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1 /* exif-mnote-data-olympus.c
2  *
3  * Copyright (c) 2002, 2003 Lutz Mueller <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., 51 Franklin Street, Fifth Floor,
18  * Boston, MA  02110-1301  USA.
19  */
20 
21 #include <config.h>
22 #include "exif-mnote-data-olympus.h"
23 
24 #include <stdlib.h>
25 #include <string.h>
26 #include <stdio.h>
27 
28 #include <libexif/exif-utils.h>
29 #include <libexif/exif-data.h>
30 
31 /* Uncomment this to fix a problem with Sanyo MakerNotes. It's probably best
32  * not to in most cases because it seems to only affect the thumbnail tag
33  * which is duplicated in IFD 1, and fixing the offset could actually cause
34  * problems with other software that expects the broken form.
35  */
36 /*#define EXIF_OVERCOME_SANYO_OFFSET_BUG */
37 
38 #define CHECKOVERFLOW(offset,datasize,structsize) (( offset >= datasize) || (structsize > datasize) || (offset > datasize - structsize ))
39 
40 static enum OlympusVersion
41 exif_mnote_data_olympus_identify_variant (const unsigned char *buf,
42 		unsigned int buf_size);
43 
44 
45 static void
exif_mnote_data_olympus_clear(ExifMnoteDataOlympus * n)46 exif_mnote_data_olympus_clear (ExifMnoteDataOlympus *n)
47 {
48 	ExifMnoteData *d = (ExifMnoteData *) n;
49 	unsigned int i;
50 
51 	if (!n) return;
52 
53 	if (n->entries) {
54 		for (i = 0; i < n->count; i++)
55 			if (n->entries[i].data) {
56 				exif_mem_free (d->mem, n->entries[i].data);
57 				n->entries[i].data = NULL;
58 			}
59 		exif_mem_free (d->mem, n->entries);
60 		n->entries = NULL;
61 		n->count = 0;
62 	}
63 }
64 
65 static void
exif_mnote_data_olympus_free(ExifMnoteData * n)66 exif_mnote_data_olympus_free (ExifMnoteData *n)
67 {
68 	if (!n) return;
69 
70 	exif_mnote_data_olympus_clear ((ExifMnoteDataOlympus *) n);
71 }
72 
73 static char *
exif_mnote_data_olympus_get_value(ExifMnoteData * d,unsigned int i,char * val,unsigned int maxlen)74 exif_mnote_data_olympus_get_value (ExifMnoteData *d, unsigned int i, char *val, unsigned int maxlen)
75 {
76 	ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
77 
78 	if (!d || !val) return NULL;
79 	if (i > n->count -1) return NULL;
80 /*
81 	exif_log (d->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
82 		  "Querying value for tag '%s'...",
83 		  mnote_olympus_tag_get_name (n->entries[i].tag));
84 */
85 	return mnote_olympus_entry_get_value (&n->entries[i], val, maxlen);
86 }
87 
88 
89 
90 
91 /**
92  * @brief save the MnoteData from ne to buf
93  *
94  * @param ne extract the data from this structure
95  * @param *buf write the mnoteData to this buffer (buffer will be allocated)
96  * @param buf_size the size of the buffer
97  */
98 static void
exif_mnote_data_olympus_save(ExifMnoteData * ne,unsigned char ** buf,unsigned int * buf_size)99 exif_mnote_data_olympus_save (ExifMnoteData *ne,
100 		unsigned char **buf, unsigned int *buf_size)
101 {
102 	ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) ne;
103 	size_t i, o, s, doff, base = 0, o2 = 6 + 2;
104 	size_t datao = 0;
105 	unsigned char *t;
106 	size_t ts;
107 
108 	if (!n || !buf || !buf_size) return;
109 
110 	/*
111 	 * Allocate enough memory for all entries and the number of entries.
