1 package org.jscsi.target.scsi.cdb;
2
3
4 import java.nio.ByteBuffer;
5
6 import org.jscsi.target.util.ReadWrite;
7
8
9 /**
10 * This class represents Command Descriptor Blocks for the <code>WRITE (6)</code> SCSI command.
11 * <p>
12 * The WRITE (6) command requests that the device server transfer the specified logical block(s) from the data-out
13 * buffer and write them.
14 * <p>
15 * Each logical block transferred includes user data but does not include protection information. Each logical block
16 * written includes user data and, if the medium is formatted with protection information enabled, protection
17 * information.
18 * <p>
19 * A TRANSFER LENGTH field set to zero specifies that 256 logical blocks shall be written. Any other value specifies the
20 * number of logical blocks that shall be written.
21 *
22 * @author Andreas Ergenzinger
23 */
24 public class Write6Cdb extends WriteCdb {
25
26 public Write6Cdb (ByteBuffer buffer) {
27 super(buffer);
28 }
29
30 @Override
31 protected long deserializeLogicalBlockAddress (ByteBuffer buffer) {
32 // the first three bits of byte 1 are reserved, i.e. must be 0,
33 // check that
34 final byte b = buffer.get(1);
35 if (((b >> 5) & 7) != 0) addIllegalFieldPointer(1);
36
37 // read the field's value
38 return ((b & 31) << 16) | ReadWrite.readTwoByteInt(buffer, 2);
39 }
40
41 @Override
42 protected int deserializeTransferLength (ByteBuffer buffer) {
43 /*
44 * A TRANSFER LENGTH field set to zero specifies that 256 logical blocks shall be written. Any other value
45 * specifies the number of logical blocks that shall be written.
46 */
47 final int value = ReadWrite.readOneByteInt(buffer, 4);
48 if (value == 0) return 256;
49 return value;
50 }
51
52 @Override
53 protected int getLogicalBlockAddressFieldIndex () {
54 return 1;
55 }
56
57 @Override
58 protected int getTransferLengthFieldIndex () {
59 return 4;
60 }
61
62 }