apps/metadata/monkeys.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2007 Dave Chapman
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <stdlib.h>
  22 #include <ctype.h>
  23 #include <inttypes.h>
  24
  25 #include "system.h"
  26 #include "id3.h"
  27 #include "metadata_common.h"
  28
  29 bool get_monkeys_metadata(int fd, struct mp3entry* id3)
  30 {
  31     /* Use the trackname part of the id3 structure as a temporary buffer */
  32     unsigned char* buf = (unsigned char *)id3->path;
  33     unsigned char* header;
  34     bool rc = false;
  35     uint32_t descriptorlength;
  36     uint32_t totalsamples;
  37     uint32_t blocksperframe, finalframeblocks, totalframes;
  38     int fileversion;
  39
  40     lseek(fd, 0, SEEK_SET);
  41
  42     if (read(fd, buf, 4) < 4)
  43     {
  44         return rc;
  45     }
  46
  47     if (memcmp(buf, "MAC ", 4) != 0)
  48     {
  49         return rc;
  50     }
  51
  52     read(fd, buf + 4, MAX_PATH - 4);
  53
  54     fileversion = get_short_le(buf+4);
  55     if (fileversion < 3970)
  56     {
  57         /* Not supported */
  58         return false;
  59     }
  60
  61     if (fileversion >= 3980)
  62     {
  63         descriptorlength = get_long_le(buf+8);
  64
  65         header = buf + descriptorlength;
  66
  67         blocksperframe = get_long_le(header+4);
  68         finalframeblocks = get_long_le(header+8);
  69         totalframes = get_long_le(header+12);
  70         id3->frequency = get_long_le(header+20);
  71     }
  72     else
  73     {
  74         /* v3.95 and later files all have a fixed framesize */
  75         blocksperframe = 73728 * 4;
  76
  77         finalframeblocks = get_long_le(buf+28);
  78         totalframes = get_long_le(buf+24);
  79         id3->frequency = get_long_le(buf+12);
  80     }
  81
  82     id3->vbr = true;   /* All APE files are VBR */
  83     id3->filesize = filesize(fd);
  84
  85     totalsamples = finalframeblocks;
  86     if (totalframes > 1)
  87         totalsamples += blocksperframe * (totalframes-1);
  88
  89     id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
  90     id3->bitrate = (id3->filesize * 8) / id3->length;
  91     return true;
  92 }