summaryrefslogtreecommitdiffstats
path: root/firmware/id3.c
blob: 3e7b392554eb8cb15f6f6eca15cccd02cc62ec4f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2002 by Daniel Stenberg
 *
 * All files in this archive are subject to the GNU General Public License.
 * See the file COPYING in the source tree root for full license agreement.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
/*
 * Parts of this code has been stolen from the Ample project and was written
 * by David H�deman. It has since been extended and enhanced pretty much by
 * all sorts of friendly Rockbox people.
 *
 */

 /* tagResolver and associated code copyright 2003 Thomas Paul Diffenbach
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdbool.h>
#include <stddef.h>
#include <ctype.h>
#include "config.h"
#include "file.h"
#include "debug.h"
#include "atoi.h"

#include "id3.h"
#include "mp3data.h"
#include "system.h"
#include "replaygain.h"
#include "rbunicode.h"

/** Database of audio formats **/
const struct afmt_entry audio_formats[AFMT_NUM_CODECS] =
{
    /* Unknown file format */
    [AFMT_UNKNOWN] =
        AFMT_ENTRY("???", NULL,       NULL,          NULL         ),

    /* MPEG Audio layer 1 */
    [AFMT_MPA_L1] =
        AFMT_ENTRY("MP1", "mpa",      NULL,          "mp1\0"      ),
    /* MPEG Audio layer 2 */
    [AFMT_MPA_L2] =
        AFMT_ENTRY("MP2", "mpa",      NULL,          "mpa\0mp2\0" ),
    /* MPEG Audio layer 3 */
    [AFMT_MPA_L3] =
        AFMT_ENTRY("MP3", "mpa",      "mp3_enc",     "mp3\0"      ),

#if CONFIG_CODEC == SWCODEC
    /* Audio Interchange File Format */
    [AFMT_AIFF] =
        AFMT_ENTRY("AIFF", "aiff",    "aiff_enc",    "aiff\0aif\0"),
    /* Uncompressed PCM in a WAV file */
    [AFMT_PCM_WAV] =
        AFMT_ENTRY("WAV",  "wav",     "wav_enc",     "wav\0"      ),
    /* Ogg Vorbis */
    [AFMT_OGG_VORBIS] =
        AFMT_ENTRY("Ogg",  "vorbis",  NULL,          "ogg\0"      ),
    /* FLAC */
    [AFMT_FLAC] =
        AFMT_ENTRY("FLAC", "flac",    NULL,          "flac\0"     ),
    /* Musepack */
    [AFMT_MPC] =
        AFMT_ENTRY("MPC",  "mpc",     NULL,          "mpc\0"      ),
    /* A/52 (aka AC3) audio */
    [AFMT_A52] =
        AFMT_ENTRY("AC3",  "a52",     NULL,          "a52\0ac3\0" ),
    /* WavPack */
    [AFMT_WAVPACK] =
        AFMT_ENTRY("WV",   "wavpack", "wavpack_enc", "wv\0"       ),
    /* Apple Lossless Audio Codec */
    [AFMT_ALAC] =
        AFMT_ENTRY("ALAC", "alac",    NULL,          "m4a\0m4b\0" ),
    /* Advanced Audio Coding in M4A container */
    [AFMT_AAC] =
        AFMT_ENTRY("AAC",  "aac",     NULL,          "mp4\0"      ),
    /* Shorten */
    [AFMT_SHN] =
        AFMT_ENTRY("SHN",  "shorten", NULL,          "shn\0"      ),
    /* SID File Format */
    [AFMT_SID] =
        AFMT_ENTRY("SID",  "sid",     NULL,          "sid\0"      ),
    /* ADX File Format */
    [AFMT_ADX] =
        AFMT_ENTRY("ADX",  "adx",     NULL,          "adx\0"      ),
    /* NESM (NES Sound Format) */
    [AFMT_NSF] =
        AFMT_ENTRY("NSF",  "nsf",     NULL,          "nsf\0nsfe\0"      ),
    /* Speex File Format */
    [AFMT_SPEEX] =
        AFMT_ENTRY("Speex","speex",   NULL,          "spx\0"      ),
    /* SPC700 Save State */
    [AFMT_SPC] =
        AFMT_ENTRY("SPC",  "spc",     NULL,          "spc\0"      ),
    /* APE (Monkey's Audio) */
    [AFMT_APE] =
        AFMT_ENTRY("APE",  "ape",     NULL,          "ape\0mac\0"      ),
#endif
};

#if CONFIG_CODEC == SWCODEC && defined (HAVE_RECORDING)
/* get REC_FORMAT_* corresponding AFMT_* */
const int rec_format_afmt[REC_NUM_FORMATS] =
{
    /* give AFMT_UNKNOWN by default */
    [0 ... REC_NUM_FORMATS-1] = AFMT_UNKNOWN,
    /* add new entries below this line */
    [REC_FORMAT_AIFF]    = AFMT_AIFF,
    [REC_FORMAT_MPA_L3]  = AFMT_MPA_L3,
    [REC_FORMAT_WAVPACK] = AFMT_WAVPACK,
    [REC_FORMAT_PCM_WAV] = AFMT_PCM_WAV,
};

