emkornfield commented on a change in pull request #9769:
URL: https://github.com/apache/arrow/pull/9769#discussion_r600131274
##########
File path:
java/compression/src/main/java/org/apache/arrow/compression/Lz4CompressionCodec.java
##########
@@ -38,109 +36,39 @@
/**
* Compression codec for the LZ4 algorithm.
*/
-public class Lz4CompressionCodec implements CompressionCodec {
+public class Lz4CompressionCodec extends AbstractCompressionCodec {
- @Override
- public ArrowBuf compress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
- Preconditions.checkArgument(uncompressedBuffer.writerIndex() <=
Integer.MAX_VALUE,
- "The uncompressed buffer size exceeds the integer limit");
-
- if (uncompressedBuffer.writerIndex() == 0L) {
- // shortcut for empty buffer
- ArrowBuf compressedBuffer =
allocator.buffer(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
- compressedBuffer.setLong(0, 0);
-
compressedBuffer.writerIndex(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
- uncompressedBuffer.close();
- return compressedBuffer;
- }
-
- try {
- ArrowBuf compressedBuffer = doCompress(allocator, uncompressedBuffer);
- long compressedLength = compressedBuffer.writerIndex() -
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH;
- if (compressedLength > uncompressedBuffer.writerIndex()) {
- // compressed buffer is larger, send the raw buffer
- compressedBuffer.close();
- compressedBuffer = CompressionUtil.packageRawBuffer(allocator,
uncompressedBuffer);
- }
-
- uncompressedBuffer.close();
- return compressedBuffer;
- } catch (IOException e) {
- throw new RuntimeException(e);
- }
- }
-
- private ArrowBuf doCompress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) throws IOException {
+ protected ArrowBuf doCompress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
byte[] inBytes = new byte[(int) uncompressedBuffer.writerIndex()];
PlatformDependent.copyMemory(uncompressedBuffer.memoryAddress(), inBytes,
0, uncompressedBuffer.writerIndex());
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try (InputStream in = new ByteArrayInputStream(inBytes);
OutputStream out = new FramedLZ4CompressorOutputStream(baos)) {
IOUtils.copy(in, out);
+ } catch (IOException e) {
+ throw new RuntimeException(e);
}
byte[] outBytes = baos.toByteArray();
ArrowBuf compressedBuffer =
allocator.buffer(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH + outBytes.length);
-
- long uncompressedLength = uncompressedBuffer.writerIndex();
- if (!MemoryUtil.LITTLE_ENDIAN) {
- uncompressedLength = Long.reverseBytes(uncompressedLength);
- }
- // first 8 bytes reserved for uncompressed length, according to the
specification
- compressedBuffer.setLong(0, uncompressedLength);
-
PlatformDependent.copyMemory(
outBytes, 0, compressedBuffer.memoryAddress() +
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH, outBytes.length);
compressedBuffer.writerIndex(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH +
outBytes.length);
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() >=
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH,
- "Not enough data to decompress.");
-
- long decompressedLength = compressedBuffer.getLong(0);
- if (!MemoryUtil.LITTLE_ENDIAN) {
- decompressedLength = Long.reverseBytes(decompressedLength);
- }
-
- if (decompressedLength == 0L) {
- // shortcut for empty buffer
- compressedBuffer.close();
- return allocator.getEmpty();
- }
-
- if (decompressedLength == CompressionUtil.NO_COMPRESSION_LENGTH) {
- // no compression
- return CompressionUtil.extractUncompressedBuffer(compressedBuffer);
- }
-
- try {
- ArrowBuf decompressedBuffer = doDecompress(allocator, compressedBuffer);
- compressedBuffer.close();
- return decompressedBuffer;
- } catch (IOException e) {
- throw new RuntimeException(e);
- }
- }
-
- private ArrowBuf doDecompress(BufferAllocator allocator, ArrowBuf
compressedBuffer) throws IOException {
- long decompressedLength = compressedBuffer.getLong(0);
- if (!MemoryUtil.LITTLE_ENDIAN) {
- decompressedLength = Long.reverseBytes(decompressedLength);
- }
+ protected ArrowBuf doDecompress(BufferAllocator allocator, ArrowBuf
compressedBuffer) {
+ long decompressedLength = readUncompressedLength(compressedBuffer);
Review comment:
i made a suggestion for a slightly different signature here that would
eliminated the need to reference methods on the parent class. If we go in that
direction, do you think it might make sense to use composition instead of
inheritance? (haven't thought about it deeply).
