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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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 org.apache.hadoop.io.compress;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class DecompressorStream extends CompressionInputStream {
/**
* The maximum input buffer size.
*/
private static final int MAX_INPUT_BUFFER_SIZE = 512;
/**
* MAX_SKIP_BUFFER_SIZE is used to determine the maximum buffer size to
* use when skipping. See {@link java.io.InputStream}.
*/
private static final int MAX_SKIP_BUFFER_SIZE = 2048;
private byte[] skipBytes;
private byte[] oneByte = new byte[1];
protected Decompressor decompressor = null;
protected byte[] buffer;
protected boolean eof = false;
protected boolean closed = false;
private int lastBytesSent = 0;
@VisibleForTesting
DecompressorStream(InputStream in, Decompressor decompressor,
int bufferSize, int skipBufferSize)
throws IOException {
super(in);
if (decompressor == null) {
throw new NullPointerException();
} else if (bufferSize <= 0) {
throw new IllegalArgumentException("Illegal bufferSize");
}
this.decompressor = decompressor;
buffer = new byte[bufferSize];
skipBytes = new byte[skipBufferSize];
}
public DecompressorStream(InputStream in, Decompressor decompressor,
int bufferSize)
throws IOException {
this(in, decompressor, bufferSize, MAX_SKIP_BUFFER_SIZE);
}
public DecompressorStream(InputStream in, Decompressor decompressor)
throws IOException {
this(in, decompressor, MAX_INPUT_BUFFER_SIZE);
}
/**
* Allow derived classes to directly set the underlying stream.
*
* @param in Underlying input stream.
* @throws IOException
*/
protected DecompressorStream(InputStream in) throws IOException {
super(in);
}
@Override
public int read() throws IOException {
checkStream();
return (read(oneByte, 0, oneByte.length) == -1) ? -1 : (oneByte[0] & 0xff);
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
checkStream();
if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return 0;
}
return decompress(b, off, len);
}
protected int decompress(byte[] b, int off, int len) throws IOException {
int n;
while ((n = decompressor.decompress(b, off, len)) == 0) {
if (decompressor.needsDictionary()) {
eof = true;
return -1;
}
if (decompressor.finished()) {
// First see if there was any leftover buffered input from previous
// stream; if not, attempt to refill buffer. If refill -> EOF, we're
// all done; else reset, fix up input buffer, and get ready for next
// concatenated substream/"member".
int nRemaining = decompressor.getRemaining();
if (nRemaining == 0) {
int m = getCompressedData();
if (m == -1) {
// apparently the previous end-of-stream was also end-of-file:
// return success, as if we had never called getCompressedData()
eof = true;
return -1;
}
decompressor.reset();
decompressor.setInput(buffer, 0, m);
lastBytesSent = m;
} else {
// looks like it's a concatenated stream: reset low-level zlib (or
// other engine) and buffers, then "resend" remaining input data
decompressor.reset();
int leftoverOffset = lastBytesSent - nRemaining;
assert (leftoverOffset >= 0);
// this recopies userBuf -> direct buffer if using native libraries:
decompressor.setInput(buffer, leftoverOffset, nRemaining);
// NOTE: this is the one place we do NOT want to save the number
// of bytes sent (nRemaining here) into lastBytesSent: since we
// are resending what we've already sent before, offset is nonzero
// in general (only way it could be zero is if it already equals
// nRemaining), which would then screw up the offset calculation
// _next_ time around. IOW, getRemaining() is in terms of the
// original, zero-offset bufferload, so lastBytesSent must be as
// well. Cheesy ASCII art:
//
// <------------ m, lastBytesSent ----------->
// +===============================================+
// buffer: |1111111111|22222222222222222|333333333333| |
// +===============================================+
// #1: <-- off -->|<-------- nRemaining --------->
// #2: <----------- off ----------->|<-- nRem. -->
// #3: (final substream: nRemaining == 0; eof = true)
//
// If lastBytesSent is anything other than m, as shown, then "off"
// will be calculated incorrectly.
}
} else if (decompressor.needsInput()) {
int m = getCompressedData();
if (m == -1) {
throw new EOFException("Unexpected end of input stream");
}
decompressor.setInput(buffer, 0, m);
lastBytesSent = m;
}
}
return n;
}
protected int getCompressedData() throws IOException {
checkStream();
// note that the _caller_ is now required to call setInput() or throw
return in.read(buffer, 0, buffer.length);
}
protected void checkStream() throws IOException {
if (closed) {
throw new IOException("Stream closed");
}
}
@Override
public void resetState() throws IOException {
decompressor.reset();
}
@Override
public long skip(long n) throws IOException {
// Sanity checks
if (n < 0) {
throw new IllegalArgumentException("negative skip length");
}
checkStream();
// Read 'n' bytes
int skipped = 0;
while (skipped < n) {
int len = Math.min(((int)n - skipped), skipBytes.length);
len = read(skipBytes, 0, len);
if (len == -1) {
eof = true;
break;
}
skipped += len;
}
return skipped;
}
@Override
public int available() throws IOException {
checkStream();
return (eof) ? 0 : 1;
}
@Override
public void close() throws IOException {
if (!closed) {
try {
super.close();
} finally {
closed = true;
}
}
}
@Override
public boolean markSupported() {
return false;
}
@Override
public synchronized void mark(int readlimit) {
}
@Override
public synchronized void reset() throws IOException {
throw new IOException("mark/reset not supported");
}
}
