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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,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License.
18   *
19   */
20  package org.apache.mina.util;
21  
22  import java.io.InputStream;
23  import java.nio.ByteBuffer;
24  
25  /**
26   * {@link InputStream} wrapper for {@link ByteBuffer}
27   * 
28   * <p>
29   * <i>Currently this class is only used and available in MINA's codec module</i>
30   * </p>
31   * 
32   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
33   * 
34   */
35  public class ByteBufferInputStream extends InputStream {
36  
37      private final ByteBuffer buffer;
38  
39      /**
40       * 
41       * @param buffer
42       *            a buffer to be wrapped
43       */
44      public ByteBufferInputStream(ByteBuffer buffer) {
45          super();
46          this.buffer = buffer;
47      }
48  
49      /**
50       * @see InputStream#available()
51       */
52      @Override
53      public int available() {
54          return buffer.remaining();
55      }
56  
57      /**
58       * @see InputStream#mark(int)
59       */
60      @Override
61      public synchronized void mark(int readlimit) {
62          buffer.mark();
63      }
64  
65      /**
66       * @see InputStream#markSupported()
67       */
68      @Override
69      public boolean markSupported() {
70          return true;
71      }
72  
73      /**
74       * @see InputStream#read()
75       */
76      @Override
77      public int read() {
78          if (buffer.hasRemaining()) {
79              return buffer.get() & 0xff;
80          }
81  
82          return -1;
83      }
84  
85      /**
86       * @see InputStream#read(byte[], int, int)
87       */
88      @Override
89      public int read(byte[] b, int off, int len) {
90          int remaining = buffer.remaining();
91          if (remaining > 0) {
92              int readBytes = Math.min(remaining, len);
93              buffer.get(b, off, readBytes);
94              return readBytes;
95          }
96  
97          return -1;
98      }
99  
100     /**
101      * @see InputStream#reset()
102      */
103     @Override
104     public synchronized void reset() {
105         buffer.reset();
106     }
107 
108     /**
109      * 
110      * @param n
111      *            the number of bytes to skip (values bigger than
112      *            {@link Integer#MAX_VALUE} push the reading head to the end).
113      * 
114      * @see InputStream#skip(long)
115      */
116     @Override
117     public long skip(long n) {
118         int bytes;
119         if (n > Integer.MAX_VALUE) {
120             bytes = buffer.remaining();
121         } else {
122             bytes = Math.min(buffer.remaining(), (int) n);
123         }
124         buffer.position(buffer.position() + bytes);
125 
126         return bytes;
127     }
128 
129 }