xref: /netbsd-src/lib/libc/gen/vis.c (revision 2a399c6883d870daece976daec6ffa7bb7f934ce)
1 /*	$NetBSD: vis.c,v 1.8 1997/07/21 14:07:47 jtc Exp $	*/
2 
3 /*-
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)vis.c	8.1 (Berkeley) 7/19/93";
40 #else
41 __RCSID("$NetBSD: vis.c,v 1.8 1997/07/21 14:07:47 jtc Exp $");
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44 
45 #include "namespace.h"
46 #include <sys/types.h>
47 #include <limits.h>
48 #include <ctype.h>
49 #include <vis.h>
50 
51 #ifdef __weak_alias
52 __weak_alias(strvis,_strvis);
53 __weak_alias(strvisx,_strvisx);
54 __weak_alias(vis,_vis);
55 #endif
56 
57 #define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
58 
59 /*
60  * vis - visually encode characters
61  */
62 char *
63 vis(dst, c, flag, nextc)
64 	register char *dst;
65 	int c, nextc;
66 	register int flag;
67 {
68 	if (((u_int)c <= UCHAR_MAX && isascii(c) && isgraph(c)) ||
69 	   ((flag & VIS_SP) == 0 && c == ' ') ||
70 	   ((flag & VIS_TAB) == 0 && c == '\t') ||
71 	   ((flag & VIS_NL) == 0 && c == '\n') ||
72 	   ((flag & VIS_SAFE) && (c == '\b' || c == '\007' || c == '\r'))) {
73 		*dst++ = c;
74 		if (c == '\\' && (flag & VIS_NOSLASH) == 0)
75 			*dst++ = '\\';
76 		*dst = '\0';
77 		return (dst);
78 	}
79 
80 	if (flag & VIS_CSTYLE) {
81 		switch(c) {
82 		case '\n':
83 			*dst++ = '\\';
84 			*dst++ = 'n';
85 			goto done;
86 		case '\r':
87 			*dst++ = '\\';
88 			*dst++ = 'r';
89 			goto done;
90 		case '\b':
91 			*dst++ = '\\';
92 			*dst++ = 'b';
93 			goto done;
94 #if __STDC__
95 		case '\a':
96 #else
97 		case '\007':
98 #endif
99 			*dst++ = '\\';
100 			*dst++ = 'a';
101 			goto done;
102 		case '\v':
103 			*dst++ = '\\';
104 			*dst++ = 'v';
105 			goto done;
106 		case '\t':
107 			*dst++ = '\\';
108 			*dst++ = 't';
109 			goto done;
110 		case '\f':
111 			*dst++ = '\\';
112 			*dst++ = 'f';
113 			goto done;
114 		case ' ':
115 			*dst++ = '\\';
116 			*dst++ = 's';
117 			goto done;
118 		case '\0':
119 			*dst++ = '\\';
120 			*dst++ = '0';
121 			if (isoctal(nextc)) {
122 				*dst++ = '0';
123 				*dst++ = '0';
124 			}
125 			goto done;
126 		}
127 	}
128 	if (((c & 0177) == ' ') || (flag & VIS_OCTAL)) {
129 		*dst++ = '\\';
130 		*dst++ = ((u_char)c >> 6 & 07) + '0';
131 		*dst++ = ((u_char)c >> 3 & 07) + '0';
132 		*dst++ = ((u_char)c & 07) + '0';
133 		goto done;
134 	}
135 	if ((flag & VIS_NOSLASH) == 0)
136 		*dst++ = '\\';
137 	if (c & 0200) {
138 		c &= 0177;
139 		*dst++ = 'M';
140 	}
141 	if (iscntrl(c)) {
142 		*dst++ = '^';
143 		if (c == 0177)
144 			*dst++ = '?';
145 		else
146 			*dst++ = c + '@';
147 	} else {
148 		*dst++ = '-';
149 		*dst++ = c;
150 	}
151 done:
152 	*dst = '\0';
153 	return (dst);
154 }
155 
156 /*
157  * strvis, strvisx - visually encode characters from src into dst
158  *
159  *	Dst must be 4 times the size of src to account for possible
160  *	expansion.  The length of dst, not including the trailing NULL,
161  *	is returned.
162  *
163  *	Strvisx encodes exactly len bytes from src into dst.
164  *	This is useful for encoding a block of data.
165  */
166 int
167 strvis(dst, src, flag)
168 	register char *dst;
169 	register const char *src;
170 	int flag;
171 {
172 	register char c;
173 	char *start;
174 
175 	for (start = dst; (c = *src) != '\0';)
176 		dst = vis(dst, c, flag, *++src);
177 	*dst = '\0';
178 	return (dst - start);
179 }
180 
181 int
182 strvisx(dst, src, len, flag)
183 	register char *dst;
184 	register const char *src;
185 	register size_t len;
186 	int flag;
187 {
188 	register char c;
189 	char *start;
190 
191 	for (start = dst; len > 1; len--) {
192 		c = *src;
193 		dst = vis(dst, c, flag, *++src);
194 	}
195 	if (len)
196 		dst = vis(dst, *src, flag, '\0');
197 	*dst = '\0';
198 
199 	return (dst - start);
200 }
201