package org.jscsi.target.scsi.cdb;

 import java.nio.ByteBuffer;

 /**

  * This is an abstract super-class for command descriptor blocks that that are used for requesting information about the

  * capacity of the storage device.

  * 

  * @author Andreas Ergenzinger

  */

 public abstract class ReadCapacityCdb extends CommandDescriptorBlock {

     /**

      * The LOGICAL BLOCK ADDRESS field specifies the LBA of the first logical block accessed by this command.

      * <p>

      * If the specified LBA exceeds the capacity of the medium, then the device server shall terminate the command with

      * CHECK CONDITION status with the sense key set to ILLEGAL REQUEST and the additional sense code set to LOGICAL

      * BLOCK ADDRESS OUT OF RANGE.

      * 

      * @see #partialMediumIndicator

      */

     protected final long logicalBlockAddress;

     /**

      * A partial medium indicator (PMI) bit set to zero specifies that the device server return information on the last

      * logical block on the direct-access block device.

      * <p>

      * A PMI bit set to one specifies that the device server return information on the last logical block after that

      * specified in the LOGICAL BLOCK ADDRESS field before a substantial vendor specific delay in data transfer may be

      * encountered.

      * <p>

      * The LOGICAL BLOCK ADDRESS field shall be set to zero if the PMI bit is set to zero. If the PMI bit is set to zero

      * and the LOGICAL BLOCK ADDRESS field is not set to zero, then the device server shall terminate the command with

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

      * FIELD IN CDB.

      * 

      * @see #logicalBlockAddress

      */

     protected final boolean partialMediumIndicator;

     public ReadCapacityCdb (final ByteBuffer buffer) {

         super(buffer);

         logicalBlockAddress = deserializeLogicalBlockAddress(buffer);

         partialMediumIndicator = deserializePartialMediumIndicator(buffer);

         // check constraint

         if (!partialMediumIndicator && logicalBlockAddress > 0) addIllegalFieldPointer(2);

     }

     protected abstract long deserializeLogicalBlockAddress (ByteBuffer buffer);

     protected abstract boolean deserializePartialMediumIndicator (ByteBuffer buffer);

     public final long getLogicalBlockAddress () {

         return logicalBlockAddress;

     }

     public final boolean getPartialMediumIndicator () {

         return partialMediumIndicator;

     }

 }