libexif/exif-data.c

   1 /* exif-data.c
   2  *
   3  * Copyright © 2001 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 #include "exif-mnote-data.h"
  23
  24 #include "exif-data.h"
  25 #include "exif-ifd.h"
  26 #include "exif-mnote-data-priv.h"
  27 #include "exif-utils.h"
  28 #include "exif-loader.h"
  29 #include "jpeg-marker.h"
  30 #include <libexif/exif-log.h>
  31
  32 #include <libexif/olympus/exif-mnote-data-olympus.h>
  33 #include <libexif/canon/exif-mnote-data-canon.h>
  34 #include <libexif/pentax/exif-mnote-data-pentax.h>
  35
  36 #include <stdlib.h>
  37 #include <stdio.h>
  38 #include <string.h>
  39
  40 #undef MAX
  41 #define MAX(a, b)  (((a) > (b)) ? (a) : (b))
  42
  43 /* #define DEBUG */
  44
  45 static const unsigned char ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};
  46
  47 struct _ExifDataPrivate
  48 {
  49         ExifByteOrder order;
  50
  51         ExifMnoteData *md;
  52
  53         ExifLog *log;
  54         ExifMem *mem;
  55
  56         unsigned int ref_count;
  57
  58         /* Temporarily used while loading data */
  59         unsigned int offset_mnote;
  60 };
  61
  62 static void *
  63 exif_data_alloc (ExifData *data, unsigned int i)
  64 {
  65         void *d;
  66
  67         if (!data || !i) return NULL;
  68
  69         d = exif_mem_alloc (data->priv->mem, i);
  70         if (d) return d;
  71
  72         EXIF_LOG_NO_MEMORY (data->priv->log, "ExifData", i);
  73         return NULL;
  74 }
  75
  76 ExifMnoteData *
  77 exif_data_get_mnote_data (ExifData *d)
  78 {
  79         return (d && d->priv) ? d->priv->md : NULL;
  80 }
  81
  82 ExifData *
  83 exif_data_new (void)
  84 {
  85         ExifMem *mem = exif_mem_new_default ();
  86         ExifData *d = exif_data_new_mem (mem);
  87
  88         exif_mem_unref (mem);
  89
  90         return d;
  91 }
  92
  93 ExifData *
  94 exif_data_new_mem (ExifMem *mem)
  95 {
  96         ExifData *data;
  97         unsigned int i;
  98
  99         if (!mem) return NULL;
 100
 101         data = exif_mem_alloc (mem, sizeof (ExifData));
 102         if (!data) return (NULL);
 103         data->priv = exif_mem_alloc (mem, sizeof (ExifDataPrivate));
 104         if (!data->priv) { exif_mem_free (mem, data); return (NULL); }
 105         data->priv->ref_count = 1;
 106
 107         data->priv->mem = mem;
 108         exif_mem_ref (mem);
 109
 110         for (i = 0; i < EXIF_IFD_COUNT; i++) {
 111                 data->ifd[i] = exif_content_new_mem (data->priv->mem);
 112                 if (!data->ifd[i]) {
 113                         exif_data_free (data);
 114                         return (NULL);
 115                 }
 116                 data->ifd[i]->parent = data;
 117         }
 118
 119         return (data);
 120 }
 121
 122 ExifData *
 123 exif_data_new_from_data (const unsigned char *data, unsigned int size)
 124 {
 125         ExifData *edata;
 126
 127         edata = exif_data_new ();
 128         exif_data_load_data (edata, data, size);
 129         return (edata);
 130 }
 131
 132 static void
 133 exif_data_load_data_entry (ExifData *data, ExifEntry *entry,
 134                            const unsigned char *d,
 135                            unsigned int size, unsigned int offset)
 136 {
 137         unsigned int s, doff;
 138
 139         entry->tag        = exif_get_short (d + offset + 0, data->priv->order);
 140         entry->format     = exif_get_short (d + offset + 2, data->priv->order);
 141         entry->components = exif_get_long  (d + offset + 4, data->priv->order);
 142
 143         exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
 144                   "Loading entry 0x%x ('%s')...", entry->tag,
 145                   exif_tag_get_name (entry->tag));
 146
 147         /*
 148          * Size? If bigger than 4 bytes, the actual data is not
 149          * in the entry but somewhere else (offset).
