4.3BSD-Reno/src/usr.bin/vis/foldit.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. Neither the name of the University nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)foldit.c	1.1 (Berkeley) 5/23/90";
#endif /* not lint */

foldit(chunk, col, max)
	char *chunk;
{
	register char *cp;

	/*
	 * Keep track of column position. Insert hidden newline
	 * if this chunk puts us over the limit.
	 */
again:
	cp = chunk;
	while (*cp) {
		switch(*cp) {
		case '\n':
		case '\r':
			col = 0;
			break;
		case '\t':
			col = col + 8 &~ 07;
			break;
		case '\b':
			col = col ? col - 1 : 0;
			break;
		default:
			col++;
		}
		if (col > (max - 2)) {
			printf("\\\n");
			col = 0;
			goto again;
		} 
		cp++;
	}
	return (col);
}