/* get AFMT_* corresponding REC_FORMAT_* */
const int afmt_rec_format[AFMT_NUM_CODECS] =
{
    /* give -1 by default */
    [0 ... AFMT_NUM_CODECS-1] = -1,
    /* add new entries below this line */
    [AFMT_AIFF]    = REC_FORMAT_AIFF,
    [AFMT_MPA_L3]  = REC_FORMAT_MPA_L3,
    [AFMT_WAVPACK] = REC_FORMAT_WAVPACK,
    [AFMT_PCM_WAV] = REC_FORMAT_PCM_WAV,
};
#endif /* CONFIG_CODEC == SWCODEC && defined (HAVE_RECORDING) */
/****/

unsigned long unsync(unsigned long b0,
                     unsigned long b1,
		     unsigned long b2,
		     unsigned long b3)
{
   return (((long)(b0 & 0x7F) << (3*7)) |
           ((long)(b1 & 0x7F) << (2*7)) |
           ((long)(b2 & 0x7F) << (1*7)) |
           ((long)(b3 & 0x7F) << (0*7)));
}

static const char* const genres[] = {
    "Blues", "Classic Rock", "Country", "Dance", "Disco", "Funk", "Grunge",
    "Hip-Hop", "Jazz", "Metal", "New Age", "Oldies", "Other", "Pop", "R&B",
    "Rap", "Reggae", "Rock", "Techno", "Industrial", "Alternative", "Ska",
    "Death Metal", "Pranks", "Soundtrack", "Euro-Techno", "Ambient", "Trip-Hop",
    "Vocal", "Jazz+Funk", "Fusion", "Trance", "Classical", "Instrumental",
    "Acid", "House", "Game", "Sound Clip", "Gospel", "Noise", "AlternRock",
    "Bass", "Soul", "Punk", "Space", "Meditative", "Instrumental Pop",
    "Instrumental Rock", "Ethnic", "Gothic", "Darkwave", "Techno-Industrial",
    "Electronic", "Pop-Folk", "Eurodance", "Dream", "Southern Rock", "Comedy",
    "Cult", "Gangsta", "Top 40", "Christian Rap", "Pop/Funk", "Jungle",
    "Native American", "Cabaret", "New Wave", "Psychadelic", "Rave",
    "Showtunes", "Trailer", "Lo-Fi", "Tribal", "Acid Punk", "Acid Jazz",
    "Polka", "Retro", "Musical", "Rock & Roll", "Hard Rock",

    /* winamp extensions */
    "Folk", "Folk-Rock", "National Folk", "Swing", "Fast Fusion", "Bebob",
    "Latin", "Revival", "Celtic", "Bluegrass", "Avantgarde", "Gothic Rock",
    "Progressive Rock", "Psychedelic Rock", "Symphonic Rock", "Slow Rock",
    "Big Band", "Chorus", "Easy Listening", "Acoustic", "Humour", "Speech",
    "Chanson", "Opera", "Chamber Music", "Sonata", "Symphony", "Booty Bass",
    "Primus", "Porn Groove", "Satire", "Slow Jam", "Club", "Tango", "Samba",
    "Folklore", "Ballad", "Power Ballad", "Rhythmic Soul", "Freestyle",
    "Duet", "Punk Rock", "Drum Solo", "A capella", "Euro-House", "Dance Hall",
    "Goa", "Drum & Bass", "Club-House", "Hardcore", "Terror", "Indie",
    "BritPop", "Negerpunk", "Polsk Punk", "Beat", "Christian Gangsta Rap",
    "Heavy Metal", "Black Metal", "Crossover", "Contemporary Christian",
    "Christian Rock", "Merengue", "Salsa", "Thrash Metal", "Anime", "Jpop",
    "Synthpop"
};

char* id3_get_num_genre(const unsigned int genre_num)
{
    if (genre_num < sizeof(genres)/sizeof(char*))
        return (char*)genres[genre_num];
    return NULL;
}

char* id3_get_codec(const struct mp3entry* id3)
{
    if (id3->codectype < AFMT_NUM_CODECS) {
        return (char*)audio_formats[id3->codectype].label;
    } else {
        return NULL;
    }
}

/*
    HOW TO ADD ADDITIONAL ID3 VERSION 2 TAGS
    Code and comments by Thomas Paul Diffenbach

    To add another ID3v2 Tag, do the following:
    1.  add a char* named for the tag to struct mp3entry in id3.h,
        (I (tpd) prefer to use char* rather than ints, even for what seems like
        numerical values, for cases where a number won't do, e.g.,
        YEAR: "circa 1765", "1790/1977" (composed/performed), "28 Feb 1969"
        TRACK: "1/12", "1 of 12", GENRE: "Freeform genre name"
        Text is more flexible, and as the main use of id3 data is to
        display it, converting it to an int just means reconverting to
        display it, at a runtime cost.)

    2. If any special processing beyond copying the tag value from the Id3
       block to the struct mp3entry is rrequired (such as converting to an
       int), write a function to perform this special processing.

