preconv.c

   1 /*      $Id: preconv.c,v 1.12 2014/11/14 04:24:04 schwarze 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 <stdio.h>
  23 #include <string.h>
  24 #include "mandoc.h"
  25 #include "libmandoc.h"
  26
  27 int
  28 preconv_encode(struct buf *ib, size_t *ii, struct buf *ob, size_t *oi,
  29     int *filenc)
  30 {
  31         size_t           i;
  32         int              state;
  33         unsigned int     accum;
  34         unsigned char    cu;
  35
  36         if ( ! (*filenc & MPARSE_UTF8))
  37                 goto latin;
  38
  39         state = 0;
  40         accum = 0U;
  41
  42         for (i = *ii; i < ib->sz; i++) {
  43                 cu = ib->buf[i];
  44                 if (state) {
  45                         if ( ! (cu & 128) || (cu & 64)) {
  46                                 /* Bad sequence header. */
  47                                 break;
  48                         }
  49
  50                         /* Accept only legitimate bit patterns. */
  51
  52                         if (cu > 191 || cu < 128) {
  53                                 /* Bad in-sequence bits. */
  54                                 break;
  55                         }
  56
  57                         accum |= (cu & 63) << --state * 6;
  58
  59                         if (state)
  60                                 continue;
  61
  62                         if (accum < 0x80)
  63                                 ob->buf[(*oi)++] = accum;
  64                         else
  65                                 *oi += snprintf(ob->buf + *oi,
  66                                     11, "\\[u%.4X]", accum);
  67                         *ii = i + 1;
  68                         *filenc &= ~MPARSE_LATIN1;
  69                         return(1);
  70                 } else {
  71                         /*
  72                          * Entering a UTF-8 state:  if we encounter a
  73                          * UTF-8 bitmask, calculate the expected UTF-8
  74                          * state from it.
  75                          */
  76                         for (state = 0; state < 7; state++)
  77                                 if ( ! (cu & (1 << (7 - state))))
  78                                         break;
  79
  80                         /* Accept only legitimate bit patterns. */
  81
  82                         switch (state--) {
  83                         case (4):
  84                                 if (cu <= 244 && cu >= 240) {
  85                                         accum = (cu & 7) << 18;
  86                                         continue;
  87                                 }
  88                                 /* Bad 4-sequence start bits. */
  89                                 break;
  90                         case (3):
  91                                 if (cu <= 239 && cu >= 224) {
  92                                         accum = (cu & 15) << 12;
  93                                         continue;
  94                                 }
  95                                 /* Bad 3-sequence start bits. */
  96                                 break;
  97                         case (2):
  98                                 if (cu <= 223 && cu >= 194) {
  99                                         accum = (cu & 31) << 6;
 100                                         continue;
 101                                 }
 102                                 /* Bad 2-sequence start bits. */
 103                                 break;
 104                         default:
 105                                 /* Bad sequence bit mask. */
 106                                 break;
 107                         }
 108                         break;
 109                 }
 110         }
 111
 112         /* FALLTHROUGH: Invalid or incomplete UTF-8 sequence. */
 113
 114 latin:
 115         if ( ! (*filenc & MPARSE_LATIN1))
 116                 return(0);
 117
 118         *oi += snprintf(ob->buf + *oi, 11,
 119             "\\[u%.4X]", (unsigned char)ib->buf[(*ii)++]);
 120
 121         *filenc &= ~MPARSE_UTF8;
 122         return(1);
 123 }
 124
 125 int
 126 preconv_cue(const struct buf *b, size_t offset)
 127 {
 128         const char      *ln, *eoln, *eoph;
 129         size_t           sz, phsz;
 130
 131         ln = b->buf + offset;
 132         sz = b->sz - offset;
 133
 134         /* Look for the end-of-line. */
 135
 136         if (NULL == (eoln = memchr(ln, '\n', sz)))
 137                 eoln = ln + sz;
 138
 139         /* Check if we have the correct header/trailer. */
 140
 141         if ((sz = (size_t)(eoln - ln)) < 10 ||
 142             memcmp(ln, ".\\\" -*-", 7) || memcmp(eoln - 3, "-*-", 3))
 143                 return(MPARSE_UTF8 | MPARSE_LATIN1);
 144
 145         /* Move after the header and adjust for the trailer. */
 146
 147         ln += 7;
 148         sz -= 10;
 149
 150         while (sz > 0) {
 151                 while (sz > 0 && ' ' == *ln) {
 152                         ln++;
 153                         sz--;
 154                 }
 155                 if (0 == sz)
 156                         break;
 157
 158                 /* Find the end-of-phrase marker (or eoln). */
 159
 160                 if (NULL == (eoph = memchr(ln, ';', sz)))
 161                         eoph = eoln - 3;
 162                 else
 163                         eoph++;
 164
 165                 /* Only account for the "coding" phrase. */
 166
 167                 if ((phsz = eoph - ln) < 7 ||
 168                     strncasecmp(ln, "coding:", 7)) {
 169                         sz -= phsz;
 170                         ln += phsz;
 171                         continue;
 172                 }
 173
 174                 sz -= 7;
 175                 ln += 7;
 176
 177                 while (sz > 0 && ' ' == *ln) {
 178                         ln++;
 179                         sz--;
 180                 }
 181                 if (0 == sz)
 182                         return(0);
 183
 184                 /* Check us against known encodings. */
 185
 186                 if (phsz > 4 && !strncasecmp(ln, "utf-8", 5))
 187                         return(MPARSE_UTF8);
 188                 if (phsz > 10 && !strncasecmp(ln, "iso-latin-1", 11))
 189                         return(MPARSE_LATIN1);
 190                 return(0);
 191         }
 192         return(MPARSE_UTF8 | MPARSE_LATIN1);
 193 }