package org.jscsi.target.scsi.inquiry;

 import java.nio.ByteBuffer;

 import org.jscsi.target.scsi.IResponseData;

 import org.jscsi.target.scsi.cdb.ScsiOperationCode;

 /**

  * The standard inquiry data, sent as a response to an {@link ScsiOperationCode#INQUIRY} command.

  * <p>

  * This class uses the singleton pattern since the returned standard inquiry data will always be the same.

  * <p>

  * Not all fields in the serialized form of the singleton have a corresponding member variable, only those fields

  * containing ASCII information.

  * 

  * @author Andreas Ergenzinger

  */

 public final class StandardInquiryData implements IResponseData {

     /**

      * The total length of the serialized Standard Inquiry Data.

      */

     private static final int SIZE = 36;

     private static final String VENDOR_ID = "disyUKon";

     private static final int VENDOR_ID_FIELD_POSITION = 8;

     private static final int VENDOR_ID_FIELD_LENGTH = 8;

     private static final String PRODUCT_ID = "jSCSI Target";

     private static final int PRODUCT_ID_FIELD_POSITION = 16;

     private static final int PRODUCT_ID_FIELD_LENGTH = 16;

     private static final String PRODUCT_REVISION_LEVEL = "1.00";

     private static final int PRODUCT_REVISION_LEVEL_FIELD_POSITION = 32;

     private static final int PRODUCT_REVISION_LEVEL_FIELD_LENGTH = 4;

     /**

      * The singleton.

      */

     private static StandardInquiryData instance;

     private StandardInquiryData () {

         // singleton pattern

     }

     /**

      * Returns the one and only {@link StandardInquiryData} object.

      * 

      * @return the one and only {@link StandardInquiryData} object

      */

     public static StandardInquiryData getInstance () {

         if (instance == null) instance = new StandardInquiryData();

         return instance;

     }

     public void serialize (ByteBuffer byteBuffer, int index) {

         // *** byte 0 ****

         /*

          * Peripheral qualifier (3 most significant bits of byte 0): 000b A peripheral device having the specified

          * peripheral device type is connected to this logical unit. If the device server is unable to determine whether

          * or not a peripheral device is connected, it also shall use this peripheral qualifier. This peripheral

          * qualifier does not mean that the peripheral device connected to the logical unit is ready for access.

          * Peripheral Device Type (5 least significant bits of byte 0): 00000b direct access block device Therefore no

          * need to change anything.

          */

         byteBuffer.position(index);

         byteBuffer.put((byte) 0);

         // *** byte 1 ***

         /*

          * RMB bit (bit 7): 0 A removable medium (RMB) bit set to zero indicates that the medium is not removable.

          * (remaining bits are RESERVED)

          */

         byteBuffer.put((byte) 0);

         // *** byte 2 ***

         /*

          * version: 0x05 The device complies to the SPC3 and respective ANSI standard

          */

         byteBuffer.put((byte) 0x05);

         // *** byte 3 - flags ***

         /*

          * (bits 7 and 6 are obsolete) NORMACA (bit 5): 0 A NORMACA (normal auto contingency allegiance) bit set to zero

          * indicates that the device server does not support a NACA bit set to one and does not support the ACA task

          * attribute. HISUP (bit 4): 0 A hierarchical support (HISUP) bit set to zero indicates the SCSI target device

          * does not use the hierarchical addressing model to assign LUNs to logical units. RESPONSE DATA FORMAT (bits

          * 3-0): 0010b RESPONSE DATA FORMAT: SPC3

          */

         byteBuffer.put((byte) 2);// 0000 0010b

         // *** byte 4 ***

         /*

          * n - 4 = 35 - 4 = 31 The ADDITIONAL LENGTH field indicates the length in bytes of the remaining standard

          * INQUIRY data.

          */

         byteBuffer.put((byte) 31);

         // *** byte 5 ***

         /*

          * SSCS (bit 7): 0 An SCC Supported bit set to zero indicates that the SCSI target device does not contain an

          * embedded storage array controller component. ACC (bit 6): 0 An ACC bit set to zero indicates that no access

          * controls coordinator may be addressed through this logical unit. TGPS field (bits 5 and 4): 00b The contents

          * of the target port group support (TPGS) indicate the support for asymmetric logical unit access. The SCSI

          * target device does not support asymmetric logical unit access or supports a form of asymmetric access that is

          * vendor specific. Neither the REPORT TARGET GROUPS nor the SET TARGET GROUPS commands is supported. 3PC (bit

          * 3): 0 A Third-Party Copy (3PC) bit set to zero indicates that the SCSI target device does not support

          * third-party copy commands such as the EXTENDED COPY command. (bits 2 and 1 are RESERVED) PROTECT (bit 0): 0 A

          * PROTECT bit set to zero indicates that the logical unit does not support protection information.

