#define IOCTL_CHANGER_BASE                FILE_DEVICE_CHANGER

#define IOCTL_CHANGER_GET_PARAMETERS         CTL_CODE(IOCTL_CHANGER_BASE, 0x0000, METHOD_BUFFERED, FILE_READ_ACCESS)
#define IOCTL_CHANGER_GET_STATUS             CTL_CODE(IOCTL_CHANGER_BASE, 0x0001, METHOD_BUFFERED, FILE_READ_ACCESS)
#define IOCTL_CHANGER_GET_PRODUCT_DATA       CTL_CODE(IOCTL_CHANGER_BASE, 0x0002, METHOD_BUFFERED, FILE_READ_ACCESS)
#define IOCTL_CHANGER_SET_ACCESS             CTL_CODE(IOCTL_CHANGER_BASE, 0x0004, METHOD_BUFFERED, FILE_READ_ACCESS | FILE_WRITE_ACCESS)
#define IOCTL_CHANGER_GET_ELEMENT_STATUS     CTL_CODE(IOCTL_CHANGER_BASE, 0x0005, METHOD_BUFFERED, FILE_READ_ACCESS | FILE_WRITE_ACCESS)
#define IOCTL_CHANGER_INITIALIZE_ELEMENT_STATUS  CTL_CODE(IOCTL_CHANGER_BASE, 0x0006, METHOD_BUFFERED, FILE_READ_ACCESS)
#define IOCTL_CHANGER_SET_POSITION           CTL_CODE(IOCTL_CHANGER_BASE, 0x0007, METHOD_BUFFERED, FILE_READ_ACCESS)
#define IOCTL_CHANGER_EXCHANGE_MEDIUM        CTL_CODE(IOCTL_CHANGER_BASE, 0x0008, METHOD_BUFFERED, FILE_READ_ACCESS)
#define IOCTL_CHANGER_MOVE_MEDIUM            CTL_CODE(IOCTL_CHANGER_BASE, 0x0009, METHOD_BUFFERED, FILE_READ_ACCESS)
#define IOCTL_CHANGER_REINITIALIZE_TRANSPORT CTL_CODE(IOCTL_CHANGER_BASE, 0x000A, METHOD_BUFFERED, FILE_READ_ACCESS)
#define IOCTL_CHANGER_QUERY_VOLUME_TAGS      CTL_CODE(IOCTL_CHANGER_BASE, 0x000B, METHOD_BUFFERED, FILE_READ_ACCESS | FILE_WRITE_ACCESS)

//
// TBD - IOCTL_CHANGER_GET_ENVIRONMENTAL_DATA
// TBD - IOCTL_CHANGER_GET_STATISTICS
// TBD - IOCTL_CHANGER_WRITE_FIRMWARE
//



#define MAX_VOLUME_ID_SIZE       36
#define MAX_VOLUME_TEMPLATE_SIZE 40

#define VENDOR_ID_LENGTH          8
#define PRODUCT_ID_LENGTH        16
#define REVISION_LENGTH           4
#define SERIAL_NUMBER_LENGTH     32

//
// Common structures describing elements.
//

typedef  enum _ELEMENT_TYPE {
    AllElements,        // As defined by SCSI
    ChangerTransport,   // As defined by SCSI
    ChangerSlot,        // As defined by SCSI
    ChangerIEPort,      // As defined by SCSI
    ChangerDrive,       // As defined by SCSI
    ChangerDoor,        // Front panel, used to access internal of cabinet.
    ChangerKeypad,      // Keypad/input on front panel.
    ChangerMaxElement   // Placeholder only. Not a valid type.
} ELEMENT_TYPE, *PELEMENT_TYPE;

typedef  struct _CHANGER_ELEMENT {
    ELEMENT_TYPE    ElementType;
    DWORD   ElementAddress;
} CHANGER_ELEMENT, *PCHANGER_ELEMENT;

typedef  struct _CHANGER_ELEMENT_LIST {
    CHANGER_ELEMENT Element;
    DWORD   NumberOfElements;
} CHANGER_ELEMENT_LIST , *PCHANGER_ELEMENT_LIST;


//
// Definitions for  IOCTL_CHANGER_GET_PARAMETERS
//

//
// Definitions for Features0 of GET_CHANGER_PARAMETERS
//

#define CHANGER_BAR_CODE_SCANNER_INSTALLED  0x00000001 // The medium-changer has a bar code scanner installed.
#define CHANGER_INIT_ELEM_STAT_WITH_RANGE   0x00000002 // The medium-changer has the ability to initialize elements within a specified range.
#define CHANGER_CLOSE_IEPORT                0x00000004 // The medium-changer has the ability to close the i/e port door.
#define CHANGER_OPEN_IEPORT                 0x00000008 // The medium-changer can open the i/e port door.

