1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package org.apache.hadoop.hbase.util;
20
21 import org.apache.hadoop.hbase.classification.InterfaceAudience;
22 import org.apache.hadoop.util.DataChecksum;
23
24 /**
25 * Checksum types. The Checksum type is a one byte number
26 * that stores a representation of the checksum algorithm
27 * used to encode a hfile. The ordinal of these cannot
28 * change or else you risk breaking all existing HFiles out there.
29 */
30 @InterfaceAudience.Private
31 public enum ChecksumType {
32
33 NULL((byte)0) {
34 @Override
35 public String getName() {
36 return "NULL";
37 }
38
39 @Override public DataChecksum.Type getDataChecksumType() {
40 return DataChecksum.Type.NULL;
41 }
42 },
43
44 CRC32((byte)1) {
45 @Override
46 public String getName() {
47 return "CRC32";
48 }
49
50 @Override public DataChecksum.Type getDataChecksumType() {
51 return DataChecksum.Type.CRC32;
52 }
53 },
54
55 CRC32C((byte)2) {
56 @Override
57 public String getName() {
58 return "CRC32C";
59 }
60
61 @Override public DataChecksum.Type getDataChecksumType() {
62 return DataChecksum.Type.CRC32C;
63 }
64 };
65
66 private final byte code;
67
68 public static ChecksumType getDefaultChecksumType() {
69 return ChecksumType.CRC32C;
70 }
71
72 /** returns the name of this checksum type */
73 public abstract String getName();
74
75 /** Function to get corresponding {@link org.apache.hadoop.util.DataChecksum.Type}. */
76 public abstract DataChecksum.Type getDataChecksumType();
77
78 private ChecksumType(final byte c) {
79 this.code = c;
80 }
81
82 public byte getCode() {
83 return this.code;
84 }
85
86 /**
87 * Cannot rely on enum ordinals . They change if item is removed or moved.
88 * Do our own codes.
89 * @param b
90 * @return Type associated with passed code.
91 */
92 public static ChecksumType codeToType(final byte b) {
93 for (ChecksumType t : ChecksumType.values()) {
94 if (t.getCode() == b) {
95 return t;
96 }
97 }
98 throw new RuntimeException("Unknown checksum type code " + b);
99 }
100
101 /**
102 * Map a checksum name to a specific type.
103 * Do our own names.
104 * @param name
105 * @return Type associated with passed code.
106 */
107 public static ChecksumType nameToType(final String name) {
108 for (ChecksumType t : ChecksumType.values()) {
109 if (t.getName().equals(name)) {
110 return t;
111 }
112 }
113 throw new RuntimeException("Unknown checksum type name " + name);
114 }
115 }