xref: /netbsd-src/lib/libc/gen/vis.c (revision cda4f8f6ee55684e8d311b86c99ea59191e6b74f)
1 /*-
2  * Copyright (c) 1989 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 /*static char sccsid[] = "from: @(#)vis.c	5.6 (Berkeley) 2/5/92";*/
36 static char rcsid[] = "$Id: vis.c,v 1.3 1993/07/30 07:57:54 mycroft Exp $";
37 #endif /* LIBC_SCCS and not lint */
38 
39 #include <sys/types.h>
40 #include <limits.h>
41 #include <ctype.h>
42 #include <vis.h>
43 
44 #define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
45 
46 /*
47  * vis - visually encode characters
48  */
49 char *
50 vis(dst, c, flag, nextc)
51 	register char *dst;
52 	int c, nextc;
53 	register int flag;
54 {
55 	if ((u_int)c <= UCHAR_MAX && isgraph(c) ||
56 	   ((flag & VIS_SP) == 0 && c == ' ') ||
57 	   ((flag & VIS_TAB) == 0 && c == '\t') ||
58 	   ((flag & VIS_NL) == 0 && c == '\n') ||
59 	   ((flag & VIS_SAFE) && (c == '\b' || c == '\007' || c == '\r'))) {
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 #if __STDC__
82 		case '\a':
83 #else
84 		case '\007':
85 #endif
86 			*dst++ = '\\';
87 			*dst++ = 'a';
88 			goto done;
89 		case '\v':
90 			*dst++ = '\\';
91 			*dst++ = 'v';
92 			goto done;
93 		case '\t':
94 			*dst++ = '\\';
95 			*dst++ = 't';
96 			goto done;
97 		case '\f':
98 			*dst++ = '\\';
99 			*dst++ = 'f';
100 			goto done;
101 		case ' ':
102 			*dst++ = '\\';
103 			*dst++ = 's';
104 			goto done;
105 		case '\0':
106 			*dst++ = '\\';
107 			*dst++ = '0';
108 			if (isoctal(nextc)) {
109 				*dst++ = '0';
110 				*dst++ = '0';
111 			}
112 			goto done;
113 		}
114 	}
115 	if (((c & 0177) == ' ') || (flag & VIS_OCTAL)) {
116 		*dst++ = '\\';
117 		*dst++ = ((u_char)c >> 6 & 07) + '0';
118 		*dst++ = ((u_char)c >> 3 & 07) + '0';
119 		*dst++ = ((u_char)c & 07) + '0';
120 		goto done;
121 	}
122 	if ((flag & VIS_NOSLASH) == 0)
123 		*dst++ = '\\';
124 	if (c & 0200) {
125 		c &= 0177;
126 		*dst++ = 'M';
127 	}
128 	if (iscntrl(c)) {
129 		*dst++ = '^';
130 		if (c == 0177)
131 			*dst++ = '?';
132 		else
133 			*dst++ = c + '@';
134 	} else {
135 		*dst++ = '-';
136 		*dst++ = c;
137 	}
138 done:
139 	*dst = '\0';
140 	return (dst);
141 }
142 
143 /*
144  * strvis, strvisx - visually encode characters from src into dst
145  *
146  *	Dst must be 4 times the size of src to account for possible
147  *	expansion.  The length of dst, not including the trailing NULL,
148  *	is returned.
149  *
150  *	Strvisx encodes exactly len bytes from src into dst.
151  *	This is useful for encoding a block of data.
152  */
153 int
154 strvis(dst, src, flag)
155 	register char *dst;
156 	register const char *src;
157 	int flag;
158 {
159 	register char c;
160 	char *start;
161 
162 	for (start = dst; c = *src;)
163 		dst = vis(dst, c, flag, *++src);
164 	*dst = '\0';
165 	return (dst - start);
166 }
167 
168 int
169 strvisx(dst, src, len, flag)
170 	register char *dst;
171 	register const char *src;
172 	register size_t len;
173 	int flag;
174 {
175 	char *start = dst;
176 
177 	while (len > 1) {
178 		dst = vis(dst, *src, flag, *(src+1));
179 		len--;
180 	}
181 	if (len)
182 		dst = vis(dst, *src, flag, '\0');
183 
184 	return (dst - start);
185 }
186