citadel/html.c

   1 /*
   2  * $Id$
   3  *
   4  * Functions which handle translation between HTML and plain text
   5  * Copyright (c) 2000-2001 by Art Cancro and others.   This program is
   6  * released under the terms of the GNU General Public License.
   7  */
   8
   9 #ifdef DLL_EXPORT
  10 #define IN_LIBCIT
  11 #endif
  12
  13 #include "sysdep.h"
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <stdio.h>
  17 #include <fcntl.h>
  18 #include <signal.h>
  19
  20 #if TIME_WITH_SYS_TIME
  21 # include <sys/time.h>
  22 # include <time.h>
  23 #else
  24 # if HAVE_SYS_TIME_H
  25 #  include <sys/time.h>
  26 # else
  27 #  include <time.h>
  28 # endif
  29 #endif
  30
  31 #include <ctype.h>
  32 #include <string.h>
  33 #include <errno.h>
  34 #include <limits.h>
  35 #include "citadel.h"
  36 #include "server.h"
  37 #include "serv_extensions.h"
  38 #include "control.h"
  39 #include "sysdep_decls.h"
  40 #include "support.h"
  41 #include "config.h"
  42 #include "msgbase.h"
  43 #include "tools.h"
  44 #include "room_ops.h"
  45 #include "html.h"
  46
  47
  48 /*
  49  * Convert HTML to plain text.
  50  *
  51  * inputmsg      = pointer to raw HTML message
  52  * screenwidth   = desired output screenwidth
  53  * do_citaformat = set to 1 to indent newlines with spaces
  54  */
  55 char *html_to_ascii(char *inputmsg, int screenwidth, int do_citaformat) {
  56         char inbuf[SIZ];
  57         char outbuf[SIZ];
  58         char tag[1024];
  59         int done_reading = 0;
  60         char *inptr;
  61         char *outptr;
  62         size_t outptr_buffer_size;
  63         size_t output_len = 0;
  64         int i, j, ch, did_out, rb, scanch;
  65         int nest = 0;           /* Bracket nesting level */
  66         int blockquote = 0;     /* BLOCKQUOTE nesting level */
  67
  68         inptr = inputmsg;
  69         strcpy(inbuf, "");
  70         strcpy(outbuf, "");
  71
  72         outptr_buffer_size = strlen(inptr) + SIZ;
  73         outptr = malloc(outptr_buffer_size);
  74         if (outptr == NULL) return NULL;
  75         strcpy(outptr, "");
  76         output_len = 0;
  77
  78         do {
  79                 /* Fill the input buffer */
  80                 if ( (done_reading == 0) && (strlen(inbuf) < (SIZ-128)) ) {
  81
  82                         ch = *inptr++;
  83                         if (ch != 0) {
  84                                 inbuf[strlen(inbuf)+1] = 0;
  85                                 inbuf[strlen(inbuf)] = ch;
  86                         }
  87                         else {
  88                                 done_reading = 1;
  89                         }
  90
  91                 }
  92
  93                 /* Do some parsing */
  94                 if (strlen(inbuf)>0) {
  95
  96                     /* Fold in all the spacing */
  97                     for (i=0; i<strlen(inbuf); ++i) {
  98                         if (inbuf[i]==10) inbuf[i]=32;
  99                         if (inbuf[i]==13) inbuf[i]=32;
 100                         if (inbuf[i]==9) inbuf[i]=32;
 101                         /*** we like foreign characters now.
