1 /*
2 * EXIF metadata parser
3 * Copyright (c) 2013 Thilo Borgmann <thilo.borgmann _at_ mail.de>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * EXIF metadata parser
25 * @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
26 */
27
28 #include "exif.h"
29
30
exif_get_tag_name(uint16_t id)31 static const char *exif_get_tag_name(uint16_t id)
32 {
33 int i;
34
35 for (i = 0; i < FF_ARRAY_ELEMS(tag_list); i++) {
36 if (tag_list[i].id == id)
37 return tag_list[i].name;
38 }
39
40 return NULL;
41 }
42
43
exif_add_metadata(void * logctx,int count,int type,const char * name,const char * sep,GetByteContext * gb,int le,AVDictionary ** metadata)44 static int exif_add_metadata(void *logctx, int count, int type,
45 const char *name, const char *sep,
46 GetByteContext *gb, int le,
47 AVDictionary **metadata)
48 {
49 switch(type) {
50 case 0:
51 av_log(logctx, AV_LOG_WARNING,
52 "Invalid TIFF tag type 0 found for %s with size %d\n",
53 name, count);
54 return 0;
55 case TIFF_DOUBLE : return ff_tadd_doubles_metadata(count, name, sep, gb, le, metadata);
56 case TIFF_SSHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, 1, metadata);
57 case TIFF_SHORT : return ff_tadd_shorts_metadata(count, name, sep, gb, le, 0, metadata);
58 case TIFF_SBYTE : return ff_tadd_bytes_metadata(count, name, sep, gb, le, 1, metadata);
59 case TIFF_BYTE :
60 case TIFF_UNDEFINED: return ff_tadd_bytes_metadata(count, name, sep, gb, le, 0, metadata);
61 case TIFF_STRING : return ff_tadd_string_metadata(count, name, gb, le, metadata);
62 case TIFF_SRATIONAL:
63 case TIFF_RATIONAL : return ff_tadd_rational_metadata(count, name, sep, gb, le, metadata);
64 case TIFF_SLONG :
65 case TIFF_LONG : return ff_tadd_long_metadata(count, name, sep, gb, le, metadata);
66 default:
67 avpriv_request_sample(logctx, "TIFF tag type (%u)", type);
68 return 0;
69 };
70 }
71
72
exif_decode_tag(void * logctx,GetByteContext * gbytes,int le,int depth,AVDictionary ** metadata)73 static int exif_decode_tag(void *logctx, GetByteContext *gbytes, int le,
74 int depth, AVDictionary **metadata)
75 {
76 int ret, cur_pos;
77 unsigned id, count;
78 enum TiffTypes type;
79
80 if (depth > 2) {
81 return 0;
82 }
83
84 ff_tread_tag(gbytes, le, &id, &type, &count, &cur_pos);
85
86 if (!bytestream2_tell(gbytes)) {
87 bytestream2_seek(gbytes, cur_pos, SEEK_SET);
88 return 0;
89 }
90
91 // read count values and add it metadata
92 // store metadata or proceed with next IFD
93 ret = ff_tis_ifd(id);
94 if (ret) {
95 ret = ff_exif_decode_ifd(logctx, gbytes, le, depth + 1, metadata);
96 } else {
97 const char *name = exif_get_tag_name(id);
98 char buf[7];
99
100 if (!name) {
101 name = buf;
102 snprintf(buf, sizeof(buf), "0x%04X", id);
103 }
104
105 ret = exif_add_metadata(logctx, count, type, name, NULL,
106 gbytes, le, metadata);
107 }
108
109 bytestream2_seek(gbytes, cur_pos, SEEK_SET);
110
111 return ret;
112 }
113
114
ff_exif_decode_ifd(void * logctx,GetByteContext * gbytes,int le,int depth,AVDictionary ** metadata)115 int ff_exif_decode_ifd(void *logctx, GetByteContext *gbytes,
116 int le, int depth, AVDictionary **metadata)
117 {
118 int i, ret;
119 int entries;
120
121 entries = ff_tget_short(gbytes, le);
122
123 if (bytestream2_get_bytes_left(gbytes) < entries * 12) {
124 return AVERROR_INVALIDDATA;
125 }
126
127 for (i = 0; i < entries; i++) {
128 if ((ret = exif_decode_tag(logctx, gbytes, le, depth, metadata)) < 0) {
129 return ret;
130 }
131 }
132
133 // return next IDF offset or 0x000000000 or a value < 0 for failure
134 return ff_tget_long(gbytes, le);
135 }
136
avpriv_exif_decode_ifd(void * logctx,const uint8_t * buf,int size,int le,int depth,AVDictionary ** metadata)137 int avpriv_exif_decode_ifd(void *logctx, const uint8_t *buf, int size,
138 int le, int depth, AVDictionary **metadata)
139 {
140 GetByteContext gb;
141
142 bytestream2_init(&gb, buf, size);
143
144 return ff_exif_decode_ifd(logctx, &gb, le, depth, metadata);
145 }
146