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1   /*
2    * Copyright 2012 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 org.jboss.netty.buffer;
17  
18  import java.io.DataOutput;
19  import java.io.DataOutputStream;
20  import java.io.IOException;
21  import java.io.OutputStream;
22  
23  /**
24   * An {@link OutputStream} which writes data to a {@link ChannelBuffer}.
25   * <p>
26   * A write operation against this stream will occur at the {@code writerIndex}
27   * of its underlying buffer and the {@code writerIndex} will increase during
28   * the write operation.
29   * <p>
30   * This stream implements {@link DataOutput} for your convenience.
31   * The endianness of the stream is not always big endian but depends on
32   * the endianness of the underlying buffer.
33   *
34   * @see ChannelBufferInputStream
35   * @apiviz.uses org.jboss.netty.buffer.ChannelBuffer
36   */
37  public class ChannelBufferOutputStream extends OutputStream implements DataOutput {
38  
39      private final ChannelBuffer buffer;
40      private final int startIndex;
41      private final DataOutputStream utf8out = new DataOutputStream(this);
42  
43      /**
44       * Creates a new stream which writes data to the specified {@code buffer}.
45       */
46      public ChannelBufferOutputStream(ChannelBuffer buffer) {
47          if (buffer == null) {
48              throw new NullPointerException("buffer");
49          }
50          this.buffer = buffer;
51          startIndex = buffer.writerIndex();
52      }
53  
54      /**
55       * Returns the number of written bytes by this stream so far.
56       */
57      public int writtenBytes() {
58          return buffer.writerIndex() - startIndex;
59      }
60  
61      @Override
62      public void write(byte[] b, int off, int len) throws IOException {
63          if (len == 0) {
64              return;
65          }
66  
67          buffer.writeBytes(b, off, len);
68      }
69  
70      @Override
71      public void write(byte[] b) throws IOException {
72          buffer.writeBytes(b);
73      }
74  
75      @Override
76      public void write(int b) throws IOException {
77          buffer.writeByte((byte) b);
78      }
79  
80      public void writeBoolean(boolean v) throws IOException {
81          write(v? (byte) 1 : (byte) 0);
82      }
83  
84      public void writeByte(int v) throws IOException {
85          write(v);
86      }
87  
88      public void writeBytes(String s) throws IOException {
89          int len = s.length();
90          for (int i = 0; i < len; i ++) {
91              write((byte) s.charAt(i));
92          }
93      }
94  
95      public void writeChar(int v) throws IOException {
96          writeShort((short) v);
97      }
98  
99      public void writeChars(String s) throws IOException {
100         int len = s.length();
101         for (int i = 0 ; i < len ; i ++) {
102             writeChar(s.charAt(i));
103         }
104     }
105 
106     public void writeDouble(double v) throws IOException {
107         writeLong(Double.doubleToLongBits(v));
108     }
109 
110     public void writeFloat(float v) throws IOException {
111         writeInt(Float.floatToIntBits(v));
112     }
113 
114     public void writeInt(int v) throws IOException {
115         buffer.writeInt(v);
116     }
117 
118     public void writeLong(long v) throws IOException {
119         buffer.writeLong(v);
120     }
121 
122     public void writeShort(int v) throws IOException {
123         buffer.writeShort((short) v);
124     }
125 
126     public void writeUTF(String s) throws IOException {
127         utf8out.writeUTF(s);
128     }
129 
130     /**
131      * Returns the buffer where this stream is writing data.
132      */
133     public ChannelBuffer buffer() {
134         return buffer;
135     }
136 }