1/* exif-content.c
2 *
3 * Copyright (c) 2001 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
23#include <libexif/exif-content.h>
24#include <libexif/exif-system.h>
25
26#include <stdlib.h>
27#include <stdio.h>
28#include <string.h>
29
30/* unused constant
31 * static const unsigned char ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};
32 */
33
34struct _ExifContentPrivate
35{
36	unsigned int ref_count;
37
38	ExifMem *mem;
39	ExifLog *log;
40};
41
42ExifContent *
43exif_content_new (void)
44{
45	ExifMem *mem = exif_mem_new_default ();
46	ExifContent *content = exif_content_new_mem (mem);
47
48	exif_mem_unref (mem);
49
50	return content;
51}
52
53ExifContent *
54exif_content_new_mem (ExifMem *mem)
55{
56	ExifContent *content;
57
58	if (!mem) return NULL;
59
60	content = exif_mem_alloc (mem, (ExifLong) sizeof (ExifContent));
61	if (!content)
62		return NULL;
63	content->priv = exif_mem_alloc (mem,
64				(ExifLong) sizeof (ExifContentPrivate));
65	if (!content->priv) {
66		exif_mem_free (mem, content);
67		return NULL;
68	}
69
70	content->priv->ref_count = 1;
71
72	content->priv->mem = mem;
73	exif_mem_ref (mem);
74
75	return content;
76}
77
78void
79exif_content_ref (ExifContent *content)
80{
81	content->priv->ref_count++;
82}
83
84void
85exif_content_unref (ExifContent *content)
86{
87	content->priv->ref_count--;
88	if (!content->priv->ref_count)
89		exif_content_free (content);
90}
91
92void
93exif_content_free (ExifContent *content)
94{
95	ExifMem *mem = (content && content->priv) ? content->priv->mem : NULL;
96	unsigned int i;
97
98	if (!content) return;
99
100	for (i = 0; i < content->count; i++)
101		exif_entry_unref (content->entries[i]);
102	exif_mem_free (mem, content->entries);
103
104	if (content->priv) {
105		exif_log_unref (content->priv->log);
106	}
107
108	exif_mem_free (mem, content->priv);
109	exif_mem_free (mem, content);
110	exif_mem_unref (mem);
111}
112
113void
114exif_content_dump (ExifContent *content, unsigned int indent)
115{
116	char buf[1024];
117	unsigned int i;
118
119	for (i = 0; i < 2 * indent; i++)
120		buf[i] = ' ';
121	buf[i] = '\0';
122
123	if (!content)
124		return;
125
126	printf ("%sDumping exif content (%u entries)...\n", buf,
127		content->count);
128	for (i = 0; i < content->count; i++)
129		exif_entry_dump (content->entries[i], indent + 1);
130}
131
132void
133exif_content_add_entry (ExifContent *c, ExifEntry *entry)
134{
135	ExifEntry **entries;
136	if (!c || !c->priv || !entry || entry->parent) return;
137
138	/* One tag can only be added once to an IFD. */
139	if (exif_content_get_entry (c, entry->tag)) {
140		exif_log (c->priv->log, EXIF_LOG_CODE_DEBUG, "ExifContent",
141			"An attempt has been made to add "
142			"the tag '%s' twice to an IFD. This is against "
143			"specification.", exif_tag_get_name (entry->tag));
144		return;
145	}
146
147	entries = exif_mem_realloc (c->priv->mem,
148		c->entries, sizeof (ExifEntry*) * (c->count + 1));
149	if (!entries) return;
150	entry->parent = c;
151	entries[c->count++] = entry;
152	c->entries = entries;
153	exif_entry_ref (entry);
154}
155
156void
157exif_content_remove_entry (ExifContent *c, ExifEntry *e)
158{
159	unsigned int i;
160	ExifEntry **t, *temp;
161
162	if (!c || !c->priv || !e || (e->parent != c)) return;
163
164	/* Search the entry */
165	for (i = 0; i < c->count; i++)
166			if (c->entries[i] == e)
167					break;
168
169	if (i == c->count)
170			return;
171
172	/* Remove the entry */
173	temp = c->entries[c->count-1];
174	if (c->count > 1) {
175		t = exif_mem_realloc (c->priv->mem, c->entries,
176					sizeof(ExifEntry*) * (c->count - 1));
177		if (!t) {
178			return;
179		}
180		c->entries = t;
181		c->count--;
182		if (i != c->count) { /* we deallocated the last slot already */
183			memmove (&t[i], &t[i + 1], sizeof (ExifEntry*) * (c->count - i - 1));
184			t[c->count-1] = temp;
185		}
186	} else {
187		exif_mem_free (c->priv->mem, c->entries);
188		c->entries = NULL;
189		c->count = 0;
