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1   /*
2    * Copyright 2014 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.handler.codec.haproxy;
17  
18  import static io.netty.handler.codec.haproxy.HAProxyConstants.*;
19  
20  /**
21   * The HAProxy proxy protocol specification version.
22   */
23  public enum HAProxyProtocolVersion {
24      /**
25       * The ONE proxy protocol version represents a version 1 (human-readable) header.
26       */
27      V1(VERSION_ONE_BYTE),
28      /**
29       * The TWO proxy protocol version represents a version 2 (binary) header.
30       */
31      V2(VERSION_TWO_BYTE);
32  
33      /**
34       * The highest 4 bits of the protocol version and command byte contain the version
35       */
36      private static final byte VERSION_MASK = (byte) 0xf0;
37  
38      private final byte byteValue;
39  
40      /**
41       * Creates a new instance
42       */
43      HAProxyProtocolVersion(byte byteValue) {
44          this.byteValue = byteValue;
45      }
46  
47      /**
48       * Returns the {@link HAProxyProtocolVersion} represented by the higest 4 bits of the specified byte.
49       *
50       * @param verCmdByte protocol version and command byte
51       */
52      public static HAProxyProtocolVersion valueOf(byte verCmdByte) {
53          int version = verCmdByte & VERSION_MASK;
54          switch ((byte) version) {
55              case VERSION_TWO_BYTE:
56                  return V2;
57              case VERSION_ONE_BYTE:
58                  return V1;
59              default:
60                  throw new IllegalArgumentException("unknown version: " + version);
61          }
62      }
63  
64      /**
65       * Returns the byte value of this version.
66       */
67      public byte byteValue() {
68          return byteValue;
69      }
70  }