1 /* EasyTAG - tag editor for audio files
2 * Copyright (C) 2014 David King <amigadave@amigadave.com>
3 * Copyright (C) 2000 Bryan Call <bc@fodder.org>
4 * Copyright (C) 2003 Oliver Schinagl <oliver@are-b.org>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc., 51
18 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
19 */
20
21 #include "crc32.h"
22 #include "id3_tag.h"
23
24 #define BUFFERSIZE 16384 /* (16k) buffer size for reading from the file */
25
26 /* TODO: Use GChecksum if https://bugzilla.gnome.org/show_bug.cgi?id=523149
27 * is fixed and CRC32 support is added to GLib.
28 */
29 static const guint32 crc32table[] = {
30 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
31 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
32 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
33 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
34 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
35 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
36 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
37 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
38 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
39 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
40 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
41 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
42 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
43 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
44 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
45 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
46 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
47 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
48 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
49 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
50 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
51 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
52 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
53 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
54 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
55 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
56 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
57 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
58 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
59 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
60 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
61 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
62 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
63 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
64 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
65 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
66 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
67 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
68 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
69 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
70 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
71 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
72 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
73 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
74 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
75 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
76 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
77 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
78 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
79 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
80 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
81 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
82 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
83 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
84 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
85 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
86 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
87 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
88 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
89 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
90 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
91 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
92 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
93 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
94 };
95
96 /*
97 * crc32_file_with_ID3_tag:
98 * @file: a file from which to read audio data
99 * @main_val: (out): the CRC32 value
100 *
101 * Calculate the CRC32 value of audio data (skips the ID3v2 and ID3v1 tags).
102 *
103 * Returns: %TRUE if the CRC calculation was successful, %FALSE otherwise
104 */
105 gboolean
crc32_file_with_ID3_tag(GFile * file,guint32 * crc32,GError ** err)106 crc32_file_with_ID3_tag (GFile *file,
107 guint32 *crc32,
108 GError **err)
109 {
110 gchar buf[BUFFERSIZE], *p;
111 gint nr;
112 guint32 crc = ~0, crc32_total = ~0;
113 guchar tmp_id3[4];
114 glong id3v2size = 0;
115 GFileInfo *info;
116 GFileInputStream *istream;
117 goffset size;
118 gsize bytes_read;
119 gboolean has_id3v1 = FALSE;
120
121 g_return_val_if_fail (file != NULL, FALSE);
122 g_return_val_if_fail (err == NULL || *err == NULL, FALSE);
123
124 info = g_file_query_info (file, G_FILE_ATTRIBUTE_STANDARD_SIZE,
125 G_FILE_QUERY_INFO_NONE, NULL, err);
126
127 if (!info)
128 {
129 g_assert (err == NULL || *err != NULL);
130 return FALSE;
131 }
132
133 size = g_file_info_get_size (info);
134 istream = g_file_read (file, NULL, err);
135
136 if (!istream)
137 {
138 g_object_unref (info);
139 g_assert (err == NULL || *err != NULL);
140 return FALSE;
141 }
142
143 /* Check if there is an ID3v1 tag. */
144 if (!g_seekable_seek (G_SEEKABLE (istream), -ID3V1_TAG_SIZE, G_SEEK_END,
145 NULL, err))
146 {
147 goto error;
148 }
149
150 if (!g_input_stream_read_all (G_INPUT_STREAM (istream), tmp_id3, 3,
151 &bytes_read, NULL, err))
152 {
153 g_debug ("Only %" G_GSIZE_FORMAT " bytes out of 3 bytes of data were "
154 "read", bytes_read);
155 goto error;
156 }
157
158 if (tmp_id3[0] == 'T' && tmp_id3[1] == 'A' && tmp_id3[2] == 'G')
159 {
160 has_id3v1 = TRUE;
161 }
162
163 /* Check if there is an ID3v2 tag. */
164 if (!g_seekable_seek (G_SEEKABLE (istream), 0L, G_SEEK_SET, NULL, err))
165 {
166 goto error;
167 }
168
169 if (!g_input_stream_read_all (G_INPUT_STREAM (istream), tmp_id3, 4,
170 &bytes_read, NULL, err))
171 {
172 g_debug ("Only %" G_GSIZE_FORMAT " bytes out of 4 bytes of data were "
173 "read", bytes_read);
174 goto error;
175 }
176
177 /* Calculate ID3v2 length. */
178 if (tmp_id3[0] == 'I' && tmp_id3[1] == 'D' && tmp_id3[2] == '3'
179 && tmp_id3[3] < 0xFF)
180 {
181 /* ID3v2 tag skipper $49 44 33 yy yy xx zz zz zz zz [zz size]. */
182 /* Size is 6-9 position. */
183 if (!g_seekable_seek (G_SEEKABLE (istream), 2, G_SEEK_CUR,
184 NULL, err))
185 {
186
187 goto error;
188 }
189
190 if (!g_input_stream_read_all (G_INPUT_STREAM (istream), tmp_id3, 4,
191 &bytes_read, NULL, err))
192 {
193 g_debug ("Only %" G_GSIZE_FORMAT " bytes out of 4 bytes of data "
194 "were read", bytes_read);
195 goto error;
196 }
197
198 id3v2size = 10 +
199 ((glong)(tmp_id3[3]) | ((glong)(tmp_id3[2]) << 7) |
200 ((glong)(tmp_id3[1]) << 14) | ((glong)(tmp_id3[0]) << 21));
201
202 if (!g_seekable_seek (G_SEEKABLE (istream), id3v2size, G_SEEK_SET,
203 NULL, err))
204 {
205 goto error;
206 }
207
208 size = size - id3v2size;
209 }
210 else
211 {
212 if (!g_seekable_seek (G_SEEKABLE (istream), id3v2size, G_SEEK_SET,
213 NULL, err))
214 {
215 goto error;
216 }
217 }
218
219 while ((nr = g_input_stream_read (G_INPUT_STREAM (istream), buf,
220 sizeof (buf), NULL, err)) > 0)
221 {
222 if (has_id3v1 && nr <= ID3V1_TAG_SIZE)
223 /* Reading the end of an ID3v1 tag. */
224 {
225 break;
226 }
227
228 if (has_id3v1 && ((size = size - nr) < ID3V1_TAG_SIZE))
229 {
230 /* ID3v1 tag is in the current buf. */
231 nr = nr - ID3V1_TAG_SIZE + size;
232 }
233
234 for (p = buf; nr--; ++p)
235 {
236 crc = (crc >> 8) ^ crc32table[(crc ^ *p) & 0xff];
237 crc32_total = (crc >> 8) ^ crc32table[(crc32_total ^ *p) & 0xff];
238 }
239 }
240
241 if (nr == -1)
242 {
243 goto error;
244 }
245
246 g_assert (err == NULL || *err == NULL);
247 out:
248 g_object_unref (info);
249 g_object_unref (istream);
250 *crc32 = ~crc;
251
252 return nr == 0;
253
254 error:
255 g_assert (err == NULL || *err != NULL);
256 nr = -1;
257 goto out;
258 }
259