       This function's prototype must match that of
       typedef tagPostProcessFunc, that is it must be:
         int func( struct mp3entry*, char* tag, int bufferpos )
       the first argument is a pointer to the current mp3entry structure the
       second argument is a pointer to the null terminated string value of the
       tag found the third argument is the offset of the next free byte in the
       mp3entry's buffer your function should return the corrected offset; if
       you don't lengthen or shorten the tag string, you can return the third
       argument unchanged.

       Unless you have a good reason no to, make the function static.
       TO JUST COPY THE TAG NO SPECIAL PROCESSING FUNCTION IS NEEDED.

    3. add one or more entries to the tagList array, using the format:
            char* ID3 Tag symbolic name -- see the ID3 specification for these,
            sizeof() that name minus 1,
            offsetof( struct mp3entry, variable_name_in_struct_mp3entry ),
            pointer to your special processing function or NULL
                if you need no special processing
            flag indicating if this tag is binary or textual
        Many ID3 symbolic names come in more than one form. You can add both
        forms, each referencing the same variable in struct mp3entry.
        If both forms are present, the last found will be used.
        Note that the offset can be zero, in which case no entry will be set
        in the mp3entry struct; the frame is still read into the buffer and
        the special processing function is called (several times, if there
        are several frames with the same name).

    4. Alternately, use the TAG_LIST_ENTRY macro with
         ID3 tag symbolic name,
         variable in struct mp3entry,
         special processing function address

    5.  Add code to wps-display.c function get_tag to assign a printf-like
        format specifier for the tag */

/* Structure for ID3 Tag extraction information */
struct tag_resolver {
    const char* tag;
    int tag_length;
    size_t offset;
    int (*ppFunc)(struct mp3entry*, char* tag, int bufferpos);
    bool binary;
};

static bool global_ff_found;

static int unsynchronize(char* tag, int len, bool *ff_found)
{
    int i;
    unsigned char c;
    unsigned char *rp, *wp;

    wp = rp = (unsigned char *)tag;

    rp = (unsigned char *)tag;
    for(i = 0;i < len;i++) {
        /* Read the next byte and write it back, but don't increment the
           write pointer */
        c = *rp++;
        *wp = c;
        if(*ff_found) {
            /* Increment the write pointer if it isn't an unsynch pattern */
            if(c != 0)
                wp++;
            *ff_found = false;
        } else {
            if(c == 0xff)
                *ff_found = true;
            wp++;
        }
    }
    return (long)wp - (long)tag;
}

static int unsynchronize_frame(char* tag, int len)
{
    bool ff_found = false;

    return unsynchronize(tag, len, &ff_found);
}

static int read_unsynched(int fd, void *buf, int len)
{
    int i;
    int rc;
    int remaining = len;
    char *wp;
    char *rp;

    wp = buf;

    while(remaining) {
        rp = wp;
        rc = read(fd, rp, remaining);
        if(rc <= 0)
            return rc;

        i = unsynchronize(wp, remaining, &global_ff_found);
        remaining -= i;
        wp += i;
    }

    return len;
}

static int skip_unsynched(int fd, int len)
{
    int rc;
    int remaining = len;
    int rlen;
    char buf[32];

    while(remaining) {
        rlen = MIN(sizeof(buf), (unsigned int)remaining);
        rc = read(fd, buf, rlen);
        if(rc <= 0)
            return rc;

        remaining -= unsynchronize(buf, rlen, &global_ff_found);
    }

    return len;
}

/* parse numeric value from string */
static int parsetracknum( struct mp3entry* entry, char* tag, int bufferpos )
{
    entry->tracknum = atoi( tag );
    return bufferpos;
}

/* parse numeric value from string */
static int parseyearnum( struct mp3entry* entry, char* tag, int bufferpos )
{
    entry->year = atoi( tag );
    return bufferpos;
}

/* parse numeric genre from string, version 2.2 and 2.3 */
static int parsegenre( struct mp3entry* entry, char* tag, int bufferpos )
{
    if(entry->id3version >= ID3_VER_2_4) {
        /* In version 2.4 and up, there are no parentheses, and the genre frame
           is a list of strings, either numbers or text. */

        /* Is it a number? */
        if(isdigit(tag[0])) {
            entry->genre_string = id3_get_num_genre(atoi( tag ));
            return tag - entry->id3v2buf;
        } else {
            entry->genre_string = tag;
            return bufferpos;
        }
    } else {
        if( tag[0] == '(' && tag[1] != '(' ) {
            entry->genre_string = id3_get_num_genre(atoi( tag + 1 ));
            return tag - entry->id3v2buf;
        }
        else {
            entry->genre_string = tag;
            return bufferpos;
        }
    }
}

#if CONFIG_CODEC == SWCODEC
/* parse user defined text, looking for replaygain information. */
static int parseuser( struct mp3entry* entry, char* tag, int bufferpos )
{
    char* value = NULL;
    int desc_len = strlen(tag);
    int value_len = 0;

    /* Note: for ID3v2.4, parse_replaygain will not overwrite replaygain
       values already parsed from RVA2 tags */
    if ((tag - entry->id3v2buf + desc_len + 2) < bufferpos) {
        /* At least part of the value was read, so we can safely try to
         * parse it
         */
        value = tag + desc_len + 1;
        value_len = parse_replaygain(tag, value, entry, tag,
            bufferpos - (tag - entry->id3v2buf));
    }

    if (value_len) {
        bufferpos = tag - entry->id3v2buf + value_len;
    } else {
        bufferpos = tag - entry->id3v2buf;
    }

    return bufferpos;
}

/* parse RVA2 binary data and convert to replaygain information. */
static int parserva2( struct mp3entry* entry, char* tag, int bufferpos )
{
    char* value = NULL;
    int desc_len = strlen(tag);
    int value_len = 0;

