1/*	$NetBSD: unvis.c,v 1.19 2000/01/22 22:19:13 mycroft 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. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#if 1
33#include <config.h>
34#include "roken.h"
35#ifndef _DIAGASSERT
36#define _DIAGASSERT(X)
37#endif
38#else
39#include <sys/cdefs.h>
40#if defined(LIBC_SCCS) && !defined(lint)
41#if 0
42static char sccsid[] = "@(#)unvis.c	8.1 (Berkeley) 6/4/93";
43#else
44__RCSID("$NetBSD: unvis.c,v 1.19 2000/01/22 22:19:13 mycroft Exp $");
45#endif
46#endif /* LIBC_SCCS and not lint */
47
48#define __LIBC12_SOURCE__
49
50#include "namespace.h"
51#endif
52#include <sys/types.h>
53
54#include <assert.h>
55#include <ctype.h>
56#include <stdio.h>
57#include <vis.h>
58
59#if 0
60#ifdef __weak_alias
61__weak_alias(strunvis,_strunvis)
62__weak_alias(unvis,_unvis)
63#endif
64
65__warn_references(unvis,
66    "warning: reference to compatibility unvis(); include <vis.h> for correct reference")
67#endif
68
69/*
70 * decode driven by state machine
71 */
72#define	S_GROUND	0	/* haven't seen escape char */
73#define	S_START		1	/* start decoding special sequence */
74#define	S_META		2	/* metachar started (M) */
75#define	S_META1		3	/* metachar more, regular char (-) */
76#define	S_CTRL		4	/* control char started (^) */
77#define	S_OCTAL2	5	/* octal digit 2 */
78#define	S_OCTAL3	6	/* octal digit 3 */
79
80#define	isoctal(c)	(((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')
81
82ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
83	rk_strunvis (char *, const char *);
84ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
85	rk_unvis (char *, int, int *, int);
86
87/*
88 * unvis - decode characters previously encoded by vis
89 */
90
91ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
92rk_unvis(char *cp, int c, int *astate, int flag)
93{
94
95	_DIAGASSERT(cp != NULL);
96	_DIAGASSERT(astate != NULL);
97
98	if (flag & UNVIS_END) {
99		if (*astate == S_OCTAL2 || *astate == S_OCTAL3) {
100			*astate = S_GROUND;
101			return (UNVIS_VALID);
102		}
103		return (*astate == S_GROUND ? UNVIS_NOCHAR : UNVIS_SYNBAD);
104	}
105
106	switch (*astate) {
107
108	case S_GROUND:
109		*cp = 0;
110		if (c == '\\') {
111			*astate = S_START;
112			return (0);
113		}
114		*cp = c;
115		return (UNVIS_VALID);
116
117	case S_START:
118		switch(c) {
119		case '\\':
120			*cp = c;
121			*astate = S_GROUND;
122			return (UNVIS_VALID);
123		case '0': case '1': case '2': case '3':
124		case '4': case '5': case '6': case '7':
125			*cp = (c - '0');
126			*astate = S_OCTAL2;
127			return (0);
128		case 'M':
129			*cp = (u_char)0200;
130			*astate = S_META;
131			return (0);
132		case '^':
133			*astate = S_CTRL;
134			return (0);
135		case 'n':
136			*cp = '\n';
137			*astate = S_GROUND;
138			return (UNVIS_VALID);
139		case 'r':
140			*cp = '\r';
141			*astate = S_GROUND;
142			return (UNVIS_VALID);
143		case 'b':
144			*cp = '\b';
145			*astate = S_GROUND;
146			return (UNVIS_VALID);
147		case 'a':
148			*cp = '\007';
149			*astate = S_GROUND;
150			return (UNVIS_VALID);
151		case 'v':
152			*cp = '\v';
153			*astate = S_GROUND;
154			return (UNVIS_VALID);
155		case 't':
156			*cp = '\t';
157			*astate = S_GROUND;
158			return (UNVIS_VALID);
159		case 'f':
160			*cp = '\f';
161			*astate = S_GROUND;
162			return (UNVIS_VALID);
163		case 's':
164			*cp = ' ';
165			*astate = S_GROUND;
166			return (UNVIS_VALID);
167		case 'E':
168			*cp = '\033';
169			*astate = S_GROUND;
170			return (UNVIS_VALID);
171		case '\n':
172			/*
173			 * hidden newline
174			 */
175			*astate = S_GROUND;
176			return (UNVIS_NOCHAR);
177		case '$':
178			/*
179			 * hidden marker
180			 */
181			*astate = S_GROUND;
182			return (UNVIS_NOCHAR);
183		}
184		*astate = S_GROUND;
185		return (UNVIS_SYNBAD);
186
187	case S_META:
188		if (c == '-')
189			*astate = S_META1;
190		else if (c == '^')
191			*astate = S_CTRL;
192		else {
193			*astate = S_GROUND;
194			return (UNVIS_SYNBAD);
195		}
196		return (0);
197
198	case S_META1:
199		*astate = S_GROUND;
200		*cp |= c;
201		return (UNVIS_VALID);
202
203	case S_CTRL:
204		if (c == '?')
205			*cp |= 0177;
206		else
207			*cp |= c & 037;
208		*astate = S_GROUND;
209		return (UNVIS_VALID);
210
211	case S_OCTAL2:	/* second possible octal digit */
212		if (isoctal(c)) {
213			/*
214			 * yes - and maybe a third
215			 */
216			*cp = (*cp << 3) + (c - '0');
217			*astate = S_OCTAL3;
218			return (0);
219		}
220		/*
221		 * no - done with current sequence, push back passed char
222		 */
223		*astate = S_GROUND;
224		return (UNVIS_VALIDPUSH);
225
226	case S_OCTAL3:	/* third possible octal digit */
227		*astate = S_GROUND;
228		if (isoctal(c)) {
229			*cp = (*cp << 3) + (c - '0');
230			return (UNVIS_VALID);
231		}
232		/*
233		 * we were done, push back passed char
234		 */
235		return (UNVIS_VALIDPUSH);
236
237	default:
238		/*
239		 * decoder in unknown state - (probably uninitialized)
240		 */
241		*astate = S_GROUND;
242		return (UNVIS_SYNBAD);
243	}
244}
245
246/*
247 * strunvis - decode src into dst
248 *
249 *	Number of chars decoded into dst is returned, -1 on error.
250 *	Dst is null terminated.
251 */
252
253ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
254rk_strunvis(char *dst, const char *src)
255{
256	char c;
257	char *start = dst;
258	int state = 0;
259
260	_DIAGASSERT(src != NULL);
261	_DIAGASSERT(dst != NULL);
262
263	while ((c = *src++) != '\0') {
264	again:
265		switch (rk_unvis(dst, (unsigned char)c, &state, 0)) {
266		case UNVIS_VALID:
267			dst++;
268			break;
269		case UNVIS_VALIDPUSH:
270			dst++;
271			goto again;
272		case 0:
273		case UNVIS_NOCHAR:
274			break;
275		default:
276			return (-1);
277		}
278	}
279	if (unvis(dst, (unsigned char)c, &state, UNVIS_END) == UNVIS_VALID)
280		dst++;
281	*dst = '\0';
282	return (dst - start);
283}
284