/*
* Copyright 2011 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.handler.stream;
import static io.netty.buffer.ChannelBuffers.*;
import java.io.InputStream;
import java.io.PushbackInputStream;
/**
* A {@link ChunkedInput} that fetches data from an {@link InputStream} chunk by
* chunk.
* <p>
* Please note that the {@link InputStream} instance that feeds data into
* {@link ChunkedStream} must implement {@link InputStream#available()} as
* accurately as possible, rather than using the default implementation.
* Otherwise, {@link ChunkedStream} will generate many too small chunks or
* block unnecessarily often.
*/
public class ChunkedStream implements ChunkedInput {
static final int DEFAULT_CHUNK_SIZE = 8192;
private final PushbackInputStream in;
private final int chunkSize;
private volatile long offset;
/**
* Creates a new instance that fetches data from the specified stream.
*/
public ChunkedStream(InputStream in) {
this(in, DEFAULT_CHUNK_SIZE);
}
/**
* Creates a new instance that fetches data from the specified stream.
*
* @param chunkSize the number of bytes to fetch on each
* {@link #nextChunk()} call
*/
public ChunkedStream(InputStream in, int chunkSize) {
if (in == null) {
throw new NullPointerException("in");
}
if (chunkSize <= 0) {
throw new IllegalArgumentException(
"chunkSize: " + chunkSize +
" (expected: a positive integer)");
}
if (in instanceof PushbackInputStream) {
this.in = (PushbackInputStream) in;
} else {
this.in = new PushbackInputStream(in);
}
this.chunkSize = chunkSize;
}
/**
* Returns the number of transferred bytes.
*/
public long getTransferredBytes() {
return offset;
}
@Override
public boolean isEndOfInput() throws Exception {
int b = in.read();
if (b < 0) {
return true;
} else {
in.unread(b);
return false;
}
}
@Override
public void close() throws Exception {
in.close();
}
@Override
public Object nextChunk() throws Exception {
if (isEndOfInput()) {
return null;
}
final int availableBytes = in.available();
final int chunkSize;
if (availableBytes <= 0) {
chunkSize = this.chunkSize;
} else {
chunkSize = Math.min(this.chunkSize, in.available());
}
final byte[] chunk = new byte[chunkSize];
int readBytes = 0;
for (;;) {
int localReadBytes = in.read(chunk, readBytes, chunkSize - readBytes);
if (localReadBytes < 0) {
break;
}
readBytes += localReadBytes;
offset += localReadBytes;
if (readBytes == chunkSize) {
break;
}
}
return wrappedBuffer(chunk, 0, readBytes);
}
}