#define CHANGER_STATUS_NON_VOLATILE         0x00000010 // The medium-changer uses non-volatile memory for element status information.
#define CHANGER_EXCHANGE_MEDIA              0x00000020 // The medium-changer supports exchange operations.
#define CHANGER_CLEANER_SLOT                0x00000040 // The medium-changer has a fixed slot designated for cleaner cartridges.
#define CHANGER_LOCK_UNLOCK                 0x00000080 // The medium-changer can be (un)secured to (allow)prevent media removal.

#define CHANGER_CARTRIDGE_MAGAZINE          0x00000100 // The medium-changer uses cartridge magazines for some storage slots.
#define CHANGER_MEDIUM_FLIP                 0x00000200 // The medium-changer can flip medium.
#define CHANGER_POSITION_TO_ELEMENT         0x00000400 // The medium-changer can position the transport to a particular element.
#define CHANGER_REPORT_IEPORT_STATE         0x00000800 // The medium-changer can determine whether media is present
                                                       // in the IE Port.

#define CHANGER_STORAGE_DRIVE               0x00001000 // The medium-changer can use a drive as an independent storage element.
#define CHANGER_STORAGE_IEPORT              0x00002000 // The medium-changer can use a i/e port as an independent storage element.
#define CHANGER_STORAGE_SLOT                0x00004000 // The medium-changer can use a slot as an independent storage element.
#define CHANGER_STORAGE_TRANSPORT           0x00008000 // The medium-changer can use a transport as an independent storage element.

#define CHANGER_DRIVE_CLEANING_REQUIRED     0x00010000 // The drives controlled by the medium changer require periodic cleaning
                                                       // initiated by an application.
#define CHANGER_PREDISMOUNT_EJECT_REQUIRED  0x00020000 // The medium-changer requires a drive eject command to be issued, before a changer
                                                       // move / exchange command can be issued to the drive.
#define CHANGER_CLEANER_EJECT_REQUIRED      0x00040000 // The medium-changer requires a drive eject command to be issued, before a changer
                                                       // move / exchange command can be issued to a cleaner cartridge.
#define CHANGER_PREMOUNT_EJECT_REQUIRED     0x00080000 // The medium-changer requires a drive eject command to be issued
                                                       // before a move / exchange command can be issued with the drive as src/dst.

#define CHANGER_VOLUME_IDENTIFICATION       0x00100000 // The medium-changer supports volume identification.
#define CHANGER_VOLUME_SEARCH               0x00200000 // The medium-changer can search for volume information.
#define CHANGER_VOLUME_ASSERT               0x00400000 // The medium-changer can verify volume information.
#define CHANGER_VOLUME_REPLACE              0x00800000 // The medium-changer can replace volume information.
#define CHANGER_VOLUME_UNDEFINE             0x01000000 // The medium-changer can undefine volume information.

#define CHANGER_SERIAL_NUMBER_VALID         0x04000000 // The serial number reported in GetProductData is valid
                                                       // and unique.

#define CHANGER_DEVICE_REINITIALIZE_CAPABLE 0x08000000 // The medium-changer must be issued a ChangerReinitializeUnit for operations.
#define CHANGER_KEYPAD_ENABLE_DISABLE       0x10000000 // Indicates that the keypad can be enabled/disabled.
#define CHANGER_DRIVE_EMPTY_ON_DOOR_ACCESS  0x20000000 // Drives must be empty before access via the door is possible.
#define CHANGER_PREDISMOUNT_ALIGN_DRIVE_TO_SLOT 0x40000000 // The drive and slot must be prepositioned prior to ejecting the media and preforming
                                                           // the move medium.
#define CHANGER_CLEANER_AUTODISMOUNT        0x80000000 // The device will move the cleaner cartridge back into the slot when cleaning has completed.

//
// Definitions for MoveFrom and ExchangeFrom
//

#define CHANGER_TO_TRANSPORT    0x01 // The device can carry out the operation to a transport from the specified element.
#define CHANGER_TO_SLOT         0x02 // The device can carry out the operation to a slot from the specified element.
#define CHANGER_TO_IEPORT       0x04 // The device can carry out the operation to an IE Port from the specified element.
#define CHANGER_TO_DRIVE        0x08 // The device can carry out the operation to a drive from the specified element.


typedef  struct _GET_CHANGER_PARAMETERS {

    //
    // Size of the structure. Can be used for versioning.
    //

    DWORD Size;

    //
    // Number of N element(s) as defined by the Element Address Page (or equivalent...).
    //

    WORD   NumberTransportElements;
    WORD   NumberStorageElements;                // for data cartridges only
    WORD   NumberCleanerSlots;                   // for cleaner cartridges
    WORD   NumberIEElements;
    WORD   NumberDataTransferElements;

