libexif/exif-loader.c

   1 /* exif-loader.c
   2  *
   3  * Copyright © 2002 Lutz Müller <lutz@users.sourceforge.net>
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include <config.h>
  22
  23 #include <libexif/exif-loader.h>
  24 #include <libexif/i18n.h>
  25
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <stdio.h>
  29
  30 #undef JPEG_MARKER_SOI
  31 #define JPEG_MARKER_SOI  0xd8
  32 #undef JPEG_MARKER_APP0
  33 #define JPEG_MARKER_APP0 0xe0
  34 #undef JPEG_MARKER_APP1
  35 #define JPEG_MARKER_APP1 0xe1
  36 #undef JPEG_MARKER_APP2
  37 #define JPEG_MARKER_APP2 0xe2
  38 #undef JPEG_MARKER_APP13
  39 #define JPEG_MARKER_APP13 0xed
  40 #undef JPEG_MARKER_COM
  41 #define JPEG_MARKER_COM 0xfe
  42
  43 #undef MAX
  44 #define MAX(a, b)  (((a) > (b)) ? (a) : (b))
  45
  46 typedef enum {
  47         EL_READ = 0,
  48         EL_READ_SIZE_BYTE_24,
  49         EL_READ_SIZE_BYTE_16,
  50         EL_READ_SIZE_BYTE_08,
  51         EL_READ_SIZE_BYTE_00,
  52         EL_SKIP_BYTES,
  53         EL_EXIF_FOUND,
  54 } ExifLoaderState;
  55
  56 typedef enum {
  57         EL_DATA_FORMAT_UNKNOWN,
  58         EL_DATA_FORMAT_EXIF,
  59         EL_DATA_FORMAT_JPEG,
  60         EL_DATA_FORMAT_FUJI_RAW
  61 } ExifLoaderDataFormat;
  62
  63 struct _ExifLoader {
  64         ExifLoaderState state;
  65         ExifLoaderDataFormat data_format;
  66
  67         /* Small buffer used for detection of format */
  68         unsigned char b[12];
  69         unsigned char b_len;
  70
  71         unsigned int size;
  72         unsigned char *buf;
  73         unsigned int bytes_read;
  74
  75         unsigned int ref_count;
  76
  77         ExifLog *log;
  78         ExifMem *mem;
  79 };
  80
  81 static const unsigned char ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};
  82
  83 static void *
  84 exif_loader_alloc (ExifLoader *l, unsigned int i)
  85 {
  86         void *d;
  87
  88         if (!l || !i)
  89                 return NULL;
  90
  91         d = exif_mem_alloc (l->mem, i);
  92         if (d)
  93                 return d;
  94
  95         EXIF_LOG_NO_MEMORY (l->log, "ExifLog", i);
  96         return NULL;
  97 }
  98
  99 #undef  MIN
 100 #define MIN(a, b)  (((a) < (b)) ? (a) : (b))
 101
 102 void
 103 exif_loader_write_file (ExifLoader *l, const char *path)
 104 {
 105         FILE *f;
 106         int size;
 107         unsigned char data[1024];
 108
 109         if (!l)
 110                 return;
 111
 112         f = fopen (path, "rb");
 113         if (!f) {
 114                 exif_log (l->log, EXIF_LOG_CODE_NONE, "ExifLoader",
 115                           _("The file '%s' could not be opened."), path);
 116                 return;
 117         }
 118         while (1) {
 119                 size = fread (data, 1, sizeof (data), f);
 120                 if (size <= 0)
 121                         break;
 122                 if (!exif_loader_write (l, data, size))
 123                         break;
 124         }
 125         fclose (f);
 126 }
 127
 128 static unsigned int
 129 exif_loader_copy (ExifLoader *eld, unsigned char *buf, unsigned int len)
 130 {
 131         if (!eld || (len && !buf) || (eld->bytes_read >= eld->size))
 132                 return 0;
 133
 134         /* If needed, allocate the buffer. */
 135         if (!eld->buf)
 136                 eld->buf = exif_loader_alloc (eld, eld->size);
 137         if (!eld->buf)
 138                 return 0;
 139
 140         /* Copy memory */
 141         len = MIN (len, eld->size - eld->bytes_read);
 142         memcpy (eld->buf + eld->bytes_read, buf, len);
 143         eld->bytes_read += len;
 144
 145         return (eld->bytes_read >= eld->size) ? 0 : 1;
 146 }
 147
 148 unsigned char
 149 exif_loader_write (ExifLoader *eld, unsigned char *buf, unsigned int len)
 150 {
 151         unsigned int i;
 152
 153         if (!eld || (len && !buf))
 154                 return 0;
 155
 156         switch (eld->state) {
 157         case EL_EXIF_FOUND:
 158                 return exif_loader_copy (eld, buf, len);
 159         case EL_SKIP_BYTES:
 160                 if (eld->size > len) {
 161                         eld->size -= len;
 162                         return 1;
 163                 }
 164                 len -= eld->size;
 165                 buf += eld->size;
 166                 eld->size = 0;
 167                 eld->b_len = 0;
 168                 switch (eld->data_format) {
 169                 case EL_DATA_FORMAT_FUJI_RAW:
 170                         eld->state = EL_READ_SIZE_BYTE_24;
 171                         break;
 172                 default:
 173                         eld->state = EL_READ;
 174                         break;
 175                 }
 176                 break;
 177         default:
 178                 break;
 179         }
 180
 181         exif_log (eld->log, EXIF_LOG_CODE_DEBUG, "ExifLoader",
 182                   "Scanning %i byte(s) of data...", len);
 183
 184         /*
 185          * First fill the small buffer. Only continue if the buffer
 186          * is filled. Note that EXIF data contains at least 12 bytes.