190	}
191	e->parent = NULL;
192	exif_entry_unref (e);
193}
194
195ExifEntry *
196exif_content_get_entry (ExifContent *content, ExifTag tag)
197{
198	unsigned int i;
199
200	if (!content)
201		return (NULL);
202
203	for (i = 0; i < content->count; i++)
204		if (content->entries[i]->tag == tag)
205			return (content->entries[i]);
206	return (NULL);
207}
208
209void
210exif_content_foreach_entry (ExifContent *content,
211			    ExifContentForeachEntryFunc func, void *data)
212{
213	unsigned int i;
214
215	if (!content || !func)
216		return;
217
218	for (i = 0; i < content->count; i++)
219		func (content->entries[i], data);
220}
221
222void
223exif_content_log (ExifContent *content, ExifLog *log)
224{
225	if (!content || !content->priv || !log || content->priv->log == log)
226		return;
227
228	if (content->priv->log) exif_log_unref (content->priv->log);
229	content->priv->log = log;
230	exif_log_ref (log);
231}
232
233ExifIfd
234exif_content_get_ifd (ExifContent *c)
235{
236	if (!c || !c->parent) return EXIF_IFD_COUNT;
237
238	return
239		((c)->parent->ifd[EXIF_IFD_0] == (c)) ? EXIF_IFD_0 :
240		((c)->parent->ifd[EXIF_IFD_1] == (c)) ? EXIF_IFD_1 :
241		((c)->parent->ifd[EXIF_IFD_EXIF] == (c)) ? EXIF_IFD_EXIF :
242		((c)->parent->ifd[EXIF_IFD_GPS] == (c)) ? EXIF_IFD_GPS :
243		((c)->parent->ifd[EXIF_IFD_INTEROPERABILITY] == (c)) ? EXIF_IFD_INTEROPERABILITY :
244		EXIF_IFD_COUNT;
245}
246
247static void
248fix_func (ExifEntry *e, void *UNUSED(data))
249{
250	exif_entry_fix (e);
251}
252
253/*!
254 * Check if this entry is unknown and if so, delete it.
255 * \note Be careful calling this function in a loop. Deleting an entry from
256 * an ExifContent changes the index of subsequent entries, as well as the
257 * total size of the entries array.
258 */
259static void
260remove_not_recorded (ExifEntry *e, void *UNUSED(data))
261{
262	ExifIfd ifd = exif_entry_get_ifd(e) ;
263	ExifContent *c = e->parent;
264	ExifDataType dt = exif_data_get_data_type (c->parent);
265	ExifTag t = e->tag;
266
267	if (exif_tag_get_support_level_in_ifd (t, ifd, dt) ==
268			 EXIF_SUPPORT_LEVEL_NOT_RECORDED) {
269		exif_log (c->priv->log, EXIF_LOG_CODE_DEBUG, "exif-content",
270				"Tag 0x%04x is not recorded in IFD '%s' and has therefore been "
271				"removed.", t, exif_ifd_get_name (ifd));
272		exif_content_remove_entry (c, e);
273	}
274
275}
276
277void
278exif_content_fix (ExifContent *c)
279{
280	ExifIfd ifd = exif_content_get_ifd (c);
281	ExifDataType dt;
282	ExifEntry *e;
283	unsigned int i, num;
284
285	if (!c)
286		return;
287
288	dt = exif_data_get_data_type (c->parent);
289
290	/*
291	 * First of all, fix all existing entries.
292	 */
293	exif_content_foreach_entry (c, fix_func, NULL);
294
295	/*
296	 * Go through each tag and if it's not recorded, remove it. If one
297	 * is removed, exif_content_foreach_entry() will skip the next entry,
298	 * so if this happens do the loop again from the beginning to ensure
299	 * they're all checked. This could be avoided if we stop relying on
300	 * exif_content_foreach_entry but loop intelligently here.
301	 */
302	do {
303		num = c->count;
304		exif_content_foreach_entry (c, remove_not_recorded, NULL);
305	} while (num != c->count);
306
307	/*
308	 * Then check for non-existing mandatory tags and create them if needed
309	 */
310	num = exif_tag_table_count();
311	for (i = 0; i < num; ++i) {
312		const ExifTag t = exif_tag_table_get_tag (i);
313		if (exif_tag_get_support_level_in_ifd (t, ifd, dt) ==
314			EXIF_SUPPORT_LEVEL_MANDATORY) {
315			if (exif_content_get_entry (c, t))
316				/* This tag already exists */
317				continue;
318			exif_log (c->priv->log, EXIF_LOG_CODE_DEBUG, "exif-content",
319					"Tag '%s' is mandatory in IFD '%s' and has therefore been added.",
320					exif_tag_get_name_in_ifd (t, ifd), exif_ifd_get_name (ifd));
321			e = exif_entry_new ();
322			exif_content_add_entry (c, e);
323			exif_entry_initialize (e, t);
324			exif_entry_unref (e);
325		}
326	}
327}
328