/* untab4.c				Howard L. Dyckman

	November 29, 1990		Public Domain

	This program reads any text file and prints out the file with
	all tabs converted to spaces, where tabstop = 4.
	This is useful if you like to code with tabstop = 4 but your
	printer is set to 8.
	(To set up the vi text editor for tabstop = 4 put the following
	line in your .login file:
	setenv EXINIT 'se ts=4'
	.)
*/

#include <stdio.h>

main (argc, argv)
int argc;
char *argv[];
{
	int i;
	char c;
	int f;
	int r;
	
	if (argc == 1) f = 0;		/*  stdin  */

	else if (argc != 2) {
		fprintf (stderr, "Usage: untab4 file\n");
		exit(1);
	};
	
	if (argc == 2) {
		if ((f = open(argv[1], 0)) == -1) {
			perror (argv[1]);
			exit(1);
		};
	};
	
	for (i = 0; ; ) {
		i = i % 4;
		r = read (f, &c, 1);
		if (r == 0) exit (0);
		
		if (c == '\t') {
			do {
				fprintf (stdout, " ");
				i++;
			} while ((i = i % 4) != 0);
		} else {
			i++;
			fprintf (stdout, "%c", c);
			if (c == '\n') i = 0;
		}
	}
}

/*

NAME = untab4
OFILES = untab4.o
CFILES = untab4.c
CFLAGS = -g
LDFLAGS = -lm

$(NAME): $(OFILES)
	cc $(CFLAGS) $(OFILES) -o $(NAME) $(LDFLAGS)

 */