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  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <stdlib.h>
  24 #include <ctype.h>
  25 #include <inttypes.h>
  26
  27 #include "system.h"
  28 #include "metadata.h"
  29 #include "metadata_common.h"
  30 #include "metadata_parsers.h"
  31
  32 bool get_monkeys_metadata(int fd, struct mp3entry* id3)
  33 {
  34     /* Use the trackname part of the id3 structure as a temporary buffer */
  35     unsigned char* buf = (unsigned char *)id3->path;
  36     unsigned char* header;
  37     bool rc = false;
  38     uint32_t descriptorlength;
  39     uint32_t totalsamples;
  40     uint32_t blocksperframe, finalframeblocks, totalframes;
  41     int fileversion;
  42
  43     lseek(fd, 0, SEEK_SET);
  44
  45     if (read(fd, buf, 4) < 4)
  46     {
  47         return rc;
  48     }
  49
  50     if (memcmp(buf, "MAC ", 4) != 0)
  51     {
  52         return rc;
  53     }
  54
  55     read(fd, buf + 4, MAX_PATH - 4);
  56
  57     fileversion = get_short_le(buf+4);
  58     if (fileversion < 3970)
  59     {
  60         /* Not supported */
  61         return false;
  62     }
  63
  64     if (fileversion >= 3980)
  65     {
  66         descriptorlength = get_long_le(buf+8);
  67
  68         header = buf + descriptorlength;
  69
  70         blocksperframe = get_long_le(header+4);
  71         finalframeblocks = get_long_le(header+8);
  72         totalframes = get_long_le(header+12);
  73         id3->frequency = get_long_le(header+20);
  74     }
  75     else
  76     {
  77         /* v3.95 and later files all have a fixed framesize */
  78         blocksperframe = 73728 * 4;
  79
  80         finalframeblocks = get_long_le(buf+28);
  81         totalframes = get_long_le(buf+24);
  82         id3->frequency = get_long_le(buf+12);
  83     }
  84
  85     id3->vbr = true;   /* All APE files are VBR */
  86     id3->filesize = filesize(fd);
  87
  88     totalsamples = finalframeblocks;
  89     if (totalframes > 1)
  90         totalsamples += blocksperframe * (totalframes-1);
  91
  92     id3->length = ((int64_t) totalsamples * 1000) / id3->frequency;
  93     id3->bitrate = (id3->filesize * 8) / id3->length;
  94     return true;
  95 }