112 	 */
113 	*buf_size = 6 + 2 + 2 + n->count * 12;
114 	switch (n->version) {
115 	case olympusV1:
116 	case sanyoV1:
117 	case epsonV1:
118 		*buf = exif_mem_alloc (ne->mem, *buf_size);
119 		if (!*buf) {
120 			EXIF_LOG_NO_MEMORY(ne->log, "ExifMnoteDataOlympus", *buf_size);
121 			return;
122 		}
123 
124 		/* Write the header and the number of entries. */
125 		strcpy ((char *)*buf, n->version==sanyoV1?"SANYO":
126 					(n->version==epsonV1?"EPSON":"OLYMP"));
127 		exif_set_short (*buf + 6, n->order, (ExifShort) 1);
128 		datao = n->offset;
129 		break;
130 
131 	case olympusV2:
132 		*buf_size += 8-6 + 4;
133 		*buf = exif_mem_alloc (ne->mem, *buf_size);
134 		if (!*buf) {
135 			EXIF_LOG_NO_MEMORY(ne->log, "ExifMnoteDataOlympus", *buf_size);
136 			return;
137 		}
138 
139 		/* Write the header and the number of entries. */
140 		strcpy ((char *)*buf, "OLYMPUS");
141 		exif_set_short (*buf + 8, n->order, (ExifShort) (
142 			(n->order == EXIF_BYTE_ORDER_INTEL) ?
143 			('I' << 8) | 'I' :
144 			('M' << 8) | 'M'));
145 		exif_set_short (*buf + 10, n->order, (ExifShort) 3);
146 		o2 += 4;
147 		break;
148 
149 	case nikonV1:
150 		base = MNOTE_NIKON1_TAG_BASE;
151 
152 		/* v1 has offsets based to main IFD, not makernote IFD */
153 		datao += n->offset + 10;
154 		/* subtract the size here, so the increment in the next case will not harm us */
155 		*buf_size -= 8 + 2;
156 		/* fall through */
157 	/* Fall through to nikonV2 handler */
158 	case nikonV2:
159 	/* Write out V0 files in V2 format */
160 	case nikonV0:
161 		*buf_size += 8 + 2;
162 		*buf_size += 4; /* Next IFD pointer */
163 		*buf = exif_mem_alloc (ne->mem, *buf_size);
164 		if (!*buf) {
165 			EXIF_LOG_NO_MEMORY(ne->log, "ExifMnoteDataOlympus", *buf_size);
166 			return;
167 		}
168 
169 		/* Write the header and the number of entries. */
170 		strcpy ((char *)*buf, "Nikon");
171 		(*buf)[6] = n->version;
172 
173 		if (n->version != nikonV1) {
174 			exif_set_short (*buf + 10, n->order, (ExifShort) (
175 				(n->order == EXIF_BYTE_ORDER_INTEL) ?
176 				('I' << 8) | 'I' :
177 				('M' << 8) | 'M'));
178 			exif_set_short (*buf + 12, n->order, (ExifShort) 0x2A);
179 			exif_set_long (*buf + 14, n->order, (ExifShort) 8);
180 			o2 += 2 + 8;
181 		}
182 		datao -= 10;
183 		/* Reset next IFD pointer */
184 		exif_set_long (*buf + o2 + 2 + n->count * 12, n->order, 0);
185 		break;
186 
187 	default:
188 		return;
189 	}
190 
191 	exif_set_short (*buf + o2, n->order, (ExifShort) n->count);
192 	o2 += 2;
193 
194 	/* Save each entry */
195 	for (i = 0; i < n->count; i++) {
196 		o = o2 + i * 12;
197 		exif_set_short (*buf + o + 0, n->order,
198 				(ExifShort) (n->entries[i].tag - base));
199 		exif_set_short (*buf + o + 2, n->order,
200 				(ExifShort) n->entries[i].format);
201 		exif_set_long  (*buf + o + 4, n->order,
202 				n->entries[i].components);
203 		o += 8;
204 		s = exif_format_get_size (n->entries[i].format) *
205 						n->entries[i].components;
206 		if (s > 65536) {
207 			/* Corrupt data: EXIF data size is limited to the
208 			 * maximum size of a JPEG segment (64 kb).
