/*
* 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.bzip2;
import java.io.IOException;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.compress.Compressor;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* A {@link Compressor} based on the popular
* bzip2 compression algorithm.
* http://www.bzip2.org/
*
*/
public class Bzip2Compressor implements Compressor {
private static final int DEFAULT_DIRECT_BUFFER_SIZE = 64*1024;
// The default values for the block size and work factor are the same
// those in Julian Seward's original bzip2 implementation.
static final int DEFAULT_BLOCK_SIZE = 9;
static final int DEFAULT_WORK_FACTOR = 30;
private static final Log LOG = LogFactory.getLog(Bzip2Compressor.class);
// HACK - Use this as a global lock in the JNI layer.
private static Class<Bzip2Compressor> clazz = Bzip2Compressor.class;
private long stream;
private int blockSize;
private int workFactor;
private int directBufferSize;
private byte[] userBuf = null;
private int userBufOff = 0, userBufLen = 0;
private Buffer uncompressedDirectBuf = null;
private int uncompressedDirectBufOff = 0, uncompressedDirectBufLen = 0;
private boolean keepUncompressedBuf = false;
private Buffer compressedDirectBuf = null;
private boolean finish, finished;
/**
* Creates a new compressor with a default values for the
* compression block size and work factor. Compressed data will be
* generated in bzip2 format.
*/
public Bzip2Compressor() {
this(DEFAULT_BLOCK_SIZE, DEFAULT_WORK_FACTOR, DEFAULT_DIRECT_BUFFER_SIZE);
}
/**
* Creates a new compressor, taking settings from the configuration.
*/
public Bzip2Compressor(Configuration conf) {
this(Bzip2Factory.getBlockSize(conf),
Bzip2Factory.getWorkFactor(conf),
DEFAULT_DIRECT_BUFFER_SIZE);
}
/**
* Creates a new compressor using the specified block size.
* Compressed data will be generated in bzip2 format.
*
* @param blockSize The block size to be used for compression. This is
* an integer from 1 through 9, which is multiplied by 100,000 to
* obtain the actual block size in bytes.
* @param workFactor This parameter is a threshold that determines when a
* fallback algorithm is used for pathological data. It ranges from
* 0 to 250.
* @param directBufferSize Size of the direct buffer to be used.
*/
public Bzip2Compressor(int blockSize, int workFactor,
int directBufferSize) {
this.blockSize = blockSize;
this.workFactor = workFactor;
this.directBufferSize = directBufferSize;
stream = init(blockSize, workFactor);
uncompressedDirectBuf = ByteBuffer.allocateDirect(directBufferSize);
compressedDirectBuf = ByteBuffer.allocateDirect(directBufferSize);
compressedDirectBuf.position(directBufferSize);
}
/**
* Prepare the compressor to be used in a new stream with settings defined in
* the given Configuration. It will reset the compressor's block size and
* and work factor.
*
* @param conf Configuration storing new settings
*/
@Override
public synchronized void reinit(Configuration conf) {
reset();
end(stream);
if (conf == null) {
stream = init(blockSize, workFactor);
return;
}
blockSize = Bzip2Factory.getBlockSize(conf);
workFactor = Bzip2Factory.getWorkFactor(conf);
stream = init(blockSize, workFactor);
if(LOG.isDebugEnabled()) {
LOG.debug("Reinit compressor with new compression configuration");
}
}
@Override
public synchronized void setInput(byte[] b, int off, int len) {
if (b == null) {
throw new NullPointerException();
}
if (off < 0 || len < 0 || off > b.length - len) {
throw new ArrayIndexOutOfBoundsException();
}
this.userBuf = b;
this.userBufOff = off;
this.userBufLen = len;
uncompressedDirectBufOff = 0;
setInputFromSavedData();
// Reinitialize bzip2's output direct buffer.
compressedDirectBuf.limit(directBufferSize);
compressedDirectBuf.position(directBufferSize);
}
// Copy enough data from userBuf to uncompressedDirectBuf.