##########
File path:
java/vector/src/main/java/org/apache/arrow/vector/compression/AbstractCompressionCodec.java
##########
@@ -0,0 +1,117 @@
+/*
+ * 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 org.apache.arrow.memory.ArrowBuf;
+import org.apache.arrow.memory.BufferAllocator;
+import org.apache.arrow.memory.util.MemoryUtil;
+import org.apache.arrow.util.Preconditions;
+
+/**
+ * The base class for concrete compression codecs, providing
+ * common logic for all compression codecs.
+ */
+public abstract class AbstractCompressionCodec implements CompressionCodec {
+
+ @Override
+ public ArrowBuf compress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
+ Preconditions.checkArgument(uncompressedBuffer.writerIndex() <=
Integer.MAX_VALUE,
+ "The uncompressed buffer size exceeds the integer limit");
+
+ if (uncompressedBuffer.writerIndex() == 0L) {
+ // shortcut for empty buffer
+ ArrowBuf compressedBuffer =
allocator.buffer(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
+ compressedBuffer.setLong(0, 0);
+
compressedBuffer.writerIndex(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
+ uncompressedBuffer.close();
+ return compressedBuffer;
+ }
+
+ ArrowBuf compressedBuffer = doCompress(allocator, uncompressedBuffer);
+ long compressedLength = compressedBuffer.writerIndex() -
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH;
+ long uncompressedLength = uncompressedBuffer.writerIndex();
+
+ if (compressedLength > uncompressedLength) {
+ // compressed buffer is larger, send the raw buffer
+ compressedBuffer.close();
+ compressedBuffer = CompressionUtil.packageRawBuffer(allocator,
uncompressedBuffer);
+ } else {
+ writeUncompressedLength(compressedBuffer, uncompressedLength);
+ }
+
+ 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() >=
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH,
+ "Not enough data to decompress.");
+
+ long decompressedLength = compressedBuffer.getLong(0);
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ decompressedLength = Long.reverseBytes(decompressedLength);
+ }
+
+ if (decompressedLength == 0L) {
+ // shortcut for empty buffer
+ compressedBuffer.close();
+ return allocator.getEmpty();
+ }
+
+ if (decompressedLength == CompressionUtil.NO_COMPRESSION_LENGTH) {
+ // no compression
+ return CompressionUtil.extractUncompressedBuffer(compressedBuffer);
+ }
+
+ ArrowBuf decompressedBuffer = doDecompress(allocator, compressedBuffer);
+ compressedBuffer.close();
+ return decompressedBuffer;
+ }
+
+ protected void writeUncompressedLength(ArrowBuf compressedBuffer, long
uncompressedLength) {
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ uncompressedLength = Long.reverseBytes(uncompressedLength);
+ }
+ // first 8 bytes reserved for uncompressed length, according to the
specification
+ compressedBuffer.setLong(0, uncompressedLength);
+ }
+
+ protected long readUncompressedLength(ArrowBuf compressedBuffer) {
+ long decompressedLength = compressedBuffer.getLong(0);
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ decompressedLength = Long.reverseBytes(decompressedLength);
+ }
+ return decompressedLength;
+ }
+
+ /**
+ * The method that actually performs the data compression.
+ * Please note that the first 8 bytes of the compressed buffer is reserved
for the uncompressed size.
Review comment:
maybe clarify that is expected that the length of the returned buffer is
always "compressed data size in bytes" + 8 bytes reserved at the beginning of
the buffer.
Can you clarify contract for ownership of uncompressed buffer?
##########
File path:
java/vector/src/main/java/org/apache/arrow/vector/compression/AbstractCompressionCodec.java
##########
@@ -0,0 +1,117 @@
+/*
+ * 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 org.apache.arrow.memory.ArrowBuf;
+import org.apache.arrow.memory.BufferAllocator;
+import org.apache.arrow.memory.util.MemoryUtil;
+import org.apache.arrow.util.Preconditions;
+
+/**
+ * The base class for concrete compression codecs, providing
+ * common logic for all compression codecs.