209 			 */
210 			continue;
211 		}
212 		if (s > 4) {
213 			doff = *buf_size;
214 			ts = *buf_size + s;
215 			t = exif_mem_realloc (ne->mem, *buf,
216 						 sizeof (char) * ts);
217 			if (!t) {
218 				EXIF_LOG_NO_MEMORY(ne->log, "ExifMnoteDataOlympus", ts);
219 				return;
220 			}
221 			*buf = t;
222 			*buf_size = ts;
223 			exif_set_long (*buf + o, n->order, datao + doff);
224 		} else
225 			doff = o;
226 
227 		/* Write the data. */
228 		if (n->entries[i].data) {
229 			memcpy (*buf + doff, n->entries[i].data, s);
230 		} else {
231 			/* Most certainly damaged input file */
232 			memset (*buf + doff, 0, s);
233 		}
234 	}
235 }
236 
237 static void
exif_mnote_data_olympus_load(ExifMnoteData * en,const unsigned char * buf,unsigned int buf_size)238 exif_mnote_data_olympus_load (ExifMnoteData *en,
239 			      const unsigned char *buf, unsigned int buf_size)
240 {
241 	ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) en;
242 	ExifShort c;
243 	size_t i, tcount, o, o2, datao = 6, base = 0;
244 
245 	if (!n || !buf || !buf_size) {
246 		exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
247 			  "ExifMnoteDataOlympus", "Short MakerNote");
248 		return;
249 	}
250 	o2 = 6 + n->offset; /* Start of interesting data */
251 	if (CHECKOVERFLOW(o2,buf_size,10)) {
252 		exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
253 			  "ExifMnoteDataOlympus", "Short MakerNote");
254 		return;
255 	}
256 
257 	/*
258 	 * Olympus headers start with "OLYMP" and need to have at least
259 	 * a size of 22 bytes (6 for 'OLYMP', 2 other bytes, 2 for the
260 	 * number of entries, and 12 for one entry.
261 	 *
262 	 * Sanyo format is identical and uses identical tags except that
263 	 * header starts with "SANYO".
264 	 *
265 	 * Epson format is identical and uses identical tags except that
266 	 * header starts with "EPSON".
267 	 *
268 	 * Nikon headers start with "Nikon" (6 bytes including '\0'),
269 	 * version number (1 or 2).
270 	 *
271 	 * Version 1 continues with 0, 1, 0, number_of_tags,
272 	 * or just with number_of_tags (models D1H, D1X...).
273 	 *
274 	 * Version 2 continues with an unknown byte (0 or 10),
275 	 * two unknown bytes (0), "MM" or "II", another byte 0 and
276 	 * lastly 0x2A.
277 	 */
278 	n->version = exif_mnote_data_olympus_identify_variant(buf+o2, buf_size-o2);
279 	switch (n->version) {
280 	case olympusV1:
281 	case sanyoV1:
282 	case epsonV1:
283 		exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
284 			"Parsing Olympus/Sanyo/Epson maker note v1...");
285 
286 		/* The number of entries is at position 8. */
287 		if (buf[o2 + 6] == 1)
288 			n->order = EXIF_BYTE_ORDER_INTEL;
289 		else if (buf[o2 + 6 + 1] == 1)
290 			n->order = EXIF_BYTE_ORDER_MOTOROLA;
291 		o2 += 8;
292 		c = exif_get_short (buf + o2, n->order);
293 		if ((!(c & 0xFF)) && (c > 0x500)) {
294 			if (n->order == EXIF_BYTE_ORDER_INTEL) {
295 				n->order = EXIF_BYTE_ORDER_MOTOROLA;
296 			} else {
297 				n->order = EXIF_BYTE_ORDER_INTEL;
298 			}
299 		}
300 		break;
301 
302 	case olympusV2:
303 		/* Olympus S760, S770 */
304 		datao = o2;
305 		o2 += 8;
306 		if (CHECKOVERFLOW(o2,buf_size,4)) return;
307 		exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
308 			"Parsing Olympus maker note v2 (0x%02x, %02x, %02x, %02x)...",
