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preconv.c revision 1.4 
      1 /*	Id: preconv.c,v 1.16 2017/02/18 13:43:52 schwarze Exp  */
      2 /*
      3  * Copyright (c) 2011 Kristaps Dzonsons <kristaps (at) bsd.lv>
      4  * Copyright (c) 2014 Ingo Schwarze <schwarze (at) 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(const struct buf *ib, size_t *ii, struct buf *ob, size_t *oi,
     30     int *filenc)
     31 {
     32 	const unsigned char	*cu;
     33 	int			 nby;
     34 	unsigned int		 accum;
     35 
     36 	cu = (const 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 = (const 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