+ */
+public abstract class AbstractCompressionCodec implements CompressionCodec {
+
+ @Override
+ public ArrowBuf compress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
+ Preconditions.checkArgument(uncompressedBuffer.writerIndex() <=
Integer.MAX_VALUE,
+ "The uncompressed buffer size exceeds the integer limit");
+
+ if (uncompressedBuffer.writerIndex() == 0L) {
+ // shortcut for empty buffer
+ ArrowBuf compressedBuffer =
allocator.buffer(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
+ compressedBuffer.setLong(0, 0);
+
compressedBuffer.writerIndex(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
+ uncompressedBuffer.close();
+ return compressedBuffer;
+ }
+
+ ArrowBuf compressedBuffer = doCompress(allocator, uncompressedBuffer);
+ long compressedLength = compressedBuffer.writerIndex() -
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH;
+ long uncompressedLength = uncompressedBuffer.writerIndex();
+
+ if (compressedLength > uncompressedLength) {
+ // compressed buffer is larger, send the raw buffer
+ compressedBuffer.close();
+ compressedBuffer = CompressionUtil.packageRawBuffer(allocator,
uncompressedBuffer);
+ } else {
+ writeUncompressedLength(compressedBuffer, uncompressedLength);
+ }
+
+ 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() >=
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH,
+ "Not enough data to decompress.");
+
+ long decompressedLength = compressedBuffer.getLong(0);
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ decompressedLength = Long.reverseBytes(decompressedLength);
+ }
+
+ if (decompressedLength == 0L) {
+ // shortcut for empty buffer
+ compressedBuffer.close();
+ return allocator.getEmpty();
+ }
+
+ if (decompressedLength == CompressionUtil.NO_COMPRESSION_LENGTH) {
+ // no compression
+ return CompressionUtil.extractUncompressedBuffer(compressedBuffer);
+ }
+
+ ArrowBuf decompressedBuffer = doDecompress(allocator, compressedBuffer);
+ compressedBuffer.close();
+ return decompressedBuffer;
+ }
+
+ protected void writeUncompressedLength(ArrowBuf compressedBuffer, long
uncompressedLength) {
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ uncompressedLength = Long.reverseBytes(uncompressedLength);
+ }
+ // first 8 bytes reserved for uncompressed length, according to the
specification
+ compressedBuffer.setLong(0, uncompressedLength);
+ }
+
+ protected long readUncompressedLength(ArrowBuf compressedBuffer) {
+ long decompressedLength = compressedBuffer.getLong(0);
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ decompressedLength = Long.reverseBytes(decompressedLength);
+ }
+ return decompressedLength;
+ }
+
+ /**
+ * The method that actually performs the data compression.
+ * Please note that the first 8 bytes of the compressed buffer is reserved
for the uncompressed size.
+ */
+ protected abstract ArrowBuf doCompress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer);
+
+ /**
+ * The method that actually performs the data decompression.
+ * Please note that the first 8 bytes of the compressed buffer is reserved
for the uncompressed size.
Review comment:
I think for decompression it probably makes sense to provide the slice
buffer only including the compressed data, and a preallocated output buffer to
simply implementations of other codec. What do you think?
##########
File path:
java/compression/src/main/java/org/apache/arrow/compression/Lz4CompressionCodec.java
##########
@@ -38,109 +36,39 @@
/**
* Compression codec for the LZ4 algorithm.
*/
-public class Lz4CompressionCodec implements CompressionCodec {
+public class Lz4CompressionCodec extends AbstractCompressionCodec {
- @Override
- public ArrowBuf compress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
- Preconditions.checkArgument(uncompressedBuffer.writerIndex() <=
Integer.MAX_VALUE,
- "The uncompressed buffer size exceeds the integer limit");
-
- if (uncompressedBuffer.writerIndex() == 0L) {
- // shortcut for empty buffer
- ArrowBuf compressedBuffer =
allocator.buffer(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
- compressedBuffer.setLong(0, 0);
-
compressedBuffer.writerIndex(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
- uncompressedBuffer.close();
- return compressedBuffer;
- }
-
- try {
- ArrowBuf compressedBuffer = doCompress(allocator, uncompressedBuffer);
- long compressedLength = compressedBuffer.writerIndex() -
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH;
- if (compressedLength > uncompressedBuffer.writerIndex()) {
- // compressed buffer is larger, send the raw buffer
- compressedBuffer.close();
- compressedBuffer = CompressionUtil.packageRawBuffer(allocator,
uncompressedBuffer);
- }
-
- uncompressedBuffer.close();
- return compressedBuffer;
- } catch (IOException e) {
- throw new RuntimeException(e);
- }
- }
-
- private ArrowBuf doCompress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) throws IOException {
+ protected ArrowBuf doCompress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
Review comment:
nit "@override"?
