xref: /illumos-gate/usr/src/cmd/mandoc/preconv.c (revision 3ba944265c4ae1fcf23ef758537c2e4f4feec16e)
1 /*	$Id: preconv.c,v 1.14 2015/03/06 09:24:59 kristaps Exp $ */
2 /*
3  * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
4  * Copyright (c) 2014 Ingo Schwarze <schwarze@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 #include "config.h"
19 
20 #include <sys/types.h>
21 
22 #include <assert.h>
23 #include <stdio.h>
24 #include <string.h>
25 #include "mandoc.h"
26 #include "libmandoc.h"
27 
28 int
29 preconv_encode(struct buf *ib, size_t *ii, struct buf *ob, size_t *oi,
30     int *filenc)
31 {
32 	unsigned char	*cu;
33 	int		 nby;
34 	unsigned int	 accum;
35 
36 	cu = (unsigned char *)ib->buf + *ii;
37 	assert(*cu & 0x80);
38 
39 	if ( ! (*filenc & MPARSE_UTF8))
40 		goto latin;
41 
42 	nby = 1;
43 	while (nby < 5 && *cu & (1 << (7 - nby)))
44 		nby++;
45 
46 	switch (nby) {
47 	case 2:
48 		accum = *cu & 0x1f;
49 		if (accum < 0x02)  /* Obfuscated ASCII. */
50 			goto latin;
51 		break;
52 	case 3:
53 		accum = *cu & 0x0f;
54 		break;
55 	case 4:
56 		accum = *cu & 0x07;
57 		if (accum > 0x04) /* Beyond Unicode. */
58 			goto latin;
59 		break;
60 	default:  /* Bad sequence header. */
61 		goto latin;
62 	}
63 
64 	cu++;
65 	switch (nby) {
66 	case 3:
67 		if ((accum == 0x00 && ! (*cu & 0x20)) ||  /* Use 2-byte. */
68 		    (accum == 0x0d && *cu & 0x20))  /* Surrogates. */
69 			goto latin;
70 		break;
71 	case 4:
72 		if ((accum == 0x00 && ! (*cu & 0x30)) ||  /* Use 3-byte. */
73 		    (accum == 0x04 && *cu & 0x30))  /* Beyond Unicode. */
74 			goto latin;
75 		break;
76 	default:
77 		break;
78 	}
79 
80 	while (--nby) {
81 		if ((*cu & 0xc0) != 0x80)  /* Invalid continuation. */
82 			goto latin;
83 		accum <<= 6;
84 		accum += *cu & 0x3f;
85 		cu++;
86 	}
87 
88 	assert(accum > 0x7f);
89 	assert(accum < 0x110000);
90 	assert(accum < 0xd800 || accum > 0xdfff);
91 
92 	*oi += snprintf(ob->buf + *oi, 11, "\\[u%.4X]", accum);
93 	*ii = (char *)cu - ib->buf;
94 	*filenc &= ~MPARSE_LATIN1;
95 	return(1);
96 
97 latin:
98 	if ( ! (*filenc & MPARSE_LATIN1))
99 		return(0);
100 
101 	*oi += snprintf(ob->buf + *oi, 11,
102 	    "\\[u%.4X]", (unsigned char)ib->buf[(*ii)++]);
103 
104 	*filenc &= ~MPARSE_UTF8;
105 	return(1);
106 }
107 
108 int
109 preconv_cue(const struct buf *b, size_t offset)
110 {
111 	const char	*ln, *eoln, *eoph;
112 	size_t		 sz, phsz;
113 
114 	ln = b->buf + offset;
115 	sz = b->sz - offset;
116 
117 	/* Look for the end-of-line. */
118 
119 	if (NULL == (eoln = memchr(ln, '\n', sz)))
120 		eoln = ln + sz;
121 
122 	/* Check if we have the correct header/trailer. */
123 
124 	if ((sz = (size_t)(eoln - ln)) < 10 ||
125 	    memcmp(ln, ".\\\" -*-", 7) || memcmp(eoln - 3, "-*-", 3))
126 		return(MPARSE_UTF8 | MPARSE_LATIN1);
127 
128 	/* Move after the header and adjust for the trailer. */
129 
130 	ln += 7;
131 	sz -= 10;
132 
133 	while (sz > 0) {
134 		while (sz > 0 && ' ' == *ln) {
135 			ln++;
136 			sz--;
137 		}
138 		if (0 == sz)
139 			break;
140 
141 		/* Find the end-of-phrase marker (or eoln). */
142 
143 		if (NULL == (eoph = memchr(ln, ';', sz)))
144 			eoph = eoln - 3;
145 		else
146 			eoph++;
147 
148 		/* Only account for the "coding" phrase. */
149 
150 		if ((phsz = eoph - ln) < 7 ||
151 		    strncasecmp(ln, "coding:", 7)) {
152 			sz -= phsz;
153 			ln += phsz;
154 			continue;
155 		}
156 
157 		sz -= 7;
158 		ln += 7;
159 
160 		while (sz > 0 && ' ' == *ln) {
161 			ln++;
162 			sz--;
163 		}
164 		if (0 == sz)
165 			return(0);
166 
167 		/* Check us against known encodings. */
168 
169 		if (phsz > 4 && !strncasecmp(ln, "utf-8", 5))
170 			return(MPARSE_UTF8);
171 		if (phsz > 10 && !strncasecmp(ln, "iso-latin-1", 11))
172 			return(MPARSE_LATIN1);
173 		return(0);
174 	}
175 	return(MPARSE_UTF8 | MPARSE_LATIN1);
176 }
177