/* vis:  make funny characters visible (version 3) */

#include <stdio.h>
#include <ctype.h>
int strip = 0;		/* 1 => discard special characters */

main(argc, argv)
	int argc;
	char *argv[];
{
	int i;
	FILE *fp;

	while (argc > 1 && argv[1][0] == '-') {
		switch (argv[1][1]) {
		case 's':	/* -s: strip funny chars */
			strip = 1;
			break;
		default:
			fprintf(stderr, "%s: unknown arg %s\n",
				argv[0], argv[1]);
			exit(1);
		}
		argc--;
		argv++;
	}
	if (argc == 1)
		vis(stdin);
	else
		for (i = 1; i < argc; i++)
			if ((fp=fopen(argv[i], "r")) == NULL) {
				fprintf(stderr, "%s: can't open %s\n",
					argv[0], argv[i]);
				exit(1);
			} else {
				vis(fp);
				fclose(fp);
			}
	exit(0);
}

vis(fp)	/* make chars visible in FILE *fp */
	FILE *fp;
{
	int c;

	while ((c = getc(fp)) != EOF)
		if (isascii(c) &&
		    (isprint(c) || c=='\n' || c=='\t' || c==' '))
			putchar(c);
		else if (!strip)
			printf("\\%03o", c);
}