1 /* $OpenBSD: unvis.c,v 1.15 2011/03/13 22:21:32 guenther 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 #include <sys/types.h>
32 #include <ctype.h>
33 #include <vis.h>
34
35 /*
36 * decode driven by state machine
37 */
38 #define S_GROUND 0 /* haven't seen escape char */
39 #define S_START 1 /* start decoding special sequence */
40 #define S_META 2 /* metachar started (M) */
41 #define S_META1 3 /* metachar more, regular char (-) */
42 #define S_CTRL 4 /* control char started (^) */
43 #define S_OCTAL2 5 /* octal digit 2 */
44 #define S_OCTAL3 6 /* octal digit 3 */
45
46 #define isoctal(c) (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
47
48 /*
49 * unvis - decode characters previously encoded by vis
50 */
51 int
unvis(char * cp,char c,int * astate,int flag)52 unvis(char *cp, char c, int *astate, int flag)
53 {
54
55 if (flag & UNVIS_END) {
56 if (*astate == S_OCTAL2 || *astate == S_OCTAL3) {
57 *astate = S_GROUND;
58 return (UNVIS_VALID);
59 }
60 return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD);
61 }
62
63 switch (*astate) {
64
65 case S_GROUND:
66 *cp = 0;
67 if (c == '\\') {
68 *astate = S_START;
69 return (0);
70 }
71 *cp = c;
72 return (UNVIS_VALID);
73
74 case S_START:
75 switch(c) {
76 case '-':
77 *cp = 0;
78 *astate = S_GROUND;
79 return (0);
80 case '\\':
81 *cp = c;
82 *astate = S_GROUND;
83 return (UNVIS_VALID);
84 case '0': case '1': case '2': case '3':
85 case '4': case '5': case '6': case '7':
86 *cp = (c - '0');
87 *astate = S_OCTAL2;
88 return (0);
89 case 'M':
90 *cp = (char) 0200;
91 *astate = S_META;
92 return (0);
93 case '^':
94 *astate = S_CTRL;
95 return (0);
96 case 'n':
97 *cp = '\n';
98 *astate = S_GROUND;
99 return (UNVIS_VALID);
100 case 'r':
101 *cp = '\r';
102 *astate = S_GROUND;
103 return (UNVIS_VALID);
104 case 'b':
105 *cp = '\b';
106 *astate = S_GROUND;
107 return (UNVIS_VALID);
108 case 'a':
109 *cp = '\007';
110 *astate = S_GROUND;
111 return (UNVIS_VALID);
112 case 'v':
113 *cp = '\v';
114 *astate = S_GROUND;
115 return (UNVIS_VALID);
116 case 't':
117 *cp = '\t';
118 *astate = S_GROUND;
119 return (UNVIS_VALID);
120 case 'f':
121 *cp = '\f';
122 *astate = S_GROUND;
123 return (UNVIS_VALID);
124 case 's':
125 *cp = ' ';
126 *astate = S_GROUND;
127 return (UNVIS_VALID);
128 case 'E':
129 *cp = '\033';
130 *astate = S_GROUND;
131 return (UNVIS_VALID);
132 case '\n':
133 /*
134 * hidden newline
135 */
136 *astate = S_GROUND;
137 return (UNVIS_NOCHAR);
138 case '$':
139 /*
140 * hidden marker
141 */
142 *astate = S_GROUND;
143 return (UNVIS_NOCHAR);
144 }
145 *astate = S_GROUND;
146 return (UNVIS_SYNBAD);
147
148 case S_META:
149 if (c == '-')
150 *astate = S_META1;
151 else if (c == '^')
152 *astate = S_CTRL;
153 else {
154 *astate = S_GROUND;
155 return (UNVIS_SYNBAD);
156 }
157 return (0);
158
159 case S_META1:
160 *astate = S_GROUND;
161 *cp |= c;
162 return (UNVIS_VALID);
163
164 case S_CTRL:
165 if (c == '?')
166 *cp |= 0177;
167 else
168 *cp |= c & 037;
169 *astate = S_GROUND;
170 return (UNVIS_VALID);
171
172 case S_OCTAL2: /* second possible octal digit */
173 if (isoctal(c)) {
174 /*
175 * yes - and maybe a third
176 */
177 *cp = (*cp << 3) + (c - '0');
178 *astate = S_OCTAL3;
179 return (0);
180 }
181 /*
182 * no - done with current sequence, push back passed char
183 */
184 *astate = S_GROUND;
185 return (UNVIS_VALIDPUSH);
186
187 case S_OCTAL3: /* third possible octal digit */
188 *astate = S_GROUND;
189 if (isoctal(c)) {
190 *cp = (*cp << 3) + (c - '0');
191 return (UNVIS_VALID);
192 }
193 /*
194 * we were done, push back passed char
195 */
196 return (UNVIS_VALIDPUSH);
197
198 default:
199 /*
200 * decoder in unknown state - (probably uninitialized)
201 */
202 *astate = S_GROUND;
203 return (UNVIS_SYNBAD);
204 }
205 }
206
207 /*
208 * strunvis - decode src into dst
209 *
210 * Number of chars decoded into dst is returned, -1 on error.
211 * Dst is null terminated.
212 */
213
214 int
strunvis(char * dst,const char * src)215 strunvis(char *dst, const char *src)
216 {
217 char c;
218 char *start = dst;
219 int state = 0;
220
221 while ((c = *src++)) {
222 again:
223 switch (unvis(dst, c, &state, 0)) {
224 case UNVIS_VALID:
225 dst++;
226 break;
227 case UNVIS_VALIDPUSH:
228 dst++;
229 goto again;
230 case 0:
231 case UNVIS_NOCHAR:
232 break;
233 default:
234 *dst = '\0';
235 return (-1);
236 }
237 }
238 if (unvis(dst, c, &state, UNVIS_END) == UNVIS_VALID)
239 dst++;
240 *dst = '\0';
241 return (dst - start);
242 }
243
244 ssize_t
strnunvis(char * dst,const char * src,size_t sz)245 strnunvis(char *dst, const char *src, size_t sz)
246 {
247 char c, p;
248 char *start = dst, *end = dst + sz - 1;
249 int state = 0;
250
251 if (sz > 0)
252 *end = '\0';
253 while ((c = *src++)) {
254 again:
255 switch (unvis(&p, c, &state, 0)) {
256 case UNVIS_VALID:
257 if (dst < end)
258 *dst = p;
259 dst++;
260 break;
261 case UNVIS_VALIDPUSH:
262 if (dst < end)
263 *dst = p;
264 dst++;
265 goto again;
266 case 0:
267 case UNVIS_NOCHAR:
268 break;
269 default:
270 if (dst <= end)
271 *dst = '\0';
272 return (-1);
273 }
274 }
275 if (unvis(&p, c, &state, UNVIS_END) == UNVIS_VALID) {
276 if (dst < end)
277 *dst = p;
278 dst++;
279 }
280 if (dst <= end)
281 *dst = '\0';
282 return (dst - start);
283 }
284
285