src/add-ons/kernel/file_systems/cdda/cddb.cpp

   1 /*
   2  * Copyright 2007, Axel Dörfler, axeld@pinc-software.de.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6
   7 #include "cddb.h"
   8
   9
  10 static int32
  11 cddb_sum(int32 n)
  12 {
  13         int32 result = 0;
  14
  15         while (n > 0) {
  16                 result = result + (n % 10);
  17                 n = n / 10;
  18         }
  19
  20         return result;
  21 }
  22
  23
  24 //      #pragma mark - exported functions
  25
  26
  27 /*!
  28         Computes the CD Disc ID as specified in the FreeDB how-to (code taken from there).
  29 */
  30 uint32
  31 compute_cddb_disc_id(scsi_toc_toc &toc)
  32 {
  33         int32 numTracks = toc.last_track + 1 - toc.first_track;
  34         uint32 n = 0;
  35
  36         for (int32 i = 0; i < numTracks; i++) {
  37                 n = n + cddb_sum((toc.tracks[i].start.time.minute * 60)
  38                         + toc.tracks[i].start.time.second);
  39         }
  40
  41         int32 t = ((toc.tracks[numTracks].start.time.minute * 60)
  42                         + toc.tracks[numTracks].start.time.second)
  43                 - ((toc.tracks[0].start.time.minute * 60)
  44                         + toc.tracks[0].start.time.second);
  45
  46         return (n % 0xff) << 24 | t << 8 | numTracks;
  47 }