/*
* Copyright (C) 2012-2015 DataStax Inc.
*
* Licensed 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 com.datastax.driver.core;
import io.netty.buffer.ByteBuf;
import net.jpountz.lz4.LZ4Factory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.nio.ByteBuffer;
class LZ4Compressor extends FrameCompressor {
private static final Logger logger = LoggerFactory.getLogger(LZ4Compressor.class);
static final LZ4Compressor instance;
static {
LZ4Compressor i;
try {
i = new LZ4Compressor();
} catch (NoClassDefFoundError e) {
i = null;
logger.warn("Cannot find LZ4 class, you should make sure the LZ4 library is in the classpath if you intend to use it. LZ4 compression will not be available for the protocol.");
} catch (Throwable e) {
i = null;
logger.warn("Error loading LZ4 library ({}). LZ4 compression will not be available for the protocol.", e.toString());
}
instance = i;
}
private static final int INTEGER_BYTES = 4;
private final net.jpountz.lz4.LZ4Compressor compressor;
private final net.jpountz.lz4.LZ4FastDecompressor decompressor;
private LZ4Compressor() {
final LZ4Factory lz4Factory = LZ4Factory.fastestInstance();
logger.info("Using {}", lz4Factory.toString());
compressor = lz4Factory.fastCompressor();
decompressor = lz4Factory.fastDecompressor();
}
@Override
Frame compress(Frame frame) throws IOException {
ByteBuf input = frame.body;
// TODO: JAVA-1306: Use the same API calls for direct and heap buffers when LZ4 updated.
ByteBuf frameBody = input.isDirect() ? compressDirect(input) : compressHeap(input);
return frame.with(frameBody);
}
private ByteBuf compressDirect(ByteBuf input) throws IOException {
int maxCompressedLength = compressor.maxCompressedLength(input.readableBytes());
// If the input is direct we will allocate a direct output buffer as well as this will allow us to use
// LZ4Compressor.compress and so eliminate memory copies.
ByteBuf output = input.alloc().directBuffer(INTEGER_BYTES + maxCompressedLength);
try {
ByteBuffer in = inputNioBuffer(input);
// Increase reader index.
input.readerIndex(input.writerIndex());
output.writeInt(in.remaining());
ByteBuffer out = outputNioBuffer(output);
int written = compressor.compress(in, in.position(), in.remaining(), out, out.position(), out.remaining());
// Set the writer index so the amount of written bytes is reflected
output.writerIndex(output.writerIndex() + written);
} catch (Exception e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw new IOException(e);
}
return output;
}
private ByteBuf compressHeap(ByteBuf input) throws IOException {
int maxCompressedLength = compressor.maxCompressedLength(input.readableBytes());
// Not a direct buffer so use byte arrays...
int inOffset = input.arrayOffset() + input.readerIndex();
byte[] in = input.array();
int len = input.readableBytes();
// Increase reader index.
input.readerIndex(input.writerIndex());
// Allocate a heap buffer from the ByteBufAllocator as we may use a PooledByteBufAllocator and so
// can eliminate the overhead of allocate a new byte[].
ByteBuf output = input.alloc().heapBuffer(INTEGER_BYTES + maxCompressedLength);
try {
output.writeInt(len);
// calculate the correct offset.
int offset = output.arrayOffset() + output.writerIndex();
byte[] out = output.array();
int written = compressor.compress(in, inOffset, len, out, offset);
// Set the writer index so the amount of written bytes is reflected
output.writerIndex(output.writerIndex() + written);
} catch (Exception e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw new IOException(e);
}
return output;
}
@Override
Frame decompress(Frame frame) throws IOException {
ByteBuf input = frame.body;
// TODO: JAVA-1306: Use the same API calls for direct and heap buffers when LZ4 updated.
ByteBuf frameBody = input.isDirect() ? decompressDirect(input) : decompressHeap(input);
return frame.with(frameBody);
}
private ByteBuf decompressDirect(ByteBuf input) throws IOException {
// If the input is direct we will allocate a direct output buffer as well as this will allow us to use
// LZ4Compressor.decompress and so eliminate memory copies.
int readable = input.readableBytes();
int uncompressedLength = input.readInt();
ByteBuffer in = inputNioBuffer(input);
// Increase reader index.
input.readerIndex(input.writerIndex());
ByteBuf output = input.alloc().directBuffer(uncompressedLength);
try {
ByteBuffer out = outputNioBuffer(output);
int read = decompressor.decompress(in, in.position(), out, out.position(), out.remaining());
if (read != readable - INTEGER_BYTES)
throw new IOException("Compressed lengths mismatch");
// Set the writer index so the amount of written bytes is reflected
output.writerIndex(output.writerIndex() + uncompressedLength);
} catch (Exception e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw new IOException(e);
}
return output;
}
private ByteBuf decompressHeap(ByteBuf input) throws IOException {
// Not a direct buffer so use byte arrays...
byte[] in = input.array();
int len = input.readableBytes();
int uncompressedLength = input.readInt();
int inOffset = input.arrayOffset() + input.readerIndex();
// Increase reader index.
input.readerIndex(input.writerIndex());
// Allocate a heap buffer from the ByteBufAllocator as we may use a PooledByteBufAllocator and so
// can eliminate the overhead of allocate a new byte[].
ByteBuf output = input.alloc().heapBuffer(uncompressedLength);
try {
int offset = output.arrayOffset() + output.writerIndex();
byte out[] = output.array();
int read = decompressor.decompress(in, inOffset, out, offset, uncompressedLength);
if (read != len - INTEGER_BYTES)
throw new IOException("Compressed lengths mismatch");
// Set the writer index so the amount of written bytes is reflected
output.writerIndex(output.writerIndex() + uncompressedLength);
} catch (Exception e) {
// release output buffer so we not leak and rethrow exception.
output.release();
throw new IOException(e);
}
return output;
}
}