package org.jscsi.target.scsi.cdb;

 import java.nio.ByteBuffer;

 import org.jscsi.target.util.BitManip;

 import org.jscsi.target.util.ReadWrite;

 /**

  * This class represents Command Descriptor Blocks for the <code>SEND DIAGNOSTIC</code> SCSI command.

  * 

  * @author Andreas Ergenzinger

  */

 public final class SendDiagnosticCdb extends CommandDescriptorBlock {

     /**

      * If the {@link #selfTest} bit is set to one, the {@link #selfTestCode} field shall contain 000b (

      * {@link SelfTestCode#ALL_ZEROS}. If the SELFTEST bit is set to zero, the contents of SELF-TEST CODE specifies

      * which diagnostic operation the device server shall perform.

      * 

      * @see SelfTestCode

      */

     private final SelfTestCode selfTestCode;

     /**

      * A self-test (SELFTEST) bit set to one specifies that the device server shall perform the logical unit default

      * self-test.

      * <p>

      * A SELFTEST bit set to zero specifies that the device server shall perform the diagnostic operation specified by

      * the {@link #selfTestCode} field or in the parameter list.

      * <p>

      * Only support for the default self-test feature, as required by SPC-3, is implemented. Request for other types of

      * self-test operations will be declined.

      */

     private final boolean selfTest;

     /**

      * A page format (PF) bit set to one specifies that the SEND DIAGNOSTIC parameters and any parameters returned by a

      * following RECEIVE DIAGNOSTIC RESULTS command with the PCV bit set to zero shall contain a single diagnostic page.

      * <p>

      * A PF bit set to zero specifies that all SEND DIAGNOSTIC parameters are vendor specific. If the PARAMETER LIST

      * LENGTH field is set to zero and the SEND DIAGNOSTIC command is not going to be followed by a corresponding

      * RECEIVE DIAGNOSTIC RESULTS command with the PCV bit set to zero, then the application client shall set the PF bit

      * to zero.

      * <p>

      * The implementation of the PF bit is optional and therefore not supported by the jSCSI Target.

      */

     private final boolean pageFormat;

     /**

      * A unit offline (UNITOFFL) bit set to one specifies that the device server may perform diagnostic operations that

      * may affect the user accessible medium on the logical unit (e.g., write operations to the user accessible medium,

      * or repositioning of the medium on sequential access devices). The device server may ignore the UNITOFFL bit. A

      * UNITOFFL bit set to zero prohibits any diagnostic operations that may be detected by subsequent tasks. When the

      * {@link #selfTest} bit is set to zero, the UNITOFFL bit shall be ignored.

      */

     private final boolean unitOffline;

     /**

      * A SCSI target device offline (DEVOFFL) bit set to one grants permission to the device server to perform

      * diagnostic operations that may affect all the logical units in the SCSI target device (e.g., alteration of

      * reservations, log parameters, or sense data). The device server may ignore the DEVOFFL bit. A DEVOFFL bit set to

      * zero prohibits diagnostic operations that may be detected by subsequent tasks. When the {@link #selfTest} bit is

      * set to zero, the DEVOFFL bit shall be ignored.

      */

     private final boolean deviceOffline;

     /**

      * The PARAMETER LIST LENGTH field specifies the length in bytes of the parameter list that shall be transferred

      * from the application client Data-Out Buffer to the device server. A parameter list length of zero specifies that

      * no data shall be transferred. This condition shall not be considered an error. If PF bit is set to one and the

      * specified parameter list length results in the truncation of the diagnostic page (e.g., the parameter list length

      * does not match the page length specified in the diagnostic page), then the command shall be terminated with CHECK

      * CONDITION status, with the sense key set to ILLEGAL REQUEST, and the additional sense code set to INVALID FIELD

      * IN CDB.

      */

     private final short parameterListLength;

     public SendDiagnosticCdb (ByteBuffer buffer) {

         super(buffer);

         // deserialize specific fields

         final byte b = buffer.get(1);

         // self test

         selfTest = BitManip.getBit(b, 2);

         if (!selfTest) addIllegalFieldPointer(1, 2);// only the default self-test feature

                                                     // is supported

         // self test code

         selfTestCode = SelfTestCode.getValue(b >>> 5);

         if (selfTest && selfTestCode != SelfTestCode.ALL_ZEROS) addIllegalFieldPointer(1, 7);

         // page format

         pageFormat = BitManip.getBit(b, 4);

         if (pageFormat) addIllegalFieldPointer(1, 4);// The implementation of the PF bit is

                                                      // optional.

         // device offline

         deviceOffline = BitManip.getBit(b, 1);

         // unit offline

         unitOffline = BitManip.getBit(b, 0);

         // parameter list length

         parameterListLength = (short) ReadWrite.readTwoByteInt(buffer, 3);

     }

     public final boolean getSelfTest () {

         return selfTest;

     }

     public final SelfTestCode getSelfTestCode () {

         return selfTestCode;

     }

     public final boolean getPageFormat () {

         return pageFormat;

     }

     public final boolean getUnitOffline () {

         return unitOffline;

     }

     public final boolean getDeviceOffline () {

         return deviceOffline;

     }

     public final short getParameterListLength () {

         return parameterListLength;

     }

 }