/**
* 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.hbase.io.compress;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.compress.CodecPool;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionInputStream;
import org.apache.hadoop.io.compress.CompressionOutputStream;
import org.apache.hadoop.io.compress.Compressor;
import org.apache.hadoop.io.compress.Decompressor;
import org.apache.hadoop.io.compress.DefaultCodec;
import org.apache.hadoop.io.compress.GzipCodec;
import org.apache.hadoop.util.ReflectionUtils;
/**
* Compression related stuff.
* Copied from hadoop-3315 tfile.
*/
@InterfaceAudience.Private
public final class Compression {
static final Log LOG = LogFactory.getLog(Compression.class);
/**
* Prevent the instantiation of class.
*/
private Compression() {
super();
}
static class FinishOnFlushCompressionStream extends FilterOutputStream {
public FinishOnFlushCompressionStream(CompressionOutputStream cout) {
super(cout);
}
@Override
public void write(byte b[], int off, int len) throws IOException {
out.write(b, off, len);
}
@Override
public void flush() throws IOException {
CompressionOutputStream cout = (CompressionOutputStream) out;
cout.finish();
cout.flush();
cout.resetState();
}
}
/**
* Returns the classloader to load the Codec class from.
* @return
*/
private static ClassLoader getClassLoaderForCodec() {
ClassLoader cl = Thread.currentThread().getContextClassLoader();
if (cl == null) {
cl = Compression.class.getClassLoader();
}
if (cl == null) {
cl = ClassLoader.getSystemClassLoader();
}
if (cl == null) {
throw new RuntimeException("A ClassLoader to load the Codec could not be determined");
}
return cl;
}
/**
* Compression algorithms. The ordinal of these cannot change or else you
* risk breaking all existing HFiles out there. Even the ones that are
* not compressed! (They use the NONE algorithm)
*/
public static enum Algorithm {
LZO("lzo") {
// Use base type to avoid compile-time dependencies.
private transient CompressionCodec lzoCodec;
@Override
CompressionCodec getCodec(Configuration conf) {
if (lzoCodec == null) {
try {
Class<?> externalCodec =
getClassLoaderForCodec().loadClass("com.hadoop.compression.lzo.LzoCodec");
lzoCodec = (CompressionCodec) ReflectionUtils.newInstance(externalCodec,
new Configuration(conf));
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
return lzoCodec;
}
},
GZ("gz") {
private transient GzipCodec codec;
@Override
DefaultCodec getCodec(Configuration conf) {
if (codec == null) {
codec = new ReusableStreamGzipCodec();
codec.setConf(new Configuration(conf));
}
return codec;
}
},
NONE("none") {
@Override
DefaultCodec getCodec(Configuration conf) {
return null;
}
@Override
public synchronized InputStream createDecompressionStream(
InputStream downStream, Decompressor decompressor,
int downStreamBufferSize) throws IOException {
if (downStreamBufferSize > 0) {
return new BufferedInputStream(downStream, downStreamBufferSize);
}
// else {
// Make sure we bypass FSInputChecker buffer.
// return new BufferedInputStream(downStream, 1024);
// }
// }
return downStream;
}
@Override
public synchronized OutputStream createCompressionStream(
OutputStream downStream, Compressor compressor,
int downStreamBufferSize) throws IOException {
if (downStreamBufferSize > 0) {
return new BufferedOutputStream(downStream, downStreamBufferSize);
}
return downStream;
}
},
SNAPPY("snappy") {
// Use base type to avoid compile-time dependencies.
private transient CompressionCodec snappyCodec;
@Override
CompressionCodec getCodec(Configuration conf) {
if (snappyCodec == null) {
try {
Class<?> externalCodec =
getClassLoaderForCodec().loadClass("org.apache.hadoop.io.compress.SnappyCodec");
snappyCodec = (CompressionCodec) ReflectionUtils.newInstance(externalCodec, conf);
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
return snappyCodec;
}
},
LZ4("lz4") {
// Use base type to avoid compile-time dependencies.
private transient CompressionCodec lz4Codec;
@Override
CompressionCodec getCodec(Configuration conf) {
if (lz4Codec == null) {
try {
Class<?> externalCodec =
getClassLoaderForCodec().loadClass("org.apache.hadoop.io.compress.Lz4Codec");
lz4Codec = (CompressionCodec) ReflectionUtils.newInstance(externalCodec, conf);
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
return lz4Codec;
}
};
private final Configuration conf;
private final String compressName;
// data input buffer size to absorb small reads from application.
private static final int DATA_IBUF_SIZE = 1 * 1024;
// data output buffer size to absorb small writes from application.
private static final int DATA_OBUF_SIZE = 4 * 1024;
Algorithm(String name) {
this.conf = new Configuration();
this.conf.setBoolean("hadoop.native.lib", true);
this.compressName = name;
}
abstract CompressionCodec getCodec(Configuration conf);
public InputStream createDecompressionStream(
InputStream downStream, Decompressor decompressor,
int downStreamBufferSize) throws IOException {
CompressionCodec codec = getCodec(conf);
// Set the internal buffer size to read from down stream.