 102                         if ((inbuf[i]<32) || (inbuf[i]>126)) {
 103                                 inbuf[i] = '?';
 104                         } */
 105                     }
 106                     for (i=0; i<strlen(inbuf); ++i) {
 107                         while ((inbuf[i]==32)&&(inbuf[i+1]==32))
 108                                 strcpy(&inbuf[i], &inbuf[i+1]);
 109                     }
 110
 111                     for (i=0; i<strlen(inbuf); ++i) {
 112
 113                         ch = inbuf[i];
 114
 115                         if (ch == '<') {
 116                                 ++nest;
 117                                 strcpy(tag, "");
 118                         }
 119
 120                         else if (ch == '>') {   /* We have a tag. */
 121                                 if (nest > 0) --nest;
 122
 123                                 /* Unqualify the tag (truncate at first space) */
 124                                 if (strchr(tag, ' ') != NULL) {
 125                                         strcpy(strchr(tag, ' '), "");
 126                                 }
 127
 128                                 if (!strcasecmp(tag, "P")) {
 129                                         strcat(outbuf, "\n\n");
 130                                 }
 131
 132                                 if (!strcasecmp(tag, "/DIV")) {
 133                                         strcat(outbuf, "\n\n");
 134                                 }
 135
 136                                 if (!strcasecmp(tag, "LI")) {
 137                                         strcat(outbuf, "\n * ");
 138                                 }
 139
 140                                 else if (!strcasecmp(tag, "/UL")) {
 141                                         strcat(outbuf, "\n\n");
 142                                 }
 143
 144                                 else if (!strcasecmp(tag, "H1")) {
 145                                         strcat(outbuf, "\n\n");
 146                                 }
 147
 148                                 else if (!strcasecmp(tag, "H2")) {
 149                                         strcat(outbuf, "\n\n");
 150                                 }
 151
 152                                 else if (!strcasecmp(tag, "H3")) {
 153                                         strcat(outbuf, "\n\n");
 154                                 }
 155
 156                                 else if (!strcasecmp(tag, "H4")) {
 157                                         strcat(outbuf, "\n\n");
 158                                 }
 159
 160                                 else if (!strcasecmp(tag, "/H1")) {
 161                                         strcat(outbuf, "\n");
 162                                 }
 163
 164                                 else if (!strcasecmp(tag, "/H2")) {
 165                                         strcat(outbuf, "\n");
 166                                 }
 167
 168                                 else if (!strcasecmp(tag, "/H3")) {
 169                                         strcat(outbuf, "\n");
 170                                 }
 171
 172                                 else if (!strcasecmp(tag, "/H4")) {
 173                                         strcat(outbuf, "\n");
 174                                 }
 175
 176                                 else if (!strcasecmp(tag, "HR")) {
 177                                         strcat(outbuf, "\n ");
 178                                         for (j=0; j<screenwidth-2; ++j)
 179                                                 strcat(outbuf, "-");
 180                                         strcat(outbuf, "\n");
 181                                 }
 182
 183                                 else if (!strcasecmp(tag, "BR")) {
 184                                         strcat(outbuf, "\n");
 185                                 }
 186
 187                                 else if (!strcasecmp(tag, "TR")) {
 188                                         strcat(outbuf, "\n");
 189                                 }
 190
 191                                 else if (!strcasecmp(tag, "/TABLE")) {
 192                                         strcat(outbuf, "\n");
 193                                 }
 194
 195                                 else if (!strcasecmp(tag, "BLOCKQUOTE")) {
 196                                         strcat(outbuf, "\n\n <<\n");
 197                                         ++blockquote;
 198                                 }
 199
 200                                 else if (!strcasecmp(tag, "/BLOCKQUOTE")) {
 201                                         strcat(outbuf, "\n >>\n\n");
 202                                         --blockquote;
 203                                 }
 204
 205                         }
 206
 207                         else if ((nest > 0) && (strlen(tag)<(sizeof(tag)-1))) {
 208                                 tag[strlen(tag)+1] = 0;
 209                                 tag[strlen(tag)] = ch;
 210                         }
 211
 212                         else if (!nest) {
 213                                 outbuf[strlen(outbuf)+1] = 0;
 214                                 outbuf[strlen(outbuf)] = ch;
 215                         }
 216                     }
 217                     strcpy(inbuf, &inbuf[i]);
 218                 }
 219
 220                 /* Convert &; tags to the forbidden characters */
 221                 if (strlen(outbuf)>0) for (i=0; i<strlen(outbuf); ++i) {
 222
 223                         if (!strncasecmp(&outbuf[i], "&nbsp;", 6)) {
 224                                 outbuf[i] = ' ';
 225                                 strcpy(&outbuf[i+1], &outbuf[i+6]);
 226                         }
 227
 228                         else if (!strncasecmp(&outbuf[i], "&lt;", 4)) {
 229                                 outbuf[i] = '<';
 230                                 strcpy(&outbuf[i+1], &outbuf[i+4]);
 231                         }
 232
 233                         else if (!strncasecmp(&outbuf[i], "&gt;", 4)) {
 234                                 outbuf[i] = '>';
 235                                 strcpy(&outbuf[i+1], &outbuf[i+4]);
