/* $Id$ */
/* 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;
}