 187          */
 188         i = MIN (len, sizeof (eld->b) - eld->b_len);
 189         if (i) {
 190                 memcpy (&eld->b[eld->b_len], buf, i);
 191                 eld->b_len += i;
 192                 if (eld->b_len < sizeof (eld->b))
 193                         return 1;
 194                 buf += i;
 195                 len -= i;
 196         }
 197
 198         switch (eld->data_format) {
 199         case EL_DATA_FORMAT_UNKNOWN:
 200
 201                 /* Check the small buffer against known formats. */
 202                 if (!memcmp (eld->b, "FUJIFILM", 8)) {
 203
 204                         /* Skip to byte 84. There is another offset there. */
 205                         eld->data_format = EL_DATA_FORMAT_FUJI_RAW;
 206                         eld->size = 84;
 207                         eld->state = EL_SKIP_BYTES;
 208                         eld->size = 84;
 209
 210                 } else if (!memcmp (eld->b + 2, ExifHeader, sizeof (ExifHeader))) {
 211
 212                         /* Read the size (2 bytes). */
 213                         eld->data_format = EL_DATA_FORMAT_EXIF;
 214                         eld->state = EL_READ_SIZE_BYTE_08;
 215                 }
 216         default:
 217                 break;
 218         }
 219
 220         for (i = 0; i < sizeof (eld->b); i++)
 221                 switch (eld->state) {
 222                 case EL_EXIF_FOUND:
 223                         if (!exif_loader_copy (eld, eld->b + i,
 224                                         sizeof (eld->b) - i))
 225                                 return 0;
 226                         return exif_loader_copy (eld, buf, len);
 227                 case EL_SKIP_BYTES:
 228                         eld->size--;
 229                         if (!eld->size)
 230                                 eld->state = EL_READ;
 231                         break;
 232
 233                 case EL_READ_SIZE_BYTE_24:
 234                         eld->size |= eld->b[i] << 24;
 235                         eld->state = EL_READ_SIZE_BYTE_16;
 236                         break;
 237                 case EL_READ_SIZE_BYTE_16:
 238                         eld->size |= eld->b[i] << 16;
 239                         eld->state = EL_READ_SIZE_BYTE_08;
 240                         break;
 241                 case EL_READ_SIZE_BYTE_08:
 242                         eld->size |= eld->b[i] << 8;
 243                         eld->state = EL_READ_SIZE_BYTE_00;
 244                         break;
 245                 case EL_READ_SIZE_BYTE_00:
 246                         eld->size |= eld->b[i] << 0;
 247                         switch (eld->data_format) {
 248                         case EL_DATA_FORMAT_JPEG:
 249                                 eld->state = EL_SKIP_BYTES;
 250                                 eld->size -= 2;
 251                                 break;
 252                         case EL_DATA_FORMAT_FUJI_RAW:
 253                                 eld->data_format = EL_DATA_FORMAT_EXIF;
 254                                 eld->state = EL_SKIP_BYTES;
 255                                 eld->size -= 86;
 256                                 break;
 257                         case EL_DATA_FORMAT_EXIF:
 258                                 eld->state = EL_EXIF_FOUND;
 259                                 break;
 260                         default:
 261                                 break;
 262                         }
 263                         break;
 264
 265                 default:
 266                         switch (eld->b[i]) {
 267                         case JPEG_MARKER_APP1:
 268                                 if (!memcmp (eld->b + i + 3, ExifHeader, MIN(sizeof (ExifHeader), MAX(0, sizeof (eld->b) - i - 3)))) {
 269                                         eld->data_format = EL_DATA_FORMAT_EXIF;
 270                                 } else {
 271                                         eld->data_format = EL_DATA_FORMAT_JPEG; /* Probably JFIF - keep searching for APP1 EXIF*/
