1 /*
2 * Copyright 2009 Red Hat, Inc.
3 *
4 * Red Hat licenses this file to you under the Apache License, version 2.0
5 * (the "License"); you may not use this file except in compliance with the
6 * 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.handler.stream;
17
18 import static org.jboss.netty.buffer.ChannelBuffers.*;
19
20 import java.io.InputStream;
21 import java.io.PushbackInputStream;
22
23 /**
24 * A {@link ChunkedInput} that fetches data from an {@link InputStream} chunk by
25 * chunk.
26 * <p>
27 * Please note that the {@link InputStream} instance that feeds data into
28 * {@link ChunkedStream} must implement {@link InputStream#available()} as
29 * accurately as possible, rather than using the default implementation.
30 * Otherwise, {@link ChunkedStream} will generate many too small chunks or
31 * block unnecessarily often.
32 *
33 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
34 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
35 * @version $Rev: 2236 $, $Date: 2010-04-12 19:22:51 +0900 (Mon, 12 Apr 2010) $
36 */
37 public class ChunkedStream implements ChunkedInput {
38
39 static final int DEFAULT_CHUNK_SIZE = 8192;
40
41 private final PushbackInputStream in;
42 private final int chunkSize;
43 private volatile long offset;
44
45 /**
46 * Creates a new instance that fetches data from the specified stream.
47 */
48 public ChunkedStream(InputStream in) {
49 this(in, DEFAULT_CHUNK_SIZE);
50 }
51
52 /**
53 * Creates a new instance that fetches data from the specified stream.
54 *
55 * @param chunkSize the number of bytes to fetch on each
56 * {@link #nextChunk()} call
57 */
58 public ChunkedStream(InputStream in, int chunkSize) {
59 if (in == null) {
60 throw new NullPointerException("in");
61 }
62 if (chunkSize <= 0) {
63 throw new IllegalArgumentException(
64 "chunkSize: " + chunkSize +
65 " (expected: a positive integer)");
66 }
67
68 if (in instanceof PushbackInputStream) {
69 this.in = (PushbackInputStream) in;
70 } else {
71 this.in = new PushbackInputStream(in);
72 }
73 this.chunkSize = chunkSize;
74 }
75
76 /**
77 * Returns the number of transferred bytes.
78 */
79 public long getTransferredBytes() {
80 return offset;
81 }
82
83 public boolean hasNextChunk() throws Exception {
84 int b = in.read();
85 if (b < 0) {
86 return false;
87 } else {
88 in.unread(b);
89 return true;
90 }
91 }
92
93 public boolean isEndOfInput() throws Exception {
94 return !hasNextChunk();
95 }
96
97 public void close() throws Exception {
98 in.close();
99 }
100
101 public Object nextChunk() throws Exception {
102 if (!hasNextChunk()) {
103 return null;
104 }
105
106 final int availableBytes = in.available();
107 final int chunkSize;
108 if (availableBytes <= 0) {
109 chunkSize = this.chunkSize;
110 } else {
111 chunkSize = Math.min(this.chunkSize, in.available());
112 }
113 final byte[] chunk = new byte[chunkSize];
114 int readBytes = 0;
115 for (;;) {
116 int localReadBytes = in.read(chunk, readBytes, chunkSize - readBytes);
117 if (localReadBytes < 0) {
118 break;
119 }
120 readBytes += localReadBytes;
121 offset += localReadBytes;
122
123 if (readBytes == chunkSize) {
124 break;
125 }
126 }
127
128 return wrappedBuffer(chunk, 0, readBytes);
129 }
130 }