 150          */
 151         s = exif_format_get_size (entry->format) * entry->components;
 152         if (!s)
 153                 return;
 154         if (s > 4)
 155                 doff = exif_get_long (d + offset + 8, data->priv->order);
 156         else
 157                 doff = offset + 8;
 158
 159         /* Sanity check */
 160         if (size < doff + s)
 161                 return;
 162
 163         entry->data = exif_data_alloc (data, s);
 164         if (entry->data) {
 165                 entry->size = s;
 166                 memcpy (entry->data, d + doff, s);
 167         }
 168
 169         /* If this is the MakerNote, remember the offset */
 170         if (entry->tag == EXIF_TAG_MAKER_NOTE) {
 171                 if (entry->size > 6) exif_log (data->priv->log,
 172                           EXIF_LOG_CODE_DEBUG, "ExifData",
 173                           "MakerNote found (%02x %02x %02x %02x "
 174                           "%02x %02x %02x...).",
 175                           entry->data[0], entry->data[1], entry->data[2],
 176                           entry->data[3], entry->data[4], entry->data[5],
 177                           entry->data[6]);
 178                 data->priv->offset_mnote = doff;
 179         }
 180
 181         exif_entry_fix (entry);
 182 }
 183
 184 static void
 185 exif_data_save_data_entry (ExifData *data, ExifEntry *e,
 186                            unsigned char **d, unsigned int *ds,
 187                            unsigned int offset)
 188 {
 189         unsigned int doff, s;
 190
 191         if (!data || !data->priv) return;
 192
 193         /*
 194          * Each entry is 12 bytes long. The memory for the entry has
 195          * already been allocated.
 196          */
 197         exif_set_short (*d + 6 + offset + 0,
 198                         data->priv->order, (ExifShort) e->tag);
 199         exif_set_short (*d + 6 + offset + 2,
 200                         data->priv->order, (ExifShort) e->format);
 201
 202         /* If this is the maker note tag, update it. */
 203         if ((e->tag == EXIF_TAG_MAKER_NOTE) && data->priv->md) {
 204                 exif_mem_free (data->priv->mem, e->data);
 205                 e->data = NULL;
 206                 e->size = 0;
 207                 exif_mnote_data_set_offset (data->priv->md, *ds - 6);
 208                 exif_mnote_data_save (data->priv->md, &e->data, &e->size);
 209                 e->components = e->size;
 210         }
 211
 212         exif_set_long  (*d + 6 + offset + 4,
 213                         data->priv->order, e->components);
 214
 215         /*
 216          * Size? If bigger than 4 bytes, the actual data is not in
 217          * the entry but somewhere else.
 218          */
 219         s = exif_format_get_size (e->format) * e->components;
 220         if (s > 4) {
 221                 doff = *ds - 6;
 222                 *ds += s;
 223                 *d = exif_mem_realloc (data->priv->mem, *d, *ds);
 224                 if (!*d) {
 225                         EXIF_LOG_NO_MEMORY (data->priv->log, "ExifData", *ds);
 226                         return;
 227                 }
 228                 exif_set_long (*d + 6 + offset + 8,
 229                                data->priv->order, doff);
 230         } else
 231                 doff = offset + 8;
 232
 233         /* Write the data. Fill unneeded bytes with 0. */
 234         memcpy (*d + 6 + doff, e->data, s);
 235         if (s < 4) memset (*d + 6 + doff + s, 0, (4 - s));
 236 }
 237
 238 static void
 239 exif_data_load_data_thumbnail (ExifData *data, const unsigned char *d,
 240                                unsigned int ds, ExifLong offset, ExifLong size)
 241 {
 242         if (ds < offset + size) {
 243                 exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
 244                           "Bogus thumbnail offset and size: %i < %i + %i.",
 245                           (int) ds, (int) offset, (int) size);
 246                 return;
 247         }
 248         if (data->data) exif_mem_free (data->priv->mem, data->data);
 249         data->size = size;
 250         data->data = exif_data_alloc (data, data->size);
 251         if (!data->data) return;
 252         memcpy (data->data, d + offset, data->size);
 253 }
 254
 255 static void
 256 exif_data_load_data_content (ExifData *data, ExifContent *ifd,
 257                              const unsigned char *d,
 258                              unsigned int ds, unsigned int offset)
 259 {
 260         ExifLong o, thumbnail_offset = 0, thumbnail_length = 0;
 261         ExifShort n;
 262         ExifEntry *entry;
 263         unsigned int i;
 264         ExifTag tag;
 265
 266         if (!data || !data->priv) return;
 267
 268         /* Read the number of entries */
 269         if (offset >= ds - 1) return;
 270         n = exif_get_short (d + offset, data->priv->order);
 271         exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
 272                   "Loading %i entries...", n);
 273         offset += 2;
 274
 275         /* Check if we have enough data. */
 276         if (offset + 12 * n > ds) n = (ds - offset) / 12;
 277
 278         for (i = 0; i < n; i++) {
 279