 236                         }
 237
 238                         else if (!strncasecmp(&outbuf[i], "&amp;", 5)) {
 239                                 strcpy(&outbuf[i+1], &outbuf[i+5]);
 240                         }
 241
 242                         else if (!strncasecmp(&outbuf[i], "&quot;", 6)) {
 243                                 outbuf[i] = '\"';
 244                                 strcpy(&outbuf[i+1], &outbuf[i+6]);
 245                         }
 246
 247                         else if (!strncasecmp(&outbuf[i], "&copy;", 6)) {
 248                                 outbuf[i] = '(';
 249                                 outbuf[i+1] = 'c';
 250                                 outbuf[i+2] = ')';
 251                                 strcpy(&outbuf[i+3], &outbuf[i+6]);
 252                         }
 253
 254                         else if (!strncasecmp(&outbuf[i], "&reg;", 5)) {
 255                                 outbuf[i] = '(';
 256                                 outbuf[i+1] = 'r';
 257                                 outbuf[i+2] = ')';
 258                                 strcpy(&outbuf[i+3], &outbuf[i+5]);
 259                         }
 260
 261                         /* two-digit decimal equivalents */
 262                         else if ((!strncmp(&outbuf[i], "&#", 2))
 263                               && (outbuf[i+4] == ';') ) {
 264                                 scanch = 0;
 265                                 sscanf(&outbuf[i+2], "%02d", &scanch);
 266                                 outbuf[i] = scanch;
 267                                 strcpy(&outbuf[i+1], &outbuf[i+5]);
 268                         }
 269
 270                         /* three-digit decimal equivalents */
 271                         else if ((!strncmp(&outbuf[i], "&#", 2))
 272                               && (outbuf[i+5] == ';') ) {
 273                                 scanch = 0;
 274                                 sscanf(&outbuf[i+2], "%03d", &scanch);
 275                                 outbuf[i] = scanch;
 276                                 strcpy(&outbuf[i+1], &outbuf[i+6]);
 277                         }
 278
 279                 }
 280
 281                 /* Make sure the output buffer is big enough */
 282                 if ((output_len + strlen(outbuf) + SIZ)
 283                    > outptr_buffer_size) {
 284                         outptr_buffer_size += SIZ;
 285                         outptr = realloc(outptr, outptr_buffer_size);
 286                 }
 287
 288                 /* Output any lines terminated with hard line breaks */
 289                 do {
 290                         did_out = 0;
 291                         if (strlen(outbuf)>0) {
 292                             for (i = 0; i<strlen(outbuf); ++i) {
 293                                 if ( (i<(screenwidth-2)) && (outbuf[i]=='\n')) {
 294
 295                                         strncpy(&outptr[output_len],
 296                                                 outbuf, i+1);
 297                                         output_len += (i+1);
 298
 299                                         if (do_citaformat) {
 300                                                 strcpy(&outptr[output_len],
 301                                                         " ");
 302                                                 ++output_len;
 303                                         }
 304
 305                                         strcpy(outbuf, &outbuf[i+1]);
 306                                         i = 0;
 307                                         did_out = 1;
 308                                 }
 309                         }
 310                     }
 311                 } while (did_out);
 312
 313                 /* Add soft line breaks */
 314                 if (strlen(outbuf) > (screenwidth - 2 )) {
 315                         rb = (-1);
 316                         for (i=0; i<(screenwidth-2); ++i) {
 317                                 if (outbuf[i]==32) rb = i;
 318                         }
 319                         if (rb>=0) {
 320                                 strncpy(&outptr[output_len], outbuf, rb);
 321                                 output_len += rb;
 322                                 strcpy(&outptr[output_len], "\n");
 323                                 output_len += 1;
 324                                 if (do_citaformat) {
 325                                         strcpy(&outptr[output_len], " ");
 326                                         ++output_len;
 327                                 }
 328                                 strcpy(outbuf, &outbuf[rb+1]);
 329                         } else {
 330                                 strncpy(&outptr[output_len], outbuf,
 331                                         screenwidth-2);
 332                                 output_len += (screenwidth-2);
 333                                 strcpy(&outptr[output_len], "\n");
 334                                 output_len += 1;
 335                                 if (do_citaformat) {
 336                                         strcpy(&outptr[output_len], " ");
 337                                         ++output_len;
 338                                 }
 339                                 strcpy(outbuf, &outbuf[screenwidth-2]);
 340                         }
 341                 }
 342
 343         } while (done_reading == 0);
 344
 345         strcpy(&outptr[output_len], outbuf);
 346         output_len += strlen(outbuf);
 347
 348         /* Strip leading/trailing whitespace.  We can't do this with
 349          * striplt() because it uses too many strlen()'s
 350          */
 351         while ((output_len > 0) && (isspace(outptr[0]))) {
 352                 strcpy(outptr, &outptr[1]);
 353                 --output_len;
 354         }
 355         while ((output_len > 0) && (isspace(outptr[output_len-1]))) {
 356                 outptr[output_len-1] = 0;
 357                 --output_len;
 358         }
 359
 360         if (outptr[output_len-1] != '\n') {
 361                 strcat(outptr, "\n");
 362                 ++output_len;
 363         }
 364
 365         return outptr;
 366
 367 }