##########
File path:
java/compression/src/main/java/org/apache/arrow/compression/Lz4CompressionCodec.java
##########
@@ -38,109 +36,39 @@
/**
* Compression codec for the LZ4 algorithm.
*/
-public class Lz4CompressionCodec implements CompressionCodec {
+public class Lz4CompressionCodec extends AbstractCompressionCodec {
- @Override
- public ArrowBuf compress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
- Preconditions.checkArgument(uncompressedBuffer.writerIndex() <=
Integer.MAX_VALUE,
- "The uncompressed buffer size exceeds the integer limit");
-
- if (uncompressedBuffer.writerIndex() == 0L) {
- // shortcut for empty buffer
- ArrowBuf compressedBuffer =
allocator.buffer(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
- compressedBuffer.setLong(0, 0);
-
compressedBuffer.writerIndex(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
- uncompressedBuffer.close();
- return compressedBuffer;
- }
-
- try {
- ArrowBuf compressedBuffer = doCompress(allocator, uncompressedBuffer);
- long compressedLength = compressedBuffer.writerIndex() -
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH;
- if (compressedLength > uncompressedBuffer.writerIndex()) {
- // compressed buffer is larger, send the raw buffer
- compressedBuffer.close();
- compressedBuffer = CompressionUtil.packageRawBuffer(allocator,
uncompressedBuffer);
- }
-
- uncompressedBuffer.close();
- return compressedBuffer;
- } catch (IOException e) {
- throw new RuntimeException(e);
- }
- }
-
- private ArrowBuf doCompress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) throws IOException {
+ protected ArrowBuf doCompress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
byte[] inBytes = new byte[(int) uncompressedBuffer.writerIndex()];
PlatformDependent.copyMemory(uncompressedBuffer.memoryAddress(), inBytes,
0, uncompressedBuffer.writerIndex());
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try (InputStream in = new ByteArrayInputStream(inBytes);
OutputStream out = new FramedLZ4CompressorOutputStream(baos)) {
IOUtils.copy(in, out);
+ } catch (IOException e) {
+ throw new RuntimeException(e);
}
byte[] outBytes = baos.toByteArray();
ArrowBuf compressedBuffer =
allocator.buffer(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH + outBytes.length);
-
- long uncompressedLength = uncompressedBuffer.writerIndex();
- if (!MemoryUtil.LITTLE_ENDIAN) {
- uncompressedLength = Long.reverseBytes(uncompressedLength);
- }
- // first 8 bytes reserved for uncompressed length, according to the
specification
- compressedBuffer.setLong(0, uncompressedLength);
-
PlatformDependent.copyMemory(
outBytes, 0, compressedBuffer.memoryAddress() +
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH, outBytes.length);
compressedBuffer.writerIndex(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH +
outBytes.length);
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() >=
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH,
- "Not enough data to decompress.");
-
- long decompressedLength = compressedBuffer.getLong(0);
- if (!MemoryUtil.LITTLE_ENDIAN) {
- decompressedLength = Long.reverseBytes(decompressedLength);
- }
-
- if (decompressedLength == 0L) {
- // shortcut for empty buffer
- compressedBuffer.close();
- return allocator.getEmpty();
- }
-
- if (decompressedLength == CompressionUtil.NO_COMPRESSION_LENGTH) {
- // no compression
- return CompressionUtil.extractUncompressedBuffer(compressedBuffer);
- }
-
- try {
- ArrowBuf decompressedBuffer = doDecompress(allocator, compressedBuffer);
- compressedBuffer.close();
- return decompressedBuffer;
- } catch (IOException e) {
- throw new RuntimeException(e);
- }
- }
-
- private ArrowBuf doDecompress(BufferAllocator allocator, ArrowBuf
compressedBuffer) throws IOException {
- long decompressedLength = compressedBuffer.getLong(0);
- if (!MemoryUtil.LITTLE_ENDIAN) {
- decompressedLength = Long.reverseBytes(decompressedLength);
- }
+ protected ArrowBuf doDecompress(BufferAllocator allocator, ArrowBuf
compressedBuffer) {
Review comment:
nit "@override"?