309 			buf[o2 + 0], buf[o2 + 1], buf[o2 + 2], buf[o2 + 3]);
310 
311 		if ((buf[o2] == 'I') && (buf[o2 + 1] == 'I'))
312 			n->order = EXIF_BYTE_ORDER_INTEL;
313 		else if ((buf[o2] == 'M') && (buf[o2 + 1] == 'M'))
314 			n->order = EXIF_BYTE_ORDER_MOTOROLA;
315 
316 		/* The number of entries is at position 8+4. */
317 		o2 += 4;
318 		break;
319 
320 	case nikonV1:
321 		o2 += 6;
322 		exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
323 			"Parsing Nikon maker note v1 (0x%02x, %02x, %02x, "
324 			"%02x)...",
325 			buf[o2 + 0], buf[o2 + 1], buf[o2 + 2], buf[o2 + 3]);
326 
327 		/* Skip version number */
328 		o2 += 1;
329 
330 		/* Skip an unknown byte (00 or 0A). */
331 		o2 += 1;
332 
333 		base = MNOTE_NIKON1_TAG_BASE;
334 		/* Fix endianness, if needed */
335 		c = exif_get_short (buf + o2, n->order);
336 		if ((!(c & 0xFF)) && (c > 0x500)) {
337 			if (n->order == EXIF_BYTE_ORDER_INTEL) {
338 				n->order = EXIF_BYTE_ORDER_MOTOROLA;
339 			} else {
340 				n->order = EXIF_BYTE_ORDER_INTEL;
341 			}
342 		}
343 		break;
344 
345 	case nikonV2:
346 		o2 += 6;
347 		if (CHECKOVERFLOW(o2,buf_size,12)) return;
348 		exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
349 			"Parsing Nikon maker note v2 (0x%02x, %02x, %02x, "
350 			"%02x, %02x, %02x, %02x, %02x)...",
351 			buf[o2 + 0], buf[o2 + 1], buf[o2 + 2], buf[o2 + 3],
352 			buf[o2 + 4], buf[o2 + 5], buf[o2 + 6], buf[o2 + 7]);
353 
354 		/* Skip version number */
355 		o2 += 1;
356 
357 		/* Skip an unknown byte (00 or 0A). */
358 		o2 += 1;
359 
360 		/* Skip 2 unknown bytes (00 00). */
361 		o2 += 2;
362 
363 		/*
364 		 * Byte order. From here the data offset
365 		 * gets calculated.
366 		 */
367 		datao = o2;
368 		if (!strncmp ((char *)&buf[o2], "II", 2))
369 			n->order = EXIF_BYTE_ORDER_INTEL;
370 		else if (!strncmp ((char *)&buf[o2], "MM", 2))
371 			n->order = EXIF_BYTE_ORDER_MOTOROLA;
372 		else {
373 			exif_log (en->log, EXIF_LOG_CODE_DEBUG,
374 				"ExifMnoteDataOlympus", "Unknown "
375 				"byte order '%c%c'", buf[o2],
376 				buf[o2 + 1]);
377 			return;
378 		}
379 		o2 += 2;
380 
381 		/* Skip 2 unknown bytes (00 2A). */
382 		o2 += 2;
383 
384 		/* Go to where the number of entries is. */
385 		o2 = datao + exif_get_long (buf + o2, n->order);
386 		break;
387 
388 	case nikonV0:
389 		exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
390 			"Parsing Nikon maker note v0 (0x%02x, %02x, %02x, "
391 			"%02x, %02x, %02x, %02x, %02x)...",
392 			buf[o2 + 0], buf[o2 + 1], buf[o2 + 2], buf[o2 + 3],
393 			buf[o2 + 4], buf[o2 + 5], buf[o2 + 6], buf[o2 + 7]);
394 		/* 00 1b is # of entries in Motorola order - the rest should also be in MM order */
395 		n->order = EXIF_BYTE_ORDER_MOTOROLA;
396 		break;
397 
398 	default:
399 		exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteDataOlympus",
400 			"Unknown Olympus variant %i.", n->version);
401 		return;
402 	}
403 
404 	/* Sanity check the offset */
405 	if (CHECKOVERFLOW(o2,buf_size,2)) {
406 		exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
407 			  "ExifMnoteOlympus", "Short MakerNote");
408 		return;
409 	}
410 
411 	/* Read the number of tags */
412 	c = exif_get_short (buf + o2, n->order);
413 	o2 += 2;
414 
415 	/* Just use an arbitrary max tag limit here to avoid needing to much memory or time. There are 150 named tags currently.
