liyafan82 commented on a change in pull request #9769:
URL: https://github.com/apache/arrow/pull/9769#discussion_r601039000
##########
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:
Here we are applying the template method design pattern, so inheritance
seems a natural choice?
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