package org.jscsi.target.scsi.cdb;

 import java.nio.ByteBuffer;

 import org.jscsi.target.util.ReadWrite;

 /**

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

  * 

  * @author Andreas Ergenzinger

  */

 public class ReportLunsCDB extends CommandDescriptorBlock {

     /**

      * The SELECT REPORT field specifies the types of logical unit addresses that shall be reported.

      * 

      * @see SelectReport

      */

     private final SelectReport selectReport;

     /**

      * The ALLOCATION LENGTH field specifies the maximum number of bytes that an application client has allocated in the

      * Data-In Buffer. An allocation length of zero specifies that no data shall be transferred. This condition shall

      * not be considered as an error. The device server shall terminate transfers to the Data-In Buffer when the number

      * of bytes specified by the ALLOCATION LENGTH field have been transferred or when all available data have been

      * transferred, whichever is less.

      * <p>

      * The allocation length is used to limit the maximum amount of variable length data (e.g., mode data, log data,

      * diagnostic data) returned to an application client. If the information being transferred to the Data-In Buffer

      * includes fields containing counts of the number of bytes in some or all of the data, then the contents of these

      * fields shall not be altered to reflect the truncation, if any, that results from an insufficient ALLOCATION

      * LENGTH value, unless the standard that describes the Data-In Buffer format states otherwise.

      * <p>

      * If the amount of information to be transferred exceeds the maximum value that the ALLOCATION LENGTH field is

      * capable of specifying, the device server shall transfer no data and 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.

      * <p>

      * If EVPD is set to zero, the allocation length should be at least five, so that the ADDITIONAL LENGTH field in the

      * parameter data is returned. If EVPD is set to one, the allocation length should be should be at least four, so

      * that the PAGE LENGTH field in the parameter data is returned.

      */

     private final int allocationLength;

     public ReportLunsCDB (ByteBuffer buffer) {

         super(buffer);

         // select report

         selectReport = SelectReport.getValue(buffer.get(2));

         if (selectReport == null) addIllegalFieldPointer(2);// reserved select report value

         // allocation length

         allocationLength = ReadWrite.readFourByteInt(buffer, 6);

         if (allocationLength < 16) addIllegalFieldPointer(6);// The allocation length should be at

                                                              // least 16.

     }

     public final int getAllocationLength () {

         return allocationLength;

     }

     public final SelectReport getSelectReport () {

         return selectReport;

     }

 }