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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 
34 struct _ExifContentPrivate
35 {
36 	unsigned int ref_count;
37 
38 	ExifMem *mem;
39 	ExifLog *log;
40 };
41 
42 ExifContent *
exif_content_new(void)43 exif_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 
53 ExifContent *
exif_content_new_mem(ExifMem * mem)54 exif_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 
78 void
exif_content_ref(ExifContent * content)79 exif_content_ref (ExifContent *content)
80 {
81 	content->priv->ref_count++;
82 }
83 
84 void
exif_content_unref(ExifContent * content)85 exif_content_unref (ExifContent *content)
86 {
87 	content->priv->ref_count--;
88 	if (!content->priv->ref_count)
89 		exif_content_free (content);
90 }
91 
92 void
exif_content_free(ExifContent * content)93 exif_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 
113 void
exif_content_dump(ExifContent * content,unsigned int indent)114 exif_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 
132 void
exif_content_add_entry(ExifContent * c,ExifEntry * entry)133 exif_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 
156 void
exif_content_remove_entry(ExifContent * c,ExifEntry * e)157 exif_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 
195 ExifEntry *
exif_content_get_entry(ExifContent * content,ExifTag tag)196 exif_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 
209 void
exif_content_foreach_entry(ExifContent * content,ExifContentForeachEntryFunc func,void * data)210 exif_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 
222 void
exif_content_log(ExifContent * content,ExifLog * log)223 exif_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 
233 ExifIfd
exif_content_get_ifd(ExifContent * c)234 exif_content_get_ifd (ExifContent *c)
235 {
236 	if (!c || !c->parent) return EXIF_IFD_COUNT;
237 
238 	return
239 		((c)->parent->ifd[EXIF_IFD_EXIF] == (c)) ? EXIF_IFD_EXIF :
240 		((c)->parent->ifd[EXIF_IFD_0] == (c)) ? EXIF_IFD_0 :
241 		((c)->parent->ifd[EXIF_IFD_1] == (c)) ? EXIF_IFD_1 :
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 
247 static void
fix_func(ExifEntry * e,void * UNUSED (data))248 fix_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  */
259 static void
remove_not_recorded(ExifEntry * e,void * UNUSED (data))260 remove_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 
277 void
exif_content_fix(ExifContent * c)278 exif_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