 280                 tag = exif_get_short (d + offset + 12 * i, data->priv->order);
 281                 switch (tag) {
 282                 case EXIF_TAG_EXIF_IFD_POINTER:
 283                 case EXIF_TAG_GPS_INFO_IFD_POINTER:
 284                 case EXIF_TAG_INTEROPERABILITY_IFD_POINTER:
 285                 case EXIF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH:
 286                 case EXIF_TAG_JPEG_INTERCHANGE_FORMAT:
 287                         o = exif_get_long (d + offset + 12 * i + 8,
 288                                            data->priv->order);
 289                         switch (tag) {
 290                         case EXIF_TAG_EXIF_IFD_POINTER:
 291                                 exif_data_load_data_content (data,
 292                                         data->ifd[EXIF_IFD_EXIF], d, ds, o);
 293                                 break;
 294                         case EXIF_TAG_GPS_INFO_IFD_POINTER:
 295                                 exif_data_load_data_content (data,
 296                                         data->ifd[EXIF_IFD_GPS], d, ds, o);
 297                                 break;
 298                         case EXIF_TAG_INTEROPERABILITY_IFD_POINTER:
 299                                 exif_data_load_data_content (data,
 300                                         data->ifd[EXIF_IFD_INTEROPERABILITY], d, ds, o);
 301                                 break;
 302                         case EXIF_TAG_JPEG_INTERCHANGE_FORMAT:
 303 #ifdef DEBUG
 304                                 printf ("Thumbnail at %i.\n", (int) o);
 305 #endif
 306                                 thumbnail_offset = o;
 307                                 if (thumbnail_offset && thumbnail_length)
 308                                         exif_data_load_data_thumbnail (data, d,
 309                                                 ds, thumbnail_offset,
 310                                                 thumbnail_length);
 311                                 break;
 312                         case EXIF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH:
 313 #ifdef DEBUG
 314                                 printf ("Thumbnail size: %i.\n", (int) o);
 315 #endif
 316                                 thumbnail_length = o;
 317                                 if (thumbnail_offset && thumbnail_length)
 318                                         exif_data_load_data_thumbnail (data, d,
 319                                                 ds, thumbnail_offset,
 320                                                 thumbnail_length);
 321                                 break;
 322                         default:
 323                                 return;
 324                         }
 325                         break;
 326                 default:
 327
 328                         /*
 329                          * If we don't know the tag, changes are high
 330                          * that the EXIF data does not follow the standard.
 331                          */
 332                         if (!exif_tag_get_name (tag)) return;
 333                         entry = exif_entry_new_mem (data->priv->mem);
 334                         exif_content_add_entry (ifd, entry);
 335                         exif_data_load_data_entry (data, entry, d, ds,
 336                                                    offset + 12 * i);
 337                         exif_entry_unref (entry);
 338                         break;
 339                 }
 340         }
 341 }
 342
 343 static void
 344 exif_data_save_data_content (ExifData *data, ExifContent *ifd,
 345                              unsigned char **d, unsigned int *ds,
 346                              unsigned int offset)
 347 {
 348         unsigned int j, n_ptr = 0, n_thumb = 0;
 349         ExifIfd i;
 350
 351         if (!data || !data->priv || !ifd || !d || !ds) return;
 352
 353         for (i = 0; i < EXIF_IFD_COUNT; i++)
 354                 if (ifd == data->ifd[i])
 355                         break;
 356         if (i == EXIF_IFD_COUNT)
 357                 return;
 358
 359         /*
 360          * Check if we need some extra entries for pointers or the thumbnail.
 361          */
 362         switch (i) {
 363         case EXIF_IFD_0:
 364
 365                 /*
 366                  * The pointer to IFD_EXIF is in IFD_0. The pointer to
 367                  * IFD_INTEROPERABILITY is in IFD_EXIF.
 368                  */
 369                 if (data->ifd[EXIF_IFD_EXIF]->count ||
 370                     data->ifd[EXIF_IFD_INTEROPERABILITY]->count)
 371                         n_ptr++;
 372
 373                 /* The pointer to IFD_GPS is in IFD_0. */
 374                 if (data->ifd[EXIF_IFD_GPS]->count)
 375                         n_ptr++;
 376
 377                 break;
 378         case EXIF_IFD_1:
 379                 if (data->size)
 380                         n_thumb = 2;
 381                 break;
 382         case EXIF_IFD_EXIF:
 383                 if (data->ifd[EXIF_IFD_INTEROPERABILITY]->count)
 384                         n_ptr++;
 385         default:
 386                 break;
 387         }
 388
 389         /*
 390          * Allocate enough memory for all entries
 391          * and the number of entries.