          */

         byteBuffer.put((byte) 0);

         // *** byte 6 ***

         /*

          * BQUE (bit 7): The CMDQUE bit and BQUE bit indicate whether the logical unit supports the full task management

          * model. 1 (and 0) Basic task management model supported. ENCSERV (bit 6): 0 An ENCSERV bit set to zero

          * indicates that the SCSI target device does not contain an embedded enclosure services component. (bit 5 is

          * VENDOR SPECIFIC i.e. 0) MULTIP (bit 4): 0 A Multi Port (MULTIP) bit set to zero indicates that this is not a

          * multi- port (two or more ports) SCSI target device and therefore does not conform to the SCSI multi-port

          * device requirements found in the applicable standards (e.g., SAM-3, a SCSI transport protocol standard and

          * possibly provisions of a command standard). MCHNGR (bit 3): 0 The MCHNGR bit is valid only when the RMB bit

          * is equal to one. A MCHNGR bit set to zero indicates that the SCSI target device does not support commands to

          * control an attached media changer. (bits 2 and 1 are RESERVED) ADDR16 (bit 0): 0 RESERVED since the SCSI

          * Parallel Interface transport protocol is not used.

          */

         byteBuffer.put((byte) 128);// 1000 0000b

         // *** byte 7 ***

         /*

          * (bits 7, 6, and 2 are OBSOLETE, bit 0 is VENDOR SPECIFIC) WBUS and SYNC (bits 5 and 4): 00b RESERVED since

          * the SCSI Parallel Interface transport protocol is not used. LINKED (bit 3): 0 A LINKED bit set to zero

          * indicates the device server does not support linked commands. CMDQUE (bit 1): 0 The CMDQUE bit and BQUE bit

          * indicate whether the logical unit supports the full task management model. (see BQUE ,byte 6)

          */

         byteBuffer.put((byte) 0);

         // *** bytes 8 to 15 ***

         /*

          * T10 VENDOR IDENTIFICATION: The T10 VENDOR IDENTIFICATION field contains eight bytes of left-aligned ASCII

          * data identifying the vendor of the product. The T10 vendor identification shall be one assigned by INCITS,

          * but obviously that is not the case here. disyUKon

          */

         putString(byteBuffer, VENDOR_ID, index + VENDOR_ID_FIELD_POSITION, VENDOR_ID_FIELD_LENGTH);

         // *** bytes 16 to 31

         /*

          * PRODUCT IDENTIFICATION: The PRODUCT IDENTIFICATION field contains sixteen bytes of left-aligned ASCII data

          * defined by the vendor.

          */

         putString(byteBuffer, PRODUCT_ID, index + PRODUCT_ID_FIELD_POSITION, PRODUCT_ID_FIELD_LENGTH);

         // *** bytes 32 to 35 ***

         /*

          * PRODUCT REVISION LEVEL: The PRODUCT REVISION LEVEL field contains four bytes of left-aligned ASCII data

          * defined by the vendor.

          */

         putString(byteBuffer, PRODUCT_REVISION_LEVEL, index + PRODUCT_REVISION_LEVEL_FIELD_POSITION, PRODUCT_REVISION_LEVEL_FIELD_LENGTH);

     }

     /**

      * Puts up to <i>fieldLength</i> of the passed {@link String} into a {@link ByteBuffer} and fills the remaining

      * bytes with zeros.

      * 

      * @param byteBuffer where the {@link String}'s characters will be copied

      * @param string contains the characters to copy

      * @param position where the first character of the {@link String} will be put

      * @param fieldLength the number of bytes in the {@link ByteBuffer} that will be overwritten

      */

     private void putString (final ByteBuffer byteBuffer, final String string, final int position, final int fieldLength) {

         // set position

         byteBuffer.position(position);

         // put string characters

         final int stringLength = Math.min(string.length(), fieldLength);

         for (int i = 0; i < stringLength; ++i)

             byteBuffer.put((byte) string.charAt(i));

         // clear remaining remaining bytes

         for (int i = stringLength; i < fieldLength; ++i)

             byteBuffer.put((byte) 0);

     }

     public int size () {

         return SIZE;

     }

 }