    /* Only parse RVA2 replaygain tags if tag version == 2.4 */
    if (entry->id3version == ID3_VER_2_4 &&
        (tag - entry->id3v2buf + desc_len + 2) < bufferpos) {
        value = tag + desc_len + 1;
        value_len = parse_replaygain_rva(tag, value, entry, tag,
            bufferpos - (tag - entry->id3v2buf));
    }

    if (value_len) {
        bufferpos = tag - entry->id3v2buf + value_len;
    } else {
        bufferpos = tag - entry->id3v2buf;
    }

    return bufferpos;
}
#endif

static const struct tag_resolver taglist[] = {
    { "TPE1", 4, offsetof(struct mp3entry, artist), NULL, false },
    { "TP1",  3, offsetof(struct mp3entry, artist), NULL, false },
    { "TIT2", 4, offsetof(struct mp3entry, title), NULL, false },
    { "TT2",  3, offsetof(struct mp3entry, title), NULL, false },
    { "TALB", 4, offsetof(struct mp3entry, album), NULL, false },
    { "TAL",  3, offsetof(struct mp3entry, album), NULL, false },
    { "TRK",  3, offsetof(struct mp3entry, track_string), &parsetracknum, false },
    { "TRCK", 4, offsetof(struct mp3entry, track_string), &parsetracknum, false },
    { "TDRC", 4, offsetof(struct mp3entry, year_string), &parseyearnum, false },
    { "TYER", 4, offsetof(struct mp3entry, year_string), &parseyearnum, false },
    { "TYE",  3, offsetof(struct mp3entry, year_string), &parseyearnum, false },
    { "TCOM", 4, offsetof(struct mp3entry, composer), NULL, false },
    { "TPE2", 4, offsetof(struct mp3entry, albumartist), NULL, false },
    { "TP2", 3, offsetof(struct mp3entry, albumartist), NULL, false },
    { "COMM", 4, offsetof(struct mp3entry, comment), NULL, false }, 
    { "TCON", 4, offsetof(struct mp3entry, genre_string), &parsegenre, false },
    { "TCO",  3, offsetof(struct mp3entry, genre_string), &parsegenre, false },
#if CONFIG_CODEC == SWCODEC
    { "TXXX", 4, 0, &parseuser, false },
    { "RVA2", 4, 0, &parserva2, true },
#endif
};

#define TAGLIST_SIZE ((int)(sizeof(taglist) / sizeof(taglist[0])))

/* Checks to see if the passed in string is a 16-bit wide Unicode v2
   string.  If it is, we convert it to a UTF-8 string.  If it's not unicode,
   we convert from the default codepage */
static int unicode_munge(char* string, char* utf8buf, int *len) {
    long tmp;
    bool le = false;
    int i = 0;
    unsigned char *str = (unsigned char *)string;
    int templen = 0;
    unsigned char* utf8 = (unsigned char *)utf8buf;

    switch (str[0]) {
        case 0x00: /* Type 0x00 is ordinary ISO 8859-1 */
            str++;
            (*len)--;
            utf8 = iso_decode(str, utf8, -1, *len);
            *utf8 = 0;
            *len = (unsigned long)utf8 - (unsigned long)utf8buf;
            break;

        case 0x01: /* Unicode with or without BOM */
        case 0x02:
            (*len)--;
            str++;

            /* Handle frames with more than one string
               (needed for TXXX frames).*/
            do {
                tmp = bytes2int(0, 0, str[0], str[1]);

                /* Now check if there is a BOM
                   (zero-width non-breaking space, 0xfeff)
                   and if it is in little or big endian format */
                if(tmp == 0xfffe) { /* Little endian? */
                    le = true;
                    str += 2;
                    (*len)-=2;
                } else if(tmp == 0xfeff) { /* Big endian? */
                    str += 2;
                    (*len)-=2;
                } else
                /* If there is no BOM (which is a specification violation),
                   let's try to guess it. If one of the bytes is 0x00, it is
                   probably the most significant one. */
                    if(str[1] == 0)
                        le = true;

                do {
                    if(le)
                        utf8 = utf16LEdecode(str, utf8, 1);
                    else
                        utf8 = utf16BEdecode(str, utf8, 1);

                    str+=2;
                    i += 2;
                } while((str[0] || str[1]) && (i < *len));

                *utf8++ = 0; /* Terminate the string */
                templen += (strlen(&utf8buf[templen]) + 1);
                str += 2;
                i+=2;
            } while(i < *len);
            *len = templen - 1;
            break;

        case 0x03: /* UTF-8 encoded string */
            for(i=0; i < *len; i++)
                utf8[i] = str[i+1];
            (*len)--;
            break;

        default: /* Plain old string */
            utf8 = iso_decode(str, utf8, -1, *len);
            *utf8 = 0;
            *len = (unsigned long)utf8 - (unsigned long)utf8buf;
            break;
    }
    return 0;
}

