fpc/packages/cdrom/README.txt
Jonas Maebe 4bf254bc32 * added .txt extensions to all README, TODO and COPYING files
(mantis #12358)

git-svn-id: trunk@12825 -
2009-02-28 17:34:08 +00:00

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This directory contains some CD-ROM support routines for Free Pascal.
The routines are demonstrated by the 'getdiscid' and 'showcds' programs.
The latter shows the available CD-rom drives on the system, the former
calculates a disc-id and query for use with a freecddb server.
Unit cdrom
----------
The unit 'cdrom' implements a cross-platform interface for handling CD-roms.
Currently, it is implemented for Linux and Windows only.
The other units are support units, needed by various implementations.
The unit presents 2 calls:
Type
TTocEntry = Record
min, sec, frame : Integer
end;
PTocEntry = ^TTocEntry;
Function GetCDRomDevices(Var Devices : Array of string) : Integer;
Function ReadCDTOC(Device : String; Var CDTOC : Array of TTocEntry) : Integer;
The GetCDRomDevices call retrieves a list of available CD-ROM devices/drives
on the system. The algorithm used to detect these devices depends on the
system. The function returns the number of devices found, or a negative
number on error. The 'Devices' array is filled with strings that describe
the devices. For unix like systems, these are the device files (/dev/hdc
etc), for windows, these can be drive letters (D: etc) or ASPI Adaptor,
Target, lun IDs triples, for example ASPI[1;0;0].
(an algorithm mapping these to drive letters would be appreciated)
The ReadCDTOC call retrieves the table of contents of a CD in the CD-rom
drive (Device) This returns the number of tracks on the CD-ROM. On return,
The CDTOC array will be filled with the length of the tracks, and the frame
number, manipulated to be usable in a disc ID calculation. There will be one
extra entry at the end of the array, describing the lead-out.
unit discid
-----------
The DISCID unit calculates a DISC-ID as needed by a freecddb server to
query for the contents of a disc.
Function CDDBDiscID(Const CDTOC : Array of TTocEntry; Count : Integer) : integer ;
The count is the number of tracks, the array should contain Count+1
elements, the last one being the lead out. The output of the ReadCDToc
function can be used as input for this function.
Function GetCDDBQueryString(Const Tracks : Array of TTocEntry; Count : Integer) : String;
This function returns a query string as expected by a freecddb server.
It consists of the disc id, number of tracks, and the frame fields of the
TCDToc records in the tracks array.
unit lincd
----------
Essentially translation of the linux/cdrom.h include file, plus 2 functions
Function IsCDDevice(Device : String) : Boolean;
Returns True if the device file is a cdrom.
Function DetectCd : String;
Detects the first cd in the system; it does this by checking a number of
well-known common device files; the first once for which IsCDDevice returns
True is returned. Note that this can take some time.
unit major
----------
Definitions of the major device numbers under linux. used by the lincd unit.
unit wincd
----------
Some CD-routines. Essentially the low-level counterpart of the cd-rom unit.
The unit tries to use the windows ASPI layer to detect cd-roms. If the layer
is not present, the common IOCTL or SPTI interfaces are used.
TCDAccessMethod = (camNone,camASPI,camSPTI,camIOCTL);
Determines which access method is used.
Records used in the low-level calls:
TTOCTrack = packed record
rsvd,
ADR,
trackNumber,
rsvd2 : Byte;
addr : Array[0..3] of byte;
end;
TTOC = packed Record
toclen : word;
firsttrack,
lastTrack : byte;
toctrack: Array[0..99] of TTocTrack;
end;
Const
AccessMethodNames : Array[TCDAccessMethod] of string
= ('None','ASPI','SPTI','IOCTL');
Function GetCDAccessMethod : TCDAccessMethod;
Returns the current CD-rom detection method.
Procedure SetCDAccessMethod (Value : TCDAccessMethod);
Sets the current CD-rom detection method.
Function ReadTOC(Device : String; Var TOC : TTOc) : Integer;
Reads the CD-Rom devices. Device is a drive letter, or if ASPI is used
a string of the form [Aid,TgID,LunID] (Adapter ID, Target ID, LUN id)
Function EnumCDDrives(Var Drives : Array of String) : Integer;
Returns the CD-ROM drive letters of the system, or strings describing ASPI
drives.
Function GetNumDrives : Integer;
Returns the number of drives.
NOTE: A function mapping an ASPI triple to a drive letter would be
appreciated.
unit Wnaspi32:
--------------
Low-level ASPI unit. Contains all structures, plus the following:
TSendASPI32Command = function( LPSRB : Pointer ) : DWORD; cdecl;
TGetASPI32SupportInfo = function : DWORD; cdecl;
SendASPI32Command : TSendASPI32Command = nil;
GetASPI32SupportInfo : TGetASPI32SupportInfo = nil;
These procedural variables map to the actual API calls. They are only valid
and usable if ASPILoaded returns TRUE.
Function ASPILoaded : Boolean;
Returns TRUE if ASPI is available and loaded.
Procedure CheckASPI;
Checks whether ASPI is available. After calling this it is possible to use
the ASPIAvailable function. This procedure is called in the initialization
section of the unit.
procedure UnloadASPI;
Unloads the ASPI library if it was loaded. This procedure is called in the
finalization section of the unit.
scsidefs.pp
-----------
Bare translation of the scsidefs.h windows SDK header.
cdromioctl.pp
-------------
This unit contains some records and constants defined in window's
cdromioctl.h
Michael.