vis.c revision 323121 
1/*	$OpenBSD: vis.c,v 1.19 2005/09/01 17:15:49 millert Exp $ */
2/*-
3 * Copyright (c) 1989, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31/* OPENBSD ORIGINAL: lib/libc/gen/vis.c */
32
33#include "includes.h"
34#if !defined(HAVE_STRNVIS) || defined(BROKEN_STRNVIS)
35
36#include <ctype.h>
37#include <string.h>
38
39#include "vis.h"
40
41#define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
42#define	isvisible(c)							\
43	(((u_int)(c) <= UCHAR_MAX && isascii((u_char)(c)) &&		\
44	(((c) != '*' && (c) != '?' && (c) != '[' && (c) != '#') ||	\
45		(flag & VIS_GLOB) == 0) && isgraph((u_char)(c))) ||	\
46	((flag & VIS_SP) == 0 && (c) == ' ') ||				\
47	((flag & VIS_TAB) == 0 && (c) == '\t') ||			\
48	((flag & VIS_NL) == 0 && (c) == '\n') ||			\
49	((flag & VIS_SAFE) && ((c) == '\b' ||				\
50		(c) == '\007' || (c) == '\r' ||				\
51		isgraph((u_char)(c)))))
52
53/*
54 * vis - visually encode characters
55 */
56char *
57vis(char *dst, int c, int flag, int nextc)
58{
59	if (isvisible(c)) {
60		*dst++ = c;
61		if (c == '\\' && (flag & VIS_NOSLASH) == 0)
62			*dst++ = '\\';
63		*dst = '\0';
64		return (dst);
65	}
66
67	if (flag & VIS_CSTYLE) {
68		switch(c) {
69		case '\n':
70			*dst++ = '\\';
71			*dst++ = 'n';
72			goto done;
73		case '\r':
74			*dst++ = '\\';
75			*dst++ = 'r';
76			goto done;
77		case '\b':
78			*dst++ = '\\';
79			*dst++ = 'b';
80			goto done;
81		case '\a':
82			*dst++ = '\\';
83			*dst++ = 'a';
84			goto done;
85		case '\v':
86			*dst++ = '\\';
87			*dst++ = 'v';
88			goto done;
89		case '\t':
90			*dst++ = '\\';
91			*dst++ = 't';
92			goto done;
93		case '\f':
94			*dst++ = '\\';
95			*dst++ = 'f';
96			goto done;
97		case ' ':
98			*dst++ = '\\';
99			*dst++ = 's';
100			goto done;
101		case '\0':
102			*dst++ = '\\';
103			*dst++ = '0';
104			if (isoctal(nextc)) {
105				*dst++ = '0';
106				*dst++ = '0';
107			}
108			goto done;
109		}
110	}
111	if (((c & 0177) == ' ') || (flag & VIS_OCTAL) ||
112	    ((flag & VIS_GLOB) && (c == '*' || c == '?' || c == '[' || c == '#'))) {
113		*dst++ = '\\';
114		*dst++ = ((u_char)c >> 6 & 07) + '0';
115		*dst++ = ((u_char)c >> 3 & 07) + '0';
116		*dst++ = ((u_char)c & 07) + '0';
117		goto done;
118	}
119	if ((flag & VIS_NOSLASH) == 0)
120		*dst++ = '\\';
121	if (c & 0200) {
122		c &= 0177;
123		*dst++ = 'M';
124	}
125	if (iscntrl((u_char)c)) {
126		*dst++ = '^';
127		if (c == 0177)
128			*dst++ = '?';
129		else
130			*dst++ = c + '@';
131	} else {
132		*dst++ = '-';
133		*dst++ = c;
134	}
135done:
136	*dst = '\0';
137	return (dst);
138}
139
140/*
141 * strvis, strnvis, strvisx - visually encode characters from src into dst
142 *
143 *	Dst must be 4 times the size of src to account for possible
144 *	expansion.  The length of dst, not including the trailing NULL,
145 *	is returned.
146 *
147 *	Strnvis will write no more than siz-1 bytes (and will NULL terminate).
148 *	The number of bytes needed to fully encode the string is returned.
149 *
150 *	Strvisx encodes exactly len bytes from src into dst.
151 *	This is useful for encoding a block of data.
152 */
153int
154strvis(char *dst, const char *src, int flag)
155{
156	char c;
157	char *start;
158
159	for (start = dst; (c = *src);)
160		dst = vis(dst, c, flag, *++src);
161	*dst = '\0';
162	return (dst - start);
163}
164
165int
166strnvis(char *dst, const char *src, size_t siz, int flag)
167{
168	char *start, *end;
169	char tbuf[5];
170	int c, i;
171
172	i = 0;
173	for (start = dst, end = start + siz - 1; (c = *src) && dst < end; ) {
174		if (isvisible(c)) {
175			i = 1;
176			*dst++ = c;
177			if (c == '\\' && (flag & VIS_NOSLASH) == 0) {
178				/* need space for the extra '\\' */
179				if (dst < end)
180					*dst++ = '\\';
181				else {
182					dst--;
183					i = 2;
184					break;
185				}
186			}
187			src++;
188		} else {
189			i = vis(tbuf, c, flag, *++src) - tbuf;
190			if (dst + i <= end) {
191				memcpy(dst, tbuf, i);
192				dst += i;
193			} else {
194				src--;
195				break;
196			}
197		}
198	}
199	if (siz > 0)
200		*dst = '\0';
201	if (dst + i > end) {
202		/* adjust return value for truncation */
203		while ((c = *src))
204			dst += vis(tbuf, c, flag, *++src) - tbuf;
205	}
206	return (dst - start);
207}
208
209int
210strvisx(char *dst, const char *src, size_t len, int flag)
211{
212	char c;
213	char *start;
214
215	for (start = dst; len > 1; len--) {
216		c = *src;
217		dst = vis(dst, c, flag, *++src);
218	}
219	if (len)
220		dst = vis(dst, *src, flag, '\0');
221	*dst = '\0';
222	return (dst - start);
223}
224
225#endif
226