416 	 * The format allows specifying the same range of memory as often as it can, so this multiplies quickly. */
417 	if (c > 300) {
418 		exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifMnoteOlympus", "Too much tags (%d) in Olympus MakerNote", c);
419 		return;
420 	}
421 
422 	/* Remove any old entries */
423 	exif_mnote_data_olympus_clear (n);
424 
425 	/* Reserve enough space for all the possible MakerNote tags */
426 	n->entries = exif_mem_alloc (en->mem, sizeof (MnoteOlympusEntry) * c);
427 	if (!n->entries) {
428 		EXIF_LOG_NO_MEMORY(en->log, "ExifMnoteOlympus", sizeof (MnoteOlympusEntry) * c);
429 		return;
430 	}
431 
432 	/* Parse all c entries, storing ones that are successfully parsed */
433 	tcount = 0;
434 	for (i = c, o = o2; i; --i, o += 12) {
435 		size_t s;
436 		memset(&n->entries[tcount], 0, sizeof(MnoteOlympusEntry));
437 		if (CHECKOVERFLOW(o, buf_size, 12)) {
438 			exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA,
439 				  "ExifMnoteOlympus", "Short MakerNote");
440 			break;
441 		}
442 
443 	    n->entries[tcount].tag        = exif_get_short (buf + o, n->order) + base;
444 	    n->entries[tcount].format     = exif_get_short (buf + o + 2, n->order);
445 	    n->entries[tcount].components = exif_get_long (buf + o + 4, n->order);
446 	    n->entries[tcount].order      = n->order;
447 
448 	    exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteOlympus",
449 		      "Loading entry 0x%x ('%s')...", n->entries[tcount].tag,
450 		      mnote_olympus_tag_get_name (n->entries[tcount].tag));
451 /*	    exif_log (en->log, EXIF_LOG_CODE_DEBUG, "ExifMnoteOlympus",
452 			    "0x%x %d %ld*(%d)",
453 		    n->entries[tcount].tag,
454 		    n->entries[tcount].format,
455 		    n->entries[tcount].components,
456 		    (int)exif_format_get_size(n->entries[tcount].format)); */
457 
458 	    /* Check if we overflow the multiplication. Use buf_size as the max size for integer overflow detection,
459 	     * we will check the buffer sizes closer later. */
460 	    if (exif_format_get_size (n->entries[tcount].format) &&
461 		buf_size / exif_format_get_size (n->entries[tcount].format) < n->entries[tcount].components
462 	    ) {
463 		exif_log (en->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifMnoteOlympus", "Tag size overflow detected (%u * %lu)", exif_format_get_size (n->entries[tcount].format), n->entries[tcount].components);
464 		continue;
465 	    }
466 	    /*
467 	     * Size? If bigger than 4 bytes, the actual data is not
468 	     * in the entry but somewhere else (offset).
469 	     */
470 	    s = exif_format_get_size (n->entries[tcount].format) *
471 		   			 n->entries[tcount].components;
472 		n->entries[tcount].size = s;
473 		if (s) {
474 			size_t dataofs = o + 8;
475 			if (s > 4) {
476 				/* The data in this case is merely a pointer */
477 				dataofs = exif_get_long (buf + dataofs, n->order) + datao;
478 #ifdef EXIF_OVERCOME_SANYO_OFFSET_BUG
479 				/* Some Sanyo models (e.g. VPC-C5, C40) suffer from a bug when
480 				 * writing the offset for the MNOTE_OLYMPUS_TAG_THUMBNAILIMAGE
481 				 * tag in its MakerNote. The offset is actually the absolute
482 				 * position in the file instead of the position within the IFD.