/*
 * Sets the title of an MP3 entry based on its ID3v1 tag.
 *
 * Arguments: file - the MP3 file to scen for a ID3v1 tag
 *            entry - the entry to set the title in
 *
 * Returns: true if a title was found and created, else false
 */
static bool setid3v1title(int fd, struct mp3entry *entry)
{
    unsigned char buffer[128];
    static const char offsets[] = {3, 33, 63, 97, 93, 125, 127};
    int i, j;
    unsigned char* utf8;

    if (-1 == lseek(fd, -128, SEEK_END))
        return false;

    if (read(fd, buffer, sizeof buffer) != sizeof buffer)
        return false;

    if (strncmp((char *)buffer, "TAG", 3))
        return false;

    entry->id3v1len = 128;
    entry->id3version = ID3_VER_1_0;

    for (i=0; i < (int)sizeof offsets; i++) {
        unsigned char* ptr = (unsigned char *)buffer + offsets[i];

        switch(i) {
            case 0:
            case 1:
            case 2:
                /* kill trailing space in strings */
                for (j=29; j && (ptr[j]==0 || ptr[j]==' '); j--)
                    ptr[j] = 0;
                /* convert string to utf8 */
                utf8 = (unsigned char *)entry->id3v1buf[i];
                utf8 = iso_decode(ptr, utf8, -1, 30);
                /* make sure string is terminated */
                *utf8 = 0;
                break;

            case 3:
                /* kill trailing space in strings */
                for (j=27; j && (ptr[j]==0 || ptr[j]==' '); j--)
                    ptr[j] = 0;
                /* convert string to utf8 */
                utf8 = (unsigned char *)entry->id3v1buf[3];
                utf8 = iso_decode(ptr, utf8, -1, 28);
                /* make sure string is terminated */
                *utf8 = 0;
                break;

            case 4:
                ptr[4] = 0;
                entry->year = atoi((char *)ptr);
                break;

            case 5:
                /* id3v1.1 uses last two bytes of comment field for track
                   number: first must be 0 and second is track num */
                if (!ptr[0] && ptr[1]) {
                    entry->tracknum = ptr[1];
                    entry->id3version = ID3_VER_1_1;
                }
                break;

            case 6:
                /* genre */
                entry->genre_string = id3_get_num_genre(ptr[0]);
                break;
        }
    }

    entry->title = entry->id3v1buf[0];
    entry->artist = entry->id3v1buf[1];
    entry->album = entry->id3v1buf[2];
    entry->comment = entry->id3v1buf[3];

    return true;
}


/*
 * Sets the title of an MP3 entry based on its ID3v2 tag.
 *
 * Arguments: file - the MP3 file to scan for a ID3v2 tag
 *            entry - the entry to set the title in
 *
 * Returns: true if a title was found and created, else false
 */
static void setid3v2title(int fd, struct mp3entry *entry)
{
    int minframesize;
    int size;
    long bufferpos = 0, totframelen, framelen;
    char header[10];
    char tmp[4];
    unsigned char version;
    char *buffer = entry->id3v2buf;
    int bytesread = 0;
    int buffersize = sizeof(entry->id3v2buf);
    unsigned char global_flags;
    int flags;
    int skip;
    bool global_unsynch = false;
    bool unsynch = false;
    int data_length_ind;
    int i, j;
    int rc;

    global_ff_found = false;

    /* Bail out if the tag is shorter than 10 bytes */
    if(entry->id3v2len < 10)
        return;

    /* Read the ID3 tag version from the header */
    lseek(fd, 0, SEEK_SET);
    if(10 != read(fd, header, 10))
        return;

    /* Get the total ID3 tag size */
    size = entry->id3v2len - 10;

    version = header[3];
    switch ( version ) {
        case 2:
            version = ID3_VER_2_2;
            minframesize = 8;
            break;

        case 3:
            version = ID3_VER_2_3;
            minframesize = 12;
            break;

        case 4:
            version = ID3_VER_2_4;
            minframesize = 12;
            break;

        default:
            /* unsupported id3 version */
            return;
    }
    entry->id3version = version;
    entry->tracknum = entry->year = 0;
    entry->title = entry->artist = entry->album = NULL; /* FIXME incomplete */

    global_flags = header[5];

    /* Skip the extended header if it is present */
    if(global_flags & 0x40) {
        if(version == ID3_VER_2_3) {
            if(10 != read(fd, header, 10))
                return;
            /* The 2.3 extended header size doesn't include the header size
               field itself. Also, it is not unsynched. */
            framelen =
                bytes2int(header[0], header[1], header[2], header[3]) + 4;

            /* Skip the rest of the header */
            lseek(fd, framelen - 10, SEEK_CUR);
        }

        if(version >= ID3_VER_2_4) {
            if(4 != read(fd, header, 4))
                return;

            /* The 2.4 extended header size does include the entire header,
               so here we can just skip it. This header is unsynched. */
            framelen = unsync(header[0], header[1],
                              header[2], header[3]);

            lseek(fd, framelen - 4, SEEK_CUR);
        }
    }

    /* Is unsynchronization applied? */
    if(global_flags & 0x80) {
        global_unsynch = true;
    }

