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 * 4. 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 */
80char *
81vis(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	}
185done:
186	*dst = '\0';
187	return (dst);
188}
189