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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.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.compress.snappy.SnappyCompressor;
import org.apache.hadoop.io.compress.snappy.SnappyDecompressor;
import org.apache.hadoop.io.compress.snappy.SnappyDecompressor.SnappyDirectDecompressor;
import org.apache.hadoop.fs.CommonConfigurationKeys;
import org.apache.hadoop.util.NativeCodeLoader;
/**
* This class creates snappy compressors/decompressors.
*/
public class SnappyCodec implements Configurable, CompressionCodec, DirectDecompressionCodec {
Configuration conf;
/**
* Set the configuration to be used by this object.
*
* @param conf the configuration object.
*/
@Override
public void setConf(Configuration conf) {
this.conf = conf;
}
/**
* Return the configuration used by this object.
*
* @return the configuration object used by this objec.
*/
@Override
public Configuration getConf() {
return conf;
}
/**
* Are the native snappy libraries loaded & initialized?
*/
public static void checkNativeCodeLoaded() {
if (!NativeCodeLoader.isNativeCodeLoaded() ||
!NativeCodeLoader.buildSupportsSnappy()) {
throw new RuntimeException("native snappy library not available: " +
"this version of libhadoop was built without " +
"snappy support.");
}
if (!SnappyCompressor.isNativeCodeLoaded()) {
throw new RuntimeException("native snappy library not available: " +
"SnappyCompressor has not been loaded.");
}
if (!SnappyDecompressor.isNativeCodeLoaded()) {
throw new RuntimeException("native snappy library not available: " +
"SnappyDecompressor has not been loaded.");
}
}
public static boolean isNativeCodeLoaded() {
return SnappyCompressor.isNativeCodeLoaded() &&
SnappyDecompressor.isNativeCodeLoaded();
}
public static String getLibraryName() {
return SnappyCompressor.getLibraryName();
}
/**
* Create a {@link CompressionOutputStream} that will write to the given
* {@link OutputStream}.
*
* @param out the location for the final output stream
* @return a stream the user can write uncompressed data to have it compressed
* @throws IOException
*/
@Override
public CompressionOutputStream createOutputStream(OutputStream out)
throws IOException {
return CompressionCodec.Util.
createOutputStreamWithCodecPool(this, conf, out);
}
/**
* Create a {@link CompressionOutputStream} that will write to the given
* {@link OutputStream} with the given {@link Compressor}.
*
* @param out the location for the final output stream
* @param compressor compressor to use
* @return a stream the user can write uncompressed data to have it compressed
* @throws IOException
*/
@Override
public CompressionOutputStream createOutputStream(OutputStream out,
Compressor compressor)
throws IOException {
checkNativeCodeLoaded();
int bufferSize = conf.getInt(
CommonConfigurationKeys.IO_COMPRESSION_CODEC_SNAPPY_BUFFERSIZE_KEY,
CommonConfigurationKeys.IO_COMPRESSION_CODEC_SNAPPY_BUFFERSIZE_DEFAULT);
int compressionOverhead = (bufferSize / 6) + 32;
return new BlockCompressorStream(out, compressor, bufferSize,
compressionOverhead);
}
/**
* Get the type of {@link Compressor} needed by this {@link CompressionCodec}.
*
* @return the type of compressor needed by this codec.
*/
@Override
public Class getCompressorType() {
checkNativeCodeLoaded();
return SnappyCompressor.class;
}
/**
* Create a new {@link Compressor} for use by this {@link CompressionCodec}.
*
* @return a new compressor for use by this codec
*/
@Override
public Compressor createCompressor() {
checkNativeCodeLoaded();
int bufferSize = conf.getInt(
CommonConfigurationKeys.IO_COMPRESSION_CODEC_SNAPPY_BUFFERSIZE_KEY,
CommonConfigurationKeys.IO_COMPRESSION_CODEC_SNAPPY_BUFFERSIZE_DEFAULT);
return new SnappyCompressor(bufferSize);
}
/**
* Create a {@link CompressionInputStream} that will read from the given
* input stream.
*
* @param in the stream to read compressed bytes from
* @return a stream to read uncompressed bytes from
* @throws IOException
*/
@Override
public CompressionInputStream createInputStream(InputStream in)
throws IOException {
return CompressionCodec.Util.
createInputStreamWithCodecPool(this, conf, in);
}
/**
* Create a {@link CompressionInputStream} that will read from the given
* {@link InputStream} with the given {@link Decompressor}.
*
* @param in the stream to read compressed bytes from
* @param decompressor decompressor to use
* @return a stream to read uncompressed bytes from
* @throws IOException
*/
@Override
public CompressionInputStream createInputStream(InputStream in,
Decompressor decompressor)
throws IOException {
checkNativeCodeLoaded();
return new BlockDecompressorStream(in, decompressor, conf.getInt(
CommonConfigurationKeys.IO_COMPRESSION_CODEC_SNAPPY_BUFFERSIZE_KEY,
CommonConfigurationKeys.IO_COMPRESSION_CODEC_SNAPPY_BUFFERSIZE_DEFAULT));
}
/**
* Get the type of {@link Decompressor} needed by this {@link CompressionCodec}.
*
* @return the type of decompressor needed by this codec.
*/
@Override
public Class getDecompressorType() {
checkNativeCodeLoaded();
return SnappyDecompressor.class;
}
/**
* Create a new {@link Decompressor} for use by this {@link CompressionCodec}.
*
* @return a new decompressor for use by this codec
*/
@Override
public Decompressor createDecompressor() {
checkNativeCodeLoaded();
int bufferSize = conf.getInt(
CommonConfigurationKeys.IO_COMPRESSION_CODEC_SNAPPY_BUFFERSIZE_KEY,
CommonConfigurationKeys.IO_COMPRESSION_CODEC_SNAPPY_BUFFERSIZE_DEFAULT);
return new SnappyDecompressor(bufferSize);
}
/**
* {@inheritDoc}
*/
@Override
public DirectDecompressor createDirectDecompressor() {
return isNativeCodeLoaded() ? new SnappyDirectDecompressor() : null;
}
/**
* Get the default filename extension for this kind of compression.
*
* @return .snappy.
*/
@Override
public String getDefaultExtension() {
return ".snappy";
}
}