 392          */
 393         *ds += (2 + (ifd->count + n_ptr + n_thumb) * 12 + 4);
 394         *d = exif_mem_realloc (data->priv->mem, *d, *ds);
 395         if (!*d) {
 396                 EXIF_LOG_NO_MEMORY (data->priv->log, "ExifData", *ds);
 397                 return;
 398         }
 399
 400         /* Save the number of entries */
 401         exif_set_short (*d + 6 + offset, data->priv->order,
 402                         (ExifShort) (ifd->count + n_ptr + n_thumb));
 403         offset += 2;
 404
 405 #ifdef DEBUG
 406         printf ("Saving %i entries (IFD '%s', offset: %i)...\n",
 407                 ifd->count, exif_ifd_get_name (i), offset);
 408 #endif
 409
 410         /* Save each entry */
 411         for (j = 0; j < ifd->count; j++)
 412                 exif_data_save_data_entry (data, ifd->entries[j],
 413                                 d, ds, offset + 12 * j);
 414         offset += 12 * ifd->count;
 415
 416         /* Now save special entries. */
 417         switch (i) {
 418         case EXIF_IFD_0:
 419
 420                 /*
 421                  * The pointer to IFD_EXIF is in IFD_0.
 422                  * However, the pointer to IFD_INTEROPERABILITY is in IFD_EXIF,
 423                  * therefore, if IFD_INTEROPERABILITY is not empty, we need
 424                  * IFD_EXIF even if latter is empty.
 425                  */
 426                 if (data->ifd[EXIF_IFD_EXIF]->count ||
 427                     data->ifd[EXIF_IFD_INTEROPERABILITY]->count) {
 428                         exif_set_short (*d + 6 + offset + 0, data->priv->order,
 429                                         EXIF_TAG_EXIF_IFD_POINTER);
 430                         exif_set_short (*d + 6 + offset + 2, data->priv->order,
 431                                         EXIF_FORMAT_LONG);
 432                         exif_set_long  (*d + 6 + offset + 4, data->priv->order,
 433                                         1);
 434                         exif_set_long  (*d + 6 + offset + 8, data->priv->order,
 435                                         *ds - 6);
 436                         exif_data_save_data_content (data,
 437                                 data->ifd[EXIF_IFD_EXIF], d, ds, *ds - 6);
 438                         offset += 12;
 439                 }
 440
 441                 /* The pointer to IFD_GPS is in IFD_0, too. */
 442                 if (data->ifd[EXIF_IFD_GPS]->count) {
 443                         exif_set_short (*d + 6 + offset + 0, data->priv->order,
 444                                         EXIF_TAG_GPS_INFO_IFD_POINTER);
 445                         exif_set_short (*d + 6 + offset + 2, data->priv->order,
 446                                         EXIF_FORMAT_LONG);
 447                         exif_set_long  (*d + 6 + offset + 4, data->priv->order,
 448                                         1);
 449                         exif_set_long  (*d + 6 + offset + 8, data->priv->order,
 450                                         *ds - 6);
 451                         exif_data_save_data_content (data,
 452                                 data->ifd[EXIF_IFD_GPS], d, ds, *ds - 6);
 453                         offset += 12;
 454                 }
 455
 456                 break;
 457         case EXIF_IFD_EXIF:
 458
 459                 /*
 460                  * The pointer to IFD_INTEROPERABILITY is in IFD_EXIF.
 461                  * See note above.
 462                  */
 463                 if (data->ifd[EXIF_IFD_INTEROPERABILITY]->count) {
 464                         exif_set_short (*d + 6 + offset + 0, data->priv->order,
 465                                         EXIF_TAG_INTEROPERABILITY_IFD_POINTER);
 466                         exif_set_short (*d + 6 + offset + 2, data->priv->order,
 467                                         EXIF_FORMAT_LONG);
 468                         exif_set_long  (*d + 6 + offset + 4, data->priv->order,
 469                                         1);
 470                         exif_set_long  (*d + 6 + offset + 8, data->priv->order,
 471                                         *ds - 6);
 472                         exif_data_save_data_content (data,
 473                                 data->ifd[EXIF_IFD_INTEROPERABILITY], d, ds,
 474                                 *ds - 6);
 475                         offset += 12;
 476                 }
 477
 478                 break;
 479         case EXIF_IFD_1:
 480
 481                 /*
 482                  * Information about the thumbnail (if any) is saved in
 483                  * IFD_1.
