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