/*-
 * Copyright (c) 1989 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)vis.c	5.3 (Berkeley) 6/26/90";
#endif /* LIBC_SCCS and not lint */

#define _KERNEL
#include "ixemul.h"

#include <ctype.h>
#include <vis.h>

#define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')

/*
 * vis - visually encode characters
 */
char *
vis(char *dst, char c, int flag, char nextc)
{
	if ((isascii(c) && isgraph(c)) ||
	   ((flag & VIS_SP) == 0 && c == ' ') ||
	   ((flag & VIS_TAB) == 0 && c == '\t') ||
	   ((flag & VIS_NL) == 0 && c == '\n') ||
	   ((flag & VIS_SAFE) && (c == '\b' || c == '\007' || c == '\r'))) {
		*dst++ = c;
		if (c == '\\' && (flag & VIS_NOSLASH) == 0)
			*dst++ = '\\';
		*dst = '\0';
		return (dst);
	}

	if (flag & VIS_CSTYLE) {
		switch(c) {
		case '\n':
			*dst++ = '\\';
			*dst++ = 'n';
			goto done;
		case '\r':
			*dst++ = '\\';
			*dst++ = 'r';
			goto done;
		case '\b':
			*dst++ = '\\';
			*dst++ = 'b';
			goto done;
		case '\a':
			*dst++ = '\\';
			*dst++ = 'a';
			goto done;
		case '\v':
			*dst++ = '\\';
			*dst++ = 'v';
			goto done;
		case '\t':
			*dst++ = '\\';
			*dst++ = 't';
			goto done;
		case '\f':
			*dst++ = '\\';
			*dst++ = 'f';
			goto done;
		case ' ':
			*dst++ = '\\';
			*dst++ = 's';
			goto done;
		case '\0':
			*dst++ = '\\';
			*dst++ = '0';
			if (isoctal(nextc)) {
				*dst++ = '0';
				*dst++ = '0';
			}
			goto done;
		}
	}
	if (((c & 0177) == ' ') || (flag & VIS_OCTAL)) {	
		*dst++ = '\\';
		*dst++ = ((u_char)c >> 6 & 07) + '0';
		*dst++ = ((u_char)c >> 3 & 07) + '0';
		*dst++ = ((u_char)c & 07) + '0';
		goto done;
	}
	if ((flag & VIS_NOSLASH) == 0)
		*dst++ = '\\';
	if (c & 0200) {
		c &= 0177;
		*dst++ = 'M';
	}
	if (iscntrl(c)) {
		*dst++ = '^';
		if (c == 0177)
			*dst++ = '?';
		else
			*dst++ = c + '@';
	} else {
		*dst++ = '-';
		*dst++ = c;
	}
done:
	*dst = '\0';
	return (dst);
}

/*
 * strvis, strvisx - visually encode characters from src into dst
 *	
 *	Dst must be 4 times the size of src to account for possible
 *	expansion.  The length of dst, not including the trailing NULL,
 *	is returned. 
 *
 *	Strvisx encodes exactly len bytes from src into dst.
 *	This is useful for encoding a block of data.
 */
int
strvis(char *dst, const char *src, int flag)
{
	register char c;
	char *start = dst;

	for (; (c = *src); src++)
		dst = vis(dst, c, flag, *(src+1));

	return (dst - start);
}

int
strvisx(char *dst, const char *src, size_t len, int flag)
{
	char *start = dst;

	while (len > 1) {
		dst = vis(dst, *src, flag, *(src+1));
		len--;
	}
	if (len)
		dst = vis(dst, *src, flag, '\0');

	return (dst - start);
}