483 				 */
484 			    if (dataofs > (buf_size - s) && n->version == sanyoV1) {
485 					/* fix pointer */
486 					dataofs -= datao + 6;
487 					exif_log (en->log, EXIF_LOG_CODE_DEBUG,
488 						  "ExifMnoteOlympus",
489 						  "Inconsistent thumbnail tag offset; attempting to recover");
490 			    }
491 #endif
492 			}
493 			if (CHECKOVERFLOW(dataofs, buf_size, s)) {
494 				exif_log (en->log, EXIF_LOG_CODE_DEBUG,
495 					  "ExifMnoteOlympus",
496 					  "Tag data past end of buffer (%u > %u)",
497 					  (unsigned)(dataofs + s), buf_size);
498 				continue;
499 			}
500 
501 			n->entries[tcount].data = exif_mem_alloc (en->mem, s);
502 			if (!n->entries[tcount].data) {
503 				EXIF_LOG_NO_MEMORY(en->log, "ExifMnoteOlympus", s);
504 				continue;
505 			}
506 			memcpy (n->entries[tcount].data, buf + dataofs, s);
507 		}
508 
509 		/* Tag was successfully parsed */
510 		++tcount;
511 	}
512 	/* Store the count of successfully parsed tags */
513 	n->count = tcount;
514 }
515 
516 static unsigned int
exif_mnote_data_olympus_count(ExifMnoteData * n)517 exif_mnote_data_olympus_count (ExifMnoteData *n)
518 {
519 	return n ? ((ExifMnoteDataOlympus *) n)->count : 0;
520 }
521 
522 static unsigned int
exif_mnote_data_olympus_get_id(ExifMnoteData * d,unsigned int n)523 exif_mnote_data_olympus_get_id (ExifMnoteData *d, unsigned int n)
524 {
525 	ExifMnoteDataOlympus *note = (ExifMnoteDataOlympus *) d;
526 
527 	if (!note) return 0;
528 	if (note->count <= n) return 0;
529 	return note->entries[n].tag;
530 }
531 
532 static const char *
exif_mnote_data_olympus_get_name(ExifMnoteData * d,unsigned int i)533 exif_mnote_data_olympus_get_name (ExifMnoteData *d, unsigned int i)
534 {
535 	ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
536 
537 	if (!n) return NULL;
538 	if (i >= n->count) return NULL;
539 	return mnote_olympus_tag_get_name (n->entries[i].tag);
540 }
541 
542 static const char *
exif_mnote_data_olympus_get_title(ExifMnoteData * d,unsigned int i)543 exif_mnote_data_olympus_get_title (ExifMnoteData *d, unsigned int i)
544 {
545 	ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
546 
547 	if (!n) return NULL;
548 	if (i >= n->count) return NULL;
549         return mnote_olympus_tag_get_title (n->entries[i].tag);
550 }
551 
552 static const char *
exif_mnote_data_olympus_get_description(ExifMnoteData * d,unsigned int i)553 exif_mnote_data_olympus_get_description (ExifMnoteData *d, unsigned int i)
554 {
555 	ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
556 
557 	if (!n) return NULL;
558 	if (i >= n->count) return NULL;
559         return mnote_olympus_tag_get_description (n->entries[i].tag);
560 }
561 
562 static void
exif_mnote_data_olympus_set_byte_order(ExifMnoteData * d,ExifByteOrder o)563 exif_mnote_data_olympus_set_byte_order (ExifMnoteData *d, ExifByteOrder o)
564 {
565 	ExifByteOrder o_orig;
566 	ExifMnoteDataOlympus *n = (ExifMnoteDataOlympus *) d;
567 	unsigned int i;
568 
569 	if (!n) return;
570 
571 	o_orig = n->order;
572 	n->order = o;
573 	for (i = 0; i < n->count; i++) {
574 		if (n->entries[i].components && (n->entries[i].size/n->entries[i].components < exif_format_get_size (n->entries[i].format)))
575 			continue;
576 		n->entries[i].order = o;
577 		exif_array_set_byte_order (n->entries[i].format, n->entries[i].data,
