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CD_TOCLSN -- Return table of contents information from CD (LSN form).
IO REQUEST
io_Device preset by the call to OpenDevice()
io_Unit preset by the call to OpenDevice()
io_Command CD_TOCLSN
io_Data pointer to array where TOC is to be stored
io_Length number of CDTOC entries to be fetched
io_Offset entry to begin at (entry 0 is summary information)
io_Error 0 for success, or an error code as defined in
<devices/cd.h>
io_Actual Actual number of entries copied
This command returns the table of contents of the disk currently in
the drive. The table of contents consists of up to 100 entries.
Entry zero is summary information describing the number of tracks
and the total number of minutes on the disk. Entries 1 through N
contain information about each individual track. All position
information will be in LSN format.
The io_Data field points to an array of CDTOC structures to receive
the TOC data.
The io_Length field specifies the total number of entries to be
fetched. The array pointed to by io_Data must be at least this many
elements in size.
The io_Offset field specifies the entry number at which to start
copying TOC data into *io_Data.
Entry zero (the summary entry) contains the following:
struct TOCSummary {
UBYTE FirstTrack; /* First track on disk (always 1) */
UBYTE LastTrack; /* Last track on disk */
union LSNMSF LeadOut; /* Beginning of lead-out track */
};
Track entries (entries 1 through number of tracks) contain:
struct TOCEntry {
UBYTE CtlAdr; /* Q-Code info */
UBYTE Track; /* Track number */
union LSNMSF Position; /* Start position of this track */
};
CDTOC is described as a union between these two structures:
union CDTOC {
struct TOCSummary Summary; /* First entry is summary info. */
struct TOCEntry Entry; /* Entries 1-N are track entries */
};
union CDTOC tocarray[100];
ior->io_Command = CD_TOCLSN; /* Retrieve TOC information */
ior->io_Offset = 0; /* Start with summary info */
ior->io_Length = 100; /* Max 99 tracks + summary */
ior->io_Data = (APTR)tocarray; /* Here's where we want it */
DoIO (ior);
if (!ior->io_Error) { /* Command succeeded */
firsttrack = tocarray[0].Summary.FirstTrack;
lasttrack = tocarray[0].Summary.LastTrack;
totalsectors = tocarray[0].Summary.LeadOut.LSN -
tocarray[1].Entry.Position.LSN;
}
In the above example, the amount of data on the disk is calculated as
being equal to the location of the lead-out track minus the start of
the first track (which is never zero).
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