 272                                 }
 273                                 eld->size = 0;
 274                                 eld->state = EL_READ_SIZE_BYTE_08;
 275                                 break;
 276                         case JPEG_MARKER_APP0:
 277                         case JPEG_MARKER_APP2:
 278                         case JPEG_MARKER_APP13:
 279                         case JPEG_MARKER_COM:
 280                                 eld->data_format = EL_DATA_FORMAT_JPEG;
 281                                 eld->size = 0;
 282                                 eld->state = EL_READ_SIZE_BYTE_08;
 283                                 break;
 284                         case 0xff:
 285                         case JPEG_MARKER_SOI:
 286                                 break;
 287                         default:
 288                                 exif_log (eld->log,
 289                                         EXIF_LOG_CODE_CORRUPT_DATA,
 290                                         "ExifLoader", _("The data supplied "
 291                                                 "does not seem to contain "
 292                                                 "EXIF data."));
 293                                 exif_loader_reset (eld);
 294                                 return 0;
 295                         }
 296                 }
 297
 298         /*
 299          * If we reach this point, the buffer has not been big enough
 300          * to read all data we need. Fill it with new data.
 301          */
 302         eld->b_len = 0;
 303         return exif_loader_write (eld, buf, len);
 304 }
 305
 306 ExifLoader *
 307 exif_loader_new (void)
 308 {
 309         ExifMem *mem = exif_mem_new_default ();
 310         ExifLoader *l = exif_loader_new_mem (mem);
 311
 312         exif_mem_unref (mem);
 313
 314         return l;
 315 }
 316
 317 ExifLoader *
 318 exif_loader_new_mem (ExifMem *mem)
 319 {
 320         ExifLoader *loader;
 321
 322         if (!mem)
 323                 return NULL;
 324
 325         loader = exif_mem_alloc (mem, sizeof (ExifLoader));
 326         if (!loader)
 327                 return NULL;
 328         loader->ref_count = 1;
 329
 330         loader->mem = mem;
 331         exif_mem_ref (mem);
 332
 333         return loader;
 334 }
 335
 336 void
 337 exif_loader_ref (ExifLoader *loader)
 338 {
 339         if (loader)
 340                 loader->ref_count++;
 341 }
 342
 343 static void
 344 exif_loader_free (ExifLoader *loader)
 345 {
 346         ExifMem *mem;
 347
 348         if (!loader)
 349                 return;
 350
 351         mem = loader->mem;
 352         exif_loader_reset (loader);
 353         exif_mem_free (mem, loader);
 354         exif_mem_unref (mem);
 355 }
 356
 357 void
 358 exif_loader_unref (ExifLoader *loader)
 359 {
 360         if (!loader)
 361                 return;
 362         if (!--loader->ref_count)
 363                 exif_loader_free (loader);
 364 }
 365
 366 void
 367 exif_loader_reset (ExifLoader *loader)
 368 {
 369         if (!loader)
 370                 return;
 371         exif_mem_free (loader->mem, loader->buf); loader->buf = NULL;
 372         loader->size = 0;
 373         loader->bytes_read = 0;
 374         loader->state = 0;
 375         loader->b_len = 0;
 376         loader->data_format = EL_DATA_FORMAT_UNKNOWN;
 377 }
 378
 379 ExifData *
 380 exif_loader_get_data (ExifLoader *loader)
 381 {
 382         ExifData *ed;
 383
 384         if (!loader)
 385                 return NULL;
 386
 387         ed = exif_data_new_mem (loader->mem);
 388         exif_data_log (ed, loader->log);
 389         exif_data_load_data (ed, loader->buf, loader->bytes_read);
 390
 391         return ed;
 392 }
 393
 394 void
 395 exif_loader_log (ExifLoader *loader, ExifLog *log)
 396 {
 397         if (!loader)
 398                 return;
 399         exif_log_unref (loader->log);
 400         loader->log = log;
 401         exif_log_ref (log);
 402 }