##########
File path:
java/vector/src/main/java/org/apache/arrow/vector/compression/AbstractCompressionCodec.java
##########
@@ -0,0 +1,117 @@
+/*
+ * 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 org.apache.arrow.memory.ArrowBuf;
+import org.apache.arrow.memory.BufferAllocator;
+import org.apache.arrow.memory.util.MemoryUtil;
+import org.apache.arrow.util.Preconditions;
+
+/**
+ * The base class for concrete compression codecs, providing
+ * common logic for all compression codecs.
+ */
+public abstract class AbstractCompressionCodec implements CompressionCodec {
+
+ @Override
+ public ArrowBuf compress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer) {
+ Preconditions.checkArgument(uncompressedBuffer.writerIndex() <=
Integer.MAX_VALUE,
+ "The uncompressed buffer size exceeds the integer limit");
+
+ if (uncompressedBuffer.writerIndex() == 0L) {
+ // shortcut for empty buffer
+ ArrowBuf compressedBuffer =
allocator.buffer(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
+ compressedBuffer.setLong(0, 0);
+
compressedBuffer.writerIndex(CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH);
+ uncompressedBuffer.close();
+ return compressedBuffer;
+ }
+
+ ArrowBuf compressedBuffer = doCompress(allocator, uncompressedBuffer);
+ long compressedLength = compressedBuffer.writerIndex() -
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH;
+ long uncompressedLength = uncompressedBuffer.writerIndex();
+
+ if (compressedLength > uncompressedLength) {
+ // compressed buffer is larger, send the raw buffer
+ compressedBuffer.close();
+ compressedBuffer = CompressionUtil.packageRawBuffer(allocator,
uncompressedBuffer);
+ } else {
+ writeUncompressedLength(compressedBuffer, uncompressedLength);
+ }
+
+ 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() >=
CompressionUtil.SIZE_OF_UNCOMPRESSED_LENGTH,
+ "Not enough data to decompress.");
+
+ long decompressedLength = compressedBuffer.getLong(0);
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ decompressedLength = Long.reverseBytes(decompressedLength);
+ }
+
+ if (decompressedLength == 0L) {
+ // shortcut for empty buffer
+ compressedBuffer.close();
+ return allocator.getEmpty();
+ }
+
+ if (decompressedLength == CompressionUtil.NO_COMPRESSION_LENGTH) {
+ // no compression
+ return CompressionUtil.extractUncompressedBuffer(compressedBuffer);
+ }
+
+ ArrowBuf decompressedBuffer = doDecompress(allocator, compressedBuffer);
+ compressedBuffer.close();
+ return decompressedBuffer;
+ }
+
+ protected void writeUncompressedLength(ArrowBuf compressedBuffer, long
uncompressedLength) {
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ uncompressedLength = Long.reverseBytes(uncompressedLength);
+ }
+ // first 8 bytes reserved for uncompressed length, according to the
specification
+ compressedBuffer.setLong(0, uncompressedLength);
+ }
+
+ protected long readUncompressedLength(ArrowBuf compressedBuffer) {
+ long decompressedLength = compressedBuffer.getLong(0);
+ if (!MemoryUtil.LITTLE_ENDIAN) {
+ decompressedLength = Long.reverseBytes(decompressedLength);
+ }
+ return decompressedLength;
+ }
+
+ /**
+ * The method that actually performs the data compression.
+ * Please note that the first 8 bytes of the compressed buffer is reserved
for the uncompressed size.
+ */
+ protected abstract ArrowBuf doCompress(BufferAllocator allocator, ArrowBuf
uncompressedBuffer);
+
+ /**
+ * The method that actually performs the data decompression.
+ * Please note that the first 8 bytes of the compressed buffer is reserved
for the uncompressed size.
Review comment:
Either way lets clarify ownership of the passed in buffer.
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