synchronized void setInputFromSavedData() {
int len = Math.min(userBufLen, uncompressedDirectBuf.remaining());
((ByteBuffer)uncompressedDirectBuf).put(userBuf, userBufOff, len);
userBufLen -= len;
userBufOff += len;
uncompressedDirectBufLen = uncompressedDirectBuf.position();
}
@Override
public synchronized void setDictionary(byte[] b, int off, int len) {
throw new UnsupportedOperationException();
}
@Override
public synchronized boolean needsInput() {
// Compressed data still available?
if (compressedDirectBuf.remaining() > 0) {
return false;
}
// Uncompressed data available in either the direct buffer or user buffer?
if (keepUncompressedBuf && uncompressedDirectBufLen > 0)
return false;
if (uncompressedDirectBuf.remaining() > 0) {
// Check if we have consumed all data in the user buffer.
if (userBufLen <= 0) {
return true;
} else {
// Copy enough data from userBuf to uncompressedDirectBuf.
setInputFromSavedData();
return uncompressedDirectBuf.remaining() > 0;
}
}
return false;
}
@Override
public synchronized void finish() {
finish = true;
}
@Override
public synchronized boolean finished() {
// Check if bzip2 says it has finished and
// all compressed data has been consumed.
return (finished && compressedDirectBuf.remaining() == 0);
}
@Override
public synchronized int compress(byte[] b, int off, int len)
throws IOException {
if (b == null) {
throw new NullPointerException();
}
if (off < 0 || len < 0 || off > b.length - len) {
throw new ArrayIndexOutOfBoundsException();
}
// Check if there is compressed data.
int n = compressedDirectBuf.remaining();
if (n > 0) {
n = Math.min(n, len);
((ByteBuffer)compressedDirectBuf).get(b, off, n);
return n;
}
// Re-initialize bzip2's output direct buffer.
compressedDirectBuf.rewind();
compressedDirectBuf.limit(directBufferSize);
// Compress the data.
n = deflateBytesDirect();
compressedDirectBuf.limit(n);
// Check if bzip2 has consumed the entire input buffer.
// Set keepUncompressedBuf properly.
if (uncompressedDirectBufLen <= 0) { // bzip2 consumed all input
keepUncompressedBuf = false;
uncompressedDirectBuf.clear();
uncompressedDirectBufOff = 0;
uncompressedDirectBufLen = 0;
} else {
keepUncompressedBuf = true;
}
// Get at most 'len' bytes.
n = Math.min(n, len);
((ByteBuffer)compressedDirectBuf).get(b, off, n);
return n;
}
/**
* Returns the total number of compressed bytes output so far.
*
* @return the total (non-negative) number of compressed bytes output so far
*/
@Override
public synchronized long getBytesWritten() {
checkStream();
return getBytesWritten(stream);
}
/**
* Returns the total number of uncompressed bytes input so far.</p>
*
* @return the total (non-negative) number of uncompressed bytes input so far
*/
@Override
public synchronized long getBytesRead() {
checkStream();
return getBytesRead(stream);
}
@Override
public synchronized void reset() {
checkStream();
end(stream);
stream = init(blockSize, workFactor);
finish = false;
finished = false;
uncompressedDirectBuf.rewind();
uncompressedDirectBufOff = uncompressedDirectBufLen = 0;
keepUncompressedBuf = false;
compressedDirectBuf.limit(directBufferSize);
compressedDirectBuf.position(directBufferSize);
userBufOff = userBufLen = 0;
}
@Override
public synchronized void end() {
if (stream != 0) {
end(stream);
stream = 0;
}
}
static void initSymbols(String libname) {
initIDs(libname);
}
private void checkStream() {
if (stream == 0)
throw new NullPointerException();
}
private native static void initIDs(String libname);
private native static long init(int blockSize, int workFactor);
private native int deflateBytesDirect();
private native static long getBytesRead(long strm);
private native static long getBytesWritten(long strm);
private native static void end(long strm);
public native static String getLibraryName();
}