org.apache.parquet.hadoop.codec.NonBlockedDecompressor Maven / Gradle / Ivy
/*
* 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.parquet.hadoop.codec;
import org.apache.hadoop.io.compress.Decompressor;
import org.apache.parquet.Preconditions;
import java.io.IOException;
import java.nio.ByteBuffer;
abstract public class NonBlockedDecompressor implements Decompressor {
// Buffer for uncompressed output. This buffer grows as necessary.
private ByteBuffer outputBuffer = ByteBuffer.allocateDirect(0);
// Buffer for compressed input. This buffer grows as necessary.
private ByteBuffer inputBuffer = ByteBuffer.allocateDirect(0);
private boolean finished;
/**
* Fills specified buffer with uncompressed data. Returns actual number
* of bytes of uncompressed data. A return value of 0 indicates that
* {@link #needsInput()} should be called in order to determine if more
* input data is required.
*
* @param buffer Buffer for the compressed data
* @param off Start offset of the data
* @param len Size of the buffer
* @return The actual number of bytes of uncompressed data.
* @throws IOException if reading or decompression fails
*/
@Override
public synchronized int decompress(byte[] buffer, int off, int len) throws IOException {
// SnappyUtil was dedicated to SnappyCodec in the past. Now it is used for both
// NonBlockedDecompressor and NonBlockedCompressor without renaming due to its
// dependency by some external downstream projects.
SnappyUtil.validateBuffer(buffer, off, len);
if (inputBuffer.position() == 0 && !outputBuffer.hasRemaining()) {
return 0;
}
if (!outputBuffer.hasRemaining()) {
inputBuffer.rewind();
Preconditions.checkArgument(inputBuffer.position() == 0, "Invalid position of 0.");
Preconditions.checkArgument(outputBuffer.position() == 0, "Invalid position of 0.");
// There is compressed input, decompress it now.
int decompressedSize = maxUncompressedLength(inputBuffer, len);
if (decompressedSize > outputBuffer.capacity()) {
ByteBuffer oldBuffer = outputBuffer;
outputBuffer = ByteBuffer.allocateDirect(decompressedSize);
CleanUtil.cleanDirectBuffer(oldBuffer);
}
// Reset the previous outputBuffer (i.e. set position to 0)
outputBuffer.clear();
int size = uncompress(inputBuffer, outputBuffer);
outputBuffer.limit(size);
// We've decompressed the entire input, reset the input now
inputBuffer.clear();
inputBuffer.limit(0);
finished = true;
}
// Return compressed output up to 'len'
int numBytes = Math.min(len, outputBuffer.remaining());
outputBuffer.get(buffer, off, numBytes);
return numBytes;
}
/**
* Sets input data for decompression.
* This should be called if and only if {@link #needsInput()} returns
* true indicating that more input data is required.
* (Both native and non-native versions of various Decompressors require
* that the data passed in via b[] remain unmodified until
* the caller is explicitly notified--via {@link #needsInput()}--that the
* buffer may be safely modified. With this requirement, an extra
* buffer-copy can be avoided.)
*
* @param buffer Input data
* @param off Start offset
* @param len Length
*/
@Override
public synchronized void setInput(byte[] buffer, int off, int len) {
// SnappyUtil was dedicated to SnappyCodec in the past. Now it is used for both
// NonBlockedDecompressor and NonBlockedCompressor without renaming due to its
// dependency by some external downstream projects.
SnappyUtil.validateBuffer(buffer, off, len);
if (inputBuffer.capacity() - inputBuffer.position() < len) {
final ByteBuffer newBuffer = ByteBuffer.allocateDirect(inputBuffer.position() + len);
inputBuffer.rewind();
newBuffer.put(inputBuffer);
final ByteBuffer oldBuffer = inputBuffer;
inputBuffer = newBuffer;
CleanUtil.cleanDirectBuffer(oldBuffer);
} else {
inputBuffer.limit(inputBuffer.position() + len);
}
inputBuffer.put(buffer, off, len);
}
@Override
public void end() {
CleanUtil.cleanDirectBuffer(inputBuffer);
CleanUtil.cleanDirectBuffer(outputBuffer);
}
@Override
public synchronized boolean finished() {
return finished && !outputBuffer.hasRemaining();
}
@Override
public int getRemaining() {
return 0;
}
@Override
public synchronized boolean needsInput() {
return !inputBuffer.hasRemaining() && !outputBuffer.hasRemaining();
}
@Override
public synchronized void reset() {
finished = false;
inputBuffer.rewind();
outputBuffer.rewind();
inputBuffer.limit(0);
outputBuffer.limit(0);
}
@Override
public boolean needsDictionary() {
return false;
}
@Override
public void setDictionary(byte[] b, int off, int len) {
// No-op
}
/**
* Get the maximum uncompressed byte size of the given compressed input. This operation takes O(1) time.
*
* @param compressed input data [pos() ... limit())
* @param maxUncompressedLength maximum length of the uncompressed data
* @return uncompressed byte length of the given input
*/
abstract protected int maxUncompressedLength(ByteBuffer compressed, int maxUncompressedLength) throws IOException;
/**
* Uncompress the content in the input buffer. The result is dumped to the
* specified output buffer.
*
* @param compressed buffer[pos() ... limit()) containing the input data
* @param uncompressed output of the the uncompressed data. It uses buffer[pos()..]
* @return uncompressed data size
*/
abstract protected int uncompress(ByteBuffer compressed, ByteBuffer uncompressed) throws IOException;
}