 484                  */
 485                 if (data->size) {
 486
 487                         /* EXIF_TAG_JPEG_INTERCHANGE_FORMAT */
 488                         exif_set_short (*d + 6 + offset + 0, data->priv->order,
 489                                         EXIF_TAG_JPEG_INTERCHANGE_FORMAT);
 490                         exif_set_short (*d + 6 + offset + 2, data->priv->order,
 491                                         EXIF_FORMAT_LONG);
 492                         exif_set_long  (*d + 6 + offset + 4, data->priv->order,
 493                                         1);
 494                         exif_set_long  (*d + 6 + offset + 8, data->priv->order,
 495                                         *ds - 6);
 496                         *ds += data->size;
 497                         *d = exif_mem_realloc (data->priv->mem, *d, *ds);
 498                         if (!*d) {
 499                                 EXIF_LOG_NO_MEMORY (data->priv->log, "ExifData",
 500                                                     *ds);
 501                                 return;
 502                         }
 503                         memcpy (*d + *ds - data->size, data->data, data->size);
 504                         offset += 12;
 505 #ifdef DEBUG
 506                         printf ("Wrote %i bytes of thumbnail data at offset "
 507                                 "%i.\n", data->size, *ds - data->size);
 508                         printf ("We currently have %i bytes EXIF data.\n", *ds);
 509 #endif
 510
 511                         /* EXIF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH */
 512                         exif_set_short (*d + 6 + offset + 0, data->priv->order,
 513                                 EXIF_TAG_JPEG_INTERCHANGE_FORMAT_LENGTH);
 514                         exif_set_short (*d + 6 + offset + 2, data->priv->order,
 515                                         EXIF_FORMAT_LONG);
 516                         exif_set_long  (*d + 6 + offset + 4, data->priv->order,
 517                                         1);
 518                         exif_set_long  (*d + 6 + offset + 8, data->priv->order,
 519                                         data->size);
 520                         offset += 12;
 521                 }
 522
 523                 break;
 524         default:
 525                 break;
 526         }
 527
 528         /* Correctly terminate the directory */
 529         if (i == EXIF_IFD_0 && (data->ifd[EXIF_IFD_1]->count ||
 530                                              data->size)) {
 531
 532                 /*
 533                  * We are saving IFD 0. Tell where IFD 1 starts and save
 534                  * IFD 1.
 535                  */
 536                 exif_set_long (*d + 6 + offset, data->priv->order, *ds - 6);
 537                 exif_data_save_data_content (data, data->ifd[EXIF_IFD_1], d, ds,
 538                                              *ds - 6);
 539         } else
 540                 exif_set_long (*d + 6 + offset, data->priv->order, 0);
 541 }
 542
 543 void
 544 exif_data_load_data (ExifData *data, const unsigned char *d_orig,
 545                      unsigned int ds_orig)
 546 {
 547         unsigned int l;
 548         ExifLong offset;
 549         ExifShort n;
 550         ExifEntry *e, *em;
 551         const unsigned char *d = d_orig;
 552         unsigned int ds = ds_orig, len;
 553
 554         if (!data || !data->priv || !d || !ds) return;
 555
 556         exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",
 557                   "Parsing %i byte(s) EXIF data...\n", ds);
 558
 559         /*
 560          * It can be that the data starts with the EXIF header. If it does
 561          * not, search the EXIF marker.
 562          */
 563         if (ds < 6) {
 564 #ifdef DEBUG
 565                 printf ("Size too small.\n");
 566 #endif
 567                 return;
 568         }
 569         if (!memcmp (d, ExifHeader, 6)) {
 570 #ifdef DEBUG
 571                 printf ("Found EXIF header.\n");
 572 #endif
 573         } else {
 574 #ifdef DEBUG
 575                 printf ("Data begins with 0x%x 0x%x 0x%x 0x%x 0x%x 0x%x "
 576                         "0x%x...\n", d[0], d[1], d[2], d[3], d[4], d[5], d[6]);
 577 #endif
 578                 while (1) {
 579                         while ((d[0] == 0xff) && ds) {
 580                                 d++;
 581                                 ds--;
 582                         }
 583
 584                         /* JPEG_MARKER_SOI */
 585                         if (d[0] == JPEG_MARKER_SOI) {
 586                                 d++;
 587                                 ds--;
 588                                 continue;
 589                         }
 590
 591                         /* JPEG_MARKER_APP0 */
 592                         if (d[0] == JPEG_MARKER_APP0) {
 593                                 d++;
 594                                 ds--;
 595                                 l = (d[0] << 8) | d[1];
 596                                 if (l > ds)
 597                                         return;
 598                                 d += l;
 599                                 ds -= l;
 600                                 continue;
 601                         }
 602
 603                         /* JPEG_MARKER_APP1 */
 604                         if (d[0] == JPEG_MARKER_APP1)
 605                                 break;
 606
 607                         /* Unknown marker or data. Give up. */
 608 #ifdef DEBUG
 609                         printf ("EXIF marker not found.\n");
 610 #endif
 611                         return;
 612                 }
 613                 d++;
 614                 ds--;
 615                 if (ds < 2) {
 616 #ifdef DEBUG
 617                         printf ("Size too small.\n");
 618 #endif
 619                         return;
 620                 }
 621                 len = (d[0] << 8) | d[1];
 622 #ifdef DEBUG
 623                 printf ("We have to deal with %i byte(s) of EXIF data.\n", len);
 624 #endif
 625                 d += 2;
 626                 ds -= 2;
 627         }
 628
 629         /*
 630          * Verify the exif header
 631          * (offset 2, length 6).
