1 /*-
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * Defived from FreeBSD head/lib/libc/gen/vis.c 165903, head/include/vis.h
30 * 203964.
31 */
32
33 #include <sys/types.h>
34 #include <limits.h>
35 #include <ctype.h>
36 #include <stdio.h>
37
38 /*
39 * to select alternate encoding format
40 */
41 #define VIS_OCTAL 0x01 /* use octal \ddd format */
42 #define VIS_CSTYLE 0x02 /* use \[nrft0..] where appropriate */
43
44 /*
45 * to alter set of characters encoded (default is to encode all
46 * non-graphic except space, tab, and newline).
47 */
48 #define VIS_SP 0x04 /* also encode space */
49 #define VIS_TAB 0x08 /* also encode tab */
50 #define VIS_NL 0x10 /* also encode newline */
51 #define VIS_WHITE (VIS_SP | VIS_TAB | VIS_NL)
52 #define VIS_SAFE 0x20 /* only encode "unsafe" characters */
53
54 /*
55 * other
56 */
57 #define VIS_NOSLASH 0x40 /* inhibit printing '\' */
58 #define VIS_HTTPSTYLE 0x80 /* http-style escape % HEX HEX */
59 #define VIS_GLOB 0x100 /* encode glob(3) magics */
60
61 /*
62 * unvis return codes
63 */
64 #define UNVIS_VALID 1 /* character valid */
65 #define UNVIS_VALIDPUSH 2 /* character valid, push back passed char */
66 #define UNVIS_NOCHAR 3 /* valid sequence, no character produced */
67 #define UNVIS_SYNBAD -1 /* unrecognized escape sequence */
68 #define UNVIS_ERROR -2 /* decoder in unknown state (unrecoverable) */
69
70 /*
71 * unvis flags
72 */
73 #define UNVIS_END 1 /* no more characters */
74
75 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
76
77 /*
78 * vis - visually encode characters
79 */
80 char *
vis(dst,c,flag,nextc)81 vis(dst, c, flag, nextc)
82 char *dst;
83 int c, nextc;
84 int flag;
85 {
86 c = (unsigned char)c;
87
88 if (flag & VIS_HTTPSTYLE) {
89 /* Described in RFC 1808 */
90 if (!(isalnum(c) /* alpha-numeric */
91 /* safe */
92 || c == '$' || c == '-' || c == '_' || c == '.' || c == '+'
93 /* extra */
94 || c == '!' || c == '*' || c == '\'' || c == '('
95 || c == ')' || c == ',')) {
96 *dst++ = '%';
97 snprintf(dst, 4, (c < 16 ? "0%X" : "%X"), c);
98 dst += 2;
99 goto done;
100 }
101 }
102
103 if ((flag & VIS_GLOB) &&
104 (c == '*' || c == '?' || c == '[' || c == '#'))
105 ;
106 else if (isgraph(c) ||
107 ((flag & VIS_SP) == 0 && c == ' ') ||
108 ((flag & VIS_TAB) == 0 && c == '\t') ||
109 ((flag & VIS_NL) == 0 && c == '\n') ||
110 ((flag & VIS_SAFE) && (c == '\b' || c == '\007' || c == '\r'))) {
111 *dst++ = c;
112 if (c == '\\' && (flag & VIS_NOSLASH) == 0)
113 *dst++ = '\\';
114 *dst = '\0';
115 return (dst);
116 }
117
118 if (flag & VIS_CSTYLE) {
119 switch(c) {
120 case '\n':
121 *dst++ = '\\';
122 *dst++ = 'n';
123 goto done;
124 case '\r':
125 *dst++ = '\\';
126 *dst++ = 'r';
127 goto done;
128 case '\b':
129 *dst++ = '\\';
130 *dst++ = 'b';
131 goto done;
132 case '\a':
133 *dst++ = '\\';
134 *dst++ = 'a';
135 goto done;
136 case '\v':
137 *dst++ = '\\';
138 *dst++ = 'v';
139 goto done;
140 case '\t':
141 *dst++ = '\\';
142 *dst++ = 't';
143 goto done;
144 case '\f':
145 *dst++ = '\\';
146 *dst++ = 'f';
147 goto done;
148 case ' ':
149 *dst++ = '\\';
150 *dst++ = 's';
151 goto done;
152 case '\0':
153 *dst++ = '\\';
154 *dst++ = '0';
155 if (isoctal(nextc)) {
156 *dst++ = '0';
157 *dst++ = '0';
158 }
159 goto done;
160 }
161 }
162 if (((c & 0177) == ' ') || isgraph(c) || (flag & VIS_OCTAL)) {
163 *dst++ = '\\';
164 *dst++ = ((u_char)c >> 6 & 07) + '0';
165 *dst++ = ((u_char)c >> 3 & 07) + '0';
166 *dst++ = ((u_char)c & 07) + '0';
167 goto done;
168 }
169 if ((flag & VIS_NOSLASH) == 0)
170 *dst++ = '\\';
171 if (c & 0200) {
172 c &= 0177;
173 *dst++ = 'M';
174 }
175 if (iscntrl(c)) {
176 *dst++ = '^';
177 if (c == 0177)
178 *dst++ = '?';
179 else
180 *dst++ = c + '@';
181 } else {
182 *dst++ = '-';
183 *dst++ = c;
184 }
185 done:
186 *dst = '\0';
187 return (dst);
188 }
189