    /*
     * We must have at least minframesize bytes left for the
     * remaining frames to be interesting
     */
    while (size >= minframesize && bufferpos < buffersize - 1) {
        flags = 0;

        /* Read frame header and check length */
        if(version >= ID3_VER_2_3) {
            if(global_unsynch && version <= ID3_VER_2_3)
                rc = read_unsynched(fd, header, 10);
            else
                rc = read(fd, header, 10);
            if(rc != 10)
                return;
            /* Adjust for the 10 bytes we read */
            size -= 10;

            flags = bytes2int(0, 0, header[8], header[9]);

            if (version >= ID3_VER_2_4) {
                framelen = unsync(header[4], header[5],
                                  header[6], header[7]);
            } else {
                /* version .3 files don't use synchsafe ints for
                 * size */
                framelen = bytes2int(header[4], header[5],
                                     header[6], header[7]);
            }
        } else {
            if(6 != read(fd, header, 6))
                return;
            /* Adjust for the 6 bytes we read */
            size -= 6;

            framelen = bytes2int(0, header[3], header[4], header[5]);
        }

        /* Keep track of the total size */
        totframelen = framelen;

        DEBUGF("framelen = %ld\n", framelen);
        if(framelen == 0){
            if (header[0] == 0 && header[1] == 0 && header[2] == 0)
                return;
            else
                continue;
        }

        unsynch = false;
        data_length_ind = 0;

        if(flags)
        {
            skip = 0;

            if (version >= ID3_VER_2_4) {
                if(flags & 0x0040) { /* Grouping identity */
                    lseek(fd, 1, SEEK_CUR); /* Skip 1 byte */
                    framelen--;
                }
            } else {
                if(flags & 0x0020) { /* Grouping identity */
                    lseek(fd, 1, SEEK_CUR); /* Skip 1 byte */
                    framelen--;
                }
            }

            if(flags & 0x000c) /* Compression or encryption */
            {
                /* Skip it using the total size in case
                   it was truncated */
                size -= totframelen;
                lseek(fd, totframelen, SEEK_CUR);
                continue;
            }

            if(flags & 0x0002) /* Unsynchronization */
                unsynch = true;

            if (version >= ID3_VER_2_4) {
                if(flags & 0x0001) { /* Data length indicator */
                    if(4 != read(fd, tmp, 4))
                        return;

                    data_length_ind = unsync(tmp[0], tmp[1], tmp[2], tmp[3]);
                    framelen -= 4;
                }
            }
        }

        /* If the frame is larger than the remaining buffer space we try
           to read as much as would fit in the buffer */
        if(framelen >= buffersize - bufferpos)
            framelen = buffersize - bufferpos - 1;

        DEBUGF("id3v2 frame: %.4s\n", header);

        /* Check for certain frame headers

           'size' is the amount of frame bytes remaining.  We decrement it by
           the amount of bytes we read.  If we fail to read as many bytes as
           we expect, we assume that we can't read from this file, and bail
           out.

           For each frame. we will iterate over the list of supported tags,
           and read the tag into entry's buffer. All tags will be kept as
           strings, for cases where a number won't do, e.g., YEAR: "circa
           1765", "1790/1977" (composed/performed), "28 Feb 1969" TRACK:
           "1/12", "1 of 12", GENRE: "Freeform genre name" Text is more
           flexible, and as the main use of id3 data is to display it,
           converting it to an int just means reconverting to display it, at a
           runtime cost.

           For tags that the current code does convert to ints, a post
           processing function will be called via a pointer to function. */

        for (i=0; i<TAGLIST_SIZE; i++) {
            const struct tag_resolver* tr = &taglist[i];
            char** ptag = tr->offset ? (char**) (((char*)entry) + tr->offset)
                : NULL;
            char* tag;
            int comm_offset=0;

            /* Only ID3_VER_2_2 uses frames with three-character names. */
            if (((version == ID3_VER_2_2) && (tr->tag_length != 3))
                || ((version > ID3_VER_2_2) && (tr->tag_length != 4))) {
                continue;
            }

            /* Note that parser functions sometimes set *ptag to NULL, so
             * the "!*ptag" check here doesn't always have the desired
             * effect. Should the parser functions (parsegenre in
             * particular) be updated to handle the case of being called
             * multiple times, or should the "*ptag" check be removed?
             */
            if( (!ptag || !*ptag) && !memcmp( header, tr->tag, tr->tag_length ) ) {

                /* found a tag matching one in tagList, and not yet filled */
                tag = buffer + bufferpos;

                if(global_unsynch && version <= ID3_VER_2_3)
                    bytesread = read_unsynched(fd, tag, framelen);
                else
                    bytesread = read(fd, tag, framelen);

                if( bytesread != framelen )
                    return;

                size -= bytesread;

                if(unsynch || (global_unsynch && version >= ID3_VER_2_4))
                    bytesread = unsynchronize_frame(tag, bytesread);