    //
    // Number of doors/front panels (allows user entry into the cabinet).
    //

    WORD   NumberOfDoors;

    //
    // The device-specific address (from user manual of the device) of the first N element. Used
    // by the UI to relate the various elements to the user.
    //

    WORD   FirstSlotNumber;
    WORD   FirstDriveNumber;
    WORD   FirstTransportNumber;
    WORD   FirstIEPortNumber;
    WORD   FirstCleanerSlotAddress;

    //
    // Indicates the capacity of each magazine, if they exist.
    //

    WORD   MagazineSize;

    //
    // Specifies the approximate number of seconds for when a cleaning should be completed.
    // Only applicable if drive cleaning is supported. See Features0.
    //

    DWORD DriveCleanTimeout;

    //
    // See features bits, above.
    //

    DWORD Features0;
    DWORD Reserved;

    //
    // Bitmask defining Move from N element to element. Defined by Device Capabilities Page (or equivalent).
    // AND-masking with the TO_XXX values will indicate legal destinations.
    //

    BYTE  MoveFromTransport;
    BYTE  MoveFromSlot;
    BYTE  MoveFromIePort;
    BYTE  MoveFromDrive;

    //
    // Bitmask defining Exchange from N element to element. Defined by Device Capabilities Page (or equivalent).
    // AND-masking with the TO_XXX values will indicate legal destinations.
    //

    BYTE  ExchangeFromTransport;
    BYTE  ExchangeFromSlot;
    BYTE  ExchangeFromIePort;
    BYTE  ExchangeFromDrive;

} GET_CHANGER_PARAMETERS, * PGET_CHANGER_PARAMETERS;


//
// Definitions for IOCTL_CHANGER_GET_PRODUCT_DATA
//

typedef  struct _CHANGER_PRODUCT_DATA {

    //
    // Device manufacturer's name - based on inquiry data
    //

    BYTE  VendorId[VENDOR_ID_LENGTH];

    //
    // Product identification as defined by the vendor - based on Inquiry data
    //

    BYTE  ProductId[PRODUCT_ID_LENGTH];

    //
    // Product revision as defined by the vendor.
    //

    BYTE  Revision[REVISION_LENGTH];

    //
    // Vendor unique value used to globally identify this device. Can
    // be from Vital Product Data, for example.
    //

    BYTE  SerialNumber[SERIAL_NUMBER_LENGTH];

    //
    // Indicates device type of data transports, as defined by SCSI-2.
    //

    BYTE  DeviceType;

} CHANGER_PRODUCT_DATA, *PCHANGER_PRODUCT_DATA;


//
// Definitions for IOCTL_CHANGER_SET_ACCESS
//

#define LOCK_ELEMENT        0
#define UNLOCK_ELEMENT      1
#define EXTEND_IEPORT       2
#define RETRACT_IEPORT      3

typedef struct _CHANGER_SET_ACCESS {

    //
    // Element can be ChangerIEPort, ChangerDoor, ChangerKeypad
    //

    CHANGER_ELEMENT Element;

    //
    // See above for possible operations.
    //

    DWORD           Control;
} CHANGER_SET_ACCESS, *PCHANGER_SET_ACCESS;


//
// Definitions for IOCTL_CHANGER_GET_ELEMENT_STATUS
//

//
// Input buffer.
//

typedef struct _CHANGER_READ_ELEMENT_STATUS {

    //
    // List describing the elements and range on which to return information.
    //

    CHANGER_ELEMENT_LIST ElementList;

    //
    // Indicates whether volume tag information is to be returned.
    //

    BOOLEAN VolumeTagInfo;
} CHANGER_READ_ELEMENT_STATUS, *PCHANGER_READ_ELEMENT_STATUS;

//
// Output buffer.
//

typedef  struct _CHANGER_ELEMENT_STATUS {

    //
    // Element to which this structure refers.
    //

    CHANGER_ELEMENT Element;

    //
    // Address of the element from which the media was originally moved.
    // Valid if ELEMENT_STATUS_SVALID bit of Flags DWORD is set.
    // Needs to be converted to a zero-based offset from the device-unique value.
    //

    CHANGER_ELEMENT SrcElementAddress;

    //
    // See below.
    //

    DWORD Flags;

    //
    // See below for possible values.
    //

    DWORD ExceptionCode;

    //
    // Scsi Target Id of this element.
    // Valid only if ELEMENT_STATUS_ID_VALID is set in Flags.
    //

    BYTE  TargetId;

    //
    // LogicalUnitNumber of this element.
    // Valid only if ELEMENT_STATUS_LUN_VALID is set in Flags.
    //

    BYTE  Lun;
    WORD   Reserved;

    //
    // Primary volume identification for the media.