[GitHub] [arrow] liyafan82 commented on a change in pull request #8949: ARROW-10880: [Java] Support compressing RecordBatch IPC buffers by LZ4

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liyafan82 commented on a change in pull request #8949:
URL: https://github.com/apache/arrow/pull/8949#discussion_r546486677



##########
File path: java/vector/src/main/java/org/apache/arrow/vector/compression/Lz4CompressionCodec.java
##########
@@ -0,0 +1,110 @@
+/*
+ * 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.arrow.vector.compression;
+
+import java.nio.ByteBuffer;
+
+import org.apache.arrow.flatbuf.CompressionType;
+import org.apache.arrow.memory.ArrowBuf;
+import org.apache.arrow.memory.BufferAllocator;
+import org.apache.arrow.memory.util.MemoryUtil;
+import org.apache.arrow.util.Preconditions;
+
+import net.jpountz.lz4.LZ4Compressor;
+import net.jpountz.lz4.LZ4Factory;
+import net.jpountz.lz4.LZ4FastDecompressor;
+
+/**
+ * Compression codec for the LZ4 algorithm.
+ */
+public class Lz4CompressionCodec implements CompressionCodec {
+
+  private static final long SIZE_OF_MESSAGE_LENGTH = 8L;
+
+  private final LZ4Factory factory;
+
+  private LZ4Compressor compressor;
+
+  private LZ4FastDecompressor decompressor;
+
+  public Lz4CompressionCodec() {
+    factory = LZ4Factory.fastestInstance();
+  }
+
+  @Override
+  public ArrowBuf compress(BufferAllocator allocator, ArrowBuf unCompressedBuffer) {
+    Preconditions.checkArgument(unCompressedBuffer.writerIndex() <= Integer.MAX_VALUE,
+        "The uncompressed buffer size exceeds the integer limit");
+
+    // create compressor lazily
+    if (compressor == null) {
+      compressor = factory.fastCompressor();
+    }
+
+    int maxCompressedLength = compressor.maxCompressedLength((int) unCompressedBuffer.writerIndex());
+
+    // first 8 bytes reserved for uncompressed length, to be consistent with the
+    // C++ implementation.
+    ArrowBuf compressedBuffer = allocator.buffer(maxCompressedLength + SIZE_OF_MESSAGE_LENGTH);
+    compressedBuffer.setLong(0, unCompressedBuffer.writerIndex());

Review comment:
       Revised accordingly. Thanks for your kind reminder.

##########
File path: java/vector/src/main/java/org/apache/arrow/vector/compression/Lz4CompressionCodec.java
##########
@@ -0,0 +1,110 @@
+/*
+ * 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.arrow.vector.compression;
+
+import java.nio.ByteBuffer;
+
+import org.apache.arrow.flatbuf.CompressionType;
+import org.apache.arrow.memory.ArrowBuf;
+import org.apache.arrow.memory.BufferAllocator;
+import org.apache.arrow.memory.util.MemoryUtil;
+import org.apache.arrow.util.Preconditions;
+
+import net.jpountz.lz4.LZ4Compressor;
+import net.jpountz.lz4.LZ4Factory;
+import net.jpountz.lz4.LZ4FastDecompressor;
+
+/**
+ * Compression codec for the LZ4 algorithm.
+ */
+public class Lz4CompressionCodec implements CompressionCodec {
+
+  private static final long SIZE_OF_MESSAGE_LENGTH = 8L;
+
+  private final LZ4Factory factory;
+
+  private LZ4Compressor compressor;
+
+  private LZ4FastDecompressor decompressor;
+
+  public Lz4CompressionCodec() {
+    factory = LZ4Factory.fastestInstance();
+  }
+
+  @Override
+  public ArrowBuf compress(BufferAllocator allocator, ArrowBuf unCompressedBuffer) {
+    Preconditions.checkArgument(unCompressedBuffer.writerIndex() <= Integer.MAX_VALUE,
+        "The uncompressed buffer size exceeds the integer limit");
+
+    // create compressor lazily
+    if (compressor == null) {
+      compressor = factory.fastCompressor();
+    }
+
+    int maxCompressedLength = compressor.maxCompressedLength((int) unCompressedBuffer.writerIndex());
+
+    // first 8 bytes reserved for uncompressed length, to be consistent with the
+    // C++ implementation.
+    ArrowBuf compressedBuffer = allocator.buffer(maxCompressedLength + SIZE_OF_MESSAGE_LENGTH);
+    compressedBuffer.setLong(0, unCompressedBuffer.writerIndex());
+
+    ByteBuffer uncompressed =
+        MemoryUtil.directBuffer(unCompressedBuffer.memoryAddress(), (int) unCompressedBuffer.writerIndex());
+    ByteBuffer compressed =
+        MemoryUtil.directBuffer(compressedBuffer.memoryAddress() + SIZE_OF_MESSAGE_LENGTH, maxCompressedLength);
+
+    int compressedLength = compressor.compress(
+        uncompressed, 0, (int) unCompressedBuffer.writerIndex(), compressed, 0, maxCompressedLength);
+    compressedBuffer.writerIndex(compressedLength + SIZE_OF_MESSAGE_LENGTH);
+
+    unCompressedBuffer.close();
+    return compressedBuffer;
+  }
+
+  @Override
+  public ArrowBuf decompress(BufferAllocator allocator, ArrowBuf compressedBuffer) {
+    Preconditions.checkArgument(compressedBuffer.writerIndex() <= Integer.MAX_VALUE,
+        "The compressed buffer size exceeds the integer limit");
+
+    Preconditions.checkArgument(compressedBuffer.writerIndex() > SIZE_OF_MESSAGE_LENGTH,
+        "Not enough data to decompress.");
+
+    // create decompressor lazily
+    if (decompressor == null) {
+      decompressor = factory.fastDecompressor();
+    }
+
+    long decompressedLength = compressedBuffer.getLong(0);

Review comment:
       Revised. Thank you.




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