("stdin is fully-buffered\n");
setvbuf(stdin, (char*)NULL, _IOFBF, BUFSIZ);
return 0;
}
int do_linebuffered(const char *name)
{
(void) name;
printf("stdin is line-buffered\n");
setvbuf(stdin, (char *)NULL, _IOLBF, 0);
return 0;
}
int do_nothing(const char *name)
{
(void) name;
printf("stdin is buffered in the default way\n");
return 0;
}
struct optact
{
const char *option;
int (*action)(const char*);
};
struct optact actions[]=
{
{ "--help", do_help },
{ "--unbuffered", do_unbuffered },
{ "--fully-buffered", do_blockbuffered },
{ "--line-buffered", do_linebuffered },
{ "--default-buffering", do_nothing }
};
#define NOPTIONS (sizeof(actions)/sizeof(actions[0]))
void usage(const char *name, int retval)
{
unsigned int j;
fprintf(stderr, "usage: %s ", name);
for (j=0u; j<NOPTIONS; ++j)
fprintf(stderr, "[%s] ", actions[j].option);
fprintf(stderr, "\n");
exit(retval);
}
int main(int argc, char *argv[])
{
int i;
unsigned int j;
for (i=1; i<argc; ++i)
{
if ('-' == argv[i][0])
{
for (j=0u; j<NOPTIONS; ++j)
{
if (0 == strcmp(argv[i], actions[j].option))
{
(*actions[j].action)(argv[0]);
break;
}
}
if (NOPTIONS == j)
{
fprintf(stderr, "Unknown option `%s'\n", argv[i]);
usage(argv[0], ERR_USAGE); /* unknown option */
}
}
else /* not an option */
{
usage(argv[0], ERR_USAGE);
}
}
#ifdef HAVE_FSETPOS
try_getpos(stdin);
#else
printf("fgetpos() not supported.\n");
#endif
try_fseek(stdin);
try_lseek();
return 0;
}
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