                /* the COMM frame has a 3 char field to hold an ISO-639-1 
                 * language string and an optional short description;
                 * remove them so unicode_munge can work correctly
                 */
                 
                if(!memcmp( header, "COMM", 4 )) {
                    comm_offset = 3 + strlen(tag+4) + 1;
                    if(bytesread>comm_offset) {
                        bytesread-=comm_offset;
                        memmove(tag+1, tag+comm_offset+1, bytesread-1);
                    }   
                }

                /* Attempt to parse Unicode string only if the tag contents
                   aren't binary */
                if(!tr->binary) {
                    /* UTF-8 could potentially be 3 times larger */
                    /* so we need to create a new buffer         */
                    char utf8buf[(3 * bytesread) + 1];

                    unicode_munge( tag, utf8buf, &bytesread );

                    if(bytesread >= buffersize - bufferpos)
                        bytesread = buffersize - bufferpos - 1;

                    for (j = 0; j < bytesread; j++)
                        tag[j] = utf8buf[j];

                    /* remove trailing spaces */
                    while ( bytesread > 0 && isspace(tag[bytesread-1]))
                        bytesread--;
                }

                tag[bytesread] = 0;
                bufferpos += bytesread + 1;

                if (ptag)
                    *ptag = tag;

                if( tr->ppFunc )
                    bufferpos = tr->ppFunc(entry, tag, bufferpos);

                /* Seek to the next frame */
                if(framelen < totframelen)
                    lseek(fd, totframelen - framelen, SEEK_CUR);
                break;
            }
        }

        if( i == TAGLIST_SIZE ) {
            /* no tag in tagList was found, or it was a repeat.
               skip it using the total size */

            if(global_unsynch && version <= ID3_VER_2_3) {
                size -= skip_unsynched(fd, totframelen);
            } else {
                if(data_length_ind)
                    totframelen = data_length_ind;

                size -= totframelen;
                if( lseek(fd, totframelen, SEEK_CUR) == -1 )
                    return;
            }
        }
    }
}

/*
 * Calculates the size of the ID3v2 tag.
 *
 * Arguments: file - the file to search for a tag.
 *
 * Returns: the size of the tag or 0 if none was found
 */
int getid3v2len(int fd)
{
    char buf[6];
    int offset;

    /* Make sure file has a ID3 tag */
    if((-1 == lseek(fd, 0, SEEK_SET)) ||
       (read(fd, buf, 6) != 6) ||
       (strncmp(buf, "ID3", strlen("ID3")) != 0))
        offset = 0;

    /* Now check what the ID3v2 size field says */
    else
        if(read(fd, buf, 4) != 4)
            offset = 0;
        else
            offset = unsync(buf[0], buf[1], buf[2], buf[3]) + 10;

    DEBUGF("ID3V2 Length: 0x%x\n", offset);
    return offset;
}

/*
 * Calculates the length (in milliseconds) of an MP3 file.
 *
 * Modified to only use integers.
 *
 * Arguments: file - the file to calculate the length upon
 *            entry - the entry to update with the length
 *
 * Returns: the song length in milliseconds,
 *          0 means that it couldn't be calculated
 */
static int getsonglength(int fd, struct mp3entry *entry)
{
    unsigned long filetime = 0;
    struct mp3info info;
    long bytecount;

    /* Start searching after ID3v2 header */
    if(-1 == lseek(fd, entry->id3v2len, SEEK_SET))
        return 0;

    bytecount = get_mp3file_info(fd, &info);

    DEBUGF("Space between ID3V2 tag and first audio frame: 0x%lx bytes\n",
           bytecount);

    if(bytecount < 0)
        return -1;

    bytecount += entry->id3v2len;

    /* Validate byte count, in case the file has been edited without
     * updating the header.
     */
    if (info.byte_count)
    {
        const unsigned long expected = entry->filesize - entry->id3v1len
            - entry->id3v2len;
        const unsigned long diff = MAX(10240, info.byte_count / 20);

        if ((info.byte_count > expected + diff)
            || (info.byte_count < expected - diff))
        {
            DEBUGF("Note: info.byte_count differs from expected value by "
                "%ld bytes\n", labs((long) (expected - info.byte_count)));
            info.byte_count = 0;
            info.frame_count = 0;
            info.file_time = 0;
            info.enc_padding = 0;

            /* Even if the bitrate was based on "known bad" values, it
             * should still be better for VBR files than using the bitrate
             * of the first audio frame.
             */
        }
    }

    entry->bitrate = info.bitrate;
    entry->frequency = info.frequency;
    entry->version = info.version;
    entry->layer = info.layer;
    switch(entry->layer) {
#if CONFIG_CODEC==SWCODEC
        case 0:
            entry->codectype=AFMT_MPA_L1;
            break;
#endif
        case 1:
            entry->codectype=AFMT_MPA_L2;
            break;
        case 2:
            entry->codectype=AFMT_MPA_L3;
            break;
    }

    /* If the file time hasn't been established, this may be a fixed
       rate MP3, so just use the default formula */

    filetime = info.file_time;

    if(filetime == 0)
    {
        /* Prevent a division by zero */
        if (info.bitrate < 8)
            filetime = 0;
        else
            filetime = (entry->filesize - bytecount) / (info.bitrate / 8);
        /* bitrate is in kbps so this delivers milliseconds. Doing bitrate / 8
         * instead of filesize * 8 is exact, because mpeg audio bitrates are
         * always multiples of 8, and it avoids overflows. */
    }

    entry->frame_count = info.frame_count;

    entry->vbr = info.is_vbr;
    entry->has_toc = info.has_toc;

