File indexing completed on 2024-04-14 04:49:17

 /*
  * This file is part of WorkMan, the civilized CD player library
  * Copyright (C) 1991-1997 by Steven Grimm (original author)
  * Copyright (C) by Dirk Försterling <milliByte@DeathsDoor.com>
  * Copyright (C) 2004-2006 Alexander Kern <alex.kern@gmx.de>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the Free
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  *
  *
  * establish connection to cddb server and get data
  * socket stuff gotten from gnu port of the finger command
  *
  * provided by Sven Oliver Moll
  *
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <strings.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/signal.h>
 #include <ctype.h>
 #include <sys/time.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netdb.h>
 
 #include "include/wm_config.h"
 #include "include/wm_struct.h"
 #include "include/wm_helpers.h"
 #include "include/wm_cddb.h"
 #include "include/wm_cdrom.h"
 
 /*
  * Subroutine from cddb_discid
  */
 static int cddb_sum(int n)
 {
     char    buf[12],
         *p;
     int ret = 0;
 
     /* For backward compatibility this algorithm must not change */
     sprintf(buf, "%lu", (unsigned long)n);
     for (p = buf; *p != '\0'; p++)
       ret += (*p - '0');
 
     return (ret);
 } /* cddb_sum() */
 
 
 /*
  * Calculate the discid of a CD according to cddb
  */
 unsigned long cddb_discid(struct wm_drive *pdrive)
 {
     int i,
         t,
         n = 0, tracks;
 
     tracks = wm_cd_getcountoftracks(pdrive);
     if(!tracks)
         return (unsigned)-1;
 
     /* For backward compatibility this algorithm must not change */
     for (i = 0; i < tracks; i++) {
 
         n += cddb_sum(wm_cd_gettrackstart(pdrive, i + 1));
     /*
      * Just for demonstration (See below)
      *
      *  t += (wm_cd_getref()->trk[i+1].start / 75) -
      *       (wm_cd_getref()->trk[i  ].start / 75);
      */
     }
 
     /*
      * Mathematics can be fun. Example: How to reduce a full loop to
      * a simple statement. The discid algorhythm is so half-hearted
      * developed that it doesn't even use the full 32bit range.
      * But it seems to be always this way: The bad standards will be
      * accepted, the good ones turned down.
          * Boy, you pulled out the /75. This is not correct here, because
          * this calculation needs the integer division for both .start
          * fields.
          */
 
         t = (wm_cd_gettrackstart(pdrive, tracks + 1)) - (wm_cd_gettrackstart(pdrive, 1));
     return ((n % 0xff) << 24 | t << 8 | tracks);
 } /* cddb_discid() */