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.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 public class ChunkedStream implements ChunkedInput {
34
35 static final int DEFAULT_CHUNK_SIZE = 8192;
36
37 private final PushbackInputStream in;
38 private final int chunkSize;
39 private long offset;
40
41 /**
42 * Creates a new instance that fetches data from the specified stream.
43 */
44 public ChunkedStream(InputStream in) {
45 this(in, DEFAULT_CHUNK_SIZE);
46 }
47
48 /**
49 * Creates a new instance that fetches data from the specified stream.
50 *
51 * @param chunkSize the number of bytes to fetch on each
52 * {@link #nextChunk()} call
53 */
54 public ChunkedStream(InputStream in, int chunkSize) {
55 if (in == null) {
56 throw new NullPointerException("in");
57 }
58 if (chunkSize <= 0) {
59 throw new IllegalArgumentException(
60 "chunkSize: " + chunkSize +
61 " (expected: a positive integer)");
62 }
63
64 if (in instanceof PushbackInputStream) {
65 this.in = (PushbackInputStream) in;
66 } else {
67 this.in = new PushbackInputStream(in);
68 }
69 this.chunkSize = chunkSize;
70 }
71
72 /**
73 * Returns the number of transferred bytes.
74 */
75 public long getTransferredBytes() {
76 return offset;
77 }
78
79 public boolean hasNextChunk() throws Exception {
80 int b = in.read();
81 if (b < 0) {
82 return false;
83 } else {
84 in.unread(b);
85 return true;
86 }
87 }
88
89 public boolean isEndOfInput() throws Exception {
90 return !hasNextChunk();
91 }
92
93 public void close() throws Exception {
94 in.close();
95 }
96
97 public Object nextChunk() throws Exception {
98 if (!hasNextChunk()) {
99 return null;
100 }
101
102 final int availableBytes = in.available();
103 final int chunkSize;
104 if (availableBytes <= 0) {
105 chunkSize = this.chunkSize;
106 } else {
107 chunkSize = Math.min(this.chunkSize, in.available());
108 }
109 final byte[] chunk = new byte[chunkSize];
110 int readBytes = 0;
111 for (;;) {
112 int localReadBytes = in.read(chunk, readBytes, chunkSize - readBytes);
113 if (localReadBytes < 0) {
114 break;
115 }
116 readBytes += localReadBytes;
117 offset += localReadBytes;
118
119 if (readBytes == chunkSize) {
120 break;
121 }
122 }
123
124 return wrappedBuffer(chunk, 0, readBytes);
125 }
126 }