#if CONFIG_CODEC==SWCODEC
    entry->lead_trim = info.enc_delay;
    entry->tail_trim = info.enc_padding;
#endif

    memcpy(entry->toc, info.toc, sizeof(info.toc));

    entry->vbr_header_pos = info.vbr_header_pos;

    /* Update the seek point for the first playable frame */
    entry->first_frame_offset = bytecount;
    DEBUGF("First frame is at %lx\n", entry->first_frame_offset);

    return filetime;
}

/*
 * Checks all relevant information (such as ID3v1 tag, ID3v2 tag, length etc)
 * about an MP3 file and updates it's entry accordingly.
 *
  Note, that this returns true for successful, false for error! */
bool get_mp3_metadata(int fd, struct mp3entry *entry, const char *filename, bool v1first)
{
    int v1found = false;

#if CONFIG_CODEC != SWCODEC
    memset(entry, 0, sizeof(struct mp3entry));
#endif

    strncpy(entry->path, filename, sizeof(entry->path));

    entry->title = NULL;
    entry->filesize = filesize(fd);
    entry->id3v2len = getid3v2len(fd);
    entry->tracknum = 0;

    if(v1first)
        v1found = setid3v1title(fd, entry);

    if (!v1found && entry->id3v2len)
        setid3v2title(fd, entry);
    entry->length = getsonglength(fd, entry);

    /* Subtract the meta information from the file size to get
       the true size of the MP3 stream */
    entry->filesize -= entry->first_frame_offset;

    /* only seek to end of file if no id3v2 tags were found,
       and we already haven't looked for a v1 tag */
    if (!v1first && !entry->id3v2len) {
        setid3v1title(fd, entry);
    }

    if(!entry->length || (entry->filesize < 8 ))
        /* no song length or less than 8 bytes is hereby considered to be an
           invalid mp3 and won't be played by us! */
        return false;

    return true;
}

/* Note, that this returns false for successful, true for error! */
bool mp3info(struct mp3entry *entry, const char *filename, bool v1first)
{
    int fd;
    bool result;

    fd = open(filename, O_RDONLY);
    if (fd < 0)
        return true;

    result = !get_mp3_metadata(fd, entry, filename, v1first);

    close(fd);

    return result;
}

void adjust_mp3entry(struct mp3entry *entry, void *dest, void *orig)
{
    long offset;
    if (orig > dest)
        offset = - ((size_t)orig - (size_t)dest);
    else
        offset = (size_t)dest - (size_t)orig;

    if (entry->title)
        entry->title += offset;
    if (entry->artist)
        entry->artist += offset;
    if (entry->album)
        entry->album += offset;
    if (entry->genre_string)
        entry->genre_string += offset;
    if (entry->track_string)
        entry->track_string += offset;
    if (entry->year_string)
        entry->year_string += offset;
    if (entry->composer)
        entry->composer += offset;
    if (entry->comment)
        entry->comment += offset;
    if (entry->albumartist)
        entry->albumartist += offset;
#if CONFIG_CODEC == SWCODEC
    if (entry->track_gain_string)
        entry->track_gain_string += offset;
    if (entry->album_gain_string)
        entry->album_gain_string += offset;
#endif
}

void copy_mp3entry(struct mp3entry *dest, struct mp3entry *orig)
{
    memcpy(dest, orig, sizeof(struct mp3entry));
    adjust_mp3entry(dest, dest, orig);
}

#ifdef DEBUG_STANDALONE

char *secs2str(int ms)
{
    static char buffer[32];
    int secs = ms/1000;
    ms %= 1000;
    snprintf(buffer, sizeof(buffer), "%d:%02d.%d", secs/60, secs%60, ms/100);
    return buffer;
}

int main(int argc, char **argv)
{
    int i;
    for(i=1; i<argc; i++) {
        struct mp3entry mp3;
        mp3.album = "Bogus";
        if(mp3info(&mp3, argv[i], false)) {
            printf("Failed to get %s\n", argv[i]);
            return 0;
        }

        printf("****** File: %s\n"
               "      Title: %s\n"
               "     Artist: %s\n"
               "      Album: %s\n"
               "      Genre: %s (%d) \n"
               "   Composer: %s\n"
               "       Year: %s (%d)\n"
               "      Track: %s (%d)\n"
               "     Length: %s / %d s\n"
               "    Bitrate: %d\n"
               "  Frequency: %d\n",
               argv[i],
               mp3.title?mp3.title:"<blank>",
               mp3.artist?mp3.artist:"<blank>",
               mp3.album?mp3.album:"<blank>",
               mp3.genre_string?mp3.genre_string:"<blank>",
                    mp3.genre,
               mp3.composer?mp3.composer:"<blank>",
               mp3.year_string?mp3.year_string:"<blank>",
                    mp3.year,
               mp3.track_string?mp3.track_string:"<blank>",
                    mp3.tracknum,
               secs2str(mp3.length),
               mp3.length/1000,
               mp3.bitrate,
               mp3.frequency);
    }

    return 0;
}

#endif