if (downStreamBufferSize > 0) {
((Configurable)codec).getConf().setInt("io.file.buffer.size",
downStreamBufferSize);
}
CompressionInputStream cis =
codec.createInputStream(downStream, decompressor);
BufferedInputStream bis2 = new BufferedInputStream(cis, DATA_IBUF_SIZE);
return bis2;
}
public OutputStream createCompressionStream(
OutputStream downStream, Compressor compressor, int downStreamBufferSize)
throws IOException {
OutputStream bos1 = null;
if (downStreamBufferSize > 0) {
bos1 = new BufferedOutputStream(downStream, downStreamBufferSize);
}
else {
bos1 = downStream;
}
CompressionOutputStream cos =
createPlainCompressionStream(bos1, compressor);
BufferedOutputStream bos2 =
new BufferedOutputStream(new FinishOnFlushCompressionStream(cos),
DATA_OBUF_SIZE);
return bos2;
}
/**
* Creates a compression stream without any additional wrapping into
* buffering streams.
*/
public CompressionOutputStream createPlainCompressionStream(
OutputStream downStream, Compressor compressor) throws IOException {
CompressionCodec codec = getCodec(conf);
((Configurable)codec).getConf().setInt("io.file.buffer.size", 32 * 1024);
return codec.createOutputStream(downStream, compressor);
}
public Compressor getCompressor() {
CompressionCodec codec = getCodec(conf);
if (codec != null) {
Compressor compressor = CodecPool.getCompressor(codec);
if (compressor != null) {
if (compressor.finished()) {
// Somebody returns the compressor to CodecPool but is still using
// it.
LOG
.warn("Compressor obtained from CodecPool is already finished()");
// throw new AssertionError(
// "Compressor obtained from CodecPool is already finished()");
}
compressor.reset();
}
return compressor;
}
return null;
}
public void returnCompressor(Compressor compressor) {
if (compressor != null) {
CodecPool.returnCompressor(compressor);
}
}
public Decompressor getDecompressor() {
CompressionCodec codec = getCodec(conf);
if (codec != null) {
Decompressor decompressor = CodecPool.getDecompressor(codec);
if (decompressor != null) {
if (decompressor.finished()) {
// Somebody returns the decompressor to CodecPool but is still using
// it.
LOG
.warn("Deompressor obtained from CodecPool is already finished()");
// throw new AssertionError(
// "Decompressor obtained from CodecPool is already finished()");
}
decompressor.reset();
}
return decompressor;
}
return null;
}
public void returnDecompressor(Decompressor decompressor) {
if (decompressor != null) {
CodecPool.returnDecompressor(decompressor);
}
}
public String getName() {
return compressName;
}
}
public static Algorithm getCompressionAlgorithmByName(String compressName) {
Algorithm[] algos = Algorithm.class.getEnumConstants();
for (Algorithm a : algos) {
if (a.getName().equals(compressName)) {
return a;
}
}
throw new IllegalArgumentException(
"Unsupported compression algorithm name: " + compressName);
}
/**
* Get names of supported compression algorithms.
*
* @return Array of strings, each represents a supported compression
* algorithm. Currently, the following compression algorithms are supported.
*/
public static String[] getSupportedAlgorithms() {
Algorithm[] algos = Algorithm.class.getEnumConstants();
String[] ret = new String[algos.length];
int i = 0;
for (Algorithm a : algos) {
ret[i++] = a.getName();
}
return ret;
}
/**
* Decompresses data from the given stream using the configured compression
* algorithm. It will throw an exception if the dest buffer does not have
* enough space to hold the decompressed data.
*
* @param dest
* the output bytes buffer
* @param destOffset
* start writing position of the output buffer
* @param bufferedBoundedStream
* a stream to read compressed data from, bounded to the exact amount
* of compressed data
* @param compressedSize
* compressed data size, header not included
* @param uncompressedSize
* uncompressed data size, header not included
* @param compressAlgo
* compression algorithm used
* @throws IOException
*/
public static void decompress(byte[] dest, int destOffset,
InputStream bufferedBoundedStream, int compressedSize,
int uncompressedSize, Compression.Algorithm compressAlgo)
throws IOException {
if (dest.length - destOffset < uncompressedSize) {
throw new IllegalArgumentException(
"Output buffer does not have enough space to hold "
+ uncompressedSize + " decompressed bytes, available: "
+ (dest.length - destOffset));
}
Decompressor decompressor = null;
try {
decompressor = compressAlgo.getDecompressor();
InputStream is = compressAlgo.createDecompressionStream(
bufferedBoundedStream, decompressor, 0);
IOUtils.readFully(is, dest, destOffset, uncompressedSize);
is.close();
} finally {
if (decompressor != null) {
compressAlgo.returnDecompressor(decompressor);
}
}
}
}