/*
* 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.cassandra.io.compress;
import org.apache.cassandra.utils.FBUtilities;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.Inflater;
public class DeflateCompressor implements ICompressor
{
public static final DeflateCompressor instance = new DeflateCompressor();
private final ThreadLocal<Deflater> deflater;
private final ThreadLocal<Inflater> inflater;
public static DeflateCompressor create(Map<String, String> compressionOptions)
{
// no specific options supported so far
return instance;
}
private DeflateCompressor()
{
deflater = new ThreadLocal<Deflater>()
{
@Override
protected Deflater initialValue()
{
return new Deflater();
}
};
inflater = new ThreadLocal<Inflater>()
{
@Override
protected Inflater initialValue()
{
return new Inflater();
}
};
}
public Set<String> supportedOptions()
{
return Collections.emptySet();
}
public int initialCompressedBufferLength(int sourceLen)
{
// Taken from zlib deflateBound(). See http://www.zlib.net/zlib_tech.html.
return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + (sourceLen >> 25) + 13;
}
public void compress(ByteBuffer input, ByteBuffer output)
{
if (input.hasArray() && output.hasArray())
{
int length = compressArray(input.array(), input.arrayOffset() + input.position(), input.remaining(),
output.array(), output.arrayOffset() + output.position(), output.remaining());
input.position(input.limit());
output.position(output.position() + length);
}
else
compressBuffer(input, output);
}
public int compressArray(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset, int maxOutputLength)
{
Deflater def = deflater.get();
def.reset();
def.setInput(input, inputOffset, inputLength);
def.finish();
if (def.needsInput())
return 0;
int len = def.deflate(output, outputOffset, maxOutputLength);
assert def.finished();
return len;
}
public void compressBuffer(ByteBuffer input, ByteBuffer output)
{
Deflater def = deflater.get();
def.reset();
byte[] buffer = FBUtilities.getThreadLocalScratchBuffer();
// Use half the buffer for input, half for output.
int chunkLen = buffer.length / 2;
while (input.remaining() > chunkLen)
{
input.get(buffer, 0, chunkLen);
def.setInput(buffer, 0, chunkLen);
while (!def.needsInput())
{
int len = def.deflate(buffer, chunkLen, chunkLen);
output.put(buffer, chunkLen, len);
}
}
int inputLength = input.remaining();
input.get(buffer, 0, inputLength);
def.setInput(buffer, 0, inputLength);
def.finish();
while (!def.finished())
{
int len = def.deflate(buffer, chunkLen, chunkLen);
output.put(buffer, chunkLen, len);
}
}
public void uncompress(ByteBuffer input, ByteBuffer output) throws IOException
{
if (input.hasArray() && output.hasArray())
{
int length = uncompress(input.array(), input.arrayOffset() + input.position(), input.remaining(),
output.array(), output.arrayOffset() + output.position(), output.remaining());
input.position(input.limit());
output.position(output.position() + length);
}
else
uncompressBuffer(input, output);
}
public void uncompressBuffer(ByteBuffer input, ByteBuffer output) throws IOException
{
try
{
Inflater inf = inflater.get();
inf.reset();
byte[] buffer = FBUtilities.getThreadLocalScratchBuffer();
// Use half the buffer for input, half for output.
int chunkLen = buffer.length / 2;
while (input.remaining() > chunkLen)
{
input.get(buffer, 0, chunkLen);
inf.setInput(buffer, 0, chunkLen);
while (!inf.needsInput())
{
int len = inf.inflate(buffer, chunkLen, chunkLen);
output.put(buffer, chunkLen, len);
}
}
int inputLength = input.remaining();
input.get(buffer, 0, inputLength);
inf.setInput(buffer, 0, inputLength);
while (!inf.needsInput())
{
int len = inf.inflate(buffer, chunkLen, chunkLen);
output.put(buffer, chunkLen, len);
}
}
catch (DataFormatException e)
{
throw new IOException(e);
}
}
public int uncompress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset) throws IOException
{
return uncompress(input, inputOffset, inputLength, output, outputOffset, output.length - outputOffset);
}
public int uncompress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset, int maxOutputLength) throws IOException
{
Inflater inf = inflater.get();
inf.reset();
inf.setInput(input, inputOffset, inputLength);
if (inf.needsInput())
return 0;
// We assume output is big enough
try
{
return inf.inflate(output, outputOffset, maxOutputLength);
}
catch (DataFormatException e)
{
throw new IOException(e);
}
}
public boolean supports(BufferType bufferType)
{
return true;
}
public BufferType preferredBufferType()
{
// Prefer array-backed buffers.
return BufferType.ON_HEAP;
}
}