578 				n->entries[i].components, o_orig, o);
579 	}
580 }
581 
582 static void
exif_mnote_data_olympus_set_offset(ExifMnoteData * n,unsigned int o)583 exif_mnote_data_olympus_set_offset (ExifMnoteData *n, unsigned int o)
584 {
585 	if (n) ((ExifMnoteDataOlympus *) n)->offset = o;
586 }
587 
588 static enum OlympusVersion
exif_mnote_data_olympus_identify_variant(const unsigned char * buf,unsigned int buf_size)589 exif_mnote_data_olympus_identify_variant (const unsigned char *buf,
590 		unsigned int buf_size)
591 {
592 	/* Olympus, Nikon, Sanyo, Epson */
593 	if (buf_size >= 8) {
594 		/* Match the terminating NUL character, too */
595 		if (!memcmp (buf, "OLYMPUS", 8))
596 			   return olympusV2;
597 		else if (!memcmp (buf, "OLYMP", 6))
598 			   return olympusV1;
599 		else if (!memcmp (buf, "SANYO", 6))
600 			   return sanyoV1;
601 		else if (!memcmp (buf, "EPSON", 6))
602 			   return epsonV1;
603 		else if (!memcmp (buf, "Nikon", 6)) {
604 			switch (buf[6]) {
605 				case 1:  return nikonV1;
606 				case 2:  return nikonV2;
607 				default: return 0; /* Unrecognized Nikon variant */
608 			}
609 		}
610 	}
611 
612 	/* Another variant of Nikon */
613 	if ((buf_size >= 2) && (buf[0] == 0x00) && (buf[1] == 0x1b)) {
614 		return nikonV0;
615 	}
616 
617 	return unrecognized;
618 }
619 
620 int
exif_mnote_data_olympus_identify(const ExifData * ed,const ExifEntry * e)621 exif_mnote_data_olympus_identify (const ExifData *ed, const ExifEntry *e)
622 {
623 	int variant = exif_mnote_data_olympus_identify_variant(e->data, e->size);
624 
625 	if (variant == nikonV0) {
626 		/* This variant needs some extra checking with the Make */
627 		char value[5];
628 		ExifEntry *em = exif_data_get_entry (ed, EXIF_TAG_MAKE);
629 		variant = unrecognized;
630 
631 		if (em) {
632 			const char *v = exif_entry_get_value (em, value, sizeof(value));
633 			if (v && (!strncmp (v, "Nikon", sizeof(value)) ||
634 					  !strncmp (v, "NIKON", sizeof(value)) ))
635 				/* When saved, this variant will be written out like the
636 				 * alternative nikonV2 form above instead
637 				 */
638 				variant = nikonV0;
639 		}
640 	}
641 
642 	return variant;
643 }
644 
645 
646 ExifMnoteData *
exif_mnote_data_olympus_new(ExifMem * mem)647 exif_mnote_data_olympus_new (ExifMem *mem)
648 {
649 	ExifMnoteData *d;
650 
651 	if (!mem) return NULL;
652 
653 	d = exif_mem_alloc (mem, sizeof (ExifMnoteDataOlympus));
654 	if (!d) return NULL;
655 
656 	exif_mnote_data_construct (d, mem);
657 
658 	/* Set up function pointers */
659 	d->methods.free            = exif_mnote_data_olympus_free;
660 	d->methods.set_byte_order  = exif_mnote_data_olympus_set_byte_order;
661 	d->methods.set_offset      = exif_mnote_data_olympus_set_offset;
662 	d->methods.load            = exif_mnote_data_olympus_load;
663 	d->methods.save            = exif_mnote_data_olympus_save;
664 	d->methods.count           = exif_mnote_data_olympus_count;
665 	d->methods.get_id          = exif_mnote_data_olympus_get_id;
666 	d->methods.get_name        = exif_mnote_data_olympus_get_name;
667 	d->methods.get_title       = exif_mnote_data_olympus_get_title;
668 	d->methods.get_description = exif_mnote_data_olympus_get_description;
669 	d->methods.get_value       = exif_mnote_data_olympus_get_value;
670 
671 	return d;
672 }
673