 632          */
 633         if (ds < 6) {
 634 #ifdef DEBUG
 635                 printf ("Size too small.\n");
 636 #endif
 637                 return;
 638         }
 639         if (memcmp (d, ExifHeader, 6)) {
 640 #ifdef DEBUG
 641                 printf ("EXIF header not found.\n");
 642 #endif
 643                 return;
 644         }
 645
 646 #ifdef DEBUG
 647         printf ("Found EXIF header.\n");
 648 #endif
 649
 650         /* Byte order (offset 6, length 2) */
 651         if (ds < 12)
 652                 return;
 653         if (!memcmp (d + 6, "II", 2))
 654                 data->priv->order = EXIF_BYTE_ORDER_INTEL;
 655         else if (!memcmp (d + 6, "MM", 2))
 656                 data->priv->order = EXIF_BYTE_ORDER_MOTOROLA;
 657         else
 658                 return;
 659
 660         /* Fixed value */
 661         if (exif_get_short (d + 8, data->priv->order) != 0x002a)
 662                 return;
 663
 664         /* IFD 0 offset */
 665         offset = exif_get_long (d + 10, data->priv->order);
 666 #ifdef DEBUG
 667         printf ("IFD 0 at %i.\n", (int) offset);
 668 #endif
 669
 670         /* Parse the actual exif data (offset 14) */
 671         exif_data_load_data_content (data, data->ifd[EXIF_IFD_0], d + 6,
 672                                      ds - 6, offset);
 673
 674         /* IFD 1 offset */
 675         n = exif_get_short (d + 6 + offset, data->priv->order);
 676         offset = exif_get_long (d + 6 + offset + 2 + 12 * n, data->priv->order);
 677         if (offset) {
 678 #ifdef DEBUG
 679                 printf ("IFD 1 at %i.\n", (int) offset);
 680 #endif
 681
 682                 /* Sanity check. */
 683                 if (offset > ds - 6) {
 684 #ifdef DEBUG
 685                         printf ("Bogus offset!\n");
 686 #endif
 687                         return;
 688                 }
 689
 690                 exif_data_load_data_content (data, data->ifd[EXIF_IFD_1], d + 6,
 691                                              ds - 6, offset);
 692         }
 693
 694         /*
 695          * If we got an EXIF_TAG_MAKER_NOTE, try to interpret it. Some
 696          * cameras use pointers in the maker note tag that point to the
 697          * space between IFDs. Here is the only place where we have access
 698          * to that data.
 699          */
 700         e = exif_data_get_entry (data, EXIF_TAG_MAKER_NOTE);
 701         if (e) {
 702
 703             /* Olympus & Nikon */
 704             if ((e->size >= 5) && (!memcmp (e->data, "OLYMP", 5) ||
 705                                    !memcmp (e->data, "Nikon", 5))) {
 706                         data->priv->md = exif_mnote_data_olympus_new (data->priv->mem);
 707             } else {
 708                         char value[7];
 709                         em = exif_data_get_entry (data, EXIF_TAG_MAKE);
 710                         /* Pentax & some variant of Nikon */
 711                         if ((e->size >= 2) && (e->data[0] == 0x00)
 712                                     && (e->data[1] == 0x1b)) {
 713                                 if (em && !strncasecmp (exif_entry_get_value (em, value, sizeof(value)), "Nikon", 5)) {
 714                                         data->priv->md = exif_mnote_data_olympus_new (data->priv->mem);
 715                                 } else {
 716                                         data->priv->md = exif_mnote_data_pentax_new (data->priv->mem);
 717                                 }
 718
 719                         } else {
 720                                 /* Canon */
 721                                 if (em) {
 722
 723                                         if (!strcmp (exif_entry_get_value (em, value, sizeof(value)), "Canon"))
 724                                                 data->priv->md = exif_mnote_data_canon_new (data->priv->mem);
 725                                 }
 726                         }
 727                 }
 728
 729             /*
 730              * If we are able to interpret the maker note, do so.
