Visualizza wikitesto di Conoscere il numero delle tracce ed i numeri dei settori logici di un CD con le funzioni del API di libcdio

La libreria '''''Libcdio''''' consente di gestire i CD ed i relativi driver presenti nel sistema.

Per utilizzare le funzioni esterne del API di ''libcdio'' sarà necessario richiamare l'attuale libreria: "''libcdio.so.17.0.0''".


Mostriamo di seguito un semplice codice che consentirà di conoscere il numero delle tracce ed i numeri dei settori logici di un CD.
 Library "libcdio:17.0.0"
 
 Private Enum DRIVER_UNKNOWN = 0, DRIVER_AIX, DRIVER_FREEBSD, DRIVER_NETBSD, DRIVER_LINUX, DRIVER_SOLARIS,
              DRIVER_OSX, DRIVER_WIN32, DRIVER_CDRDAO, DRIVER_BINCUE, DRIVER_NRG, DRIVER_DEVICE
 Private Const CDIO_INVALID_LSN As Integer = -45301
 Private Const CDIO_CDROM_LEADOUT_TRACK As Integer = &AA
 
 <FONT color=gray>' ''CdIo_t * cdio_open (const char *psz_source, driver_id_t driver_id)''
 ' ''Sets up to read from place specified by psz_source and driver_id.''</font>
 Private Extern cdio_open(psz_source As String, driver_id As Integer) As Pointer
 
 <FONT color=gray>' ''track_t cdio_get_num_tracks(const CdIo_t * p_cdio)''
 ' ''Get the number of tracks on the CD.''</font>
 Private Extern cdio_get_num_tracks(cdioP As Pointer) As Byte
 
 <FONT color=gray>' ''track_t cdio_get_first_track_num(const CdIo_t * p_cdio)''
 ' ''Get the number of the first track.''</font>
 Private Extern cdio_get_first_track_num(cdioP As Pointer) As Byte
 
 <FONT color=gray>' ''lsn_t cdio_get_track_lsn(const CdIo_t * p_cdio, track_t u_track)''
 ' ''Return the starting LSN for track number i_track in p_cdio.''</font>
 Private Extern cdio_get_track_lsn(cdioP As Pointer, u_track As Integer) As Integer
 
 <FONT color=gray>' ''void cdio_destroy(CdIo_t * p_cdio)''
 ' ''Free any resources associated with p_cdio.''</font>
 Private Extern cdio_destroy(cdioP As Pointer)
  
 
 '''Public''' Sub Main()
 
  Dim p_cdio As Pointer
  Dim tracce, prima_traccia As Byte
  Dim i, j, lsn As Integer
  
   p_cdio = cdio_open(Null, DRIVER_LINUX)
   If p_cdio = 0 Then Error.Raise("Impossibile trovare il driver per il cd-rom !")
    
   tracce = cdio_get_num_tracks(p_cdio)
   i = CInt(cdio_get_first_track_num(p_cdio))
   prima_traccia = i
   Print "Tracce del CD-ROM ("; prima_traccia; " - "; prima_traccia + tracce - 1; ")"
   Print " #:  LSN"
   For j = 0 To tracce - 1
     lsn = cdio_get_track_lsn(p_cdio, i)
     If (CDIO_INVALID_LSN <> lsn) Then Print Format(i, "#0:"), Format(CLong(lsn), "000000")
     Inc i
   Next
   Print Hex(CDIO_CDROM_LEADOUT_TRACK, 2); ": "; CLong(cdio_get_track_lsn(p_cdio, CDIO_CDROM_LEADOUT_TRACK)); " leadout"
    
    
 <FONT color=gray>' ''Va in chiusura:''</font>
   cdio_destroy(p_cdio)
   
  '''End'''




=Riferimenti=
* http://www.gnu.org/software/libcdio/
* http://fossies.org/dox/libcdio-0.92/index.html