utils/src/cat.c

123 lines
2.4 KiB
C

/* $Id$ */
/* Copyright (c) 2009 Pierre Pronchery <khorben@defora.org> */
/* This file is part of DeforaOS Unix utils */
/* 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, version 3 of the License.
*
* 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/>. */
#include <unistd.h>
#include <stdio.h>
#include <string.h>
/* cat */
/* types */
typedef enum _OutputDelay {
OD_NONE,
OD_BUFFER
} OutputDelay;
/* cat */
/* PRE
* POST the requested files have been printed on standard output
* returns:
* 0 successful
* 2 an error occured */
static int _cat_error(char const * message, int ret);
static void _cat_file(FILE * fp, OutputDelay od);
static int _write_nonbuf(int c);
static int _write_buf(int c);
static int _cat(OutputDelay od, int argc, char * argv[])
{
int ret = 0;
int i;
FILE * fp;
if(argc == 0)
{
_cat_file(stdin, od);
return 0;
}
for(i = 0; i < argc; i++)
{
if(strcmp("-", argv[i]) == 0)
fp = stdin;
else if((fp = fopen(argv[i], "r")) == NULL)
{
ret |= _cat_error(argv[i], 1);
continue;
}
_cat_file(fp, od);
if(fp != stdin && fclose(fp) != 0)
ret |= _cat_error(argv[i], 1);
}
return ret;
}
static int _cat_error(char const * message, int ret)
{
fputs("cat: ", stderr);
perror(message);
return ret;
}
static void _cat_file(FILE * fp, OutputDelay od)
{
int c;
int (*func)(int c);
func = (od == OD_NONE ? _write_nonbuf : _write_buf);
while((c = fgetc(fp)) != EOF)
func(c);
}
static int _write_buf(int c)
{
return fputc(c, stdout);
}
static int _write_nonbuf(int c)
{
return write(1, &c, sizeof(char));
}
/* usage */
static int _usage(void)
{
fputs("Usage: cat [-u][file ...]\n\
-u Write without delay\n", stderr);
return 1;
}
/* main */
int main(int argc, char * argv[])
{
int o;
OutputDelay flagu = OD_BUFFER;
while((o = getopt(argc, argv, "u")) != -1)
switch(o)
{
case 'u':
flagu = OD_NONE;
break;
default:
return _usage();
}
return _cat(flagu, argc - optind, &argv[optind]) == 0 ? 0 : 2;
}