 731              */
 732             if (data->priv->md) {
 733                     exif_mnote_data_log (data->priv->md, data->priv->log);
 734                     exif_mnote_data_set_byte_order (data->priv->md,
 735                                                     data->priv->order);
 736                     exif_mnote_data_set_offset (data->priv->md,
 737                                                 data->priv->offset_mnote);
 738                     exif_mnote_data_load (data->priv->md, d, ds);
 739             }
 740         }
 741 }
 742
 743 void
 744 exif_data_save_data (ExifData *data, unsigned char **d, unsigned int *ds)
 745 {
 746         if (!data || !d || !ds)
 747                 return;
 748
 749         /* Header */
 750         *ds = 14;
 751         *d = exif_data_alloc (data, *ds);
 752         if (!*d) return;
 753         memcpy (*d, ExifHeader, 6);
 754
 755         /* Order (offset 6) */
 756         if (data->priv->order == EXIF_BYTE_ORDER_INTEL) {
 757                 memcpy (*d + 6, "II", 2);
 758         } else {
 759                 memcpy (*d + 6, "MM", 2);
 760         }
 761
 762         /* Fixed value (2 bytes, offset 8) */
 763         exif_set_short (*d + 8, data->priv->order, 0x002a);
 764
 765         /*
 766          * IFD 0 offset (4 bytes, offset 10).
 767          * We will start 8 bytes after the
 768          * EXIF header (2 bytes for order, another 2 for the test, and
 769          * 4 bytes for the IFD 0 offset make 8 bytes together).
 770          */
 771         exif_set_long (*d + 10, data->priv->order, 8);
 772
 773         /* Now save IFD 0. IFD 1 will be saved automatically. */
 774 #ifdef DEBUG
 775         printf ("Saving IFDs...\n");
 776 #endif
 777         exif_data_save_data_content (data, data->ifd[EXIF_IFD_0], d, ds,
 778                                      *ds - 6);
 779
 780 #ifdef DEBUG
 781         printf ("Saved %i byte(s) EXIF data.\n", *ds);
 782 #endif
 783 }
 784
 785 ExifData *
 786 exif_data_new_from_file (const char *path)
 787 {
 788         ExifData *edata;
 789         ExifLoader *loader;
 790
 791         loader = exif_loader_new ();
 792         exif_loader_write_file (loader, path);
 793         edata = exif_loader_get_data (loader);
 794         exif_loader_unref (loader);
 795
 796         return (edata);
 797 }
 798
 799 void
 800 exif_data_ref (ExifData *data)
 801 {
 802         if (!data)
 803                 return;
 804
 805         data->priv->ref_count++;
 806 }
 807
 808 void
 809 exif_data_unref (ExifData *data)
 810 {
 811         if (!data)
 812                 return;
 813
 814         data->priv->ref_count--;
 815         if (!data->priv->ref_count)
 816                 exif_data_free (data);
 817 }
 818
 819 void
 820 exif_data_free (ExifData *data)
 821 {
 822         unsigned int i;
 823
 824         if (!data) return;
 825
 826         for (i = 0; i < EXIF_IFD_COUNT; i++) {
 827                 if (data->ifd[i]) {
 828                         exif_content_unref (data->ifd[i]);
 829                         data->ifd[i] = NULL;
 830                 }
 831         }
 832
 833         if (data->priv) {
 834                 ExifMem *mem = data->priv->mem;
 835                 if (data->data) {
 836                         exif_mem_free (data->priv->mem, data->data);
 837                         data->data = NULL;
 838                 }
 839                 if (data->priv->md) {
 840                         exif_mnote_data_unref (data->priv->md);
 841                         data->priv->md = NULL;
 842                 }
 843                 exif_mem_free (mem, data->priv);
 844                 exif_mem_free (mem, data);
 845                 exif_mem_unref (mem);
 846         }
 847 }
 848
 849 void
 850 exif_data_dump (ExifData *data)
 851 {
 852         unsigned int i;
 853
 854         if (!data)
 855                 return;
 856
 857         for (i = 0; i < EXIF_IFD_COUNT; i++) {
 858                 if (data->ifd[i] && data->ifd[i]->count) {
 859                         printf ("Dumping IFD '%s'...\n",
 860                                 exif_ifd_get_name (i));
 861                         exif_content_dump (data->ifd[i], 0);
 862                 }
 863         }
 864
 865         if (data->data) {
 866                 printf ("%i byte(s) thumbnail data available.", data->size);
 867                 if (data->size >= 4) {
 868                         printf ("0x%02x 0x%02x ... 0x%02x 0x%02x\n",
 869                                 data->data[0], data->data[1],
 870                                 data->data[data->size - 2],
 871                                 data->data[data->size - 1]);
 872                 }
 873         }
 874 }
 875
 876 ExifByteOrder
 877 exif_data_get_byte_order (ExifData *data)
 878 {
 879         if (!data)
 880                 return (0);
 881
 882         return (data->priv->order);
 883 }
 884
