package org.jscsi.target.scsi.inquiry;

 import java.nio.ByteBuffer;

 /**

  * The null-terminated, null-padded (see 4.4.2) SCSI NAME STRING field contains a UTF-8 format string. The number of

  * bytes in the SCSI NAME STRING field (i.e., the value in the IDENTIFIER LENGTH field) shall be no larger than 256 and

  * shall be a multiple of four.

  * 

  * @author Andreas Ergenzinger

  */

 public class ScsiNameStringIdentifier extends Identifier {

     /**

      * The maximum {@link #size()} of this {@link Identifier}.

      */

     private static final int MAX_SIZE = 256;

     /**

      * The identifying string.

      */

     private final String nameString;

     /**

      * The logical unit name extension is a UTF-8 string containing no more than 16 hexadecimal digits. The logical unit

      * name extension is assigned by the SCSI target device vendor and shall be assigned so the logical unit name is

      * worldwide unique.

      * <p>

      * This Logical Unit Name Extension has been randomly generated.<br>

      * (0x493f51ba986f9800 = 5278027150164727808)

      */

     private static final String logicalUnitNameExtension = "493f51ba986f9800";

     public ScsiNameStringIdentifier (String targetName) {

         /*

          * The SCSI NAME STRING field starts with either:<br> ...<br> c) The four UTF-8 characters "iqn." concatenated

          * with an iSCSI Name for an iSCSI-name based identifier (see iSCSI). If the ASSOCIATION field is set to 00b

          * (i.e., logical unit) and the SCSI NAME STRING field starts with the four UTF-8 characters "iqn.", the SCSI

          * NAME STRING field ends with the five UTF-8 characters ",L,0x" concatenated with 16 hexadecimal digits for the

          * logical unit name extension.

          */

         nameString = targetName + ",L,0x" + logicalUnitNameExtension;

     }

     public void serialize (ByteBuffer byteBuffer, int index) {

         byteBuffer.position(index);

         final int size = size();// this many bytes will be written

         int stringLength = Math.min(nameString.length(), MAX_SIZE);

         if (stringLength == MAX_SIZE) --stringLength;// at least one null character as padding

         // copy string characters

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

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

         // add padding

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

             byteBuffer.put((byte) 0);

     }

     public int size () {

         return Math.min(nameString.length() + getNullTerminatedPaddingLength(), MAX_SIZE);

     }

     /**

      * Returns the number of null-character padding bytes that have to be appended to the {@link #nameString} when used

      * in serialized form.

      * 

      * @return the required number of null-character padding bytes

      */

     private int getNullTerminatedPaddingLength () {

         return 4 - (nameString.length() % 4);

     }

 }