1 package org.jscsi.target.scsi.cdb;
2
3 /**
4 * The OPERATION CODE of a Command Descriptor Block specifies the type of command the initiator wants the target to
5 * perform.
6 * <p>
7 * The OPERATION CODE of the {@link CommandDescriptorBlock} has a GROUP CODE field and a COMMAND CODE field. The
8 * three-bit GROUP CODE field provides for eight groups of command codes. The five-bit COMMAND CODE field provides for
9 * thirty-two command codes in each group. A total of 256 possible operation codes exist.
10 * <p>
11 * The value of the GROUP CODE field specifies the {@link CommandDescriptorBlock}'s length.
12 *
13 * @see CdbType
14 * @author Andreas Ergenzinger
15 */
16 public enum ScsiOperationCode {
17 TEST_UNIT_READY((byte) 0x00), REQUEST_SENSE((byte) 0x03), FORMAT_UNIT((byte) 0x04), READ_6((byte) 0x08), WRITE_6((byte) 0x0a), INQUIRY((byte) 0x12), MODE_SELECT_6((byte) 0x15), MODE_SENSE_6((byte) 0x1a), SEND_DIAGNOSTIC((byte) 0x1d), READ_CAPACITY_10((byte) 0x25), READ_10((byte) 0x28), WRITE_10((byte) 0x2a), READ_CAPACITY_16((byte) 0x9e), REPORT_LUNS((byte) 0xa0);
18
19 /**
20 * The serialized value of the operation code.
21 */
22 private final byte value;
23
24 /**
25 * Maps byte values/index positions to {@link ScsiOperationCode} constants.
26 */
27 private static final ScsiOperationCode[] mapping = new ScsiOperationCode[256];
28 static {// initialize mapping
29 final ScsiOperationCode[] values = values();
30 int index;
31 for (ScsiOperationCode v : values) {
32 index = (v.value & 255);
33 mapping[index] = v;
34 }
35 }
36
37 /**
38 * Returns the {@link ScsiOperationCode} corresponding to the passed byte value.
39 *
40 * @param value the serialized value of a SCSI operation code
41 * @return the corresponding {@link ScsiOperationCode} or <code>null</code> if the passed value is not known by the
42 * jSCSI Target
43 */
44 public static final ScsiOperationCode valueOf (final byte value) {
45 return mapping[value & 255];
46 }
47
48 private ScsiOperationCode (final byte value) {
49 this.value = value;
50 }
51
52 /**
53 * Returns the serialized value of the operation code.
54 *
55 * @return the serialized value of the operation code
56 */
57 public final byte value () {
58 return value;
59 }
60
61 /**
62 * The three-bit GROUP CODE field provides for eight groups of command codes.
63 *
64 * @return the three-bit GROUP CODE field
65 */
66 public int getGroupCode () {
67 return (value >>> 5) & 7;
68 }
69
70 /**
71 * Returns the five-bit COMMAND CODE field.
72 *
73 * @return the five-bit COMMAND CODE field
74 */
75 public int getCommandCode () {
76 return value & 31;
77 }
78
79 /**
80 * Returns the {@link CdbType} for this operation code.
81 *
82 * @return the {@link CdbType} for this operation code
83 */
84 public CdbType getCdbType () {
85 return CdbType.getCdbType(this);
86 }
87 }