 885 void
 886 exif_data_foreach_content (ExifData *data, ExifDataForeachContentFunc func,
 887                            void *user_data)
 888 {
 889         unsigned int i;
 890
 891         if (!data || !func)
 892                 return;
 893
 894         for (i = 0; i < EXIF_IFD_COUNT; i++)
 895                 func (data->ifd[i], user_data);
 896 }
 897
 898 typedef struct _ByteOrderChangeData ByteOrderChangeData;
 899 struct _ByteOrderChangeData {
 900         ExifByteOrder old, new;
 901 };
 902
 903 static void
 904 entry_set_byte_order (ExifEntry *e, void *data)
 905 {
 906         ByteOrderChangeData *d = data;
 907         unsigned int i;
 908         ExifShort s;
 909         ExifLong l;
 910         ExifSLong sl;
 911         ExifRational r;
 912         ExifSRational sr;
 913
 914         if (!e)
 915                 return;
 916
 917         switch (e->format) {
 918         case EXIF_FORMAT_SHORT:
 919                 for (i = 0; i < e->components; i++) {
 920                         s = exif_get_short (e->data +
 921                                 (i * exif_format_get_size (e->format)),
 922                                 d->old);
 923                         exif_set_short (e->data +
 924                                 (i * exif_format_get_size (e->format)),
 925                                 d->new, s);
 926                 }
 927                 break;
 928         case EXIF_FORMAT_LONG:
 929                 for (i = 0; i < e->components; i++) {
 930                         l = exif_get_long (e->data +
 931                                 (i * exif_format_get_size (e->format)),
 932                                 d->old);
 933                         exif_set_long (e->data +
 934                                 (i * exif_format_get_size (e->format)),
 935                                 d->new, l);
 936                 }
 937                 break;
 938         case EXIF_FORMAT_RATIONAL:
 939                 for (i = 0; i < e->components; i++) {
 940                         r = exif_get_rational (e->data +
 941                                 (i * exif_format_get_size (e->format)),
 942                                 d->old);
 943                         exif_set_rational (e->data +
 944                                 (i * exif_format_get_size (e->format)),
 945                                 d->new, r);
 946                 }
 947                 break;
 948         case EXIF_FORMAT_SLONG:
 949                 for (i = 0; i < e->components; i++) {
 950                         sl = exif_get_slong (e->data +
 951                                 (i * exif_format_get_size (e->format)),
 952                                 d->old);
 953                         exif_set_slong (e->data +
 954                                 (i * exif_format_get_size (e->format)),
 955                                 d->new, sl);
 956                 }
 957                 break;
 958         case EXIF_FORMAT_SRATIONAL:
 959                 for (i = 0; i < e->components; i++) {
 960                         sr = exif_get_srational (e->data +
 961                                 (i * exif_format_get_size (e->format)),
 962                                 d->old);
 963                         exif_set_srational (e->data +
 964                                 (i * exif_format_get_size (e->format)),
 965                                 d->new, sr);
 966                 }
 967                 break;
 968         case EXIF_FORMAT_UNDEFINED:
 969         case EXIF_FORMAT_BYTE:
 970         case EXIF_FORMAT_SBYTE:
 971         case EXIF_FORMAT_ASCII:
 972         default:
 973                 /* Nothing here. */
 974                 break;
 975         }
 976 }
 977
 978 static void
 979 content_set_byte_order (ExifContent *content, void *data)
 980 {
 981         exif_content_foreach_entry (content, entry_set_byte_order, data);
 982 }
 983
 984 void
 985 exif_data_set_byte_order (ExifData *data, ExifByteOrder order)
 986 {
 987         ByteOrderChangeData d;
 988
 989         if (!data || (order == data->priv->order))
 990                 return;
 991
 992         d.old = data->priv->order;
 993         d.new = order;
 994         exif_data_foreach_content (data, content_set_byte_order, &d);
 995         data->priv->order = order;
 996         if (data->priv->md)
 997                 exif_mnote_data_set_byte_order (data->priv->md, order);
 998 }
 999
1000 void
1001 exif_data_log (ExifData *data, ExifLog *log)
1002 {
1003         if (!data || !data->priv) return;
1004         exif_log_unref (data->priv->log);
1005         data->priv->log = log;
1006         exif_log_ref (log);
1007 }
1008
1009 /* Used internally within libexif */
1010 ExifLog *exif_data_get_log (ExifData *);
1011 ExifLog *
1012 exif_data_get_log (ExifData *data)
1013 {
1014         if (!data || !data->priv) return NULL;
1015         return data->priv->log;
1016 }