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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 java.io.DataInput;
22  import java.io.IOException;
23  
24  public abstract class ProtoUtil {
25  
26    /**
27     * Read a variable length integer in the same format that ProtoBufs encodes.
28     * @param in the input stream to read from
29     * @return the integer
30     * @throws IOException if it is malformed or EOF.
31     */
32    public static int readRawVarint32(DataInput in) throws IOException {
33      byte tmp = in.readByte();
34      if (tmp >= 0) {
35        return tmp;
36      }
37      int result = tmp & 0x7f;
38      if ((tmp = in.readByte()) >= 0) {
39        result |= tmp << 7;
40      } else {
41        result |= (tmp & 0x7f) << 7;
42        if ((tmp = in.readByte()) >= 0) {
43          result |= tmp << 14;
44        } else {
45          result |= (tmp & 0x7f) << 14;
46          if ((tmp = in.readByte()) >= 0) {
47            result |= tmp << 21;
48          } else {
49            result |= (tmp & 0x7f) << 21;
50            result |= (tmp = in.readByte()) << 28;
51            if (tmp < 0) {
52              // Discard upper 32 bits.
53              for (int i = 0; i < 5; i++) {
54                if (in.readByte() >= 0) {
55                  return result;
56                }
57              }
58              throw new IOException("Malformed varint");
59            }
60          }
61        }
62      }
63      return result;
64    }
65  
66  }